Add conversion support & large refactor

.github/workflows/build.yaml

@@ -95,42 +95,42 @@ jobs:
             target: x86_64-unknown-linux-musl
             name: linux-x86_64
             build: zigbuild
-            features: asm
+            features: openssl-vendored
           - platform: ubuntu-latest
             target: i686-unknown-linux-musl
             name: linux-i686
             build: zigbuild
-            features: asm
+            features: openssl-vendored
           - platform: ubuntu-latest
             target: aarch64-unknown-linux-musl
             name: linux-aarch64
             build: zigbuild
-            features: nightly
+            features: openssl-vendored
           - platform: windows-latest
             target: i686-pc-windows-msvc
             name: windows-x86
             build: build
-            features: default
+            features: openssl-vendored
           - platform: windows-latest
             target: x86_64-pc-windows-msvc
             name: windows-x86_64
             build: build
-            features: default
+            features: openssl-vendored
           - platform: windows-latest
             target: aarch64-pc-windows-msvc
             name: windows-arm64
             build: build
-            features: nightly
+            features: openssl-vendored
           - platform: macos-latest
             target: x86_64-apple-darwin
             name: macos-x86_64
             build: build
-            features: asm
+            features: openssl
           - platform: macos-latest
             target: aarch64-apple-darwin
             name: macos-arm64
             build: build
-            features: nightly
+            features: openssl
       fail-fast: false
     runs-on: ${{ matrix.platform }}
     steps:

Cargo.toml

@@ -2,6 +2,9 @@
 members = ["nod", "nodtool"]
 resolver = "2"
 
+[profile.release]
+debug = 1
+
 [profile.release-lto]
 inherits = "release"
 lto = "fat"
@@ -16,3 +19,10 @@ authors = ["Luke Street <luke@street.dev>"]
 license = "MIT OR Apache-2.0"
 repository = "https://github.com/encounter/nod"
 keywords = ["gamecube", "wii", "iso", "wbfs", "rvz"]
+
+[workspace.dependencies]
+digest = { version = "0.11.0-pre.9", default-features = false }
+md-5 = { version = "0.11.0-pre.4", default-features = false }
+sha1 = { version = "0.11.0-pre.4", default-features = false }
+tracing = "0.1"
+zerocopy = { version = "0.8", features = ["alloc", "derive"] }

nod/Cargo.toml

@@ -16,27 +16,42 @@ categories = ["command-line-utilities", "parser-implementations"]
 
 [features]
 default = ["compress-bzip2", "compress-lzma", "compress-zlib", "compress-zstd"]
-asm = ["sha1/asm"]
 compress-bzip2 = ["bzip2"]
-compress-lzma = ["liblzma"]
+compress-lzma = ["liblzma", "liblzma-sys"]
 compress-zlib = ["adler", "miniz_oxide"]
-compress-zstd = ["zstd"]
+compress-zstd = ["zstd", "zstd-safe"]
+openssl = ["dep:openssl"]
+openssl-vendored = ["openssl", "openssl/vendored"]
 
 [dependencies]
 adler = { version = "1.0", optional = true }
-aes = "0.8"
+aes = "0.9.0-pre.2"
 base16ct = "0.2"
+bit-set = "0.8"
+bytes = "1.8"
 bzip2 = { version = "0.4", features = ["static"], optional = true }
-cbc = "0.1"
-digest = "0.10"
+cbc = "0.2.0-pre.2"
+crc32fast = "1.4"
+crossbeam-channel = "0.5"
+crossbeam-utils = "0.8"
+digest = { workspace = true }
 dyn-clone = "1.0"
 encoding_rs = "0.8"
 itertools = "0.13"
 liblzma = { version = "0.3", features = ["static"], optional = true }
-log = "0.4"
+liblzma-sys = { version = "0.3", features = ["static"], optional = true }
+lru = "0.12"
+md-5 = { workspace = true }
+memmap2 = "0.9"
 miniz_oxide = { version = "0.8", optional = true }
+openssl = { version = "0.10", optional = true }
+rand = "0.8"
 rayon = "1.10"
-sha1 = "0.10"
-thiserror = "1.0"
-zerocopy = { version = "0.8", features = ["alloc", "derive"] }
-zstd = { version = "0.13", optional = true }
+sha1 = { workspace = true }
+simple_moving_average = "1.0"
+thiserror = "2.0"
+tracing = { workspace = true }
+xxhash-rust = { version = "0.8", features = ["xxh64"] }
+zerocopy = { workspace = true }
+zstd = { version = "0.13", optional = true, default-features = false }
+zstd-safe = { version = "7.2", optional = true, default-features = false }

nod/src/build/gc.rs

@@ -0,0 +1,827 @@
+#![allow(missing_docs)] // TODO
+use std::{
+    io,
+    io::{Read, Seek, Write},
+    sync::Arc,
+};
+
+use tracing::debug;
+use zerocopy::{FromZeros, IntoBytes};
+
+use crate::{
+    disc::{
+        fst::{Fst, FstBuilder},
+        DiscHeader, PartitionHeader, BI2_SIZE, BOOT_SIZE, GCN_MAGIC, MINI_DVD_SIZE, SECTOR_SIZE,
+        WII_MAGIC,
+    },
+    read::DiscStream,
+    util::{align_up_64, array_ref, array_ref_mut, lfg::LaggedFibonacci},
+    Error, Result, ResultContext,
+};
+
+pub trait FileCallback: Clone + Send + Sync {
+    fn read_file(&mut self, out: &mut [u8], name: &str, offset: u64) -> io::Result<()>;
+}
+
+#[derive(Debug, Clone)]
+pub struct FileInfo {
+    pub name: String,
+    pub size: u64,
+    pub offset: Option<u64>,
+    pub alignment: Option<u32>,
+}
+
+pub struct GCPartitionBuilder {
+    disc_header: Box<DiscHeader>,
+    partition_header: Box<PartitionHeader>,
+    user_files: Vec<FileInfo>,
+    overrides: PartitionOverrides,
+    junk_files: Vec<String>,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum WriteKind {
+    File(String),
+    Static(Arc<[u8]>, &'static str),
+    Junk,
+}
+
+impl WriteKind {
+    fn name(&self) -> &str {
+        match self {
+            WriteKind::File(name) => name,
+            WriteKind::Static(_, name) => name,
+            WriteKind::Junk => "[junk data]",
+        }
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct WriteInfo {
+    pub kind: WriteKind,
+    pub size: u64,
+    pub offset: u64,
+}
+
+pub struct GCPartitionWriter {
+    write_info: Vec<WriteInfo>,
+    disc_size: u64,
+    disc_id: [u8; 4],
+    disc_num: u8,
+}
+
+const BI2_OFFSET: u64 = BOOT_SIZE as u64;
+const APPLOADER_OFFSET: u64 = BI2_OFFSET + BI2_SIZE as u64;
+
+#[derive(Debug, Clone, Default)]
+pub struct PartitionOverrides {
+    pub game_id: Option<[u8; 6]>,
+    pub game_title: Option<String>,
+    pub disc_num: Option<u8>,
+    pub disc_version: Option<u8>,
+    pub audio_streaming: Option<bool>,
+    pub audio_stream_buf_size: Option<u8>,
+    pub junk_id: Option<[u8; 4]>,
+    pub region: Option<u8>,
+}
+
+impl GCPartitionBuilder {
+    pub fn new(is_wii: bool, overrides: PartitionOverrides) -> Self {
+        let mut disc_header = DiscHeader::new_box_zeroed().unwrap();
+        if is_wii {
+            disc_header.gcn_magic = [0u8; 4];
+            disc_header.wii_magic = WII_MAGIC;
+        } else {
+            disc_header.gcn_magic = GCN_MAGIC;
+            disc_header.wii_magic = [0u8; 4];
+        }
+        Self {
+            disc_header,
+            partition_header: PartitionHeader::new_box_zeroed().unwrap(),
+            user_files: Vec::new(),
+            overrides,
+            junk_files: Vec::new(),
+        }
+    }
+
+    #[inline]
+    pub fn set_disc_header(&mut self, disc_header: Box<DiscHeader>) {
+        self.disc_header = disc_header;
+    }
+
+    #[inline]
+    pub fn set_partition_header(&mut self, partition_header: Box<PartitionHeader>) {
+        self.partition_header = partition_header;
+    }
+
+    pub fn add_file(&mut self, info: FileInfo) -> Result<()> {
+        if let (Some(offset), Some(alignment)) = (info.offset, info.alignment) {
+            if offset % alignment as u64 != 0 {
+                return Err(Error::Other(format!(
+                    "File {} offset {:#X} is not aligned to {}",
+                    info.name, offset, alignment
+                )));
+            }
+        }
+        self.user_files.push(info);
+        Ok(())
+    }
+
+    /// A junk file exists in the FST, but is excluded from the disc layout, so junk data will be
+    /// written in its place.
+    pub fn add_junk_file(&mut self, name: String) { self.junk_files.push(name); }
+
+    pub fn build(
+        &self,
+        sys_file_callback: impl FnMut(&mut dyn Write, &str) -> io::Result<()>,
+    ) -> Result<GCPartitionWriter> {
+        let mut layout = GCPartitionLayout::new(self);
+        layout.locate_sys_files(sys_file_callback)?;
+        layout.apply_overrides(&self.overrides)?;
+        let write_info = layout.layout_files()?;
+        let disc_size = layout.partition_header.user_offset.get() as u64
+            + layout.partition_header.user_size.get() as u64;
+        let junk_id = layout.junk_id();
+        Ok(GCPartitionWriter::new(write_info, disc_size, junk_id, self.disc_header.disc_num))
+    }
+}
+
+struct GCPartitionLayout {
+    disc_header: Box<DiscHeader>,
+    partition_header: Box<PartitionHeader>,
+    user_files: Vec<FileInfo>,
+    apploader_file: Option<FileInfo>,
+    dol_file: Option<FileInfo>,
+    raw_fst: Option<Box<[u8]>>,
+    raw_bi2: Option<Box<[u8]>>,
+    junk_id: Option<[u8; 4]>,
+    junk_files: Vec<String>,
+}
+
+impl GCPartitionLayout {
+    fn new(builder: &GCPartitionBuilder) -> Self {
+        GCPartitionLayout {
+            disc_header: builder.disc_header.clone(),
+            partition_header: builder.partition_header.clone(),
+            user_files: builder.user_files.clone(),
+            apploader_file: None,
+            dol_file: None,
+            raw_fst: None,
+            raw_bi2: None,
+            junk_id: builder.overrides.junk_id,
+            junk_files: builder.junk_files.clone(),
+        }
+    }
+
+    fn locate_sys_files(
+        &mut self,
+        mut file_callback: impl FnMut(&mut dyn Write, &str) -> io::Result<()>,
+    ) -> Result<()> {
+        let mut handled = vec![false; self.user_files.len()];
+
+        // Locate fixed offset system files
+        for (info, handled) in self.user_files.iter().zip(handled.iter_mut()) {
+            if info.offset == Some(0) || info.name == "sys/boot.bin" {
+                let mut data = Vec::with_capacity(BOOT_SIZE);
+                file_callback(&mut data, &info.name)
+                    .with_context(|| format!("Failed to read file {}", info.name))?;
+                if data.len() != BOOT_SIZE {
+                    return Err(Error::Other(format!(
+                        "Boot file {} is {} bytes, expected {}",
+                        info.name,
+                        data.len(),
+                        BOOT_SIZE
+                    )));
+                }
+                self.disc_header.as_mut_bytes().copy_from_slice(&data[..size_of::<DiscHeader>()]);
+                self.partition_header
+                    .as_mut_bytes()
+                    .copy_from_slice(&data[size_of::<DiscHeader>()..]);
+                *handled = true;
+                continue;
+            }
+
+            if info.offset == Some(BI2_OFFSET) || info.name == "sys/bi2.bin" {
+                let mut data = Vec::with_capacity(BI2_SIZE);
+                file_callback(&mut data, &info.name)
+                    .with_context(|| format!("Failed to read file {}", info.name))?;
+                if data.len() != BI2_SIZE {
+                    return Err(Error::Other(format!(
+                        "BI2 file {} is {} bytes, expected {}",
+                        info.name,
+                        data.len(),
+                        BI2_SIZE
+                    )));
+                }
+                self.raw_bi2 = Some(data.into_boxed_slice());
+                *handled = true;
+                continue;
+            }
+
+            if info.offset == Some(APPLOADER_OFFSET) || info.name == "sys/apploader.img" {
+                self.apploader_file = Some(info.clone());
+                *handled = true;
+                continue;
+            }
+        }
+
+        // Locate other system files
+        let is_wii = self.disc_header.is_wii();
+        for (info, handled) in self.user_files.iter().zip(handled.iter_mut()) {
+            let dol_offset = self.partition_header.dol_offset(is_wii);
+            if (dol_offset != 0 && info.offset == Some(dol_offset)) || info.name == "sys/main.dol" {
+                let mut info = info.clone();
+                if info.alignment.is_none() {
+                    info.alignment = Some(128);
+                }
+                self.dol_file = Some(info);
+                *handled = true; // TODO DOL in user data
+                continue;
+            }
+
+            let fst_offset = self.partition_header.fst_offset(is_wii);
+            if (fst_offset != 0 && info.offset == Some(fst_offset)) || info.name == "sys/fst.bin" {
+                let mut data = Vec::with_capacity(info.size as usize);
+                file_callback(&mut data, &info.name)
+                    .with_context(|| format!("Failed to read file {}", info.name))?;
+                if data.len() != info.size as usize {
+                    return Err(Error::Other(format!(
+                        "FST file {} is {} bytes, expected {}",
+                        info.name,
+                        data.len(),
+                        info.size
+                    )));
+                }
+                self.raw_fst = Some(data.into_boxed_slice());
+                *handled = true;
+                continue;
+            }
+        }
+
+        // Remove handled files
+        let mut iter = handled.iter();
+        self.user_files.retain(|_| !iter.next().unwrap());
+        Ok(())
+    }
+
+    fn apply_overrides(&mut self, overrides: &PartitionOverrides) -> Result<()> {
+        if let Some(game_id) = overrides.game_id {
+            self.disc_header.game_id.copy_from_slice(&game_id);
+        }
+        if let Some(game_title) = overrides.game_title.as_ref() {
+            let max_size = self.disc_header.game_title.len() - 1; // nul terminator
+            if game_title.len() > max_size {
+                return Err(Error::Other(format!(
+                    "Game title \"{}\" is too long ({} > {})",
+                    game_title,
+                    game_title.len(),
+                    max_size
+                )));
+            }
+            let len = game_title.len().min(max_size);
+            self.disc_header.game_title[..len].copy_from_slice(&game_title.as_bytes()[..len]);
+        }
+        if let Some(disc_num) = overrides.disc_num {
+            self.disc_header.disc_num = disc_num;
+        }
+        if let Some(disc_version) = overrides.disc_version {
+            self.disc_header.disc_version = disc_version;
+        }
+        if let Some(audio_streaming) = overrides.audio_streaming {
+            self.disc_header.audio_streaming = audio_streaming as u8;
+        }
+        if let Some(audio_stream_buf_size) = overrides.audio_stream_buf_size {
+            self.disc_header.audio_stream_buf_size = audio_stream_buf_size;
+        }
+        let set_bi2 = self.raw_bi2.is_none() && overrides.region.is_some();
+        let raw_bi2 = self.raw_bi2.get_or_insert_with(|| {
+            <[u8]>::new_box_zeroed_with_elems(BI2_SIZE).expect("Failed to allocate BI2")
+        });
+        if set_bi2 {
+            let region = overrides.region.unwrap_or(0xFF) as u32;
+            *array_ref_mut![raw_bi2, 0x18, 4] = region.to_be_bytes();
+        }
+        Ok(())
+    }
+
+    fn can_use_orig_fst(&self) -> bool {
+        if let Some(existing) = self.raw_fst.as_deref() {
+            let Ok(existing_fst) = Fst::new(existing) else {
+                return false;
+            };
+            for (_, node, path) in existing_fst.iter() {
+                if node.is_dir() {
+                    continue;
+                }
+                if !self.user_files.iter().any(|info| info.name == path)
+                    && !self.junk_files.contains(&path)
+                {
+                    println!("FST file {} not found", path);
+                    return false;
+                }
+            }
+            println!("Using existing FST");
+            return true;
+        }
+        false
+    }
+
+    fn calculate_fst_size(&self) -> Result<u64> {
+        if self.can_use_orig_fst() {
+            return Ok(self.raw_fst.as_deref().unwrap().len() as u64);
+        }
+
+        let mut file_names = Vec::with_capacity(self.user_files.len());
+        for info in &self.user_files {
+            file_names.push(info.name.as_str());
+        }
+        // file_names.sort_unstable();
+        let is_wii = self.disc_header.is_wii();
+        let mut builder = if let Some(existing) = self.raw_fst.as_deref() {
+            let existing_fst = Fst::new(existing)?;
+            FstBuilder::new_with_string_table(is_wii, Vec::from(existing_fst.string_table))?
+        } else {
+            FstBuilder::new(is_wii)
+        };
+        for name in file_names {
+            builder.add_file(name, 0, 0);
+        }
+        let size = builder.byte_size() as u64;
+        // if size != self.partition_header.fst_size(is_wii) {
+        //     return Err(Error::Other(format!(
+        //         "FST size {} != {}",
+        //         size,
+        //         self.partition_header.fst_size(is_wii)
+        //     )));
+        // }
+        Ok(size)
+    }
+
+    fn generate_fst(&mut self, write_info: &[WriteInfo]) -> Result<Arc<[u8]>> {
+        if self.can_use_orig_fst() {
+            let fst_data = self.raw_fst.as_ref().unwrap().clone();
+            // TODO update offsets and sizes
+            // let node_count = Fst::new(fst_data.as_ref())?.nodes.len();
+            // let string_base = node_count * size_of::<Node>();
+            // let (node_buf, string_table) = fst_data.split_at_mut(string_base);
+            // let nodes = <[Node]>::mut_from_bytes(node_buf).unwrap();
+            return Ok(Arc::from(fst_data));
+        }
+
+        let files = write_info.to_vec();
+        // files.sort_unstable_by(|a, b| a.name.cmp(&b.name));
+        let is_wii = self.disc_header.is_wii();
+        let mut builder = if let Some(existing) = self.raw_fst.as_deref() {
+            let existing_fst = Fst::new(existing)?;
+            FstBuilder::new_with_string_table(is_wii, Vec::from(existing_fst.string_table))?
+        } else {
+            FstBuilder::new(is_wii)
+        };
+        for info in files {
+            if let WriteKind::File(name) = info.kind {
+                builder.add_file(&name, info.offset, info.size as u32);
+            }
+        }
+        let raw_fst = builder.finalize();
+        if raw_fst.len() != self.partition_header.fst_size(is_wii) as usize {
+            return Err(Error::Other(format!(
+                "FST size mismatch: {} != {}",
+                raw_fst.len(),
+                self.partition_header.fst_size(is_wii)
+            )));
+        }
+        Ok(Arc::from(raw_fst))
+    }
+
+    fn layout_system_data(&mut self, write_info: &mut Vec<WriteInfo>) -> Result<u64> {
+        let mut last_offset = 0;
+
+        let Some(apploader_file) = self.apploader_file.as_ref() else {
+            return Err(Error::Other("Apploader not set".to_string()));
+        };
+        let Some(dol_file) = self.dol_file.as_ref() else {
+            return Err(Error::Other("DOL not set".to_string()));
+        };
+        let Some(raw_bi2) = self.raw_bi2.as_ref() else {
+            return Err(Error::Other("BI2 not set".to_string()));
+        };
+        // let Some(raw_fst) = self.raw_fst.as_ref() else {
+        //     return Err(Error::Other("FST not set".to_string()));
+        // };
+
+        let mut boot = <[u8]>::new_box_zeroed_with_elems(BOOT_SIZE)?;
+        boot[..size_of::<DiscHeader>()].copy_from_slice(self.disc_header.as_bytes());
+        boot[size_of::<DiscHeader>()..].copy_from_slice(self.partition_header.as_bytes());
+        write_info.push(WriteInfo {
+            kind: WriteKind::Static(Arc::from(boot), "[BOOT]"),
+            size: BOOT_SIZE as u64,
+            offset: last_offset,
+        });
+        last_offset += BOOT_SIZE as u64;
+        write_info.push(WriteInfo {
+            kind: WriteKind::Static(Arc::from(raw_bi2.as_ref()), "[BI2]"),
+            size: BI2_SIZE as u64,
+            offset: last_offset,
+        });
+        last_offset += BI2_SIZE as u64;
+        write_info.push(WriteInfo {
+            kind: WriteKind::File(apploader_file.name.clone()),
+            size: apploader_file.size,
+            offset: last_offset,
+        });
+        last_offset += apploader_file.size;
+
+        // Update DOL and FST offsets if not set
+        let is_wii = self.disc_header.is_wii();
+        let mut dol_offset = self.partition_header.dol_offset(is_wii);
+        if dol_offset == 0 {
+            dol_offset = align_up_64(last_offset, dol_file.alignment.unwrap() as u64);
+            self.partition_header.set_dol_offset(dol_offset, is_wii);
+        }
+        let mut fst_offset = self.partition_header.fst_offset(is_wii);
+        if fst_offset == 0 {
+            // TODO handle DOL in user data
+            fst_offset = align_up_64(dol_offset + dol_file.size, 128);
+            self.partition_header.set_fst_offset(fst_offset, is_wii);
+        }
+        let fst_size = self.calculate_fst_size()?;
+        self.partition_header.set_fst_size(fst_size, is_wii);
+        if self.partition_header.fst_max_size(is_wii) < fst_size {
+            self.partition_header.set_fst_max_size(fst_size, is_wii);
+        }
+
+        if dol_offset < fst_offset {
+            write_info.push(WriteInfo {
+                kind: WriteKind::File(dol_file.name.clone()),
+                size: dol_file.size,
+                offset: dol_offset,
+            });
+        } else {
+            // DOL in user data
+        }
+        // write_info.push(WriteInfo {
+        //     kind: WriteKind::Static(Arc::from(raw_fst.as_ref()), "[FST]"),
+        //     size: fst_size,
+        //     offset: fst_offset,
+        // });
+
+        Ok(fst_offset + fst_size)
+    }
+
+    fn layout_files(&mut self) -> Result<Vec<WriteInfo>> {
+        let mut system_write_info = Vec::new();
+        let mut write_info = Vec::with_capacity(self.user_files.len());
+        let mut last_offset = self.layout_system_data(&mut system_write_info)?;
+
+        // Layout user data
+        let mut user_offset = self.partition_header.user_offset.get() as u64;
+        if user_offset == 0 {
+            user_offset = align_up_64(last_offset, SECTOR_SIZE as u64);
+            self.partition_header.user_offset.set(user_offset as u32);
+        } else if user_offset < last_offset {
+            return Err(Error::Other(format!(
+                "User offset {:#X} is before FST {:#X}",
+                user_offset, last_offset
+            )));
+        }
+        last_offset = user_offset;
+        for info in &self.user_files {
+            let offset = info
+                .offset
+                .unwrap_or_else(|| align_up_64(last_offset, info.alignment.unwrap_or(32) as u64));
+            write_info.push(WriteInfo {
+                kind: WriteKind::File(info.name.clone()),
+                offset,
+                size: info.size,
+            });
+            last_offset = offset + info.size;
+        }
+
+        // Generate FST from only user files
+        let is_wii = self.disc_header.is_wii();
+        let fst_data = self.generate_fst(&write_info)?;
+        let fst_size = fst_data.len() as u64;
+        write_info.push(WriteInfo {
+            kind: WriteKind::Static(fst_data, "[FST]"),
+            size: fst_size,
+            offset: self.partition_header.fst_offset(is_wii),
+        });
+        // Add system files to write info
+        write_info.extend(system_write_info);
+        // Sort files by offset
+        sort_files(&mut write_info)?;
+
+        // Update user size if not set
+        if self.partition_header.user_size.get() == 0 {
+            let user_end = if self.disc_header.is_wii() {
+                align_up_64(last_offset, SECTOR_SIZE as u64)
+            } else {
+                MINI_DVD_SIZE
+            };
+            self.partition_header.user_size.set((user_end - user_offset) as u32);
+        }
+
+        // Insert junk data
+        let write_info = insert_junk_data(write_info, &self.partition_header);
+
+        Ok(write_info)
+    }
+
+    fn junk_id(&self) -> [u8; 4] {
+        self.junk_id.unwrap_or_else(|| *array_ref![self.disc_header.game_id, 0, 4])
+    }
+}
+
+pub(crate) fn insert_junk_data(
+    write_info: Vec<WriteInfo>,
+    partition_header: &PartitionHeader,
+) -> Vec<WriteInfo> {
+    let mut new_write_info = Vec::with_capacity(write_info.len());
+
+    let fst_end = partition_header.fst_offset(false) + partition_header.fst_size(false);
+    let file_gap = find_file_gap(&write_info, fst_end);
+    let mut last_file_end = 0;
+    for info in write_info {
+        if let WriteKind::File(..) | WriteKind::Static(..) = &info.kind {
+            let aligned_end = gcm_align(last_file_end);
+            if info.offset > aligned_end && last_file_end >= fst_end {
+                // Junk data is aligned to 4 bytes with a 28 byte padding (aka `(n + 31) & !3`)
+                // but a few cases don't have the 28 byte padding. Namely, the junk data after the
+                // FST, and the junk data in between the inner and outer rim files. This attempts to
+                // determine the correct alignment, but is not 100% accurate.
+                let junk_start = if file_gap == Some(last_file_end) {
+                    align_up_64(last_file_end, 4)
+                } else {
+                    aligned_end
+                };
+                new_write_info.push(WriteInfo {
+                    kind: WriteKind::Junk,
+                    size: info.offset - junk_start,
+                    offset: junk_start,
+                });
+            }
+            last_file_end = info.offset + info.size;
+        }
+        new_write_info.push(info);
+    }
+    let aligned_end = gcm_align(last_file_end);
+    let user_end =
+        partition_header.user_offset.get() as u64 + partition_header.user_size.get() as u64;
+    if aligned_end < user_end && aligned_end >= fst_end {
+        new_write_info.push(WriteInfo {
+            kind: WriteKind::Junk,
+            size: user_end - aligned_end,
+            offset: aligned_end,
+        });
+    }
+
+    new_write_info
+}
+
+impl GCPartitionWriter {
+    fn new(write_info: Vec<WriteInfo>, disc_size: u64, disc_id: [u8; 4], disc_num: u8) -> Self {
+        Self { write_info, disc_size, disc_id, disc_num }
+    }
+
+    pub fn write_to<W>(
+        &self,
+        out: &mut W,
+        mut file_callback: impl FnMut(&mut dyn Write, &str) -> io::Result<()>,
+    ) -> Result<()>
+    where
+        W: Write + ?Sized,
+    {
+        let mut out = WriteCursor { inner: out, position: 0 };
+        let mut lfg = LaggedFibonacci::default();
+        for info in &self.write_info {
+            out.write_zeroes_until(info.offset).context("Writing padding")?;
+            match &info.kind {
+                WriteKind::File(name) => file_callback(&mut out, name)
+                    .with_context(|| format!("Writing file {}", name))?,
+                WriteKind::Static(data, name) => out.write_all(data).with_context(|| {
+                    format!("Writing static data {} ({} bytes)", name, data.len())
+                })?,
+                WriteKind::Junk => {
+                    lfg.write_sector_chunked(
+                        &mut out,
+                        info.size,
+                        self.disc_id,
+                        self.disc_num,
+                        info.offset,
+                    )
+                    .with_context(|| {
+                        format!(
+                            "Writing junk data at {:X} -> {:X}",
+                            info.offset,
+                            info.offset + info.size
+                        )
+                    })?;
+                }
+            };
+            if out.position != info.offset + info.size {
+                return Err(Error::Other(format!(
+                    "File {}: Wrote {} bytes, expected {}",
+                    info.kind.name(),
+                    out.position - info.offset,
+                    info.size
+                )));
+            }
+        }
+        out.write_zeroes_until(self.disc_size).context("Writing end of file")?;
+        out.flush().context("Flushing output")?;
+        Ok(())
+    }
+
+    pub fn into_stream<Cb>(self, file_callback: Cb) -> Result<Box<dyn DiscStream>>
+    where Cb: FileCallback + 'static {
+        Ok(Box::new(GCPartitionStream::new(
+            file_callback,
+            Arc::from(self.write_info),
+            self.disc_size,
+            self.disc_id,
+            self.disc_num,
+        )))
+    }
+}
+
+struct WriteCursor<W> {
+    inner: W,
+    position: u64,
+}
+
+impl<W> WriteCursor<W>
+where W: Write
+{
+    fn write_zeroes_until(&mut self, until: u64) -> io::Result<()> {
+        const ZEROES: [u8; 0x1000] = [0u8; 0x1000];
+        let mut remaining = until.saturating_sub(self.position);
+        while remaining > 0 {
+            let write_len = remaining.min(ZEROES.len() as u64) as usize;
+            let written = self.write(&ZEROES[..write_len])?;
+            remaining -= written as u64;
+        }
+        Ok(())
+    }
+}
+
+impl<W> Write for WriteCursor<W>
+where W: Write
+{
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        let len = self.inner.write(buf)?;
+        self.position += len as u64;
+        Ok(len)
+    }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { self.inner.flush() }
+}
+
+#[derive(Clone)]
+pub(crate) struct GCPartitionStream<Cb> {
+    file_callback: Cb,
+    pos: u64,
+    write_info: Arc<[WriteInfo]>,
+    size: u64,
+    disc_id: [u8; 4],
+    disc_num: u8,
+}
+
+impl<Cb> GCPartitionStream<Cb> {
+    pub fn new(
+        file_callback: Cb,
+        write_info: Arc<[WriteInfo]>,
+        size: u64,
+        disc_id: [u8; 4],
+        disc_num: u8,
+    ) -> Self {
+        Self { file_callback, pos: 0, write_info, size, disc_id, disc_num }
+    }
+
+    #[inline]
+    pub fn set_position(&mut self, pos: u64) { self.pos = pos; }
+
+    #[inline]
+    pub fn len(&self) -> u64 { self.size }
+}
+
+impl<Cb> Read for GCPartitionStream<Cb>
+where Cb: FileCallback
+{
+    fn read(&mut self, out: &mut [u8]) -> io::Result<usize> {
+        if self.pos >= self.size {
+            // Out of bounds
+            return Ok(0);
+        }
+
+        let end = (self.size - self.pos).min(out.len() as u64) as usize;
+        let mut buf = &mut out[..end];
+        let mut curr = self
+            .write_info
+            .binary_search_by_key(&self.pos, |i| i.offset)
+            .unwrap_or_else(|idx| idx.saturating_sub(1));
+        let mut pos = self.pos;
+        let mut total = 0;
+        while !buf.is_empty() {
+            let Some(info) = self.write_info.get(curr) else {
+                buf.fill(0);
+                total += buf.len();
+                break;
+            };
+            if pos > info.offset + info.size {
+                curr += 1;
+                continue;
+            }
+            let read = if pos < info.offset {
+                let read = buf.len().min((info.offset - pos) as usize);
+                buf[..read].fill(0);
+                read
+            } else {
+                let read = buf.len().min((info.offset + info.size - pos) as usize);
+                match &info.kind {
+                    WriteKind::File(name) => {
+                        self.file_callback.read_file(&mut buf[..read], name, pos - info.offset)?;
+                    }
+                    WriteKind::Static(data, _) => {
+                        let offset = (pos - info.offset) as usize;
+                        buf[..read].copy_from_slice(&data[offset..offset + read]);
+                    }
+                    WriteKind::Junk => {
+                        let mut lfg = LaggedFibonacci::default();
+                        lfg.fill_sector_chunked(&mut buf[..read], self.disc_id, self.disc_num, pos);
+                    }
+                }
+                curr += 1;
+                read
+            };
+            buf = &mut buf[read..];
+            pos += read as u64;
+            total += read;
+        }
+
+        Ok(total)
+    }
+}
+
+impl<Cb> Seek for GCPartitionStream<Cb> {
+    fn seek(&mut self, pos: io::SeekFrom) -> io::Result<u64> {
+        self.pos = match pos {
+            io::SeekFrom::Start(pos) => pos,
+            io::SeekFrom::End(v) => self.size.saturating_add_signed(v),
+            io::SeekFrom::Current(v) => self.pos.saturating_add_signed(v),
+        };
+        Ok(self.pos)
+    }
+}
+
+#[inline(always)]
+fn gcm_align(n: u64) -> u64 { (n + 31) & !3 }
+
+fn sort_files(files: &mut [WriteInfo]) -> Result<()> {
+    files.sort_unstable_by_key(|info| (info.offset, info.size));
+    for i in 1..files.len() {
+        let prev = &files[i - 1];
+        let cur = &files[i];
+        if cur.offset < prev.offset + prev.size {
+            let name = match &cur.kind {
+                WriteKind::File(name) => name.as_str(),
+                WriteKind::Static(_, name) => name,
+                WriteKind::Junk => "[junk data]",
+            };
+            let prev_name = match &prev.kind {
+                WriteKind::File(name) => name.as_str(),
+                WriteKind::Static(_, name) => name,
+                WriteKind::Junk => "[junk data]",
+            };
+            return Err(Error::Other(format!(
+                "File {} ({:#X}-{:#X}) overlaps with {} ({:#X}-{:#X})",
+                name,
+                cur.offset,
+                cur.offset + cur.size,
+                prev_name,
+                prev.offset,
+                prev.offset + prev.size
+            )));
+        }
+    }
+    Ok(())
+}
+
+/// Files can be located on the inner rim of the disc (closer to the center) or the outer rim
+/// (closer to the edge). The inner rim is slower to read, so developers often configured certain
+/// files to be located on the outer rim. This function attempts to find a gap in the file offsets
+/// between the inner and outer rim, which we need to recreate junk data properly.
+fn find_file_gap(file_infos: &[WriteInfo], fst_end: u64) -> Option<u64> {
+    let mut last_offset = 0;
+    for info in file_infos {
+        if let WriteKind::File(..) | WriteKind::Static(..) = &info.kind {
+            if last_offset > fst_end && info.offset > last_offset + SECTOR_SIZE as u64 {
+                debug!("Found file gap at {:X} -> {:X}", last_offset, info.offset);
+                return Some(last_offset);
+            }
+            last_offset = info.offset + info.size;
+        }
+    }
+    None
+}

nod/src/build/mod.rs

@@ -0,0 +1,4 @@
+//! Disc image building.
+
+pub mod gc;
+pub mod wii;

nod/src/build/wii.rs

@@ -0,0 +1 @@
+#![allow(missing_docs)] // TODO

nod/src/common.rs

@@ -0,0 +1,325 @@
+//! Common types.
+
+use std::{borrow::Cow, fmt, str::FromStr, sync::Arc};
+
+use crate::{
+    disc::{wii::WiiPartitionHeader, DiscHeader, PartitionHeader, SECTOR_SIZE},
+    Error, Result,
+};
+
+/// SHA-1 hash bytes
+pub type HashBytes = [u8; 20];
+
+/// AES key bytes
+pub type KeyBytes = [u8; 16];
+
+/// Magic bytes
+pub type MagicBytes = [u8; 4];
+
+/// The disc file format.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
+pub enum Format {
+    /// ISO / GCM (GameCube master disc)
+    #[default]
+    Iso,
+    /// CISO (Compact ISO)
+    Ciso,
+    /// GCZ
+    Gcz,
+    /// NFS (Wii U VC)
+    Nfs,
+    /// RVZ
+    Rvz,
+    /// WBFS
+    Wbfs,
+    /// WIA
+    Wia,
+    /// TGC
+    Tgc,
+}
+
+impl Format {
+    /// Returns the default block size for the disc format, if any.
+    pub fn default_block_size(self) -> u32 {
+        match self {
+            Format::Ciso => crate::io::ciso::DEFAULT_BLOCK_SIZE,
+            #[cfg(feature = "compress-zlib")]
+            Format::Gcz => crate::io::gcz::DEFAULT_BLOCK_SIZE,
+            Format::Rvz => crate::io::wia::RVZ_DEFAULT_CHUNK_SIZE,
+            Format::Wbfs => crate::io::wbfs::DEFAULT_BLOCK_SIZE,
+            Format::Wia => crate::io::wia::WIA_DEFAULT_CHUNK_SIZE,
+            _ => 0,
+        }
+    }
+
+    /// Returns the default compression algorithm for the disc format.
+    pub fn default_compression(self) -> Compression {
+        match self {
+            #[cfg(feature = "compress-zlib")]
+            Format::Gcz => crate::io::gcz::DEFAULT_COMPRESSION,
+            Format::Rvz => crate::io::wia::RVZ_DEFAULT_COMPRESSION,
+            Format::Wia => crate::io::wia::WIA_DEFAULT_COMPRESSION,
+            _ => Compression::None,
+        }
+    }
+}
+
+impl fmt::Display for Format {
+    #[inline]
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Format::Iso => write!(f, "ISO"),
+            Format::Ciso => write!(f, "CISO"),
+            Format::Gcz => write!(f, "GCZ"),
+            Format::Nfs => write!(f, "NFS"),
+            Format::Rvz => write!(f, "RVZ"),
+            Format::Wbfs => write!(f, "WBFS"),
+            Format::Wia => write!(f, "WIA"),
+            Format::Tgc => write!(f, "TGC"),
+        }
+    }
+}
+
+/// The disc file format's compression algorithm.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
+pub enum Compression {
+    /// No compression
+    #[default]
+    None,
+    /// BZIP2
+    Bzip2(u8),
+    /// Deflate (GCZ only)
+    Deflate(u8),
+    /// LZMA
+    Lzma(u8),
+    /// LZMA2
+    Lzma2(u8),
+    /// Zstandard
+    Zstandard(i8),
+}
+
+impl Compression {
+    /// Validates the compression level. Sets the default level if the level is 0.
+    pub fn validate_level(&mut self) -> Result<()> {
+        match self {
+            Compression::Bzip2(level) => {
+                if *level == 0 {
+                    *level = 9;
+                }
+                if *level > 9 {
+                    return Err(Error::Other(format!(
+                        "Invalid BZIP2 compression level: {level} (expected 1-9)"
+                    )));
+                }
+            }
+            Compression::Deflate(level) => {
+                if *level == 0 {
+                    *level = 9;
+                }
+                if *level > 10 {
+                    return Err(Error::Other(format!(
+                        "Invalid Deflate compression level: {level} (expected 1-10)"
+                    )));
+                }
+            }
+            Compression::Lzma(level) => {
+                if *level == 0 {
+                    *level = 6;
+                }
+                if *level > 9 {
+                    return Err(Error::Other(format!(
+                        "Invalid LZMA compression level: {level} (expected 1-9)"
+                    )));
+                }
+            }
+            Compression::Lzma2(level) => {
+                if *level == 0 {
+                    *level = 6;
+                }
+                if *level > 9 {
+                    return Err(Error::Other(format!(
+                        "Invalid LZMA2 compression level: {level} (expected 1-9)"
+                    )));
+                }
+            }
+            Compression::Zstandard(level) => {
+                if *level == 0 {
+                    *level = 19;
+                }
+                if *level < -22 || *level > 22 {
+                    return Err(Error::Other(format!(
+                        "Invalid Zstandard compression level: {level} (expected -22 to 22)"
+                    )));
+                }
+            }
+            _ => {}
+        }
+        Ok(())
+    }
+}
+
+impl fmt::Display for Compression {
+    #[inline]
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Compression::None => write!(f, "None"),
+            Compression::Bzip2(level) => {
+                if *level == 0 {
+                    write!(f, "BZIP2")
+                } else {
+                    write!(f, "BZIP2 ({level})")
+                }
+            }
+            Compression::Deflate(level) => {
+                if *level == 0 {
+                    write!(f, "Deflate")
+                } else {
+                    write!(f, "Deflate ({level})")
+                }
+            }
+            Compression::Lzma(level) => {
+                if *level == 0 {
+                    write!(f, "LZMA")
+                } else {
+                    write!(f, "LZMA ({level})")
+                }
+            }
+            Compression::Lzma2(level) => {
+                if *level == 0 {
+                    write!(f, "LZMA2")
+                } else {
+                    write!(f, "LZMA2 ({level})")
+                }
+            }
+            Compression::Zstandard(level) => {
+                if *level == 0 {
+                    write!(f, "Zstandard")
+                } else {
+                    write!(f, "Zstandard ({level})")
+                }
+            }
+        }
+    }
+}
+
+impl FromStr for Compression {
+    type Err = String;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        let (format, level) =
+            if let Some((format, level_str)) = s.split_once(':').or_else(|| s.split_once('.')) {
+                let level = level_str
+                    .parse::<i32>()
+                    .map_err(|_| format!("Failed to parse compression level: {level_str:?}"))?;
+                (format, level)
+            } else {
+                (s, 0)
+            };
+        match format.to_ascii_lowercase().as_str() {
+            "" | "none" => Ok(Compression::None),
+            "bz2" | "bzip2" => Ok(Compression::Bzip2(level as u8)),
+            "deflate" | "gz" | "gzip" => Ok(Compression::Deflate(level as u8)),
+            "lzma" => Ok(Compression::Lzma(level as u8)),
+            "lzma2" | "xz" => Ok(Compression::Lzma2(level as u8)),
+            "zst" | "zstd" | "zstandard" => Ok(Compression::Zstandard(level as i8)),
+            _ => Err(format!("Unknown compression type: {format:?}")),
+        }
+    }
+}
+
+/// The kind of disc partition.
+#[derive(Debug, PartialEq, Eq, Copy, Clone)]
+pub enum PartitionKind {
+    /// Data partition.
+    Data,
+    /// Update partition.
+    Update,
+    /// Channel partition.
+    Channel,
+    /// Other partition kind.
+    Other(u32),
+}
+
+impl fmt::Display for PartitionKind {
+    #[inline]
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Self::Data => write!(f, "Data"),
+            Self::Update => write!(f, "Update"),
+            Self::Channel => write!(f, "Channel"),
+            Self::Other(v) => {
+                let bytes = v.to_be_bytes();
+                write!(f, "Other ({:08X}, {})", v, String::from_utf8_lossy(&bytes))
+            }
+        }
+    }
+}
+
+impl PartitionKind {
+    /// Returns the directory name for the partition kind.
+    #[inline]
+    pub fn dir_name(&self) -> Cow<str> {
+        match self {
+            Self::Data => Cow::Borrowed("DATA"),
+            Self::Update => Cow::Borrowed("UPDATE"),
+            Self::Channel => Cow::Borrowed("CHANNEL"),
+            Self::Other(v) => {
+                let bytes = v.to_be_bytes();
+                Cow::Owned(format!("P-{}", String::from_utf8_lossy(&bytes)))
+            }
+        }
+    }
+}
+
+impl From<u32> for PartitionKind {
+    #[inline]
+    fn from(v: u32) -> Self {
+        match v {
+            0 => Self::Data,
+            1 => Self::Update,
+            2 => Self::Channel,
+            v => Self::Other(v),
+        }
+    }
+}
+
+/// Wii partition information.
+#[derive(Debug, Clone)]
+pub struct PartitionInfo {
+    /// The partition index.
+    pub index: usize,
+    /// The kind of disc partition.
+    pub kind: PartitionKind,
+    /// The start sector of the partition.
+    pub start_sector: u32,
+    /// The start sector of the partition's (usually encrypted) data.
+    pub data_start_sector: u32,
+    /// The end sector of the partition's (usually encrypted) data.
+    pub data_end_sector: u32,
+    /// The AES key for the partition, also known as the "title key".
+    pub key: KeyBytes,
+    /// The Wii partition header.
+    pub header: Arc<WiiPartitionHeader>,
+    /// The disc header within the partition.
+    pub disc_header: Arc<DiscHeader>,
+    /// The partition header within the partition.
+    pub partition_header: Arc<PartitionHeader>,
+    /// Whether the partition data is encrypted
+    pub has_encryption: bool,
+    /// Whether the partition data hashes are present
+    pub has_hashes: bool,
+}
+
+impl PartitionInfo {
+    /// Returns the size of the partition's data region in bytes.
+    #[inline]
+    pub fn data_size(&self) -> u64 {
+        (self.data_end_sector as u64 - self.data_start_sector as u64) * SECTOR_SIZE as u64
+    }
+
+    /// Returns whether the given sector is within the partition's data region.
+    #[inline]
+    pub fn data_contains_sector(&self, sector: u32) -> bool {
+        sector >= self.data_start_sector && sector < self.data_end_sector
+    }
+}

nod/src/disc/direct.rs

@@ -0,0 +1,124 @@
+use std::{
+    io,
+    io::{BufRead, Seek, SeekFrom},
+    sync::Arc,
+};
+
+use zerocopy::FromZeros;
+
+use crate::{
+    common::KeyBytes,
+    disc::{wii::SECTOR_DATA_SIZE, DiscHeader, SECTOR_SIZE},
+    io::block::{Block, BlockReader},
+    util::impl_read_for_bufread,
+    Result,
+};
+
+pub enum DirectDiscReaderMode {
+    Raw,
+    Partition { disc_header: Arc<DiscHeader>, data_start_sector: u32, key: KeyBytes },
+}
+
+/// Simplified disc reader that uses a block reader directly.
+///
+/// This is used to read disc and partition metadata before we can construct a full disc reader.
+pub struct DirectDiscReader {
+    io: Box<dyn BlockReader>,
+    block: Block,
+    block_buf: Box<[u8]>,
+    block_decrypted: bool,
+    pos: u64,
+    mode: DirectDiscReaderMode,
+}
+
+impl DirectDiscReader {
+    pub fn new(inner: Box<dyn BlockReader>) -> Result<Box<Self>> {
+        let block_size = inner.block_size() as usize;
+        Ok(Box::new(Self {
+            io: inner,
+            block: Block::default(),
+            block_buf: <[u8]>::new_box_zeroed_with_elems(block_size)?,
+            block_decrypted: false,
+            pos: 0,
+            mode: DirectDiscReaderMode::Raw,
+        }))
+    }
+
+    pub fn reset(&mut self, mode: DirectDiscReaderMode) {
+        self.block = Block::default();
+        self.block_decrypted = false;
+        self.pos = 0;
+        self.mode = mode;
+    }
+
+    pub fn into_inner(self) -> Box<dyn BlockReader> { self.io }
+}
+
+impl BufRead for DirectDiscReader {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> {
+        match &self.mode {
+            DirectDiscReaderMode::Raw => {
+                // Read new block if necessary
+                let sector = (self.pos / SECTOR_SIZE as u64) as u32;
+                if self.block_decrypted || !self.block.contains(sector) {
+                    self.block = self.io.read_block(self.block_buf.as_mut(), sector)?;
+                    self.block_decrypted = false;
+                }
+                self.block.data(self.block_buf.as_ref(), self.pos)
+            }
+            DirectDiscReaderMode::Partition { disc_header, data_start_sector, key } => {
+                let has_encryption = disc_header.has_partition_encryption();
+                let has_hashes = disc_header.has_partition_hashes();
+                let part_sector = if has_hashes {
+                    (self.pos / SECTOR_DATA_SIZE as u64) as u32
+                } else {
+                    (self.pos / SECTOR_SIZE as u64) as u32
+                };
+
+                // Read new block if necessary
+                let abs_sector = data_start_sector + part_sector;
+                if !self.block.contains(abs_sector) {
+                    self.block = self.io.read_block(self.block_buf.as_mut(), abs_sector)?;
+                    self.block_decrypted = false;
+                }
+
+                // Allow reusing the same block from raw mode, just decrypt it if necessary
+                if !self.block_decrypted {
+                    self.block
+                        .decrypt_block(self.block_buf.as_mut(), has_encryption.then_some(*key))?;
+                    self.block_decrypted = true;
+                }
+
+                self.block.partition_data(
+                    self.block_buf.as_ref(),
+                    self.pos,
+                    *data_start_sector,
+                    has_hashes,
+                )
+            }
+        }
+    }
+
+    #[inline]
+    fn consume(&mut self, amt: usize) { self.pos += amt as u64; }
+}
+
+impl_read_for_bufread!(DirectDiscReader);
+
+impl Seek for DirectDiscReader {
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+        self.pos = match pos {
+            SeekFrom::Start(v) => v,
+            SeekFrom::End(_) => {
+                return Err(io::Error::new(
+                    io::ErrorKind::Unsupported,
+                    "DirectDiscReader: SeekFrom::End is not supported",
+                ));
+            }
+            SeekFrom::Current(v) => self.pos.saturating_add_signed(v),
+        };
+        Ok(self.pos)
+    }
+
+    fn stream_position(&mut self) -> io::Result<u64> { Ok(self.pos) }
+}

nod/src/disc/fst.rs

@@ -1,11 +1,15 @@
-//! Disc file system types
+//! File system table (FST) types.
 
 use std::{borrow::Cow, ffi::CStr, mem::size_of};
 
 use encoding_rs::SHIFT_JIS;
-use zerocopy::{big_endian::*, FromBytes, Immutable, IntoBytes, KnownLayout};
+use itertools::Itertools;
+use zerocopy::{big_endian::*, FromBytes, FromZeros, Immutable, IntoBytes, KnownLayout};
 
-use crate::{static_assert, Result};
+use crate::{
+    util::{array_ref, static_assert},
+    Error, Result,
+};
 
 /// File system node kind.
 #[derive(Clone, Debug, PartialEq)]
@@ -25,13 +29,31 @@ pub struct Node {
     kind: u8,
     // u24 big-endian
     name_offset: [u8; 3],
-    pub(crate) offset: U32,
+    offset: U32,
     length: U32,
 }
 
 static_assert!(size_of::<Node>() == 12);
 
 impl Node {
+    /// Create a new node.
+    #[inline]
+    pub fn new(kind: NodeKind, name_offset: u32, offset: u64, length: u32, is_wii: bool) -> Self {
+        Self {
+            kind: match kind {
+                NodeKind::File => 0,
+                NodeKind::Directory => 1,
+                NodeKind::Invalid => u8::MAX,
+            },
+            name_offset: *array_ref![name_offset.to_be_bytes(), 1, 3],
+            offset: U32::new(match kind {
+                NodeKind::File if is_wii => (offset / 4) as u32,
+                _ => offset as u32,
+            }),
+            length: U32::new(length),
+        }
+    }
+
     /// File system node kind.
     #[inline]
     pub fn kind(&self) -> NodeKind {
@@ -42,6 +64,16 @@ impl Node {
         }
     }
 
+    /// Set the node kind.
+    #[inline]
+    pub fn set_kind(&mut self, kind: NodeKind) {
+        self.kind = match kind {
+            NodeKind::File => 0,
+            NodeKind::Directory => 1,
+            NodeKind::Invalid => u8::MAX,
+        };
+    }
+
     /// Whether the node is a file.
     #[inline]
     pub fn is_file(&self) -> bool { self.kind == 0 }
@@ -56,6 +88,12 @@ impl Node {
         u32::from_be_bytes([0, self.name_offset[0], self.name_offset[1], self.name_offset[2]])
     }
 
+    /// Set the name offset of the node.
+    #[inline]
+    pub fn set_name_offset(&mut self, name_offset: u32) {
+        self.name_offset = *array_ref![name_offset.to_be_bytes(), 1, 3];
+    }
+
     /// For files, this is the partition offset of the file data. (Wii: >> 2)
     ///
     /// For directories, this is the parent node index in the FST.
@@ -68,16 +106,27 @@ impl Node {
         }
     }
 
+    /// Set the offset of the node. See [`Node::offset`] for details.
+    #[inline]
+    pub fn set_offset(&mut self, offset: u64, is_wii: bool) {
+        self.offset.set(if is_wii && self.is_file() { (offset / 4) as u32 } else { offset as u32 });
+    }
+
     /// For files, this is the byte size of the file.
     ///
     /// For directories, this is the child end index in the FST.
     ///
     /// Number of child files and directories recursively is `length - offset`.
     #[inline]
-    pub fn length(&self) -> u64 { self.length.get() as u64 }
+    pub fn length(&self) -> u32 { self.length.get() }
+
+    /// Set the length of the node. See [`Node::length`] for details.
+    #[inline]
+    pub fn set_length(&mut self, length: u32) { self.length.set(length); }
 }
 
 /// A view into the file system table (FST).
+#[derive(Clone)]
 pub struct Fst<'a> {
     /// The nodes in the FST.
     pub nodes: &'a [Node],
@@ -87,14 +136,13 @@ pub struct Fst<'a> {
 
 impl<'a> Fst<'a> {
     /// Create a new FST view from a buffer.
-    #[allow(clippy::missing_inline_in_public_items)]
     pub fn new(buf: &'a [u8]) -> Result<Self, &'static str> {
         let Ok((root_node, _)) = Node::ref_from_prefix(buf) else {
             return Err("FST root node not found");
         };
         // String table starts after the last node
-        let string_base = root_node.length() * size_of::<Node>() as u64;
-        if string_base >= buf.len() as u64 {
+        let string_base = root_node.length() * size_of::<Node>() as u32;
+        if string_base > buf.len() as u32 {
             return Err("FST string table out of bounds");
         }
         let (node_buf, string_table) = buf.split_at(string_base as usize);
@@ -104,10 +152,9 @@ impl<'a> Fst<'a> {
 
     /// Iterate over the nodes in the FST.
     #[inline]
-    pub fn iter(&self) -> FstIter { FstIter { fst: self, idx: 1 } }
+    pub fn iter(&self) -> FstIter { FstIter { fst: self.clone(), idx: 1, segments: vec![] } }
 
     /// Get the name of a node.
-    #[allow(clippy::missing_inline_in_public_items)]
     pub fn get_name(&self, node: Node) -> Result<Cow<'a, str>, String> {
         let name_buf = self.string_table.get(node.name_offset() as usize..).ok_or_else(|| {
             format!(
@@ -126,7 +173,6 @@ impl<'a> Fst<'a> {
     }
 
     /// Finds a particular file or directory by path.
-    #[allow(clippy::missing_inline_in_public_items)]
     pub fn find(&self, path: &str) -> Option<(usize, Node)> {
         let mut split = path.trim_matches('/').split('/');
         let mut current = next_non_empty(&mut split);
@@ -160,23 +206,46 @@ impl<'a> Fst<'a> {
         }
         None
     }
+
+    /// Count the number of files in the FST.
+    pub fn num_files(&self) -> usize { self.nodes.iter().filter(|n| n.is_file()).count() }
 }
 
 /// Iterator over the nodes in an FST.
+///
+/// For each node, the iterator yields the node index, the node itself,
+/// and the full path to the node (separated by `/`).
 pub struct FstIter<'a> {
-    fst: &'a Fst<'a>,
+    fst: Fst<'a>,
     idx: usize,
+    segments: Vec<(Cow<'a, str>, usize)>,
 }
 
 impl<'a> Iterator for FstIter<'a> {
-    type Item = (usize, Node, Result<Cow<'a, str>, String>);
+    type Item = (usize, Node, String);
 
     fn next(&mut self) -> Option<Self::Item> {
         let idx = self.idx;
         let node = self.fst.nodes.get(idx).copied()?;
-        let name = self.fst.get_name(node);
+        let name = self.fst.get_name(node).unwrap_or("<invalid>".into());
         self.idx += 1;
-        Some((idx, node, name))
+
+        // Remove ended path segments
+        let mut new_size = 0;
+        for (_, end) in self.segments.iter() {
+            if *end == idx {
+                break;
+            }
+            new_size += 1;
+        }
+        self.segments.truncate(new_size);
+
+        // Add the new path segment
+        let length = node.length() as u64;
+        let end = if node.is_dir() { length as usize } else { idx + 1 };
+        self.segments.push((name, end));
+        let path = self.segments.iter().map(|(name, _)| name.as_ref()).join("/");
+        Some((idx, node, path))
     }
 }
 
@@ -190,3 +259,117 @@ fn next_non_empty<'a>(iter: &mut impl Iterator<Item = &'a str>) -> &'a str {
         }
     }
 }
+
+/// A builder for creating a file system table (FST).
+pub struct FstBuilder {
+    nodes: Vec<Node>,
+    string_table: Vec<u8>,
+    stack: Vec<(String, u32)>,
+    is_wii: bool,
+}
+
+impl FstBuilder {
+    /// Create a new FST builder.
+    pub fn new(is_wii: bool) -> Self {
+        let mut builder = Self { nodes: vec![], string_table: vec![], stack: vec![], is_wii };
+        builder.add_node(NodeKind::Directory, "<root>", 0, 0);
+        builder
+    }
+
+    /// Create a new FST builder with an existing string table. This allows matching the string
+    /// ordering of an existing FST.
+    pub fn new_with_string_table(is_wii: bool, string_table: Vec<u8>) -> Result<Self> {
+        if matches!(string_table.last(), Some(n) if *n != 0) {
+            return Err(Error::DiscFormat("String table must be null-terminated".to_string()));
+        }
+        let root_name = CStr::from_bytes_until_nul(&string_table)
+            .map_err(|_| {
+                Error::DiscFormat("String table root name not null-terminated".to_string())
+            })?
+            .to_str()
+            .unwrap_or("<root>")
+            .to_string();
+        let mut builder = Self { nodes: vec![], string_table, stack: vec![], is_wii };
+        builder.add_node(NodeKind::Directory, &root_name, 0, 0);
+        Ok(builder)
+    }
+
+    /// Add a file to the FST. All paths within a directory must be added sequentially,
+    /// otherwise the output FST will be invalid.
+    pub fn add_file(&mut self, path: &str, offset: u64, size: u32) {
+        let components = path.split('/').collect::<Vec<_>>();
+        for i in 0..components.len() - 1 {
+            if matches!(self.stack.get(i), Some((name, _)) if name != components[i]) {
+                // Pop directories
+                while self.stack.len() > i {
+                    let (_, idx) = self.stack.pop().unwrap();
+                    let length = self.nodes.len() as u32;
+                    self.nodes[idx as usize].set_length(length);
+                }
+            }
+            while i >= self.stack.len() {
+                // Push a new directory node
+                let component_idx = self.stack.len();
+                let parent = if component_idx == 0 { 0 } else { self.stack[component_idx - 1].1 };
+                let node_idx =
+                    self.add_node(NodeKind::Directory, components[component_idx], parent as u64, 0);
+                self.stack.push((components[i].to_string(), node_idx));
+            }
+        }
+        if components.len() == 1 {
+            // Pop all directories
+            while let Some((_, idx)) = self.stack.pop() {
+                let length = self.nodes.len() as u32;
+                self.nodes[idx as usize].set_length(length);
+            }
+        }
+        // Add file node
+        self.add_node(NodeKind::File, components.last().unwrap(), offset, size);
+    }
+
+    /// Get the byte size of the FST.
+    pub fn byte_size(&self) -> usize {
+        size_of_val(self.nodes.as_slice()) + self.string_table.len()
+    }
+
+    /// Finalize the FST and return the serialized data.
+    pub fn finalize(mut self) -> Box<[u8]> {
+        // Finalize directory lengths
+        let node_count = self.nodes.len() as u32;
+        while let Some((_, idx)) = self.stack.pop() {
+            self.nodes[idx as usize].set_length(node_count);
+        }
+        self.nodes[0].set_length(node_count);
+
+        // Serialize nodes and string table
+        let nodes_data = self.nodes.as_bytes();
+        let string_table_data = self.string_table.as_bytes();
+        let mut data =
+            <[u8]>::new_box_zeroed_with_elems(nodes_data.len() + string_table_data.len()).unwrap();
+        data[..nodes_data.len()].copy_from_slice(self.nodes.as_bytes());
+        data[nodes_data.len()..].copy_from_slice(self.string_table.as_bytes());
+        data
+    }
+
+    fn add_node(&mut self, kind: NodeKind, name: &str, offset: u64, length: u32) -> u32 {
+        let (bytes, _, _) = SHIFT_JIS.encode(name);
+        // Check if the name already exists in the string table
+        let mut name_offset = 0;
+        while name_offset < self.string_table.len() {
+            let string_buf = &self.string_table[name_offset..];
+            let existing = CStr::from_bytes_until_nul(string_buf).unwrap();
+            if existing.to_bytes() == bytes.as_ref() {
+                break;
+            }
+            name_offset += existing.to_bytes_with_nul().len();
+        }
+        // Otherwise, add the name to the string table
+        if name_offset == self.string_table.len() {
+            self.string_table.extend_from_slice(bytes.as_ref());
+            self.string_table.push(0);
+        }
+        let idx = self.nodes.len() as u32;
+        self.nodes.push(Node::new(kind, name_offset as u32, offset, length, self.is_wii));
+        idx
+    }
+}

nod/src/disc/gcn.rs

@@ -2,190 +2,144 @@ use std::{
     io,
     io::{BufRead, Read, Seek, SeekFrom},
     mem::size_of,
+    sync::Arc,
 };
 
-use zerocopy::{FromBytes, FromZeros};
+use zerocopy::FromBytes;
 
-use super::{
-    ApploaderHeader, DiscHeader, DolHeader, FileStream, Node, PartitionBase, PartitionHeader,
-    PartitionMeta, BI2_SIZE, BOOT_SIZE, SECTOR_SIZE,
-};
 use crate::{
-    disc::streams::OwnedFileStream,
-    io::block::{Block, BlockIO},
-    util::read::{read_box, read_box_slice, read_vec},
+    disc::{
+        preloader::{Preloader, SectorGroup, SectorGroupRequest},
+        ApploaderHeader, DiscHeader, DolHeader, PartitionHeader, BI2_SIZE, BOOT_SIZE,
+        SECTOR_GROUP_SIZE, SECTOR_SIZE,
+    },
+    io::block::BlockReader,
+    read::{PartitionEncryption, PartitionMeta, PartitionReader},
+    util::{
+        impl_read_for_bufread,
+        read::{read_arc, read_arc_slice, read_vec},
+    },
     Result, ResultContext,
 };
 
-pub struct PartitionGC {
-    io: Box<dyn BlockIO>,
-    block: Block,
-    block_buf: Box<[u8]>,
-    block_idx: u32,
-    sector_buf: Box<[u8; SECTOR_SIZE]>,
-    sector: u32,
+pub struct PartitionReaderGC {
+    io: Box<dyn BlockReader>,
+    preloader: Arc<Preloader>,
     pos: u64,
-    disc_header: Box<DiscHeader>,
+    disc_size: u64,
+    sector_group: Option<SectorGroup>,
+    meta: Option<PartitionMeta>,
 }
 
-impl Clone for PartitionGC {
+impl Clone for PartitionReaderGC {
     fn clone(&self) -> Self {
         Self {
             io: self.io.clone(),
-            block: Block::default(),
-            block_buf: <[u8]>::new_box_zeroed_with_elems(self.block_buf.len()).unwrap(),
-            block_idx: u32::MAX,
-            sector_buf: <[u8; SECTOR_SIZE]>::new_box_zeroed().unwrap(),
-            sector: u32::MAX,
+            preloader: self.preloader.clone(),
             pos: 0,
-            disc_header: self.disc_header.clone(),
+            disc_size: self.disc_size,
+            sector_group: None,
+            meta: self.meta.clone(),
         }
     }
 }
 
-impl PartitionGC {
-    pub fn new(inner: Box<dyn BlockIO>, disc_header: Box<DiscHeader>) -> Result<Box<Self>> {
-        let block_size = inner.block_size();
+impl PartitionReaderGC {
+    pub fn new(
+        inner: Box<dyn BlockReader>,
+        preloader: Arc<Preloader>,
+        disc_size: u64,
+    ) -> Result<Box<Self>> {
         Ok(Box::new(Self {
             io: inner,
-            block: Block::default(),
-            block_buf: <[u8]>::new_box_zeroed_with_elems(block_size as usize).unwrap(),
-            block_idx: u32::MAX,
-            sector_buf: <[u8; SECTOR_SIZE]>::new_box_zeroed().unwrap(),
-            sector: u32::MAX,
+            preloader,
             pos: 0,
-            disc_header,
+            disc_size,
+            sector_group: None,
+            meta: None,
         }))
     }
-
-    pub fn into_inner(self) -> Box<dyn BlockIO> { self.io }
 }
 
-impl BufRead for PartitionGC {
+impl BufRead for PartitionReaderGC {
     fn fill_buf(&mut self) -> io::Result<&[u8]> {
-        let sector = (self.pos / SECTOR_SIZE as u64) as u32;
-        let block_idx = (sector as u64 * SECTOR_SIZE as u64 / self.block_buf.len() as u64) as u32;
-
-        // Read new block if necessary
-        if block_idx != self.block_idx {
-            self.block = self.io.read_block(self.block_buf.as_mut(), block_idx, None)?;
-            self.block_idx = block_idx;
+        if self.pos >= self.disc_size {
+            return Ok(&[]);
         }
 
-        // Copy sector if necessary
-        if sector != self.sector {
-            self.block.copy_raw(
-                self.sector_buf.as_mut(),
-                self.block_buf.as_ref(),
-                sector,
-                &self.disc_header,
-            )?;
-            self.sector = sector;
-        }
+        let abs_sector = (self.pos / SECTOR_SIZE as u64) as u32;
+        let group_idx = abs_sector / 64;
+        let abs_group_sector = group_idx * 64;
+        let max_groups = self.disc_size.div_ceil(SECTOR_GROUP_SIZE as u64) as u32;
+        let request = SectorGroupRequest {
+            group_idx,
+            partition_idx: None,
+            mode: PartitionEncryption::Original,
+        };
 
-        let offset = (self.pos % SECTOR_SIZE as u64) as usize;
-        Ok(&self.sector_buf[offset..])
+        let sector_group = if matches!(&self.sector_group, Some(sector_group) if sector_group.request == request)
+        {
+            // We can improve this in Rust 2024 with `if_let_rescope`
+            // https://github.com/rust-lang/rust/issues/124085
+            self.sector_group.as_ref().unwrap()
+        } else {
+            self.sector_group.insert(self.preloader.fetch(request, max_groups)?)
+        };
+
+        // Calculate the number of consecutive sectors in the group
+        let group_sector = abs_sector - abs_group_sector;
+        let consecutive_sectors = sector_group.consecutive_sectors(group_sector);
+        if consecutive_sectors == 0 {
+            return Ok(&[]);
+        }
+        let num_sectors = group_sector + consecutive_sectors;
+
+        // Read from sector group buffer
+        let group_start = abs_group_sector as u64 * SECTOR_SIZE as u64;
+        let offset = (self.pos - group_start) as usize;
+        let end =
+            (num_sectors as u64 * SECTOR_SIZE as u64).min(self.disc_size - group_start) as usize;
+        Ok(&sector_group.data[offset..end])
     }
 
     #[inline]
     fn consume(&mut self, amt: usize) { self.pos += amt as u64; }
 }
 
-impl Read for PartitionGC {
-    #[inline]
-    fn read(&mut self, out: &mut [u8]) -> io::Result<usize> {
-        let buf = self.fill_buf()?;
-        let len = buf.len().min(out.len());
-        out[..len].copy_from_slice(&buf[..len]);
-        self.consume(len);
-        Ok(len)
-    }
-}
+impl_read_for_bufread!(PartitionReaderGC);
 
-impl Seek for PartitionGC {
+impl Seek for PartitionReaderGC {
     fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
         self.pos = match pos {
             SeekFrom::Start(v) => v,
-            SeekFrom::End(_) => {
-                return Err(io::Error::new(
-                    io::ErrorKind::Unsupported,
-                    "GCPartitionReader: SeekFrom::End is not supported".to_string(),
-                ));
-            }
+            SeekFrom::End(v) => self.disc_size.saturating_add_signed(v),
             SeekFrom::Current(v) => self.pos.saturating_add_signed(v),
         };
         Ok(self.pos)
     }
+
+    fn stream_position(&mut self) -> io::Result<u64> { Ok(self.pos) }
 }
 
-impl PartitionBase for PartitionGC {
-    fn meta(&mut self) -> Result<Box<PartitionMeta>> {
-        self.seek(SeekFrom::Start(0)).context("Seeking to partition metadata")?;
-        read_part_meta(self, false)
-    }
+impl PartitionReader for PartitionReaderGC {
+    fn is_wii(&self) -> bool { false }
 
-    fn open_file(&mut self, node: Node) -> io::Result<FileStream> {
-        if !node.is_file() {
-            return Err(io::Error::new(
-                io::ErrorKind::InvalidInput,
-                "Node is not a file".to_string(),
-            ));
+    fn meta(&mut self) -> Result<PartitionMeta> {
+        if let Some(meta) = &self.meta {
+            Ok(meta.clone())
+        } else {
+            let meta = read_part_meta(self, false)?;
+            self.meta = Some(meta.clone());
+            Ok(meta)
         }
-        FileStream::new(self, node.offset(false), node.length())
-    }
-
-    fn into_open_file(self: Box<Self>, node: Node) -> io::Result<OwnedFileStream> {
-        if !node.is_file() {
-            return Err(io::Error::new(
-                io::ErrorKind::InvalidInput,
-                "Node is not a file".to_string(),
-            ));
-        }
-        OwnedFileStream::new(self, node.offset(false), node.length())
     }
 }
 
-pub(crate) fn read_part_meta(
-    reader: &mut dyn PartitionBase,
+pub(crate) fn read_dol(
+    reader: &mut dyn PartitionReader,
+    partition_header: &PartitionHeader,
     is_wii: bool,
-) -> Result<Box<PartitionMeta>> {
-    // boot.bin
-    let raw_boot: Box<[u8; BOOT_SIZE]> = read_box(reader).context("Reading boot.bin")?;
-    let partition_header =
-        PartitionHeader::ref_from_bytes(&raw_boot[size_of::<DiscHeader>()..]).unwrap();
-
-    // bi2.bin
-    let raw_bi2: Box<[u8; BI2_SIZE]> = read_box(reader).context("Reading bi2.bin")?;
-
-    // apploader.bin
-    let mut raw_apploader: Vec<u8> =
-        read_vec(reader, size_of::<ApploaderHeader>()).context("Reading apploader header")?;
-    let apploader_header = ApploaderHeader::ref_from_bytes(raw_apploader.as_slice()).unwrap();
-    raw_apploader.resize(
-        size_of::<ApploaderHeader>()
-            + apploader_header.size.get() as usize
-            + apploader_header.trailer_size.get() as usize,
-        0,
-    );
-    reader
-        .read_exact(&mut raw_apploader[size_of::<ApploaderHeader>()..])
-        .context("Reading apploader")?;
-    let raw_apploader = raw_apploader.into_boxed_slice();
-
-    // fst.bin
-    reader
-        .seek(SeekFrom::Start(partition_header.fst_offset(is_wii)))
-        .context("Seeking to FST offset")?;
-    let raw_fst: Box<[u8]> = read_box_slice(reader, partition_header.fst_size(is_wii) as usize)
-        .with_context(|| {
-            format!(
-                "Reading partition FST (offset {}, size {})",
-                partition_header.fst_offset(is_wii),
-                partition_header.fst_size(is_wii)
-            )
-        })?;
-
-    // main.dol
+) -> Result<Arc<[u8]>> {
     reader
         .seek(SeekFrom::Start(partition_header.dol_offset(is_wii)))
         .context("Seeking to DOL offset")?;
@@ -208,9 +162,65 @@ pub(crate) fn read_part_meta(
         .unwrap_or(size_of::<DolHeader>() as u32);
     raw_dol.resize(dol_size as usize, 0);
     reader.read_exact(&mut raw_dol[size_of::<DolHeader>()..]).context("Reading DOL")?;
-    let raw_dol = raw_dol.into_boxed_slice();
+    Ok(Arc::from(raw_dol.as_slice()))
+}
 
-    Ok(Box::new(PartitionMeta {
+pub(crate) fn read_fst<R>(
+    reader: &mut R,
+    partition_header: &PartitionHeader,
+    is_wii: bool,
+) -> Result<Arc<[u8]>>
+where
+    R: Read + Seek + ?Sized,
+{
+    reader
+        .seek(SeekFrom::Start(partition_header.fst_offset(is_wii)))
+        .context("Seeking to FST offset")?;
+    let raw_fst: Arc<[u8]> = read_arc_slice(reader, partition_header.fst_size(is_wii) as usize)
+        .with_context(|| {
+            format!(
+                "Reading partition FST (offset {}, size {})",
+                partition_header.fst_offset(is_wii),
+                partition_header.fst_size(is_wii)
+            )
+        })?;
+    Ok(raw_fst)
+}
+
+pub(crate) fn read_part_meta(
+    reader: &mut dyn PartitionReader,
+    is_wii: bool,
+) -> Result<PartitionMeta> {
+    // boot.bin
+    let raw_boot: Arc<[u8; BOOT_SIZE]> = read_arc(reader).context("Reading boot.bin")?;
+    let partition_header =
+        PartitionHeader::ref_from_bytes(&raw_boot[size_of::<DiscHeader>()..]).unwrap();
+
+    // bi2.bin
+    let raw_bi2: Arc<[u8; BI2_SIZE]> = read_arc(reader).context("Reading bi2.bin")?;
+
+    // apploader.bin
+    let mut raw_apploader: Vec<u8> =
+        read_vec(reader, size_of::<ApploaderHeader>()).context("Reading apploader header")?;
+    let apploader_header = ApploaderHeader::ref_from_bytes(raw_apploader.as_slice()).unwrap();
+    raw_apploader.resize(
+        size_of::<ApploaderHeader>()
+            + apploader_header.size.get() as usize
+            + apploader_header.trailer_size.get() as usize,
+        0,
+    );
+    reader
+        .read_exact(&mut raw_apploader[size_of::<ApploaderHeader>()..])
+        .context("Reading apploader")?;
+    let raw_apploader = Arc::from(raw_apploader.as_slice());
+
+    // fst.bin
+    let raw_fst = read_fst(reader, partition_header, is_wii)?;
+
+    // main.dol
+    let raw_dol = read_dol(reader, partition_header, is_wii)?;
+
+    Ok(PartitionMeta {
         raw_boot,
         raw_bi2,
         raw_apploader,
@@ -220,5 +230,5 @@ pub(crate) fn read_part_meta(
         raw_tmd: None,
         raw_cert_chain: None,
         raw_h3_table: None,
-    }))
+    })
 }

nod/src/disc/hashes.rs

@@ -1,202 +1,92 @@
-use std::{
-    io::{Read, Seek, SeekFrom},
-    sync::{Arc, Mutex},
-    time::Instant,
-};
-
-use rayon::iter::{IntoParallelIterator, ParallelIterator};
-use sha1::{Digest, Sha1};
-use zerocopy::FromZeros;
+use tracing::instrument;
+use zerocopy::{FromZeros, IntoBytes};
 
 use crate::{
-    array_ref, array_ref_mut,
+    common::HashBytes,
     disc::{
-        reader::DiscReader,
         wii::{HASHES_SIZE, SECTOR_DATA_SIZE},
+        SECTOR_GROUP_SIZE, SECTOR_SIZE,
     },
-    io::HashBytes,
-    util::read::read_box_slice,
-    PartitionOptions, Result, ResultContext, SECTOR_SIZE,
+    util::{array_ref, array_ref_mut},
 };
 
-/// In a sector, following the 0x400 byte block of hashes, each 0x400 bytes of decrypted data is
-/// hashed, yielding 31 H0 hashes.
-/// Then, 8 sectors are aggregated into a subgroup, and the 31 H0 hashes for each sector are hashed,
-/// yielding 8 H1 hashes.
-/// Then, 8 subgroups are aggregated into a group, and the 8 H1 hashes for each subgroup are hashed,
-/// yielding 8 H2 hashes.
-/// Finally, the 8 H2 hashes for each group are hashed, yielding 1 H3 hash.
-/// The H3 hashes for each group are stored in the partition's H3 table.
-#[derive(Clone, Debug)]
-pub struct HashTable {
-    /// SHA-1 hash of each 0x400 byte block of decrypted data.
-    pub h0_hashes: Box<[HashBytes]>,
-    /// SHA-1 hash of the 31 H0 hashes for each sector.
-    pub h1_hashes: Box<[HashBytes]>,
-    /// SHA-1 hash of the 8 H1 hashes for each subgroup.
-    pub h2_hashes: Box<[HashBytes]>,
-    /// SHA-1 hash of the 8 H2 hashes for each group.
-    pub h3_hashes: Box<[HashBytes]>,
-}
-
+/// Hashes for a single sector group (64 sectors).
 #[derive(Clone, FromZeros)]
-struct HashResult {
-    h0_hashes: [HashBytes; 1984],
-    h1_hashes: [HashBytes; 64],
-    h2_hashes: [HashBytes; 8],
-    h3_hash: HashBytes,
+pub struct GroupHashes {
+    pub h3_hash: HashBytes,
+    pub h2_hashes: [HashBytes; 8],
+    pub h1_hashes: [HashBytes; 64],
+    pub h0_hashes: [HashBytes; 1984],
 }
 
-impl HashTable {
-    fn new(num_sectors: u32) -> Self {
-        let num_sectors = num_sectors.next_multiple_of(64) as usize;
-        let num_data_hashes = num_sectors * 31;
-        let num_subgroups = num_sectors / 8;
-        let num_groups = num_subgroups / 8;
-        Self {
-            h0_hashes: <[HashBytes]>::new_box_zeroed_with_elems(num_data_hashes).unwrap(),
-            h1_hashes: <[HashBytes]>::new_box_zeroed_with_elems(num_sectors).unwrap(),
-            h2_hashes: <[HashBytes]>::new_box_zeroed_with_elems(num_subgroups).unwrap(),
-            h3_hashes: <[HashBytes]>::new_box_zeroed_with_elems(num_groups).unwrap(),
-        }
+impl GroupHashes {
+    #[inline]
+    pub fn hashes_for_sector(
+        &self,
+        sector: usize,
+    ) -> (&[HashBytes; 31], &[HashBytes; 8], &[HashBytes; 8]) {
+        let h1_hashes = array_ref![self.h1_hashes, sector & !7, 8];
+        let h0_hashes = array_ref![self.h0_hashes, sector * 31, 31];
+        (h0_hashes, h1_hashes, &self.h2_hashes)
     }
 
-    fn extend(&mut self, group_index: usize, result: &HashResult) {
-        *array_ref_mut![self.h0_hashes, group_index * 1984, 1984] = result.h0_hashes;
-        *array_ref_mut![self.h1_hashes, group_index * 64, 64] = result.h1_hashes;
-        *array_ref_mut![self.h2_hashes, group_index * 8, 8] = result.h2_hashes;
-        self.h3_hashes[group_index] = result.h3_hash;
+    #[inline]
+    pub fn apply(&self, sector_data: &mut [u8; SECTOR_SIZE], sector: usize) {
+        let (h0_hashes, h1_hashes, h2_hashes) = self.hashes_for_sector(sector);
+        array_ref_mut![sector_data, 0, 0x26C].copy_from_slice(h0_hashes.as_bytes());
+        array_ref_mut![sector_data, 0x280, 0xA0].copy_from_slice(h1_hashes.as_bytes());
+        array_ref_mut![sector_data, 0x340, 0xA0].copy_from_slice(h2_hashes.as_bytes());
     }
 }
 
-pub fn rebuild_hashes(reader: &mut DiscReader) -> Result<()> {
-    const NUM_H0_HASHES: usize = SECTOR_DATA_SIZE / HASHES_SIZE;
+pub const NUM_H0_HASHES: usize = SECTOR_DATA_SIZE / HASHES_SIZE;
 
-    log::info!(
-        "Rebuilding hashes for Wii partition data (using {} threads)",
-        rayon::current_num_threads()
-    );
-
-    let start = Instant::now();
-
-    // Precompute hashes for zeroed sectors.
-    const ZERO_H0_BYTES: &[u8] = &[0u8; HASHES_SIZE];
-    let zero_h0_hash = sha1_hash(ZERO_H0_BYTES);
-
-    let partitions = reader.partitions();
-    let mut hash_tables = Vec::with_capacity(partitions.len());
-    for part in partitions {
-        let part_sectors = part.data_end_sector - part.data_start_sector;
-        let hash_table = HashTable::new(part_sectors);
-        log::debug!(
-            "Rebuilding hashes: {} sectors, {} subgroups, {} groups",
-            hash_table.h1_hashes.len(),
-            hash_table.h2_hashes.len(),
-            hash_table.h3_hashes.len()
-        );
-
-        let group_count = hash_table.h3_hashes.len();
-        let mutex = Arc::new(Mutex::new(hash_table));
-        let partition_options = PartitionOptions { validate_hashes: false };
-        (0..group_count).into_par_iter().try_for_each_with(
-            (reader.open_partition(part.index, &partition_options)?, mutex.clone()),
-            |(stream, mutex), h3_index| -> Result<()> {
-                let mut result = HashResult::new_box_zeroed()?;
-                let mut data_buf = <[u8]>::new_box_zeroed_with_elems(SECTOR_DATA_SIZE)?;
-                let mut h3_hasher = Sha1::new();
-                for h2_index in 0..8 {
-                    let mut h2_hasher = Sha1::new();
-                    for h1_index in 0..8 {
+#[instrument(skip_all)]
+pub fn hash_sector_group(sector_group: &[u8; SECTOR_GROUP_SIZE]) -> Box<GroupHashes> {
+    let mut result = GroupHashes::new_box_zeroed().unwrap();
+    for (h2_index, h2_hash) in result.h2_hashes.iter_mut().enumerate() {
+        let out_h1_hashes = array_ref_mut![result.h1_hashes, h2_index * 8, 8];
+        for (h1_index, h1_hash) in out_h1_hashes.iter_mut().enumerate() {
             let sector = h1_index + h2_index * 8;
-                        let part_sector = sector as u32 + h3_index as u32 * 64;
-                        let mut h1_hasher = Sha1::new();
-                        if part_sector >= part_sectors {
-                            for h0_index in 0..NUM_H0_HASHES {
-                                result.h0_hashes[h0_index + sector * 31] = zero_h0_hash;
-                                h1_hasher.update(zero_h0_hash);
-                            }
+            let out_h0_hashes =
+                array_ref_mut![result.h0_hashes, sector * NUM_H0_HASHES, NUM_H0_HASHES];
+            if array_ref![sector_group, sector * SECTOR_SIZE, 20].iter().any(|&v| v != 0) {
+                // Hash block already present, use it
+                out_h0_hashes.as_mut_bytes().copy_from_slice(array_ref![
+                    sector_group,
+                    sector * SECTOR_SIZE,
+                    0x26C
+                ]);
             } else {
-                            stream
-                                .seek(SeekFrom::Start(part_sector as u64 * SECTOR_DATA_SIZE as u64))
-                                .with_context(|| format!("Seeking to sector {}", part_sector))?;
-                            stream
-                                .read_exact(&mut data_buf)
-                                .with_context(|| format!("Reading sector {}", part_sector))?;
-                            for h0_index in 0..NUM_H0_HASHES {
-                                let h0_hash = sha1_hash(array_ref![
-                                    data_buf,
-                                    h0_index * HASHES_SIZE,
+                for (h0_index, h0_hash) in out_h0_hashes.iter_mut().enumerate() {
+                    *h0_hash = sha1_hash(array_ref![
+                        sector_group,
+                        sector * SECTOR_SIZE + HASHES_SIZE + h0_index * HASHES_SIZE,
                         HASHES_SIZE
                     ]);
-                                result.h0_hashes[h0_index + sector * 31] = h0_hash;
-                                h1_hasher.update(h0_hash);
-                            }
-                        };
-                        let h1_hash = h1_hasher.finalize().into();
-                        result.h1_hashes[sector] = h1_hash;
-                        h2_hasher.update(h1_hash);
-                    }
-                    let h2_hash = h2_hasher.finalize().into();
-                    result.h2_hashes[h2_index] = h2_hash;
-                    h3_hasher.update(h2_hash);
-                }
-                result.h3_hash = h3_hasher.finalize().into();
-                let mut hash_table = mutex.lock().map_err(|_| "Failed to lock mutex")?;
-                hash_table.extend(h3_index, &result);
-                Ok(())
-            },
-        )?;
-
-        let hash_table = Arc::try_unwrap(mutex)
-            .map_err(|_| "Failed to unwrap Arc")?
-            .into_inner()
-            .map_err(|_| "Failed to lock mutex")?;
-        hash_tables.push(hash_table);
-    }
-
-    // Verify against H3 table
-    for (part, hash_table) in reader.partitions.clone().iter().zip(hash_tables.iter()) {
-        log::debug!(
-            "Verifying H3 table for partition {} (count {})",
-            part.index,
-            hash_table.h3_hashes.len()
-        );
-        reader
-            .seek(SeekFrom::Start(
-                part.start_sector as u64 * SECTOR_SIZE as u64 + part.header.h3_table_off(),
-            ))
-            .context("Seeking to H3 table")?;
-        let h3_table: Box<[HashBytes]> =
-            read_box_slice(reader, hash_table.h3_hashes.len()).context("Reading H3 table")?;
-        let mut mismatches = 0;
-        for (idx, (expected_hash, h3_hash)) in
-            h3_table.iter().zip(hash_table.h3_hashes.iter()).enumerate()
-        {
-            if expected_hash != h3_hash {
-                let mut got_bytes = [0u8; 40];
-                let got = base16ct::lower::encode_str(h3_hash, &mut got_bytes).unwrap();
-                let mut expected_bytes = [0u8; 40];
-                let expected =
-                    base16ct::lower::encode_str(expected_hash, &mut expected_bytes).unwrap();
-                log::debug!(
-                    "Partition {} H3 table does not match:\n\tindex {}\n\texpected: {}\n\tgot:      {}",
-                    part.index, idx, expected, got
-                );
-                mismatches += 1;
                 }
             }
-        if mismatches > 0 {
-            log::warn!("Partition {} H3 table has {} hash mismatches", part.index, mismatches);
+            *h1_hash = sha1_hash(out_h0_hashes.as_bytes());
         }
+        *h2_hash = sha1_hash(out_h1_hashes.as_bytes());
     }
-
-    for (part, hash_table) in reader.partitions.iter_mut().zip(hash_tables) {
-        part.hash_table = Some(hash_table);
-    }
-    log::info!("Rebuilt hashes in {:?}", start.elapsed());
-    Ok(())
+    result.h3_hash = sha1_hash(result.h2_hashes.as_bytes());
+    result
 }
 
 /// Hashes a byte slice with SHA-1.
-#[inline]
-pub fn sha1_hash(buf: &[u8]) -> HashBytes { HashBytes::from(Sha1::digest(buf)) }
+#[instrument(skip_all)]
+pub fn sha1_hash(buf: &[u8]) -> HashBytes {
+    #[cfg(feature = "openssl")]
+    {
+        // The one-shot openssl::sha::sha1 ends up being much slower
+        let mut hasher = openssl::sha::Sha1::new();
+        hasher.update(buf);
+        hasher.finish()
+    }
+    #[cfg(not(feature = "openssl"))]
+    {
+        use sha1::Digest;
+        HashBytes::from(sha1::Sha1::digest(buf))
+    }
+}

nod/src/disc/mod.rs

@@ -1,40 +1,54 @@
-//! Disc type related logic (GameCube, Wii)
+//! GameCube/Wii disc format types.
 
-use std::{
-    borrow::Cow,
-    ffi::CStr,
-    fmt::{Debug, Display, Formatter},
-    io,
-    io::{BufRead, Seek},
-    mem::size_of,
-    str::from_utf8,
-};
+use std::{ffi::CStr, str::from_utf8};
 
-use dyn_clone::DynClone;
 use zerocopy::{big_endian::*, FromBytes, Immutable, IntoBytes, KnownLayout};
 
-use crate::{io::MagicBytes, static_assert, Result};
+use crate::{common::MagicBytes, util::static_assert};
 
-pub(crate) mod fst;
+pub(crate) mod direct;
+pub mod fst;
 pub(crate) mod gcn;
 pub(crate) mod hashes;
+pub(crate) mod preloader;
 pub(crate) mod reader;
-pub(crate) mod streams;
-pub(crate) mod wii;
-
-pub use fst::{Fst, Node, NodeKind};
-pub use streams::{FileStream, OwnedFileStream, WindowedStream};
-pub use wii::{ContentMetadata, SignedHeader, Ticket, TicketLimit, TmdHeader, REGION_SIZE};
+pub mod wii;
+pub(crate) mod writer;
 
 /// Size in bytes of a disc sector. (32 KiB)
 pub const SECTOR_SIZE: usize = 0x8000;
 
+/// Size in bytes of a Wii partition sector group. (32 KiB * 64, 2 MiB)
+pub const SECTOR_GROUP_SIZE: usize = SECTOR_SIZE * 64;
+
 /// Magic bytes for Wii discs. Located at offset 0x18.
 pub const WII_MAGIC: MagicBytes = [0x5D, 0x1C, 0x9E, 0xA3];
 
 /// Magic bytes for GameCube discs. Located at offset 0x1C.
 pub const GCN_MAGIC: MagicBytes = [0xC2, 0x33, 0x9F, 0x3D];
 
+/// Size in bytes of the disc header and partition header. (boot.bin)
+pub const BOOT_SIZE: usize = size_of::<DiscHeader>() + size_of::<PartitionHeader>();
+
+/// Size in bytes of the debug and region information. (bi2.bin)
+pub const BI2_SIZE: usize = 0x2000;
+
+/// The size of a single-layer MiniDVD. (1.4 GB)
+///
+/// GameCube games and some third-party Wii discs (Datel) use this format.
+pub const MINI_DVD_SIZE: u64 = 1_459_978_240;
+
+/// The size of a single-layer DVD. (4.7 GB)
+///
+/// The vast majority of Wii games use this format.
+pub const SL_DVD_SIZE: u64 = 4_699_979_776;
+
+/// The size of a dual-layer DVD. (8.5 GB)
+///
+/// A few larger Wii games use this format.
+/// (Super Smash Bros. Brawl, Metroid Prime Trilogy, etc.)
+pub const DL_DVD_SIZE: u64 = 8_511_160_320;
+
 /// Shared GameCube & Wii disc header.
 ///
 /// This header is always at the start of the disc image and within each Wii partition.
@@ -53,7 +67,7 @@ pub struct DiscHeader {
     pub audio_stream_buf_size: u8,
     /// Padding
     _pad1: [u8; 14],
-    /// If this is a Wii disc, this will be 0x5D1C9EA3
+    /// If this is a Wii disc, this will bPartitionKinde 0x5D1C9EA3
     pub wii_magic: MagicBytes,
     /// If this is a GameCube disc, this will be 0xC2339F3D
     pub gcn_magic: MagicBytes,
@@ -112,7 +126,7 @@ pub struct PartitionHeader {
     pub debug_mon_offset: U32,
     /// Debug monitor load address
     pub debug_load_address: U32,
-    /// Padding
+    /// PaddingPartitionKind
     _pad1: [u8; 0x18],
     /// Offset to main DOL (Wii: >> 2)
     pub dol_offset: U32,
@@ -145,6 +159,16 @@ impl PartitionHeader {
         }
     }
 
+    /// Set the offset within the partition to the main DOL.
+    #[inline]
+    pub fn set_dol_offset(&mut self, offset: u64, is_wii: bool) {
+        if is_wii {
+            self.dol_offset.set((offset / 4) as u32);
+        } else {
+            self.dol_offset.set(offset as u32);
+        }
+    }
+
     /// Offset within the partition to the file system table (FST).
     #[inline]
     pub fn fst_offset(&self, is_wii: bool) -> u64 {
@@ -155,6 +179,16 @@ impl PartitionHeader {
         }
     }
 
+    /// Set the offset within the partition to the file system table (FST).
+    #[inline]
+    pub fn set_fst_offset(&mut self, offset: u64, is_wii: bool) {
+        if is_wii {
+            self.fst_offset.set((offset / 4) as u32);
+        } else {
+            self.fst_offset.set(offset as u32);
+        }
+    }
+
     /// Size of the file system table (FST).
     #[inline]
     pub fn fst_size(&self, is_wii: bool) -> u64 {
@@ -165,6 +199,16 @@ impl PartitionHeader {
         }
     }
 
+    /// Set the size of the file system table (FST).
+    #[inline]
+    pub fn set_fst_size(&mut self, size: u64, is_wii: bool) {
+        if is_wii {
+            self.fst_size.set((size / 4) as u32);
+        } else {
+            self.fst_size.set(size as u32);
+        }
+    }
+
     /// Maximum size of the file system table (FST) across multi-disc games.
     #[inline]
     pub fn fst_max_size(&self, is_wii: bool) -> u64 {
@@ -174,6 +218,16 @@ impl PartitionHeader {
             self.fst_max_size.get() as u64
         }
     }
+
+    /// Set the maximum size of the file system table (FST) across multi-disc games.
+    #[inline]
+    pub fn set_fst_max_size(&mut self, size: u64, is_wii: bool) {
+        if is_wii {
+            self.fst_max_size.set((size / 4) as u32);
+        } else {
+            self.fst_max_size.set(size as u32);
+        }
+    }
 }
 
 /// Apploader header.
@@ -231,225 +285,3 @@ pub struct DolHeader {
 }
 
 static_assert!(size_of::<DolHeader>() == 0x100);
-
-/// The kind of disc partition.
-#[derive(Debug, PartialEq, Eq, Copy, Clone)]
-pub enum PartitionKind {
-    /// Data partition.
-    Data,
-    /// Update partition.
-    Update,
-    /// Channel partition.
-    Channel,
-    /// Other partition kind.
-    Other(u32),
-}
-
-impl Display for PartitionKind {
-    #[inline]
-    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
-        match self {
-            Self::Data => write!(f, "Data"),
-            Self::Update => write!(f, "Update"),
-            Self::Channel => write!(f, "Channel"),
-            Self::Other(v) => {
-                let bytes = v.to_be_bytes();
-                write!(f, "Other ({:08X}, {})", v, String::from_utf8_lossy(&bytes))
-            }
-        }
-    }
-}
-
-impl PartitionKind {
-    /// Returns the directory name for the partition kind.
-    #[inline]
-    pub fn dir_name(&self) -> Cow<str> {
-        match self {
-            Self::Data => Cow::Borrowed("DATA"),
-            Self::Update => Cow::Borrowed("UPDATE"),
-            Self::Channel => Cow::Borrowed("CHANNEL"),
-            Self::Other(v) => {
-                let bytes = v.to_be_bytes();
-                Cow::Owned(format!("P-{}", String::from_utf8_lossy(&bytes)))
-            }
-        }
-    }
-}
-
-impl From<u32> for PartitionKind {
-    #[inline]
-    fn from(v: u32) -> Self {
-        match v {
-            0 => Self::Data,
-            1 => Self::Update,
-            2 => Self::Channel,
-            v => Self::Other(v),
-        }
-    }
-}
-
-/// An open disc partition.
-pub trait PartitionBase: DynClone + BufRead + Seek + Send + Sync {
-    /// Reads the partition header and file system table.
-    fn meta(&mut self) -> Result<Box<PartitionMeta>>;
-
-    /// Seeks the partition stream to the specified file system node
-    /// and returns a windowed stream.
-    ///
-    /// # Examples
-    ///
-    /// Basic usage:
-    /// ```no_run
-    /// use std::io::Read;
-    ///
-    /// use nod::{Disc, PartitionKind};
-    ///
-    /// fn main() -> nod::Result<()> {
-    ///     let disc = Disc::new("path/to/file.iso")?;
-    ///     let mut partition = disc.open_partition_kind(PartitionKind::Data)?;
-    ///     let meta = partition.meta()?;
-    ///     let fst = meta.fst()?;
-    ///     if let Some((_, node)) = fst.find("/MP3/Worlds.txt") {
-    ///         let mut s = String::new();
-    ///         partition
-    ///             .open_file(node)
-    ///             .expect("Failed to open file stream")
-    ///             .read_to_string(&mut s)
-    ///             .expect("Failed to read file");
-    ///         println!("{}", s);
-    ///     }
-    ///     Ok(())
-    /// }
-    /// ```
-    fn open_file(&mut self, node: Node) -> io::Result<FileStream>;
-
-    /// Consumes the partition instance and returns a windowed stream.
-    ///
-    /// # Examples
-    ///
-    /// ```no_run
-    /// use std::io::Read;
-    ///
-    /// use nod::{Disc, PartitionKind, OwnedFileStream};
-    ///
-    /// fn main() -> nod::Result<()> {
-    ///     let disc = Disc::new("path/to/file.iso")?;
-    ///     let mut partition = disc.open_partition_kind(PartitionKind::Data)?;
-    ///     let meta = partition.meta()?;
-    ///     let fst = meta.fst()?;
-    ///     if let Some((_, node)) = fst.find("/disc.tgc") {
-    ///         let file: OwnedFileStream = partition
-    ///             .clone() // Clone the Box<dyn PartitionBase>
-    ///             .into_open_file(node) // Get an OwnedFileStream
-    ///             .expect("Failed to open file stream");
-    ///         // Open the inner disc image using the owned stream
-    ///         let inner_disc = Disc::new_stream(Box::new(file))
-    ///             .expect("Failed to open inner disc");
-    ///         // ...
-    ///     }
-    ///     Ok(())
-    /// }
-    /// ```
-    fn into_open_file(self: Box<Self>, node: Node) -> io::Result<OwnedFileStream>;
-}
-
-dyn_clone::clone_trait_object!(PartitionBase);
-
-/// Size of the disc header and partition header (boot.bin)
-pub const BOOT_SIZE: usize = size_of::<DiscHeader>() + size_of::<PartitionHeader>();
-/// Size of the debug and region information (bi2.bin)
-pub const BI2_SIZE: usize = 0x2000;
-
-/// Extra disc partition data. (DOL, FST, etc.)
-#[derive(Clone, Debug)]
-pub struct PartitionMeta {
-    /// Disc and partition header (boot.bin)
-    pub raw_boot: Box<[u8; BOOT_SIZE]>,
-    /// Debug and region information (bi2.bin)
-    pub raw_bi2: Box<[u8; BI2_SIZE]>,
-    /// Apploader (apploader.bin)
-    pub raw_apploader: Box<[u8]>,
-    /// Main binary (main.dol)
-    pub raw_dol: Box<[u8]>,
-    /// File system table (fst.bin)
-    pub raw_fst: Box<[u8]>,
-    /// Ticket (ticket.bin, Wii only)
-    pub raw_ticket: Option<Box<[u8]>>,
-    /// TMD (tmd.bin, Wii only)
-    pub raw_tmd: Option<Box<[u8]>>,
-    /// Certificate chain (cert.bin, Wii only)
-    pub raw_cert_chain: Option<Box<[u8]>>,
-    /// H3 hash table (h3.bin, Wii only)
-    pub raw_h3_table: Option<Box<[u8]>>,
-}
-
-impl PartitionMeta {
-    /// A view into the disc header.
-    #[inline]
-    pub fn header(&self) -> &DiscHeader {
-        DiscHeader::ref_from_bytes(&self.raw_boot[..size_of::<DiscHeader>()])
-            .expect("Invalid header alignment")
-    }
-
-    /// A view into the partition header.
-    #[inline]
-    pub fn partition_header(&self) -> &PartitionHeader {
-        PartitionHeader::ref_from_bytes(&self.raw_boot[size_of::<DiscHeader>()..])
-            .expect("Invalid partition header alignment")
-    }
-
-    /// A view into the apploader header.
-    #[inline]
-    pub fn apploader_header(&self) -> &ApploaderHeader {
-        ApploaderHeader::ref_from_prefix(&self.raw_apploader)
-            .expect("Invalid apploader alignment")
-            .0
-    }
-
-    /// A view into the file system table (FST).
-    #[inline]
-    pub fn fst(&self) -> Result<Fst, &'static str> { Fst::new(&self.raw_fst) }
-
-    /// A view into the DOL header.
-    #[inline]
-    pub fn dol_header(&self) -> &DolHeader {
-        DolHeader::ref_from_prefix(&self.raw_dol).expect("Invalid DOL alignment").0
-    }
-
-    /// A view into the ticket. (Wii only)
-    #[inline]
-    pub fn ticket(&self) -> Option<&Ticket> {
-        let raw_ticket = self.raw_ticket.as_deref()?;
-        Some(Ticket::ref_from_bytes(raw_ticket).expect("Invalid ticket alignment"))
-    }
-
-    /// A view into the TMD. (Wii only)
-    #[inline]
-    pub fn tmd_header(&self) -> Option<&TmdHeader> {
-        let raw_tmd = self.raw_tmd.as_deref()?;
-        Some(TmdHeader::ref_from_prefix(raw_tmd).expect("Invalid TMD alignment").0)
-    }
-
-    /// A view into the TMD content metadata. (Wii only)
-    #[inline]
-    pub fn content_metadata(&self) -> Option<&[ContentMetadata]> {
-        let raw_cmd = &self.raw_tmd.as_deref()?[size_of::<TmdHeader>()..];
-        Some(<[ContentMetadata]>::ref_from_bytes(raw_cmd).expect("Invalid CMD alignment"))
-    }
-}
-
-/// The size of a single-layer MiniDVD. (1.4 GB)
-///
-/// GameCube games and some third-party Wii discs (Datel) use this format.
-pub const MINI_DVD_SIZE: u64 = 1_459_978_240;
-
-/// The size of a single-layer DVD. (4.7 GB)
-///
-/// The vast majority of Wii games use this format.
-pub const SL_DVD_SIZE: u64 = 4_699_979_776;
-
-/// The size of a dual-layer DVD. (8.5 GB)
-///
-/// A few larger Wii games use this format.
-/// (Super Smash Bros. Brawl, Metroid Prime Trilogy, etc.)
-pub const DL_DVD_SIZE: u64 = 8_511_160_320;

nod/src/disc/preloader.rs

@@ -0,0 +1,558 @@
+use std::{
+    collections::HashMap,
+    io,
+    num::NonZeroUsize,
+    sync::{Arc, Mutex},
+    thread::JoinHandle,
+    time::{Duration, Instant},
+};
+
+use bytes::{Bytes, BytesMut};
+use crossbeam_channel::{Receiver, Sender};
+use crossbeam_utils::sync::WaitGroup;
+use lru::LruCache;
+use simple_moving_average::{SingleSumSMA, SMA};
+use tracing::{debug, error, instrument, span, Level};
+use zerocopy::FromZeros;
+
+use crate::{
+    common::PartitionInfo,
+    disc::{
+        hashes::hash_sector_group, wii::HASHES_SIZE, DiscHeader, SECTOR_GROUP_SIZE, SECTOR_SIZE,
+    },
+    io::{
+        block::{Block, BlockKind, BlockReader},
+        wia::WIAException,
+    },
+    read::PartitionEncryption,
+    util::{
+        aes::{decrypt_sector, encrypt_sector},
+        array_ref_mut,
+    },
+};
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub struct SectorGroupRequest {
+    pub group_idx: u32,
+    pub partition_idx: Option<u8>,
+    pub mode: PartitionEncryption,
+}
+
+#[derive(Clone)]
+pub struct SectorGroup {
+    pub request: SectorGroupRequest,
+    pub data: Bytes,
+    pub sector_bitmap: u64,
+    pub io_duration: Option<Duration>,
+}
+
+impl SectorGroup {
+    /// Calculate the number of consecutive sectors starting from `start`.
+    #[inline]
+    pub fn consecutive_sectors(&self, start: u32) -> u32 {
+        (self.sector_bitmap >> start).trailing_ones()
+    }
+}
+
+pub type SectorGroupResult = io::Result<SectorGroup>;
+
+#[allow(unused)]
+pub struct Preloader {
+    request_tx: Sender<SectorGroupRequest>,
+    request_rx: Receiver<SectorGroupRequest>,
+    stat_tx: Sender<PreloaderThreadStats>,
+    stat_rx: Receiver<PreloaderThreadStats>,
+    threads: Mutex<PreloaderThreads>,
+    cache: Arc<Mutex<PreloaderCache>>,
+    // Fallback single-threaded loader
+    loader: Mutex<SectorGroupLoader>,
+}
+
+#[allow(unused)]
+struct PreloaderThreads {
+    join_handles: Vec<JoinHandle<()>>,
+    last_adjust: Instant,
+    num_samples: usize,
+    wait_time_avg: SingleSumSMA<Duration, u32, 100>,
+    req_time_avg: SingleSumSMA<Duration, u32, 100>,
+    io_time_avg: SingleSumSMA<Duration, u32, 100>,
+}
+
+impl PreloaderThreads {
+    fn new(join_handles: Vec<JoinHandle<()>>) -> Self {
+        Self {
+            join_handles,
+            last_adjust: Instant::now(),
+            num_samples: 0,
+            wait_time_avg: SingleSumSMA::<_, _, 100>::from_zero(Duration::default()),
+            req_time_avg: SingleSumSMA::<_, _, 100>::from_zero(Duration::default()),
+            io_time_avg: SingleSumSMA::<_, _, 100>::from_zero(Duration::default()),
+        }
+    }
+
+    fn push_stats(&mut self, stat: PreloaderThreadStats, _outer: &Preloader) {
+        self.wait_time_avg.add_sample(stat.wait_time);
+        self.req_time_avg.add_sample(stat.req_time);
+        self.io_time_avg.add_sample(stat.io_time);
+        self.num_samples += 1;
+        if self.num_samples % 100 == 0 {
+            let avg_wait = self.wait_time_avg.get_average();
+            let avg_req = self.req_time_avg.get_average();
+            let avg_io = self.io_time_avg.get_average();
+            let utilization =
+                avg_req.as_secs_f64() / (avg_req.as_secs_f64() + avg_wait.as_secs_f64());
+            let io_time = avg_io.as_secs_f64() / avg_req.as_secs_f64();
+            debug!(
+                "Preloader stats: count {}, wait: {:?}, req: {:?}, util: {:.2}%, io: {:.2}%",
+                self.num_samples,
+                avg_wait,
+                avg_req,
+                utilization * 100.0,
+                io_time * 100.0
+            );
+            // if self.last_adjust.elapsed() > Duration::from_secs(2) {
+            //     if utilization > 0.9 && io_time < 0.1 {
+            //         println!("Preloader is CPU-bound, increasing thread count");
+            //         let id = self.join_handles.len();
+            //         self.join_handles.push(preloader_thread(
+            //             id,
+            //             outer.request_rx.clone(),
+            //             outer.cache.clone(),
+            //             outer.loader.lock().unwrap().clone(),
+            //             outer.stat_tx.clone(),
+            //         ));
+            //         self.last_adjust = Instant::now();
+            //     } /*else if io_time > 0.9 {
+            //         println!("Preloader is I/O-bound, decreasing thread count");
+            //         if self.join_handles.len() > 1 {
+            //             let handle = self.join_handles.pop().unwrap();
+            //
+            //         }
+            //     }*/
+            // }
+        }
+    }
+}
+
+struct PreloaderCache {
+    inflight: HashMap<SectorGroupRequest, WaitGroup>,
+    lru_cache: LruCache<SectorGroupRequest, SectorGroup>,
+}
+
+impl Default for PreloaderCache {
+    fn default() -> Self {
+        Self {
+            inflight: Default::default(),
+            lru_cache: LruCache::new(NonZeroUsize::new(64).unwrap()),
+        }
+    }
+}
+
+impl PreloaderCache {
+    fn push(&mut self, request: SectorGroupRequest, group: SectorGroup) {
+        self.lru_cache.push(request, group);
+        self.inflight.remove(&request);
+    }
+
+    fn remove(&mut self, request: &SectorGroupRequest) { self.inflight.remove(request); }
+
+    fn contains(&self, request: &SectorGroupRequest) -> bool {
+        self.lru_cache.contains(request) || self.inflight.contains_key(request)
+    }
+}
+
+#[allow(unused)]
+struct PreloaderThreadStats {
+    thread_id: usize,
+    wait_time: Duration,
+    req_time: Duration,
+    io_time: Duration,
+}
+
+fn preloader_thread(
+    thread_id: usize,
+    request_rx: Receiver<SectorGroupRequest>,
+    cache: Arc<Mutex<PreloaderCache>>,
+    mut loader: SectorGroupLoader,
+    stat_tx: Sender<PreloaderThreadStats>,
+) -> JoinHandle<()> {
+    std::thread::Builder::new()
+        .name(format!("Preloader {thread_id}"))
+        .spawn(move || {
+            let mut last_request_end: Option<Instant> = None;
+            while let Ok(request) = request_rx.recv() {
+                let wait_time = if let Some(last_request) = last_request_end {
+                    last_request.elapsed()
+                } else {
+                    Duration::default()
+                };
+                let start = Instant::now();
+                let mut io_time = Duration::default();
+                match loader.load(request) {
+                    Ok(group) => {
+                        let Ok(mut cache_guard) = cache.lock() else {
+                            break;
+                        };
+                        io_time = group.io_duration.unwrap_or_default();
+                        cache_guard.push(request, group);
+                    }
+                    Err(_) => {
+                        let Ok(mut cache_guard) = cache.lock() else {
+                            break;
+                        };
+                        // Just drop the request if it failed
+                        cache_guard.remove(&request);
+                    }
+                }
+                let end = Instant::now();
+                last_request_end = Some(end);
+                let req_time = end - start;
+                stat_tx
+                    .send(PreloaderThreadStats { thread_id, wait_time, req_time, io_time })
+                    .expect("Failed to send preloader stats");
+            }
+        })
+        .expect("Failed to spawn preloader thread")
+}
+
+impl Preloader {
+    pub fn new(loader: SectorGroupLoader, num_threads: usize) -> Arc<Self> {
+        debug!("Creating preloader with {} threads", num_threads);
+
+        let (request_tx, request_rx) = crossbeam_channel::unbounded();
+        let (stat_tx, stat_rx) = crossbeam_channel::unbounded();
+        let cache = Arc::new(Mutex::new(PreloaderCache::default()));
+        let mut join_handles = Vec::with_capacity(num_threads);
+        for i in 0..num_threads {
+            join_handles.push(preloader_thread(
+                i,
+                request_rx.clone(),
+                cache.clone(),
+                loader.clone(),
+                stat_tx.clone(),
+            ));
+        }
+        let threads = Mutex::new(PreloaderThreads::new(join_handles));
+        let loader = Mutex::new(loader);
+        Arc::new(Self { request_tx, request_rx, stat_tx, stat_rx, threads, cache, loader })
+    }
+
+    #[allow(unused)]
+    pub fn shutdown(self) {
+        let guard = self.threads.into_inner().unwrap();
+        for handle in guard.join_handles {
+            handle.join().unwrap();
+        }
+    }
+
+    #[instrument(name = "Preloader::fetch", skip_all)]
+    pub fn fetch(&self, request: SectorGroupRequest, max_groups: u32) -> SectorGroupResult {
+        let num_threads = {
+            let mut threads_guard = self.threads.lock().map_err(map_poisoned)?;
+            while let Ok(stat) = self.stat_rx.try_recv() {
+                threads_guard.push_stats(stat, self);
+            }
+            threads_guard.join_handles.len()
+        };
+        let mut cache_guard = self.cache.lock().map_err(map_poisoned)?;
+        // Preload n groups ahead
+        for i in 0..num_threads as u32 {
+            let group_idx = request.group_idx + i;
+            if group_idx >= max_groups {
+                break;
+            }
+            let request = SectorGroupRequest { group_idx, ..request };
+            if cache_guard.contains(&request) {
+                continue;
+            }
+            if self.request_tx.send(request).is_ok() {
+                cache_guard.inflight.insert(request, WaitGroup::new());
+            }
+        }
+        if let Some(cached) = cache_guard.lru_cache.get(&request) {
+            return Ok(cached.clone());
+        }
+        if let Some(wg) = cache_guard.inflight.get(&request) {
+            // Wait for inflight request to finish
+            let wg = wg.clone();
+            drop(cache_guard);
+            {
+                let _span = span!(Level::TRACE, "wg.wait").entered();
+                wg.wait();
+            }
+            let mut cache_guard = self.cache.lock().map_err(map_poisoned)?;
+            if let Some(cached) = cache_guard.lru_cache.get(&request) {
+                return Ok(cached.clone());
+            }
+        } else {
+            drop(cache_guard);
+        }
+        // No threads are running, fallback to single-threaded loader
+        let result = {
+            let mut loader = self.loader.lock().map_err(map_poisoned)?;
+            loader.load(request)
+        };
+        match result {
+            Ok(group) => {
+                let mut cache_guard = self.cache.lock().map_err(map_poisoned)?;
+                cache_guard.push(request, group.clone());
+                Ok(group)
+            }
+            Err(e) => Err(e),
+        }
+    }
+}
+
+fn map_poisoned<T>(_: std::sync::PoisonError<T>) -> io::Error {
+    io::Error::new(io::ErrorKind::Other, "Mutex poisoned")
+}
+
+pub struct SectorGroupLoader {
+    io: Box<dyn BlockReader>,
+    disc_header: Arc<DiscHeader>,
+    partitions: Arc<[PartitionInfo]>,
+    block: Block,
+    block_buf: Box<[u8]>,
+}
+
+impl Clone for SectorGroupLoader {
+    fn clone(&self) -> Self {
+        let block_size = self.io.block_size() as usize;
+        Self {
+            io: self.io.clone(),
+            disc_header: self.disc_header.clone(),
+            partitions: self.partitions.clone(),
+            block: Block::default(),
+            block_buf: <[u8]>::new_box_zeroed_with_elems(block_size).unwrap(),
+        }
+    }
+}
+
+impl SectorGroupLoader {
+    pub fn new(
+        io: Box<dyn BlockReader>,
+        disc_header: Arc<DiscHeader>,
+        partitions: Arc<[PartitionInfo]>,
+    ) -> Self {
+        let block_buf = <[u8]>::new_box_zeroed_with_elems(io.block_size() as usize).unwrap();
+        Self { io, disc_header, partitions, block: Block::default(), block_buf }
+    }
+
+    #[instrument(name = "SectorGroupLoader::load", skip_all)]
+    pub fn load(&mut self, request: SectorGroupRequest) -> SectorGroupResult {
+        let mut sector_group_buf = BytesMut::zeroed(SECTOR_GROUP_SIZE);
+
+        let out = array_ref_mut![sector_group_buf, 0, SECTOR_GROUP_SIZE];
+        let (sector_bitmap, io_duration) = if request.partition_idx.is_some() {
+            self.load_partition_group(request, out)?
+        } else {
+            self.load_raw_group(request, out)?
+        };
+
+        Ok(SectorGroup { request, data: sector_group_buf.freeze(), sector_bitmap, io_duration })
+    }
+
+    /// Load a sector group from a partition.
+    ///
+    /// This will handle encryption, decryption, and hash recovery as needed.
+    fn load_partition_group(
+        &mut self,
+        request: SectorGroupRequest,
+        sector_group_buf: &mut [u8; SECTOR_GROUP_SIZE],
+    ) -> io::Result<(u64, Option<Duration>)> {
+        let Some(partition) =
+            request.partition_idx.and_then(|idx| self.partitions.get(idx as usize))
+        else {
+            return Ok((0, None));
+        };
+
+        let abs_group_sector = partition.data_start_sector + request.group_idx * 64;
+        if abs_group_sector >= partition.data_end_sector {
+            return Ok((0, None));
+        }
+
+        // Bitmap of sectors that were read
+        let mut sector_bitmap = 0u64;
+        // Bitmap of sectors that are decrypted
+        let mut decrypted_sectors = 0u64;
+        // Bitmap of sectors that need hash recovery
+        let mut hash_recovery_sectors = 0u64;
+        // Hash exceptions
+        let mut hash_exceptions = Vec::<WIAException>::new();
+        // Total duration of I/O operations
+        let mut io_duration = None;
+
+        // Read sector group
+        for sector in 0..64 {
+            let sector_data =
+                array_ref_mut![sector_group_buf, sector as usize * SECTOR_SIZE, SECTOR_SIZE];
+            let abs_sector = abs_group_sector + sector;
+            if abs_sector >= partition.data_end_sector {
+                // Already zeroed
+                decrypted_sectors |= 1 << sector;
+                hash_recovery_sectors |= 1 << sector;
+                continue;
+            }
+
+            // Read new block
+            if !self.block.contains(abs_sector) {
+                self.block = self.io.read_block(self.block_buf.as_mut(), abs_sector)?;
+                if let Some(duration) = self.block.io_duration {
+                    *io_duration.get_or_insert_with(Duration::default) += duration;
+                }
+                if self.block.kind == BlockKind::None {
+                    error!("Failed to read block for sector {}", abs_sector);
+                    break;
+                }
+            }
+
+            // Add hash exceptions
+            self.block.append_hash_exceptions(abs_sector, sector, &mut hash_exceptions)?;
+
+            // Read new sector into buffer
+            let (encrypted, has_hashes) = self.block.copy_sector(
+                sector_data,
+                self.block_buf.as_mut(),
+                abs_sector,
+                &partition.disc_header,
+                Some(partition),
+            )?;
+            if !encrypted {
+                decrypted_sectors |= 1 << sector;
+            }
+            if !has_hashes && partition.has_hashes {
+                hash_recovery_sectors |= 1 << sector;
+            }
+            sector_bitmap |= 1 << sector;
+        }
+
+        // Recover hashes
+        if request.mode != PartitionEncryption::ForceDecryptedNoHashes && hash_recovery_sectors != 0
+        {
+            // Decrypt any encrypted sectors
+            if decrypted_sectors != u64::MAX {
+                for sector in 0..64 {
+                    let sector_data =
+                        array_ref_mut![sector_group_buf, sector * SECTOR_SIZE, SECTOR_SIZE];
+                    if (decrypted_sectors >> sector) & 1 == 0 {
+                        decrypt_sector(sector_data, &partition.key);
+                    }
+                }
+                decrypted_sectors = u64::MAX;
+            }
+
+            // Recover hashes
+            let group_hashes = hash_sector_group(sector_group_buf);
+
+            // Apply hashes
+            for sector in 0..64 {
+                let sector_data =
+                    array_ref_mut![sector_group_buf, sector * SECTOR_SIZE, SECTOR_SIZE];
+                if (hash_recovery_sectors >> sector) & 1 == 1 {
+                    group_hashes.apply(sector_data, sector);
+                }
+            }
+        }
+
+        // Apply hash exceptions
+        if request.mode != PartitionEncryption::ForceDecryptedNoHashes
+            && !hash_exceptions.is_empty()
+        {
+            for exception in hash_exceptions {
+                let offset = exception.offset.get();
+                let sector = offset / HASHES_SIZE as u16;
+
+                // Decrypt sector if needed
+                let sector_data =
+                    array_ref_mut![sector_group_buf, sector as usize * SECTOR_SIZE, SECTOR_SIZE];
+                if (decrypted_sectors >> sector) & 1 == 0 {
+                    decrypt_sector(sector_data, &partition.key);
+                    decrypted_sectors |= 1 << sector;
+                }
+
+                let sector_offset = (offset - (sector * HASHES_SIZE as u16)) as usize;
+                *array_ref_mut![sector_data, sector_offset, 20] = exception.hash;
+            }
+        }
+
+        // Encrypt/decrypt sectors
+        if match request.mode {
+            PartitionEncryption::Original => partition.has_encryption,
+            PartitionEncryption::ForceEncrypted => true,
+            PartitionEncryption::ForceDecrypted | PartitionEncryption::ForceDecryptedNoHashes => {
+                false
+            }
+        } {
+            // Encrypt any decrypted sectors
+            if decrypted_sectors != 0 {
+                for sector in 0..64 {
+                    let sector_data = array_ref_mut![
+                        sector_group_buf,
+                        sector as usize * SECTOR_SIZE,
+                        SECTOR_SIZE
+                    ];
+                    if (decrypted_sectors >> sector) & 1 == 1 {
+                        encrypt_sector(sector_data, &partition.key);
+                    }
+                }
+            }
+        } else if decrypted_sectors != u64::MAX {
+            // Decrypt any encrypted sectors
+            for sector in 0..64 {
+                let sector_data =
+                    array_ref_mut![sector_group_buf, sector as usize * SECTOR_SIZE, SECTOR_SIZE];
+                if (decrypted_sectors >> sector) & 1 == 0 {
+                    decrypt_sector(sector_data, &partition.key);
+                }
+            }
+        }
+
+        Ok((sector_bitmap, io_duration))
+    }
+
+    /// Loads a non-partition sector group.
+    fn load_raw_group(
+        &mut self,
+        request: SectorGroupRequest,
+        sector_group_buf: &mut [u8; SECTOR_GROUP_SIZE],
+    ) -> io::Result<(u64, Option<Duration>)> {
+        let abs_group_sector = request.group_idx * 64;
+
+        // Bitmap of sectors that were read
+        let mut sector_bitmap = 0u64;
+        // Total duration of I/O operations
+        let mut io_duration = None;
+
+        for sector in 0..64 {
+            let sector_data =
+                array_ref_mut![sector_group_buf, sector as usize * SECTOR_SIZE, SECTOR_SIZE];
+            let abs_sector = abs_group_sector + sector;
+            if self.partitions.iter().any(|p| p.data_contains_sector(abs_sector)) {
+                continue;
+            }
+
+            // Read new block
+            if !self.block.contains(abs_sector) {
+                self.block = self.io.read_block(self.block_buf.as_mut(), abs_sector)?;
+                if let Some(duration) = self.block.io_duration {
+                    *io_duration.get_or_insert_with(Duration::default) += duration;
+                }
+                if self.block.kind == BlockKind::None {
+                    break;
+                }
+            }
+
+            // Read new sector into buffer
+            self.block.copy_sector(
+                sector_data,
+                self.block_buf.as_mut(),
+                abs_sector,
+                self.disc_header.as_ref(),
+                None,
+            )?;
+            sector_bitmap |= 1 << sector;
+        }
+
+        Ok((sector_bitmap, io_duration))
+    }
+}

nod/src/disc/reader.rs

@@ -1,130 +1,163 @@
 use std::{
     io,
-    io::{BufRead, Read, Seek, SeekFrom},
+    io::{BufRead, Seek, SeekFrom},
+    sync::Arc,
 };
 
-use zerocopy::{FromBytes, FromZeros};
+use bytes::Bytes;
+use tracing::warn;
+use zerocopy::IntoBytes;
 
-use super::{
-    gcn::PartitionGC,
-    hashes::{rebuild_hashes, HashTable},
-    wii::{PartitionWii, WiiPartEntry, WiiPartGroup, WiiPartitionHeader, WII_PART_GROUP_OFF},
-    DiscHeader, PartitionBase, PartitionHeader, PartitionKind, DL_DVD_SIZE, MINI_DVD_SIZE,
-    REGION_SIZE, SL_DVD_SIZE,
-};
 use crate::{
-    disc::wii::REGION_OFFSET,
-    io::block::{Block, BlockIO, PartitionInfo},
-    util::read::{read_box, read_from, read_vec},
-    DiscMeta, Error, OpenOptions, PartitionEncryptionMode, PartitionOptions, Result, ResultContext,
-    SECTOR_SIZE,
+    common::{PartitionInfo, PartitionKind},
+    disc::{
+        direct::{DirectDiscReader, DirectDiscReaderMode},
+        fst::{Fst, NodeKind},
+        gcn::{read_fst, PartitionReaderGC},
+        preloader::{Preloader, SectorGroup, SectorGroupLoader, SectorGroupRequest},
+        wii::{
+            PartitionReaderWii, WiiPartEntry, WiiPartGroup, WiiPartitionHeader, REGION_OFFSET,
+            REGION_SIZE, WII_PART_GROUP_OFF,
+        },
+        DiscHeader, DL_DVD_SIZE, MINI_DVD_SIZE, SECTOR_GROUP_SIZE, SECTOR_SIZE, SL_DVD_SIZE,
+    },
+    io::block::BlockReader,
+    read::{DiscMeta, DiscOptions, PartitionEncryption, PartitionOptions, PartitionReader},
+    util::{
+        impl_read_for_bufread,
+        read::{read_arc, read_from, read_vec},
+    },
+    Error, Result, ResultContext,
 };
 
 pub struct DiscReader {
-    io: Box<dyn BlockIO>,
-    block: Block,
-    block_buf: Box<[u8]>,
-    block_idx: u32,
-    sector_buf: Box<[u8; SECTOR_SIZE]>,
-    sector_idx: u32,
+    io: Box<dyn BlockReader>,
     pos: u64,
-    mode: PartitionEncryptionMode,
-    disc_header: Box<DiscHeader>,
-    pub(crate) partitions: Vec<PartitionInfo>,
-    hash_tables: Vec<HashTable>,
+    size: u64,
+    mode: PartitionEncryption,
+    disc_header: Arc<DiscHeader>,
+    partitions: Arc<[PartitionInfo]>,
     region: Option<[u8; REGION_SIZE]>,
+    sector_group: Option<SectorGroup>,
+    preloader: Arc<Preloader>,
+    alt_disc_header: Option<Arc<DiscHeader>>,
+    alt_partitions: Option<Arc<[PartitionInfo]>>,
 }
 
 impl Clone for DiscReader {
     fn clone(&self) -> Self {
         Self {
             io: self.io.clone(),
-            block: Block::default(),
-            block_buf: <[u8]>::new_box_zeroed_with_elems(self.block_buf.len()).unwrap(),
-            block_idx: u32::MAX,
-            sector_buf: <[u8; SECTOR_SIZE]>::new_box_zeroed().unwrap(),
-            sector_idx: u32::MAX,
             pos: 0,
+            size: self.size,
             mode: self.mode,
             disc_header: self.disc_header.clone(),
             partitions: self.partitions.clone(),
-            hash_tables: self.hash_tables.clone(),
             region: self.region,
+            sector_group: None,
+            preloader: self.preloader.clone(),
+            alt_disc_header: self.alt_disc_header.clone(),
+            alt_partitions: self.alt_partitions.clone(),
         }
     }
 }
 
 impl DiscReader {
-    pub fn new(inner: Box<dyn BlockIO>, options: &OpenOptions) -> Result<Self> {
-        let block_size = inner.block_size();
-        let meta = inner.meta();
-        let mut reader = Self {
-            io: inner,
-            block: Block::default(),
-            block_buf: <[u8]>::new_box_zeroed_with_elems(block_size as usize)?,
-            block_idx: u32::MAX,
-            sector_buf: <[u8; SECTOR_SIZE]>::new_box_zeroed()?,
-            sector_idx: u32::MAX,
-            pos: 0,
-            mode: options.partition_encryption,
-            disc_header: DiscHeader::new_box_zeroed()?,
-            partitions: vec![],
-            hash_tables: vec![],
-            region: None,
-        };
-        let disc_header: Box<DiscHeader> = read_box(&mut reader).context("Reading disc header")?;
-        reader.disc_header = disc_header;
-        if reader.disc_header.is_wii() {
-            if reader.disc_header.has_partition_encryption()
-                && !reader.disc_header.has_partition_hashes()
-            {
+    pub fn new(inner: Box<dyn BlockReader>, options: &DiscOptions) -> Result<Self> {
+        let mut reader = DirectDiscReader::new(inner)?;
+
+        let disc_header: Arc<DiscHeader> = read_arc(&mut reader).context("Reading disc header")?;
+        let mut alt_disc_header = None;
+        let mut region = None;
+        let mut partitions = Arc::<[PartitionInfo]>::default();
+        let mut alt_partitions = None;
+        if disc_header.is_wii() {
+            // Sanity check
+            if disc_header.has_partition_encryption() && !disc_header.has_partition_hashes() {
                 return Err(Error::DiscFormat(
                     "Wii disc is encrypted but has no partition hashes".to_string(),
                 ));
             }
-            if !reader.disc_header.has_partition_hashes()
-                && options.partition_encryption == PartitionEncryptionMode::ForceEncrypted
+            if !disc_header.has_partition_hashes()
+                && options.partition_encryption == PartitionEncryption::ForceEncrypted
             {
                 return Err(Error::Other(
                     "Unsupported: Rebuilding encryption for Wii disc without hashes".to_string(),
                 ));
             }
+
+            // Read region info
             reader.seek(SeekFrom::Start(REGION_OFFSET)).context("Seeking to region info")?;
-            reader.region = Some(read_from(&mut reader).context("Reading region info")?);
-            reader.partitions = read_partition_info(&mut reader)?;
-            // Rebuild hashes if the format requires it
-            if options.partition_encryption != PartitionEncryptionMode::AsIs
-                && meta.needs_hash_recovery
-                && reader.disc_header.has_partition_hashes()
-            {
-                rebuild_hashes(&mut reader)?;
+            region = Some(read_from(&mut reader).context("Reading region info")?);
+
+            // Read partition info
+            partitions = Arc::from(read_partition_info(&mut reader, disc_header.clone())?);
+
+            // Update disc header with encryption mode
+            if matches!(
+                options.partition_encryption,
+                PartitionEncryption::ForceDecrypted | PartitionEncryption::ForceEncrypted
+            ) {
+                let mut disc_header = Box::new(disc_header.as_ref().clone());
+                let mut partitions = Box::<[PartitionInfo]>::from(partitions.as_ref());
+                disc_header.no_partition_encryption = match options.partition_encryption {
+                    PartitionEncryption::ForceDecrypted => 1,
+                    PartitionEncryption::ForceEncrypted => 0,
+                    _ => unreachable!(),
+                };
+                for partition in &mut partitions {
+                    partition.has_encryption = disc_header.has_partition_encryption();
                 }
+                alt_disc_header = Some(Arc::from(disc_header));
+                alt_partitions = Some(Arc::from(partitions));
             }
-        reader.reset();
-        Ok(reader)
+        } else if !disc_header.is_gamecube() {
+            return Err(Error::DiscFormat("Invalid disc header".to_string()));
         }
 
-    pub fn reset(&mut self) {
-        self.block = Block::default();
-        self.block_buf.fill(0);
-        self.block_idx = u32::MAX;
-        self.sector_buf.fill(0);
-        self.sector_idx = u32::MAX;
-        self.pos = 0;
-    }
-
-    pub fn disc_size(&self) -> u64 {
-        self.io.meta().disc_size.unwrap_or_else(|| guess_disc_size(&self.partitions))
+        // Calculate disc size
+        let io = reader.into_inner();
+        let size = io.meta().disc_size.unwrap_or_else(|| guess_disc_size(&partitions));
+        let preloader = Preloader::new(
+            SectorGroupLoader::new(io.clone(), disc_header.clone(), partitions.clone()),
+            options.preloader_threads,
+        );
+        Ok(Self {
+            io,
+            pos: 0,
+            size,
+            mode: options.partition_encryption,
+            disc_header,
+            partitions,
+            region,
+            sector_group: None,
+            preloader,
+            alt_disc_header,
+            alt_partitions,
+        })
     }
 
     #[inline]
-    pub fn header(&self) -> &DiscHeader { &self.disc_header }
+    pub fn reset(&mut self) { self.pos = 0; }
+
+    #[inline]
+    pub fn position(&self) -> u64 { self.pos }
+
+    #[inline]
+    pub fn disc_size(&self) -> u64 { self.size }
+
+    #[inline]
+    pub fn header(&self) -> &DiscHeader {
+        self.alt_disc_header.as_ref().unwrap_or(&self.disc_header)
+    }
 
     #[inline]
     pub fn region(&self) -> Option<&[u8; REGION_SIZE]> { self.region.as_ref() }
 
     #[inline]
-    pub fn partitions(&self) -> &[PartitionInfo] { &self.partitions }
+    pub fn partitions(&self) -> &[PartitionInfo] {
+        self.alt_partitions.as_deref().unwrap_or(&self.partitions)
+    }
 
     #[inline]
     pub fn meta(&self) -> DiscMeta { self.io.meta() }
@@ -134,15 +167,19 @@ impl DiscReader {
         &self,
         index: usize,
         options: &PartitionOptions,
-    ) -> Result<Box<dyn PartitionBase>> {
+    ) -> Result<Box<dyn PartitionReader>> {
         if self.disc_header.is_gamecube() {
             if index == 0 {
-                Ok(PartitionGC::new(self.io.clone(), self.disc_header.clone())?)
+                Ok(PartitionReaderGC::new(
+                    self.io.clone(),
+                    self.preloader.clone(),
+                    self.disc_size(),
+                )?)
             } else {
                 Err(Error::DiscFormat("GameCube discs only have one partition".to_string()))
             }
         } else if let Some(part) = self.partitions.get(index) {
-            Ok(PartitionWii::new(self.io.clone(), self.disc_header.clone(), part, options)?)
+            Ok(PartitionReaderWii::new(self.io.clone(), self.preloader.clone(), part, options)?)
         } else {
             Err(Error::DiscFormat(format!("Partition {index} not found")))
         }
@@ -154,108 +191,151 @@ impl DiscReader {
         &self,
         kind: PartitionKind,
         options: &PartitionOptions,
-    ) -> Result<Box<dyn PartitionBase>> {
+    ) -> Result<Box<dyn PartitionReader>> {
         if self.disc_header.is_gamecube() {
             if kind == PartitionKind::Data {
-                Ok(PartitionGC::new(self.io.clone(), self.disc_header.clone())?)
+                Ok(PartitionReaderGC::new(
+                    self.io.clone(),
+                    self.preloader.clone(),
+                    self.disc_size(),
+                )?)
             } else {
                 Err(Error::DiscFormat("GameCube discs only have a data partition".to_string()))
             }
         } else if let Some(part) = self.partitions.iter().find(|v| v.kind == kind) {
-            Ok(PartitionWii::new(self.io.clone(), self.disc_header.clone(), part, options)?)
+            Ok(PartitionReaderWii::new(self.io.clone(), self.preloader.clone(), part, options)?)
         } else {
             Err(Error::DiscFormat(format!("Partition type {kind} not found")))
         }
     }
+
+    pub fn fill_buf_internal(&mut self) -> io::Result<Bytes> {
+        if self.pos >= self.size {
+            return Ok(Bytes::new());
+        }
+
+        // Read from modified disc header
+        if self.pos < size_of::<DiscHeader>() as u64 {
+            if let Some(alt_disc_header) = &self.alt_disc_header {
+                return Ok(Bytes::copy_from_slice(
+                    &alt_disc_header.as_bytes()[self.pos as usize..],
+                ));
+            }
+        }
+
+        // Build sector group request
+        let abs_sector = (self.pos / SECTOR_SIZE as u64) as u32;
+        let (request, abs_group_sector, max_groups) = if let Some(partition) =
+            self.partitions.iter().find(|part| part.data_contains_sector(abs_sector))
+        {
+            let group_idx = (abs_sector - partition.data_start_sector) / 64;
+            let abs_group_sector = partition.data_start_sector + group_idx * 64;
+            let max_groups = (partition.data_end_sector - partition.data_start_sector).div_ceil(64);
+            let request = SectorGroupRequest {
+                group_idx,
+                partition_idx: Some(partition.index as u8),
+                mode: self.mode,
+            };
+            (request, abs_group_sector, max_groups)
+        } else {
+            let group_idx = abs_sector / 64;
+            let abs_group_sector = group_idx * 64;
+            let max_groups = self.size.div_ceil(SECTOR_GROUP_SIZE as u64) as u32;
+            let request = SectorGroupRequest { group_idx, partition_idx: None, mode: self.mode };
+            (request, abs_group_sector, max_groups)
+        };
+
+        // Load sector group
+        let sector_group = if matches!(&self.sector_group, Some(sector_group) if sector_group.request == request)
+        {
+            // We can improve this in Rust 2024 with `if_let_rescope`
+            // https://github.com/rust-lang/rust/issues/124085
+            self.sector_group.as_ref().unwrap()
+        } else {
+            self.sector_group.insert(self.preloader.fetch(request, max_groups)?)
+        };
+
+        // Calculate the number of consecutive sectors in the group
+        let group_sector = abs_sector - abs_group_sector;
+        let consecutive_sectors = sector_group.consecutive_sectors(group_sector);
+        if consecutive_sectors == 0 {
+            return Ok(Bytes::new());
+        }
+        let num_sectors = group_sector + consecutive_sectors;
+
+        // Read from sector group buffer
+        let group_start = abs_group_sector as u64 * SECTOR_SIZE as u64;
+        let offset = (self.pos - group_start) as usize;
+        let end = (num_sectors as u64 * SECTOR_SIZE as u64).min(self.size - group_start) as usize;
+        Ok(sector_group.data.slice(offset..end))
+    }
 }
 
 impl BufRead for DiscReader {
     fn fill_buf(&mut self) -> io::Result<&[u8]> {
-        let block_idx = (self.pos / self.block_buf.len() as u64) as u32;
+        if self.pos >= self.size {
+            return Ok(&[]);
+        }
+
+        // Read from modified disc header
+        if self.pos < size_of::<DiscHeader>() as u64 {
+            if let Some(alt_disc_header) = &self.alt_disc_header {
+                return Ok(&alt_disc_header.as_bytes()[self.pos as usize..]);
+            }
+        }
+
+        // Build sector group request
         let abs_sector = (self.pos / SECTOR_SIZE as u64) as u32;
-
-        let partition = if self.disc_header.is_wii() {
-            self.partitions.iter().find(|part| {
-                abs_sector >= part.data_start_sector && abs_sector < part.data_end_sector
-            })
-        } else {
-            None
-        };
-
-        // Read new block
-        if block_idx != self.block_idx {
-            self.block = self.io.read_block(self.block_buf.as_mut(), block_idx, partition)?;
-            self.block_idx = block_idx;
-        }
-
-        // Read new sector into buffer
-        if abs_sector != self.sector_idx {
-            match (self.mode, partition, self.disc_header.has_partition_encryption()) {
-                (PartitionEncryptionMode::Original, Some(partition), true)
-                | (PartitionEncryptionMode::ForceEncrypted, Some(partition), _) => {
-                    self.block.encrypt(
-                        self.sector_buf.as_mut(),
-                        self.block_buf.as_ref(),
-                        abs_sector,
-                        partition,
-                    )?;
-                }
-                (PartitionEncryptionMode::ForceDecrypted, Some(partition), _) => {
-                    self.block.decrypt(
-                        self.sector_buf.as_mut(),
-                        self.block_buf.as_ref(),
-                        abs_sector,
-                        partition,
-                    )?;
-                }
-                (PartitionEncryptionMode::AsIs, _, _) | (_, None, _) | (_, _, false) => {
-                    self.block.copy_raw(
-                        self.sector_buf.as_mut(),
-                        self.block_buf.as_ref(),
-                        abs_sector,
-                        &self.disc_header,
-                    )?;
-                }
-            }
-            self.sector_idx = abs_sector;
-
-            if self.sector_idx == 0
-                && self.disc_header.is_wii()
-                && matches!(
-                    self.mode,
-                    PartitionEncryptionMode::ForceDecrypted
-                        | PartitionEncryptionMode::ForceEncrypted
-                )
+        let (request, abs_group_sector, max_groups) = if let Some(partition) =
+            self.partitions.iter().find(|part| part.data_contains_sector(abs_sector))
         {
-                let (disc_header, _) = DiscHeader::mut_from_prefix(self.sector_buf.as_mut())
-                    .expect("Invalid disc header alignment");
-                disc_header.no_partition_encryption = match self.mode {
-                    PartitionEncryptionMode::ForceDecrypted => 1,
-                    PartitionEncryptionMode::ForceEncrypted => 0,
-                    _ => unreachable!(),
+            let group_idx = (abs_sector - partition.data_start_sector) / 64;
+            let abs_group_sector = partition.data_start_sector + group_idx * 64;
+            let max_groups = (partition.data_end_sector - partition.data_start_sector).div_ceil(64);
+            let request = SectorGroupRequest {
+                group_idx,
+                partition_idx: Some(partition.index as u8),
+                mode: self.mode,
+            };
+            (request, abs_group_sector, max_groups)
+        } else {
+            let group_idx = abs_sector / 64;
+            let abs_group_sector = group_idx * 64;
+            let max_groups = self.size.div_ceil(SECTOR_GROUP_SIZE as u64) as u32;
+            let request = SectorGroupRequest { group_idx, partition_idx: None, mode: self.mode };
+            (request, abs_group_sector, max_groups)
         };
-            }
-        }
 
-        // Read from sector buffer
-        let offset = (self.pos % SECTOR_SIZE as u64) as usize;
-        Ok(&self.sector_buf[offset..])
+        // Load sector group
+        let sector_group = if matches!(&self.sector_group, Some(sector_group) if sector_group.request == request)
+        {
+            // We can improve this in Rust 2024 with `if_let_rescope`
+            // https://github.com/rust-lang/rust/issues/124085
+            self.sector_group.as_ref().unwrap()
+        } else {
+            self.sector_group.insert(self.preloader.fetch(request, max_groups)?)
+        };
+
+        // Calculate the number of consecutive sectors in the group
+        let group_sector = abs_sector - abs_group_sector;
+        let consecutive_sectors = sector_group.consecutive_sectors(group_sector);
+        if consecutive_sectors == 0 {
+            return Ok(&[]);
+        }
+        let num_sectors = group_sector + consecutive_sectors;
+
+        // Read from sector group buffer
+        let group_start = abs_group_sector as u64 * SECTOR_SIZE as u64;
+        let offset = (self.pos - group_start) as usize;
+        let end = (num_sectors as u64 * SECTOR_SIZE as u64).min(self.size - group_start) as usize;
+        Ok(&sector_group.data[offset..end])
     }
 
     #[inline]
     fn consume(&mut self, amt: usize) { self.pos += amt as u64; }
 }
 
-impl Read for DiscReader {
-    #[inline]
-    fn read(&mut self, out: &mut [u8]) -> io::Result<usize> {
-        let buf = self.fill_buf()?;
-        let len = buf.len().min(out.len());
-        out[..len].copy_from_slice(&buf[..len]);
-        self.consume(len);
-        Ok(len)
-    }
-}
+impl_read_for_bufread!(DiscReader);
 
 impl Seek for DiscReader {
     fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
@@ -273,7 +353,10 @@ impl Seek for DiscReader {
     }
 }
 
-fn read_partition_info(reader: &mut DiscReader) -> Result<Vec<PartitionInfo>> {
+fn read_partition_info(
+    reader: &mut DirectDiscReader,
+    disc_header: Arc<DiscHeader>,
+) -> Result<Vec<PartitionInfo>> {
     reader.seek(SeekFrom::Start(WII_PART_GROUP_OFF)).context("Seeking to partition groups")?;
     let part_groups: [WiiPartGroup; 4] = read_from(reader).context("Reading partition groups")?;
     let mut part_info = Vec::new();
@@ -292,7 +375,7 @@ fn read_partition_info(reader: &mut DiscReader) -> Result<Vec<PartitionInfo>> {
             reader
                 .seek(SeekFrom::Start(offset))
                 .with_context(|| format!("Seeking to partition data {group_idx}:{part_idx}"))?;
-            let header: Box<WiiPartitionHeader> = read_box(reader)
+            let header: Arc<WiiPartitionHeader> = read_arc(reader)
                 .with_context(|| format!("Reading partition header {group_idx}:{part_idx}"))?;
 
             let key = header.ticket.decrypt_title_key()?;
@@ -303,17 +386,8 @@ fn read_partition_info(reader: &mut DiscReader) -> Result<Vec<PartitionInfo>> {
                 )));
             }
 
-            let disc_header = reader.header();
             let data_start_offset = entry.offset() + header.data_off();
-            let mut data_size = header.data_size();
-            if data_size == 0 {
-                // Read until next partition or end of disc
-                // TODO: handle multiple partition groups
-                data_size = entries
-                    .get(part_idx + 1)
-                    .map(|part| part.offset() - data_start_offset)
-                    .unwrap_or(reader.disc_size() - data_start_offset);
-            }
+            let data_size = header.data_size();
             let data_end_offset = data_start_offset + data_size;
             if data_start_offset % SECTOR_SIZE as u64 != 0
                 || data_end_offset % SECTOR_SIZE as u64 != 0
@@ -322,32 +396,58 @@ fn read_partition_info(reader: &mut DiscReader) -> Result<Vec<PartitionInfo>> {
                     "Partition {group_idx}:{part_idx} data is not sector aligned",
                 )));
             }
-            let mut info = PartitionInfo {
+            let start_sector = (start_offset / SECTOR_SIZE as u64) as u32;
+            let data_start_sector = (data_start_offset / SECTOR_SIZE as u64) as u32;
+            let mut data_end_sector = (data_end_offset / SECTOR_SIZE as u64) as u32;
+
+            reader.reset(DirectDiscReaderMode::Partition {
+                disc_header: disc_header.clone(),
+                data_start_sector,
+                key,
+            });
+            let partition_disc_header: Arc<DiscHeader> =
+                read_arc(reader).context("Reading partition disc header")?;
+            let partition_header = read_arc(reader).context("Reading partition header")?;
+            if partition_disc_header.is_wii() {
+                let raw_fst = read_fst(reader, &partition_header, true)?;
+                let fst = Fst::new(&raw_fst)?;
+                let max_fst_offset = fst
+                    .nodes
+                    .iter()
+                    .filter_map(|n| match n.kind() {
+                        NodeKind::File => Some(n.offset(true) + n.length() as u64),
+                        _ => None,
+                    })
+                    .max()
+                    .unwrap_or(0);
+                if max_fst_offset > data_size {
+                    if data_size == 0 {
+                        // Guess data size for decrypted partitions
+                        data_end_sector = max_fst_offset.div_ceil(SECTOR_SIZE as u64) as u32;
+                    } else {
+                        return Err(Error::DiscFormat(format!(
+                            "Partition {group_idx}:{part_idx} FST exceeds data size",
+                        )));
+                    }
+                }
+            } else {
+                warn!("Partition {group_idx}:{part_idx} is not valid");
+            }
+            reader.reset(DirectDiscReaderMode::Raw);
+
+            part_info.push(PartitionInfo {
                 index: part_info.len(),
                 kind: entry.kind.get().into(),
-                start_sector: (start_offset / SECTOR_SIZE as u64) as u32,
-                data_start_sector: (data_start_offset / SECTOR_SIZE as u64) as u32,
-                data_end_sector: (data_end_offset / SECTOR_SIZE as u64) as u32,
+                start_sector,
+                data_start_sector,
+                data_end_sector,
                 key,
                 header,
-                disc_header: DiscHeader::new_box_zeroed()?,
-                partition_header: PartitionHeader::new_box_zeroed()?,
-                hash_table: None,
+                disc_header: partition_disc_header,
+                partition_header,
                 has_encryption: disc_header.has_partition_encryption(),
                 has_hashes: disc_header.has_partition_hashes(),
-            };
-
-            let mut partition_reader = PartitionWii::new(
-                reader.io.clone(),
-                reader.disc_header.clone(),
-                &info,
-                &PartitionOptions { validate_hashes: false },
-            )?;
-            info.disc_header = read_box(&mut partition_reader).context("Reading disc header")?;
-            info.partition_header =
-                read_box(&mut partition_reader).context("Reading partition header")?;
-
-            part_info.push(info);
+            });
         }
     }
     Ok(part_info)
@@ -356,18 +456,9 @@ fn read_partition_info(reader: &mut DiscReader) -> Result<Vec<PartitionInfo>> {
 fn guess_disc_size(part_info: &[PartitionInfo]) -> u64 {
     let max_offset = part_info
         .iter()
-        .flat_map(|v| {
-            let offset = v.start_sector as u64 * SECTOR_SIZE as u64;
-            [
-                offset + v.header.tmd_off() + v.header.tmd_size(),
-                offset + v.header.cert_chain_off() + v.header.cert_chain_size(),
-                offset + v.header.h3_table_off() + v.header.h3_table_size(),
-                offset + v.header.data_off() + v.header.data_size(),
-            ]
-        })
+        .map(|v| v.data_end_sector as u64 * SECTOR_SIZE as u64)
         .max()
         .unwrap_or(0x50000);
-    // TODO add FST offsets (decrypted partitions)
     if max_offset <= MINI_DVD_SIZE && !part_info.iter().any(|v| v.kind == PartitionKind::Data) {
         // Datel disc
         MINI_DVD_SIZE

nod/src/disc/streams.rs

@@ -1,101 +0,0 @@
-//! Partition file read stream.
-
-use std::{
-    io,
-    io::{BufRead, Read, Seek, SeekFrom},
-};
-
-use super::PartitionBase;
-
-/// A file read stream borrowing a [`PartitionBase`].
-pub type FileStream<'a> = WindowedStream<&'a mut dyn PartitionBase>;
-
-/// A file read stream owning a [`PartitionBase`].
-pub type OwnedFileStream = WindowedStream<Box<dyn PartitionBase>>;
-
-/// A read stream with a fixed window.
-#[derive(Clone)]
-pub struct WindowedStream<T>
-where T: BufRead + Seek
-{
-    base: T,
-    pos: u64,
-    begin: u64,
-    end: u64,
-}
-
-impl<T> WindowedStream<T>
-where T: BufRead + Seek
-{
-    /// Creates a new windowed stream with offset and size.
-    ///
-    /// Seeks underlying stream immediately.
-    #[inline]
-    pub fn new(mut base: T, offset: u64, size: u64) -> io::Result<Self> {
-        base.seek(SeekFrom::Start(offset))?;
-        Ok(Self { base, pos: offset, begin: offset, end: offset + size })
-    }
-
-    /// Returns the length of the window.
-    #[inline]
-    #[allow(clippy::len_without_is_empty)]
-    pub fn len(&self) -> u64 { self.end - self.begin }
-}
-
-impl<T> Read for WindowedStream<T>
-where T: BufRead + Seek
-{
-    #[inline]
-    fn read(&mut self, out: &mut [u8]) -> io::Result<usize> {
-        let buf = self.fill_buf()?;
-        let len = buf.len().min(out.len());
-        out[..len].copy_from_slice(&buf[..len]);
-        self.consume(len);
-        Ok(len)
-    }
-}
-
-impl<T> BufRead for WindowedStream<T>
-where T: BufRead + Seek
-{
-    #[inline]
-    fn fill_buf(&mut self) -> io::Result<&[u8]> {
-        let limit = self.end.saturating_sub(self.pos);
-        if limit == 0 {
-            return Ok(&[]);
-        }
-        let buf = self.base.fill_buf()?;
-        let max = (buf.len() as u64).min(limit) as usize;
-        Ok(&buf[..max])
-    }
-
-    #[inline]
-    fn consume(&mut self, amt: usize) {
-        self.base.consume(amt);
-        self.pos += amt as u64;
-    }
-}
-
-impl<T> Seek for WindowedStream<T>
-where T: BufRead + Seek
-{
-    #[inline]
-    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
-        let mut pos = match pos {
-            SeekFrom::Start(p) => self.begin + p,
-            SeekFrom::End(p) => self.end.saturating_add_signed(p),
-            SeekFrom::Current(p) => self.pos.saturating_add_signed(p),
-        };
-        if pos < self.begin {
-            pos = self.begin;
-        } else if pos > self.end {
-            pos = self.end;
-        }
-        let result = self.base.seek(SeekFrom::Start(pos))?;
-        self.pos = result;
-        Ok(result - self.begin)
-    }
-
-    #[inline]
-    fn stream_position(&mut self) -> io::Result<u64> { Ok(self.pos) }
-}

nod/src/disc/wii.rs

@@ -1,46 +1,53 @@
+//! Wii disc types.
+
 use std::{
     ffi::CStr,
     io,
-    io::{BufRead, Read, Seek, SeekFrom},
+    io::{BufRead, Seek, SeekFrom},
     mem::size_of,
+    sync::Arc,
 };
 
-use sha1::{Digest, Sha1};
-use zerocopy::{big_endian::*, FromBytes, FromZeros, Immutable, IntoBytes, KnownLayout};
+use zerocopy::{big_endian::*, FromBytes, Immutable, IntoBytes, KnownLayout};
 
-use super::{
-    gcn::{read_part_meta, PartitionGC},
-    DiscHeader, FileStream, Node, PartitionBase, PartitionMeta, SECTOR_SIZE,
-};
 use crate::{
-    array_ref,
-    disc::streams::OwnedFileStream,
-    io::{
-        aes_cbc_decrypt,
-        block::{Block, BlockIO, PartitionInfo},
-        HashBytes, KeyBytes,
+    common::{HashBytes, KeyBytes, PartitionInfo},
+    disc::{
+        gcn::{read_part_meta, PartitionReaderGC},
+        hashes::sha1_hash,
+        preloader::{Preloader, SectorGroup, SectorGroupRequest},
+        SECTOR_GROUP_SIZE, SECTOR_SIZE,
     },
+    io::block::BlockReader,
+    read::{PartitionEncryption, PartitionMeta, PartitionOptions, PartitionReader},
+    util::{
+        aes::aes_cbc_decrypt,
+        array_ref, div_rem, impl_read_for_bufread,
+        read::{read_arc, read_arc_slice},
         static_assert,
-    util::{div_rem, read::read_box_slice},
-    Error, PartitionOptions, Result, ResultContext,
+    },
+    Error, Result, ResultContext,
 };
 
 /// Size in bytes of the hashes block in a Wii disc sector
-pub(crate) const HASHES_SIZE: usize = 0x400;
+pub const HASHES_SIZE: usize = 0x400;
 
 /// Size in bytes of the data block in a Wii disc sector (excluding hashes)
-pub(crate) const SECTOR_DATA_SIZE: usize = SECTOR_SIZE - HASHES_SIZE; // 0x7C00
+pub const SECTOR_DATA_SIZE: usize = SECTOR_SIZE - HASHES_SIZE; // 0x7C00
 
-/// Size of the disc region info (region.bin)
+/// Size in bytes of the disc region info (region.bin)
 pub const REGION_SIZE: usize = 0x20;
 
+/// Size in bytes of the H3 table (h3.bin)
+pub const H3_TABLE_SIZE: usize = 0x18000;
+
 /// Offset of the disc region info
 pub const REGION_OFFSET: u64 = 0x4E000;
 
 // ppki (Retail)
-const RVL_CERT_ISSUER_PPKI_TICKET: &str = "Root-CA00000001-XS00000003";
+pub(crate) const RVL_CERT_ISSUER_PPKI_TICKET: &str = "Root-CA00000001-XS00000003";
 #[rustfmt::skip]
-const RETAIL_COMMON_KEYS: [KeyBytes; 3] = [
+pub(crate) const RETAIL_COMMON_KEYS: [KeyBytes; 3] = [
     /* RVL_KEY_RETAIL */
     [0xeb, 0xe4, 0x2a, 0x22, 0x5e, 0x85, 0x93, 0xe4, 0x48, 0xd9, 0xc5, 0x45, 0x73, 0x81, 0xaa, 0xf7],
     /* RVL_KEY_KOREAN */
@@ -50,9 +57,9 @@ const RETAIL_COMMON_KEYS: [KeyBytes; 3] = [
 ];
 
 // dpki (Debug)
-const RVL_CERT_ISSUER_DPKI_TICKET: &str = "Root-CA00000002-XS00000006";
+pub(crate) const RVL_CERT_ISSUER_DPKI_TICKET: &str = "Root-CA00000002-XS00000006";
 #[rustfmt::skip]
-const DEBUG_COMMON_KEYS: [KeyBytes; 3] = [
+pub(crate) const DEBUG_COMMON_KEYS: [KeyBytes; 3] = [
     /* RVL_KEY_DEBUG */
     [0xa1, 0x60, 0x4a, 0x6a, 0x71, 0x23, 0xb5, 0x29, 0xae, 0x8b, 0xec, 0x32, 0xc8, 0x16, 0xfc, 0xaa],
     /* RVL_KEY_KOREAN_DEBUG */
@@ -159,7 +166,6 @@ static_assert!(size_of::<Ticket>() == 0x2A4);
 
 impl Ticket {
     /// Decrypts the ticket title key using the appropriate common key
-    #[allow(clippy::missing_inline_in_public_items)]
     pub fn decrypt_title_key(&self) -> Result<KeyBytes> {
         let mut iv: KeyBytes = [0; 16];
         iv[..8].copy_from_slice(&self.title_id);
@@ -249,11 +255,11 @@ pub struct ContentMetadata {
 
 static_assert!(size_of::<ContentMetadata>() == 0x24);
 
-pub const H3_TABLE_SIZE: usize = 0x18000;
-
+/// Wii partition header.
 #[derive(Debug, Clone, PartialEq, FromBytes, IntoBytes, Immutable, KnownLayout)]
 #[repr(C, align(4))]
 pub struct WiiPartitionHeader {
+    /// Ticket
     pub ticket: Ticket,
     tmd_size: U32,
     tmd_off: U32,
@@ -267,172 +273,146 @@ pub struct WiiPartitionHeader {
 static_assert!(size_of::<WiiPartitionHeader>() == 0x2C0);
 
 impl WiiPartitionHeader {
+    /// TMD size in bytes
     pub fn tmd_size(&self) -> u64 { self.tmd_size.get() as u64 }
 
+    /// TMD offset in bytes (relative to the partition start)
     pub fn tmd_off(&self) -> u64 { (self.tmd_off.get() as u64) << 2 }
 
+    /// Certificate chain size in bytes
     pub fn cert_chain_size(&self) -> u64 { self.cert_chain_size.get() as u64 }
 
+    /// Certificate chain offset in bytes (relative to the partition start)
     pub fn cert_chain_off(&self) -> u64 { (self.cert_chain_off.get() as u64) << 2 }
 
+    /// H3 table offset in bytes (relative to the partition start)
     pub fn h3_table_off(&self) -> u64 { (self.h3_table_off.get() as u64) << 2 }
 
+    /// H3 table size in bytes (always H3_TABLE_SIZE)
     pub fn h3_table_size(&self) -> u64 { H3_TABLE_SIZE as u64 }
 
+    /// Data offset in bytes (relative to the partition start)
     pub fn data_off(&self) -> u64 { (self.data_off.get() as u64) << 2 }
 
+    /// Data size in bytes
     pub fn data_size(&self) -> u64 { (self.data_size.get() as u64) << 2 }
 }
 
-pub struct PartitionWii {
-    io: Box<dyn BlockIO>,
+pub(crate) struct PartitionReaderWii {
+    io: Box<dyn BlockReader>,
+    preloader: Arc<Preloader>,
     partition: PartitionInfo,
-    block: Block,
-    block_buf: Box<[u8]>,
-    block_idx: u32,
-    sector_buf: Box<[u8; SECTOR_SIZE]>,
-    sector: u32,
     pos: u64,
     options: PartitionOptions,
-    raw_tmd: Option<Box<[u8]>>,
-    raw_cert_chain: Option<Box<[u8]>>,
-    raw_h3_table: Option<Box<[u8]>>,
+    sector_group: Option<SectorGroup>,
+    meta: Option<PartitionMeta>,
 }
 
-impl Clone for PartitionWii {
+impl Clone for PartitionReaderWii {
     fn clone(&self) -> Self {
         Self {
             io: self.io.clone(),
+            preloader: self.preloader.clone(),
             partition: self.partition.clone(),
-            block: Block::default(),
-            block_buf: <[u8]>::new_box_zeroed_with_elems(self.block_buf.len()).unwrap(),
-            block_idx: u32::MAX,
-            sector_buf: <[u8; SECTOR_SIZE]>::new_box_zeroed().unwrap(),
-            sector: u32::MAX,
             pos: 0,
             options: self.options.clone(),
-            raw_tmd: self.raw_tmd.clone(),
-            raw_cert_chain: self.raw_cert_chain.clone(),
-            raw_h3_table: self.raw_h3_table.clone(),
+            sector_group: None,
+            meta: self.meta.clone(),
         }
     }
 }
 
-impl PartitionWii {
+impl PartitionReaderWii {
     pub fn new(
-        inner: Box<dyn BlockIO>,
-        disc_header: Box<DiscHeader>,
+        io: Box<dyn BlockReader>,
+        preloader: Arc<Preloader>,
         partition: &PartitionInfo,
         options: &PartitionOptions,
     ) -> Result<Box<Self>> {
-        let block_size = inner.block_size();
-        let mut reader = PartitionGC::new(inner, disc_header)?;
-
-        // Read TMD, cert chain, and H3 table
-        let offset = partition.start_sector as u64 * SECTOR_SIZE as u64;
-        let raw_tmd = if partition.header.tmd_size() != 0 {
-            reader
-                .seek(SeekFrom::Start(offset + partition.header.tmd_off()))
-                .context("Seeking to TMD offset")?;
-            Some(
-                read_box_slice::<u8, _>(&mut reader, partition.header.tmd_size() as usize)
-                    .context("Reading TMD")?,
-            )
-        } else {
-            None
-        };
-        let raw_cert_chain = if partition.header.cert_chain_size() != 0 {
-            reader
-                .seek(SeekFrom::Start(offset + partition.header.cert_chain_off()))
-                .context("Seeking to cert chain offset")?;
-            Some(
-                read_box_slice::<u8, _>(&mut reader, partition.header.cert_chain_size() as usize)
-                    .context("Reading cert chain")?,
-            )
-        } else {
-            None
-        };
-        let raw_h3_table = if partition.has_hashes {
-            reader
-                .seek(SeekFrom::Start(offset + partition.header.h3_table_off()))
-                .context("Seeking to H3 table offset")?;
-            Some(read_box_slice::<u8, _>(&mut reader, H3_TABLE_SIZE).context("Reading H3 table")?)
-        } else {
-            None
-        };
-
-        Ok(Box::new(Self {
-            io: reader.into_inner(),
+        let mut reader = Self {
+            io,
+            preloader,
             partition: partition.clone(),
-            block: Block::default(),
-            block_buf: <[u8]>::new_box_zeroed_with_elems(block_size as usize)?,
-            block_idx: u32::MAX,
-            sector_buf: <[u8; SECTOR_SIZE]>::new_box_zeroed()?,
-            sector: u32::MAX,
             pos: 0,
             options: options.clone(),
-            raw_tmd,
-            raw_cert_chain,
-            raw_h3_table,
-        }))
+            sector_group: None,
+            meta: None,
+        };
+        if options.validate_hashes {
+            // Ensure we cache the H3 table
+            reader.meta()?;
         }
+        Ok(Box::new(reader))
+    }
+
+    #[inline]
+    pub fn len(&self) -> u64 { self.partition.data_size() }
 }
 
-impl BufRead for PartitionWii {
+impl BufRead for PartitionReaderWii {
     fn fill_buf(&mut self) -> io::Result<&[u8]> {
-        let part_sector = if self.partition.has_hashes {
-            (self.pos / SECTOR_DATA_SIZE as u64) as u32
+        let (part_sector, sector_offset) = if self.partition.has_hashes {
+            (
+                (self.pos / SECTOR_DATA_SIZE as u64) as u32,
+                (self.pos % SECTOR_DATA_SIZE as u64) as usize,
+            )
         } else {
-            (self.pos / SECTOR_SIZE as u64) as u32
+            ((self.pos / SECTOR_SIZE as u64) as u32, (self.pos % SECTOR_SIZE as u64) as usize)
         };
         let abs_sector = self.partition.data_start_sector + part_sector;
         if abs_sector >= self.partition.data_end_sector {
             return Ok(&[]);
         }
 
-        // Read new block if necessary
-        let block_idx =
-            (abs_sector as u64 * SECTOR_SIZE as u64 / self.block_buf.len() as u64) as u32;
-        if block_idx != self.block_idx {
-            self.block = self.io.read_block(
-                self.block_buf.as_mut(),
-                block_idx,
-                self.partition.has_encryption.then_some(&self.partition),
-            )?;
-            self.block_idx = block_idx;
-        }
+        let group_idx = part_sector / 64;
+        let group_sector = part_sector % 64;
 
-        // Decrypt sector if necessary
-        if abs_sector != self.sector {
-            if self.partition.has_encryption {
-                self.block.decrypt(
-                    self.sector_buf.as_mut(),
-                    self.block_buf.as_ref(),
-                    abs_sector,
-                    &self.partition,
-                )?;
+        let max_groups =
+            (self.partition.data_end_sector - self.partition.data_start_sector).div_ceil(64);
+        let request = SectorGroupRequest {
+            group_idx,
+            partition_idx: Some(self.partition.index as u8),
+            mode: if self.options.validate_hashes {
+                PartitionEncryption::ForceDecrypted
             } else {
-                self.block.copy_raw(
-                    self.sector_buf.as_mut(),
-                    self.block_buf.as_ref(),
-                    abs_sector,
-                    &self.partition.disc_header,
-                )?;
-            }
+                PartitionEncryption::ForceDecryptedNoHashes
+            },
+        };
+        let sector_group = if matches!(&self.sector_group, Some(sector_group) if sector_group.request == request)
+        {
+            // We can improve this in Rust 2024 with `if_let_rescope`
+            // https://github.com/rust-lang/rust/issues/124085
+            self.sector_group.as_ref().unwrap()
+        } else {
+            let sector_group = self.preloader.fetch(request, max_groups)?;
             if self.options.validate_hashes {
-                if let Some(h3_table) = self.raw_h3_table.as_deref() {
-                    verify_hashes(self.sector_buf.as_ref(), part_sector, h3_table)?;
+                if let Some(h3_table) = self.meta.as_ref().and_then(|m| m.raw_h3_table.as_deref()) {
+                    verify_hashes(
+                        array_ref![sector_group.data, 0, SECTOR_GROUP_SIZE],
+                        group_idx,
+                        h3_table,
+                    )?;
                 }
             }
-            self.sector = abs_sector;
-        }
+            self.sector_group.insert(sector_group)
+        };
 
+        // Read from sector group buffer
+        let consecutive_sectors = sector_group.consecutive_sectors(group_sector);
+        if consecutive_sectors == 0 {
+            return Ok(&[]);
+        }
+        let group_sector_offset = group_sector as usize * SECTOR_SIZE;
         if self.partition.has_hashes {
-            let offset = (self.pos % SECTOR_DATA_SIZE as u64) as usize;
-            Ok(&self.sector_buf[HASHES_SIZE + offset..])
+            // Read until end of sector (avoid the next hash block)
+            let offset = group_sector_offset + HASHES_SIZE + sector_offset;
+            let end = group_sector_offset + SECTOR_SIZE;
+            Ok(&sector_group.data[offset..end])
         } else {
-            let offset = (self.pos % SECTOR_SIZE as u64) as usize;
-            Ok(&self.sector_buf[offset..])
+            // Read until end of sector group (no hashes)
+            let offset = group_sector_offset + sector_offset;
+            let end = (group_sector + consecutive_sectors) as usize * SECTOR_SIZE;
+            Ok(&sector_group.data[offset..end])
         }
     }
 
@@ -440,133 +420,130 @@ impl BufRead for PartitionWii {
     fn consume(&mut self, amt: usize) { self.pos += amt as u64; }
 }
 
-impl Read for PartitionWii {
-    #[inline]
-    fn read(&mut self, out: &mut [u8]) -> io::Result<usize> {
-        let buf = self.fill_buf()?;
-        let len = buf.len().min(out.len());
-        out[..len].copy_from_slice(&buf[..len]);
-        self.consume(len);
-        Ok(len)
-    }
-}
+impl_read_for_bufread!(PartitionReaderWii);
 
-impl Seek for PartitionWii {
+impl Seek for PartitionReaderWii {
     fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
         self.pos = match pos {
             SeekFrom::Start(v) => v,
-            SeekFrom::End(_) => {
-                return Err(io::Error::new(
-                    io::ErrorKind::Unsupported,
-                    "WiiPartitionReader: SeekFrom::End is not supported".to_string(),
-                ));
-            }
+            SeekFrom::End(v) => self.len().saturating_add_signed(v),
             SeekFrom::Current(v) => self.pos.saturating_add_signed(v),
         };
         Ok(self.pos)
     }
+
+    fn stream_position(&mut self) -> io::Result<u64> { Ok(self.pos) }
 }
 
-#[inline(always)]
-pub(crate) fn as_digest(slice: &[u8; 20]) -> digest::Output<Sha1> { (*slice).into() }
-
-fn verify_hashes(buf: &[u8; SECTOR_SIZE], part_sector: u32, h3_table: &[u8]) -> io::Result<()> {
+fn verify_hashes(buf: &[u8; SECTOR_GROUP_SIZE], group_idx: u32, h3_table: &[u8]) -> io::Result<()> {
+    for sector in 0..64 {
+        let buf = array_ref![buf, sector * SECTOR_SIZE, SECTOR_SIZE];
+        let part_sector = group_idx * 64 + sector as u32;
         let (cluster, sector) = div_rem(part_sector as usize, 8);
         let (group, sub_group) = div_rem(cluster, 8);
 
         // H0 hashes
         for i in 0..31 {
-        let mut hash = Sha1::new();
-        hash.update(array_ref![buf, (i + 1) * 0x400, 0x400]);
-        let expected = as_digest(array_ref![buf, i * 20, 20]);
-        let output = hash.finalize();
-        if output != expected {
+            let expected = array_ref![buf, i * 20, 20];
+            let output = sha1_hash(array_ref![buf, (i + 1) * 0x400, 0x400]);
+            if output != *expected {
                 return Err(io::Error::new(
                     io::ErrorKind::InvalidData,
-                format!("Invalid H0 hash! (block {:?}) {:x}\n\texpected {:x}", i, output, expected),
+                    format!("Invalid H0 hash! (block {i})"),
                 ));
             }
         }
 
         // H1 hash
         {
-        let mut hash = Sha1::new();
-        hash.update(array_ref![buf, 0, 0x26C]);
-        let expected = as_digest(array_ref![buf, 0x280 + sector * 20, 20]);
-        let output = hash.finalize();
-        if output != expected {
+            let expected = array_ref![buf, 0x280 + sector * 20, 20];
+            let output = sha1_hash(array_ref![buf, 0, 0x26C]);
+            if output != *expected {
                 return Err(io::Error::new(
                     io::ErrorKind::InvalidData,
-                format!(
-                    "Invalid H1 hash! (subgroup {:?}) {:x}\n\texpected {:x}",
-                    sector, output, expected
-                ),
+                    format!("Invalid H1 hash! (sector {sector})",),
                 ));
             }
         }
 
         // H2 hash
         {
-        let mut hash = Sha1::new();
-        hash.update(array_ref![buf, 0x280, 0xA0]);
-        let expected = as_digest(array_ref![buf, 0x340 + sub_group * 20, 20]);
-        let output = hash.finalize();
-        if output != expected {
+            let expected = array_ref![buf, 0x340 + sub_group * 20, 20];
+            let output = sha1_hash(array_ref![buf, 0x280, 0xA0]);
+            if output != *expected {
                 return Err(io::Error::new(
                     io::ErrorKind::InvalidData,
-                format!(
-                    "Invalid H2 hash! (group {:?}) {:x}\n\texpected {:x}",
-                    sub_group, output, expected
-                ),
+                    format!("Invalid H2 hash! (subgroup {sub_group})"),
                 ));
             }
         }
 
         // H3 hash
         {
-        let mut hash = Sha1::new();
-        hash.update(array_ref![buf, 0x340, 0xA0]);
-        let expected = as_digest(array_ref![h3_table, group * 20, 20]);
-        let output = hash.finalize();
-        if output != expected {
+            let expected = array_ref![h3_table, group * 20, 20];
+            let output = sha1_hash(array_ref![buf, 0x340, 0xA0]);
+            if output != *expected {
                 return Err(io::Error::new(
                     io::ErrorKind::InvalidData,
-                format!("Invalid H3 hash! {:x}\n\texpected {:x}", output, expected),
+                    format!("Invalid H3 hash! (group {group})"),
                 ));
             }
         }
+    }
 
     Ok(())
 }
 
-impl PartitionBase for PartitionWii {
-    fn meta(&mut self) -> Result<Box<PartitionMeta>> {
+impl PartitionReader for PartitionReaderWii {
+    fn is_wii(&self) -> bool { true }
+
+    fn meta(&mut self) -> Result<PartitionMeta> {
+        if let Some(meta) = &self.meta {
+            return Ok(meta.clone());
+        }
         self.seek(SeekFrom::Start(0)).context("Seeking to partition header")?;
         let mut meta = read_part_meta(self, true)?;
-        meta.raw_ticket = Some(Box::from(self.partition.header.ticket.as_bytes()));
-        meta.raw_tmd = self.raw_tmd.clone();
-        meta.raw_cert_chain = self.raw_cert_chain.clone();
-        meta.raw_h3_table = self.raw_h3_table.clone();
+        meta.raw_ticket = Some(Arc::from(self.partition.header.ticket.as_bytes()));
+
+        // Read TMD, cert chain, and H3 table
+        let mut reader = PartitionReaderGC::new(self.io.clone(), self.preloader.clone(), u64::MAX)?;
+        let offset = self.partition.start_sector as u64 * SECTOR_SIZE as u64;
+        meta.raw_tmd = if self.partition.header.tmd_size() != 0 {
+            reader
+                .seek(SeekFrom::Start(offset + self.partition.header.tmd_off()))
+                .context("Seeking to TMD offset")?;
+            Some(
+                read_arc_slice::<u8, _>(&mut reader, self.partition.header.tmd_size() as usize)
+                    .context("Reading TMD")?,
+            )
+        } else {
+            None
+        };
+        meta.raw_cert_chain = if self.partition.header.cert_chain_size() != 0 {
+            reader
+                .seek(SeekFrom::Start(offset + self.partition.header.cert_chain_off()))
+                .context("Seeking to cert chain offset")?;
+            Some(
+                read_arc_slice::<u8, _>(
+                    &mut reader,
+                    self.partition.header.cert_chain_size() as usize,
+                )
+                .context("Reading cert chain")?,
+            )
+        } else {
+            None
+        };
+        meta.raw_h3_table = if self.partition.has_hashes {
+            reader
+                .seek(SeekFrom::Start(offset + self.partition.header.h3_table_off()))
+                .context("Seeking to H3 table offset")?;
+
+            Some(read_arc::<[u8; H3_TABLE_SIZE], _>(&mut reader).context("Reading H3 table")?)
+        } else {
+            None
+        };
+
+        self.meta = Some(meta.clone());
         Ok(meta)
     }
-
-    fn open_file(&mut self, node: Node) -> io::Result<FileStream> {
-        if !node.is_file() {
-            return Err(io::Error::new(
-                io::ErrorKind::InvalidInput,
-                "Node is not a file".to_string(),
-            ));
-        }
-        FileStream::new(self, node.offset(true), node.length())
-    }
-
-    fn into_open_file(self: Box<Self>, node: Node) -> io::Result<OwnedFileStream> {
-        if !node.is_file() {
-            return Err(io::Error::new(
-                io::ErrorKind::InvalidInput,
-                "Node is not a file".to_string(),
-            ));
-        }
-        OwnedFileStream::new(self, node.offset(true), node.length())
-    }
 }

nod/src/disc/writer.rs

@@ -0,0 +1,273 @@
+use std::{
+    io,
+    io::{BufRead, Read},
+};
+
+use bytes::{Bytes, BytesMut};
+use dyn_clone::DynClone;
+use rayon::prelude::*;
+
+use crate::{
+    common::PartitionInfo,
+    disc::{
+        reader::DiscReader,
+        wii::{HASHES_SIZE, SECTOR_DATA_SIZE},
+        SECTOR_SIZE,
+    },
+    util::{aes::decrypt_sector_b2b, array_ref, array_ref_mut, lfg::LaggedFibonacci},
+    write::{DiscFinalization, DiscWriterWeight, ProcessOptions},
+    Error, Result, ResultContext,
+};
+
+/// A callback for writing disc data.
+///
+/// The callback should write all data to the output stream before returning, or return an error if
+/// writing fails. The second and third arguments are the current bytes processed and the total
+/// bytes to process, respectively. For most formats, this has no relation to the written disc size,
+/// but can be used to display progress.
+pub type DataCallback<'a> = dyn FnMut(Bytes, u64, u64) -> io::Result<()> + Send + 'a;
+
+/// A trait for writing disc images.
+pub trait DiscWriter: DynClone {
+    /// Processes the disc writer to completion.
+    ///
+    /// The data callback will be called, in order, for each block of data to write to the output
+    /// file. The callback should write all data before returning, or return an error if writing
+    /// fails.
+    fn process(
+        &self,
+        data_callback: &mut DataCallback,
+        options: &ProcessOptions,
+    ) -> Result<DiscFinalization>;
+
+    /// Returns the progress upper bound for the disc writer.
+    ///
+    /// For most formats, this has no relation to the written disc size, but can be used to display
+    /// progress.
+    fn progress_bound(&self) -> u64;
+
+    /// Returns the weight of the disc writer.
+    ///
+    /// This can help determine the number of threads to dedicate for output processing, and may
+    /// differ based on the format's configuration, such as whether compression is enabled.
+    fn weight(&self) -> DiscWriterWeight;
+}
+
+dyn_clone::clone_trait_object!(DiscWriter);
+
+#[derive(Default)]
+pub struct BlockResult<T> {
+    /// Input block index
+    pub block_idx: u32,
+    /// Input disc data (before processing)
+    pub disc_data: Bytes,
+    /// Output block data (after processing). If None, the disc data is used.
+    pub block_data: Bytes,
+    /// Output metadata
+    pub meta: T,
+}
+
+pub trait BlockProcessor: Clone + Send + Sync {
+    type BlockMeta;
+
+    fn process_block(&mut self, block_idx: u32) -> io::Result<BlockResult<Self::BlockMeta>>;
+}
+
+pub fn read_block(reader: &mut DiscReader, block_size: usize) -> io::Result<(Bytes, Bytes)> {
+    let initial_block = reader.fill_buf_internal()?;
+    if initial_block.len() >= block_size {
+        // Happy path: we have a full block that we can cheaply slice
+        let data = initial_block.slice(0..block_size);
+        reader.consume(block_size);
+        return Ok((data.clone(), data));
+    } else if initial_block.is_empty() {
+        return Err(io::Error::from(io::ErrorKind::UnexpectedEof));
+    }
+    reader.consume(initial_block.len());
+
+    // Combine smaller blocks into a new buffer
+    let mut buf = BytesMut::zeroed(block_size);
+    let mut len = initial_block.len();
+    buf[..len].copy_from_slice(initial_block.as_ref());
+    drop(initial_block);
+    while len < block_size {
+        let read = reader.read(&mut buf[len..])?;
+        if read == 0 {
+            break;
+        }
+        len += read;
+    }
+    // The block data is full size, padded with zeroes
+    let block_data = buf.freeze();
+    // The disc data is the actual data read, without padding
+    let disc_data = block_data.slice(0..len);
+    Ok((block_data, disc_data))
+}
+
+/// Process blocks in parallel, ensuring that they are written in order.
+pub(crate) fn par_process<P, T>(
+    create_processor: impl Fn() -> P + Sync,
+    block_count: u32,
+    num_threads: usize,
+    mut callback: impl FnMut(BlockResult<T>) -> Result<()> + Send,
+) -> Result<()>
+where
+    T: Send,
+    P: BlockProcessor<BlockMeta = T>,
+{
+    if num_threads == 0 {
+        // Fall back to single-threaded processing
+        let mut processor = create_processor();
+        for block_idx in 0..block_count {
+            let block = processor
+                .process_block(block_idx)
+                .with_context(|| format!("Failed to process block {block_idx}"))?;
+            callback(block)?;
+        }
+        return Ok(());
+    }
+
+    let (block_tx, block_rx) = crossbeam_channel::bounded(block_count as usize);
+    for block_idx in 0..block_count {
+        block_tx.send(block_idx).unwrap();
+    }
+    drop(block_tx); // Disconnect channel
+
+    let (result_tx, result_rx) = crossbeam_channel::bounded(0);
+    let mut process_error = None;
+    let mut write_error = None;
+    rayon::join(
+        || {
+            if let Err(e) = (0..num_threads).into_par_iter().try_for_each_init(
+                || (block_rx.clone(), result_tx.clone(), create_processor()),
+                |(receiver, block_tx, processor), _| {
+                    while let Ok(block_idx) = receiver.recv() {
+                        let block = processor
+                            .process_block(block_idx)
+                            .with_context(|| format!("Failed to process block {block_idx}"))?;
+                        if block_tx.send(block).is_err() {
+                            break;
+                        }
+                    }
+                    Ok::<_, Error>(())
+                },
+            ) {
+                process_error = Some(e);
+            }
+            drop(result_tx); // Disconnect channel
+        },
+        || {
+            let mut current_block = 0;
+            let mut out_of_order = Vec::<BlockResult<T>>::new();
+            'outer: while let Ok(result) = result_rx.recv() {
+                if result.block_idx == current_block {
+                    if let Err(e) = callback(result) {
+                        write_error = Some(e);
+                        break;
+                    }
+                    current_block += 1;
+                    // Check if any out of order blocks can be written
+                    while out_of_order.first().is_some_and(|r| r.block_idx == current_block) {
+                        let result = out_of_order.remove(0);
+                        if let Err(e) = callback(result) {
+                            write_error = Some(e);
+                            break 'outer;
+                        }
+                        current_block += 1;
+                    }
+                } else {
+                    out_of_order.push(result);
+                    out_of_order.sort_unstable_by_key(|r| r.block_idx);
+                }
+            }
+        },
+    );
+    if let Some(e) = process_error {
+        return Err(e);
+    }
+    if let Some(e) = write_error {
+        return Err(e);
+    }
+
+    Ok(())
+}
+
+/// The determined block type.
+pub enum CheckBlockResult {
+    Normal,
+    Zeroed,
+    Junk,
+}
+
+/// Check if a block is zeroed or junk data.
+pub(crate) fn check_block(
+    buf: &[u8],
+    decrypted_block: &mut [u8],
+    input_position: u64,
+    partition_info: &[PartitionInfo],
+    lfg: &mut LaggedFibonacci,
+    disc_id: [u8; 4],
+    disc_num: u8,
+) -> io::Result<CheckBlockResult> {
+    let start_sector = (input_position / SECTOR_SIZE as u64) as u32;
+    let end_sector = ((input_position + buf.len() as u64) / SECTOR_SIZE as u64) as u32;
+    if let Some(partition) = partition_info.iter().find(|p| {
+        p.has_hashes && start_sector >= p.data_start_sector && end_sector < p.data_end_sector
+    }) {
+        if input_position % SECTOR_SIZE as u64 != 0 {
+            return Err(io::Error::new(
+                io::ErrorKind::Other,
+                "Partition block not aligned to sector boundary",
+            ));
+        }
+        if buf.len() % SECTOR_SIZE != 0 {
+            return Err(io::Error::new(
+                io::ErrorKind::Other,
+                "Partition block not a multiple of sector size",
+            ));
+        }
+        let block = if partition.has_encryption {
+            if decrypted_block.len() < buf.len() {
+                return Err(io::Error::new(
+                    io::ErrorKind::Other,
+                    "Decrypted block buffer too small",
+                ));
+            }
+            for i in 0..buf.len() / SECTOR_SIZE {
+                decrypt_sector_b2b(
+                    array_ref![buf, SECTOR_SIZE * i, SECTOR_SIZE],
+                    array_ref_mut![decrypted_block, SECTOR_SIZE * i, SECTOR_SIZE],
+                    &partition.key,
+                );
+            }
+            &decrypted_block[..buf.len()]
+        } else {
+            buf
+        };
+        if sector_data_iter(block).all(|sector_data| sector_data.iter().all(|&b| b == 0)) {
+            return Ok(CheckBlockResult::Zeroed);
+        }
+        let partition_start = partition.data_start_sector as u64 * SECTOR_SIZE as u64;
+        let partition_offset =
+            ((input_position - partition_start) / SECTOR_SIZE as u64) * SECTOR_DATA_SIZE as u64;
+        if sector_data_iter(block).enumerate().all(|(i, sector_data)| {
+            let sector_offset = partition_offset + i as u64 * SECTOR_DATA_SIZE as u64;
+            lfg.check_sector_chunked(sector_data, disc_id, disc_num, sector_offset)
+        }) {
+            return Ok(CheckBlockResult::Junk);
+        }
+    } else {
+        if buf.iter().all(|&b| b == 0) {
+            return Ok(CheckBlockResult::Zeroed);
+        }
+        if lfg.check_sector_chunked(buf, disc_id, disc_num, input_position) {
+            return Ok(CheckBlockResult::Junk);
+        }
+    }
+    Ok(CheckBlockResult::Normal)
+}
+
+#[inline]
+fn sector_data_iter(buf: &[u8]) -> impl Iterator<Item = &[u8; SECTOR_DATA_SIZE]> {
+    buf.chunks_exact(SECTOR_SIZE).map(|chunk| (&chunk[HASHES_SIZE..]).try_into().unwrap())
+}

nod/src/io/block.rs

@@ -1,106 +1,45 @@
-use std::{
-    fs, io,
-    io::{Read, Seek},
-    path::Path,
-};
+use std::{fs, io, io::Read, path::Path};
 
 use dyn_clone::DynClone;
-use zerocopy::transmute_ref;
 
 use crate::{
-    array_ref,
+    common::{Format, KeyBytes, MagicBytes, PartitionInfo},
     disc::{
-        hashes::HashTable,
-        wii::{WiiPartitionHeader, HASHES_SIZE, SECTOR_DATA_SIZE},
-        DiscHeader, PartitionHeader, PartitionKind, GCN_MAGIC, SECTOR_SIZE, WII_MAGIC,
+        wii::{HASHES_SIZE, SECTOR_DATA_SIZE},
+        DiscHeader, GCN_MAGIC, SECTOR_SIZE, WII_MAGIC,
     },
     io::{
-        aes_cbc_decrypt, aes_cbc_encrypt, split::SplitFileReader, DiscMeta, Format, KeyBytes,
-        MagicBytes,
+        split::SplitFileReader,
+        wia::{WIAException, WIAExceptionList},
     },
-    util::{lfg::LaggedFibonacci, read::read_from},
+    read::{DiscMeta, DiscStream},
+    util::{aes::decrypt_sector, array_ref, array_ref_mut, lfg::LaggedFibonacci, read::read_from},
     Error, Result, ResultContext,
 };
 
-/// Required trait bounds for reading disc images.
-pub trait DiscStream: Read + Seek + DynClone + Send + Sync {}
-
-impl<T> DiscStream for T where T: Read + Seek + DynClone + Send + Sync + ?Sized {}
-
-dyn_clone::clone_trait_object!(DiscStream);
-
-/// Block I/O trait for reading disc images.
-pub trait BlockIO: DynClone + Send + Sync {
-    /// Reads a block from the disc image.
-    fn read_block_internal(
-        &mut self,
-        out: &mut [u8],
-        block: u32,
-        partition: Option<&PartitionInfo>,
-    ) -> io::Result<Block>;
-
-    /// Reads a full block from the disc image, combining smaller blocks if necessary.
-    fn read_block(
-        &mut self,
-        out: &mut [u8],
-        block: u32,
-        partition: Option<&PartitionInfo>,
-    ) -> io::Result<Block> {
-        let block_size_internal = self.block_size_internal();
-        let block_size = self.block_size();
-        if block_size_internal == block_size {
-            self.read_block_internal(out, block, partition)
-        } else {
-            let mut offset = 0usize;
-            let mut result = None;
-            let mut block_idx =
-                ((block as u64 * block_size as u64) / block_size_internal as u64) as u32;
-            while offset < block_size as usize {
-                let block = self.read_block_internal(
-                    &mut out[offset..offset + block_size_internal as usize],
-                    block_idx,
-                    partition,
-                )?;
-                if result.is_none() {
-                    result = Some(block);
-                } else if result != Some(block) {
-                    if block == Block::Zero {
-                        out[offset..offset + block_size_internal as usize].fill(0);
-                    } else {
-                        return Err(io::Error::new(
-                            io::ErrorKind::InvalidData,
-                            "Inconsistent block types in split block",
-                        ));
-                    }
-                }
-                offset += block_size_internal as usize;
-                block_idx += 1;
-            }
-            Ok(result.unwrap_or_default())
-        }
-    }
-
-    /// The format's block size in bytes. Can be smaller than the sector size (0x8000).
-    fn block_size_internal(&self) -> u32;
+/// Block reader trait for reading disc images.
+pub trait BlockReader: DynClone + Send + Sync {
+    /// Reads a block from the disc image containing the specified sector.
+    fn read_block(&mut self, out: &mut [u8], sector: u32) -> io::Result<Block>;
 
     /// The block size used for processing. Must be a multiple of the sector size (0x8000).
-    fn block_size(&self) -> u32 { self.block_size_internal().max(SECTOR_SIZE as u32) }
+    fn block_size(&self) -> u32;
 
     /// Returns extra metadata included in the disc file format, if any.
     fn meta(&self) -> DiscMeta;
 }
 
-dyn_clone::clone_trait_object!(BlockIO);
+dyn_clone::clone_trait_object!(BlockReader);
 
-/// Creates a new [`BlockIO`] instance from a stream.
-pub fn new(mut stream: Box<dyn DiscStream>) -> Result<Box<dyn BlockIO>> {
-    let io: Box<dyn BlockIO> = match detect(stream.as_mut()).context("Detecting file type")? {
-        Some(Format::Iso) => crate::io::iso::DiscIOISO::new(stream)?,
-        Some(Format::Ciso) => crate::io::ciso::DiscIOCISO::new(stream)?,
+/// Creates a new [`BlockReader`] instance from a stream.
+pub fn new(mut stream: Box<dyn DiscStream>) -> Result<Box<dyn BlockReader>> {
+    let io: Box<dyn BlockReader> = match detect(stream.as_mut()).context("Detecting file type")? {
+        Some(Format::Iso) => crate::io::iso::BlockReaderISO::new(stream)?,
+        Some(Format::Ciso) => crate::io::ciso::BlockReaderCISO::new(stream)?,
         Some(Format::Gcz) => {
             #[cfg(feature = "compress-zlib")]
             {
-                crate::io::gcz::DiscIOGCZ::new(stream)?
+                crate::io::gcz::BlockReaderGCZ::new(stream)?
             }
             #[cfg(not(feature = "compress-zlib"))]
             return Err(Error::DiscFormat("GCZ support is disabled".to_string()));
@@ -108,17 +47,17 @@ pub fn new(mut stream: Box<dyn DiscStream>) -> Result<Box<dyn BlockIO>> {
         Some(Format::Nfs) => {
             return Err(Error::DiscFormat("NFS requires a filesystem path".to_string()))
         }
-        Some(Format::Wbfs) => crate::io::wbfs::DiscIOWBFS::new(stream)?,
-        Some(Format::Wia | Format::Rvz) => crate::io::wia::DiscIOWIA::new(stream)?,
-        Some(Format::Tgc) => crate::io::tgc::DiscIOTGC::new(stream)?,
+        Some(Format::Wbfs) => crate::io::wbfs::BlockReaderWBFS::new(stream)?,
+        Some(Format::Wia | Format::Rvz) => crate::io::wia::BlockReaderWIA::new(stream)?,
+        Some(Format::Tgc) => crate::io::tgc::BlockReaderTGC::new(stream)?,
         None => return Err(Error::DiscFormat("Unknown disc format".to_string())),
     };
     check_block_size(io.as_ref())?;
     Ok(io)
 }
 
-/// Creates a new [`BlockIO`] instance from a filesystem path.
-pub fn open(filename: &Path) -> Result<Box<dyn BlockIO>> {
+/// Creates a new [`BlockReader`] instance from a filesystem path.
+pub fn open(filename: &Path) -> Result<Box<dyn BlockReader>> {
     let path_result = fs::canonicalize(filename);
     if let Err(err) = path_result {
         return Err(Error::Io(format!("Failed to open {}", filename.display()), err));
@@ -132,28 +71,28 @@ pub fn open(filename: &Path) -> Result<Box<dyn BlockIO>> {
         return Err(Error::DiscFormat(format!("Input is not a file: {}", filename.display())));
     }
     let mut stream = Box::new(SplitFileReader::new(filename)?);
-    let io: Box<dyn BlockIO> = match detect(stream.as_mut()).context("Detecting file type")? {
-        Some(Format::Iso) => crate::io::iso::DiscIOISO::new(stream)?,
-        Some(Format::Ciso) => crate::io::ciso::DiscIOCISO::new(stream)?,
+    let io: Box<dyn BlockReader> = match detect(stream.as_mut()).context("Detecting file type")? {
+        Some(Format::Iso) => crate::io::iso::BlockReaderISO::new(stream)?,
+        Some(Format::Ciso) => crate::io::ciso::BlockReaderCISO::new(stream)?,
         Some(Format::Gcz) => {
             #[cfg(feature = "compress-zlib")]
             {
-                crate::io::gcz::DiscIOGCZ::new(stream)?
+                crate::io::gcz::BlockReaderGCZ::new(stream)?
             }
             #[cfg(not(feature = "compress-zlib"))]
             return Err(Error::DiscFormat("GCZ support is disabled".to_string()));
         }
         Some(Format::Nfs) => match path.parent() {
             Some(parent) if parent.is_dir() => {
-                crate::io::nfs::DiscIONFS::new(path.parent().unwrap())?
+                crate::io::nfs::BlockReaderNFS::new(path.parent().unwrap())?
             }
             _ => {
                 return Err(Error::DiscFormat("Failed to locate NFS parent directory".to_string()));
             }
         },
-        Some(Format::Tgc) => crate::io::tgc::DiscIOTGC::new(stream)?,
-        Some(Format::Wbfs) => crate::io::wbfs::DiscIOWBFS::new(stream)?,
-        Some(Format::Wia | Format::Rvz) => crate::io::wia::DiscIOWIA::new(stream)?,
+        Some(Format::Tgc) => crate::io::tgc::BlockReaderTGC::new(stream)?,
+        Some(Format::Wbfs) => crate::io::wbfs::BlockReaderWBFS::new(stream)?,
+        Some(Format::Wia | Format::Rvz) => crate::io::wia::BlockReaderWIA::new(stream)?,
         None => return Err(Error::DiscFormat("Unknown disc format".to_string())),
     };
     check_block_size(io.as_ref())?;
@@ -163,7 +102,7 @@ pub fn open(filename: &Path) -> Result<Box<dyn BlockIO>> {
 pub const CISO_MAGIC: MagicBytes = *b"CISO";
 pub const GCZ_MAGIC: MagicBytes = [0x01, 0xC0, 0x0B, 0xB1];
 pub const NFS_MAGIC: MagicBytes = *b"EGGS";
-pub const TGC_MAGIC: MagicBytes = [0xae, 0x0f, 0x38, 0xa2];
+pub const TGC_MAGIC: MagicBytes = [0xAE, 0x0F, 0x38, 0xA2];
 pub const WBFS_MAGIC: MagicBytes = *b"WBFS";
 pub const WIA_MAGIC: MagicBytes = *b"WIA\x01";
 pub const RVZ_MAGIC: MagicBytes = *b"RVZ\x01";
@@ -190,16 +129,7 @@ pub fn detect<R: Read + ?Sized>(stream: &mut R) -> io::Result<Option<Format>> {
     Ok(out)
 }
 
-fn check_block_size(io: &dyn BlockIO) -> Result<()> {
-    if io.block_size_internal() < SECTOR_SIZE as u32
-        && SECTOR_SIZE as u32 % io.block_size_internal() != 0
-    {
-        return Err(Error::DiscFormat(format!(
-            "Sector size {} is not divisible by block size {}",
-            SECTOR_SIZE,
-            io.block_size_internal(),
-        )));
-    }
+fn check_block_size(io: &dyn BlockReader) -> Result<()> {
     if io.block_size() % SECTOR_SIZE as u32 != 0 {
         return Err(Error::DiscFormat(format!(
             "Block size {} is not a multiple of sector size {}",
@@ -210,182 +140,263 @@ fn check_block_size(io: &dyn BlockIO) -> Result<()> {
     Ok(())
 }
 
-/// Wii partition information.
-#[derive(Debug, Clone)]
-pub struct PartitionInfo {
-    /// The partition index.
-    pub index: usize,
-    /// The kind of disc partition.
-    pub kind: PartitionKind,
-    /// The start sector of the partition.
-    pub start_sector: u32,
-    /// The start sector of the partition's data.
-    pub data_start_sector: u32,
-    /// The end sector of the partition's data.
-    pub data_end_sector: u32,
-    /// The AES key for the partition, also known as the "title key".
-    pub key: KeyBytes,
-    /// The Wii partition header.
-    pub header: Box<WiiPartitionHeader>,
-    /// The disc header within the partition.
-    pub disc_header: Box<DiscHeader>,
-    /// The partition header within the partition.
-    pub partition_header: Box<PartitionHeader>,
-    /// The hash table for the partition, if rebuilt.
-    pub hash_table: Option<HashTable>,
-    /// Whether the partition data is encrypted
-    pub has_encryption: bool,
-    /// Whether the partition data hashes are present
-    pub has_hashes: bool,
+/// A block of sectors within a disc image.
+#[derive(Debug, Clone, Default)]
+pub struct Block {
+    /// The starting sector of the block.
+    pub sector: u32,
+    /// The number of sectors in the block.
+    pub count: u32,
+    /// The block kind.
+    pub kind: BlockKind,
+    /// Any hash exceptions for the block.
+    pub hash_exceptions: Box<[WIAExceptionList]>,
+    /// The duration of I/O operations, if available.
+    pub io_duration: Option<std::time::Duration>,
 }
 
-/// The block kind returned by [`BlockIO::read_block`].
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
-pub enum Block {
+impl Block {
+    /// Creates a new block from a block of sectors.
+    #[inline]
+    pub fn new(block_idx: u32, block_size: u32, kind: BlockKind) -> Self {
+        let sectors_per_block = block_size / SECTOR_SIZE as u32;
+        Self {
+            sector: block_idx * sectors_per_block,
+            count: sectors_per_block,
+            kind,
+            hash_exceptions: Default::default(),
+            io_duration: None,
+        }
+    }
+
+    /// Creates a new block from a single sector.
+    #[inline]
+    pub fn sector(sector: u32, kind: BlockKind) -> Self {
+        Self { sector, count: 1, kind, hash_exceptions: Default::default(), io_duration: None }
+    }
+
+    /// Creates a new block from a range of sectors.
+    #[inline]
+    pub fn sectors(sector: u32, count: u32, kind: BlockKind) -> Self {
+        Self { sector, count, kind, hash_exceptions: Default::default(), io_duration: None }
+    }
+
+    /// Returns whether the block contains the specified sector.
+    #[inline]
+    pub fn contains(&self, sector: u32) -> bool {
+        sector >= self.sector && sector < self.sector + self.count
+    }
+
+    /// Returns an error if the block does not contain the specified sector.
+    pub fn ensure_contains(&self, sector: u32) -> io::Result<()> {
+        if !self.contains(sector) {
+            return Err(io::Error::new(
+                io::ErrorKind::Other,
+                format!(
+                    "Sector {} not in block range {}-{}",
+                    sector,
+                    self.sector,
+                    self.sector + self.count
+                ),
+            ));
+        }
+        Ok(())
+    }
+
+    /// Decrypts block data in-place. The decrypted data can be accessed using
+    /// [`partition_data`](Block::partition_data).
+    pub(crate) fn decrypt_block(&self, data: &mut [u8], key: Option<KeyBytes>) -> io::Result<()> {
+        match self.kind {
+            BlockKind::None => {}
+            BlockKind::Raw => {
+                if let Some(key) = key {
+                    for i in 0..self.count as usize {
+                        decrypt_sector(array_ref_mut![data, i * SECTOR_SIZE, SECTOR_SIZE], &key);
+                    }
+                }
+            }
+            BlockKind::PartDecrypted { .. } => {
+                // no-op
+            }
+            BlockKind::Junk => {
+                // unsupported, used for DirectDiscReader
+                data.fill(0);
+            }
+            BlockKind::Zero => data.fill(0),
+        }
+        Ok(())
+    }
+
+    /// Copies a sector's raw data to the output buffer. Returns whether the sector is encrypted
+    /// and whether it has hashes.
+    pub(crate) fn copy_sector(
+        &self,
+        out: &mut [u8; SECTOR_SIZE],
+        data: &[u8],
+        abs_sector: u32,
+        disc_header: &DiscHeader,
+        partition: Option<&PartitionInfo>,
+    ) -> io::Result<(bool, bool)> {
+        let mut encrypted = false;
+        let mut has_hashes = false;
+        match self.kind {
+            BlockKind::None => {}
+            BlockKind::Raw => {
+                *out = *self.sector_buf(data, abs_sector)?;
+                if partition.is_some_and(|p| p.has_encryption) {
+                    encrypted = true;
+                }
+                if partition.is_some_and(|p| p.has_hashes) {
+                    has_hashes = true;
+                }
+            }
+            BlockKind::PartDecrypted { hash_block } => {
+                if hash_block {
+                    *out = *self.sector_buf(data, abs_sector)?;
+                    has_hashes = partition.is_some_and(|p| p.has_hashes);
+                } else {
+                    *array_ref_mut![out, HASHES_SIZE, SECTOR_DATA_SIZE] =
+                        *self.sector_data_buf(data, abs_sector)?;
+                }
+            }
+            BlockKind::Junk => generate_junk_sector(out, abs_sector, partition, disc_header),
+            BlockKind::Zero => out.fill(0),
+        }
+        Ok((encrypted, has_hashes))
+    }
+
+    /// Returns a sector's data from the block buffer.
+    pub(crate) fn sector_buf<'a>(
+        &self,
+        data: &'a [u8],
+        abs_sector: u32,
+    ) -> io::Result<&'a [u8; SECTOR_SIZE]> {
+        self.ensure_contains(abs_sector)?;
+        let block_offset = ((abs_sector - self.sector) * SECTOR_SIZE as u32) as usize;
+        Ok(array_ref!(data, block_offset, SECTOR_SIZE))
+    }
+
+    /// Returns a sector's partition data (excluding hashes) from the block buffer.
+    pub(crate) fn sector_data_buf<'a>(
+        &self,
+        data: &'a [u8],
+        abs_sector: u32,
+    ) -> io::Result<&'a [u8; SECTOR_DATA_SIZE]> {
+        self.ensure_contains(abs_sector)?;
+        let block_offset = ((abs_sector - self.sector) * SECTOR_DATA_SIZE as u32) as usize;
+        Ok(array_ref!(data, block_offset, SECTOR_DATA_SIZE))
+    }
+
+    /// Returns raw data from the block buffer, starting at the specified position.
+    pub(crate) fn data<'a>(&self, data: &'a [u8], pos: u64) -> io::Result<&'a [u8]> {
+        if self.kind == BlockKind::None {
+            return Ok(&[]);
+        }
+        self.ensure_contains((pos / SECTOR_SIZE as u64) as u32)?;
+        let offset = (pos - self.sector as u64 * SECTOR_SIZE as u64) as usize;
+        let end = self.count as usize * SECTOR_SIZE;
+        Ok(&data[offset..end])
+    }
+
+    /// Returns partition data (excluding hashes) from the block buffer, starting at the specified
+    /// position within the partition.
+    ///
+    /// If the block does not contain hashes, this will return the full block data. Otherwise, this
+    /// will return only the corresponding sector's data, ending at the sector boundary, to avoid
+    /// reading into the next sector's hash block.
+    pub(crate) fn partition_data<'a>(
+        &self,
+        data: &'a [u8],
+        pos: u64,
+        data_start_sector: u32,
+        partition_has_hashes: bool,
+    ) -> io::Result<&'a [u8]> {
+        let block_has_hashes = match self.kind {
+            BlockKind::Raw => partition_has_hashes,
+            BlockKind::PartDecrypted { hash_block, .. } => hash_block && partition_has_hashes,
+            BlockKind::Junk | BlockKind::Zero => false,
+            BlockKind::None => return Ok(&[]),
+        };
+        let (part_sector, sector_offset) = if partition_has_hashes {
+            ((pos / SECTOR_DATA_SIZE as u64) as u32, (pos % SECTOR_DATA_SIZE as u64) as usize)
+        } else {
+            ((pos / SECTOR_SIZE as u64) as u32, (pos % SECTOR_SIZE as u64) as usize)
+        };
+        let abs_sector = part_sector + data_start_sector;
+        self.ensure_contains(abs_sector)?;
+        let block_sector = (abs_sector - self.sector) as usize;
+        if block_has_hashes {
+            let offset = block_sector * SECTOR_SIZE + HASHES_SIZE + sector_offset;
+            let end = (block_sector + 1) * SECTOR_SIZE; // end of sector
+            Ok(&data[offset..end])
+        } else if partition_has_hashes {
+            let offset = block_sector * SECTOR_DATA_SIZE + sector_offset;
+            let end = self.count as usize * SECTOR_DATA_SIZE; // end of block
+            Ok(&data[offset..end])
+        } else {
+            let offset = block_sector * SECTOR_SIZE + sector_offset;
+            let end = self.count as usize * SECTOR_SIZE; // end of block
+            Ok(&data[offset..end])
+        }
+    }
+
+    pub(crate) fn append_hash_exceptions(
+        &self,
+        abs_sector: u32,
+        group_sector: u32,
+        out: &mut Vec<WIAException>,
+    ) -> io::Result<()> {
+        self.ensure_contains(abs_sector)?;
+        let block_sector = abs_sector - self.sector;
+        let group = (block_sector / 64) as usize;
+        let base_offset = ((block_sector % 64) as usize * HASHES_SIZE) as u16;
+        let new_base_offset = (group_sector * HASHES_SIZE as u32) as u16;
+        out.extend(self.hash_exceptions.get(group).iter().flat_map(|list| {
+            list.iter().filter_map(|exception| {
+                let offset = exception.offset.get();
+                if offset >= base_offset && offset < base_offset + HASHES_SIZE as u16 {
+                    let new_offset = (offset - base_offset) + new_base_offset;
+                    Some(WIAException { offset: new_offset.into(), hash: exception.hash })
+                } else {
+                    None
+                }
+            })
+        }));
+        Ok(())
+    }
+}
+
+/// The block kind.
+#[derive(Debug, Copy, Clone, PartialEq, Default)]
+pub enum BlockKind {
+    /// Empty block, likely end of disc
+    #[default]
+    None,
     /// Raw data or encrypted Wii partition data
     Raw,
-    /// Encrypted Wii partition data
-    PartEncrypted,
     /// Decrypted Wii partition data
     PartDecrypted {
         /// Whether the sector has its hash block intact
-        has_hashes: bool,
+        hash_block: bool,
     },
     /// Wii partition junk data
     Junk,
     /// All zeroes
-    #[default]
     Zero,
 }
 
-impl Block {
-    /// Decrypts the block's data (if necessary) and writes it to the output buffer.
-    pub(crate) fn decrypt(
-        self,
+/// Generates junk data for a single sector.
+pub fn generate_junk_sector(
     out: &mut [u8; SECTOR_SIZE],
-        data: &[u8],
     abs_sector: u32,
-        partition: &PartitionInfo,
-    ) -> io::Result<()> {
-        let part_sector = abs_sector - partition.data_start_sector;
-        match self {
-            Block::Raw => {
-                out.copy_from_slice(block_sector::<SECTOR_SIZE>(data, abs_sector)?);
-            }
-            Block::PartEncrypted => {
-                out.copy_from_slice(block_sector::<SECTOR_SIZE>(data, abs_sector)?);
-                decrypt_sector(out, partition);
-            }
-            Block::PartDecrypted { has_hashes } => {
-                out.copy_from_slice(block_sector::<SECTOR_SIZE>(data, abs_sector)?);
-                if !has_hashes {
-                    rebuild_hash_block(out, part_sector, partition);
-                }
-            }
-            Block::Junk => {
-                generate_junk(out, part_sector, Some(partition), &partition.disc_header);
-                rebuild_hash_block(out, part_sector, partition);
-            }
-            Block::Zero => {
-                out.fill(0);
-                rebuild_hash_block(out, part_sector, partition);
-            }
-        }
-        Ok(())
-    }
-
-    /// Encrypts the block's data (if necessary) and writes it to the output buffer.
-    pub(crate) fn encrypt(
-        self,
-        out: &mut [u8; SECTOR_SIZE],
-        data: &[u8],
-        abs_sector: u32,
-        partition: &PartitionInfo,
-    ) -> io::Result<()> {
-        let part_sector = abs_sector - partition.data_start_sector;
-        match self {
-            Block::Raw => {
-                out.copy_from_slice(block_sector::<SECTOR_SIZE>(data, abs_sector)?);
-                encrypt_sector(out, partition);
-            }
-            Block::PartEncrypted => {
-                out.copy_from_slice(block_sector::<SECTOR_SIZE>(data, abs_sector)?);
-            }
-            Block::PartDecrypted { has_hashes } => {
-                out.copy_from_slice(block_sector::<SECTOR_SIZE>(data, abs_sector)?);
-                if !has_hashes {
-                    rebuild_hash_block(out, part_sector, partition);
-                }
-                encrypt_sector(out, partition);
-            }
-            Block::Junk => {
-                generate_junk(out, part_sector, Some(partition), &partition.disc_header);
-                rebuild_hash_block(out, part_sector, partition);
-                encrypt_sector(out, partition);
-            }
-            Block::Zero => {
-                out.fill(0);
-                rebuild_hash_block(out, part_sector, partition);
-                encrypt_sector(out, partition);
-            }
-        }
-        Ok(())
-    }
-
-    /// Copies the block's raw data to the output buffer.
-    pub(crate) fn copy_raw(
-        self,
-        out: &mut [u8; SECTOR_SIZE],
-        data: &[u8],
-        abs_sector: u32,
-        disc_header: &DiscHeader,
-    ) -> io::Result<()> {
-        match self {
-            Block::Raw | Block::PartEncrypted | Block::PartDecrypted { .. } => {
-                out.copy_from_slice(block_sector::<SECTOR_SIZE>(data, abs_sector)?);
-            }
-            Block::Junk => generate_junk(out, abs_sector, None, disc_header),
-            Block::Zero => out.fill(0),
-        }
-        Ok(())
-    }
-}
-
-#[inline(always)]
-fn block_sector<const N: usize>(data: &[u8], sector_idx: u32) -> io::Result<&[u8; N]> {
-    if data.len() % N != 0 {
-        return Err(io::Error::new(
-            io::ErrorKind::InvalidData,
-            format!("Expected block size {} to be a multiple of {}", data.len(), N),
-        ));
-    }
-    let rel_sector = sector_idx % (data.len() / N) as u32;
-    let offset = rel_sector as usize * N;
-    data.get(offset..offset + N)
-        .ok_or_else(|| {
-            io::Error::new(
-                io::ErrorKind::InvalidData,
-                format!(
-                    "Sector {} out of range (block size {}, sector size {})",
-                    rel_sector,
-                    data.len(),
-                    N
-                ),
-            )
-        })
-        .map(|v| unsafe { &*(v as *const [u8] as *const [u8; N]) })
-}
-
-fn generate_junk(
-    out: &mut [u8; SECTOR_SIZE],
-    sector: u32,
     partition: Option<&PartitionInfo>,
     disc_header: &DiscHeader,
 ) {
-    let (pos, offset) = if partition.is_some() {
+    let (pos, offset) = if partition.is_some_and(|p| p.has_hashes) {
+        let sector = abs_sector - partition.unwrap().data_start_sector;
         (sector as u64 * SECTOR_DATA_SIZE as u64, HASHES_SIZE)
     } else {
-        (sector as u64 * SECTOR_SIZE as u64, 0)
+        (abs_sector as u64 * SECTOR_SIZE as u64, 0)
     };
     out[..offset].fill(0);
     let mut lfg = LaggedFibonacci::default();
@@ -396,33 +407,3 @@ fn generate_junk(
         pos,
     );
 }
-
-fn rebuild_hash_block(out: &mut [u8; SECTOR_SIZE], part_sector: u32, partition: &PartitionInfo) {
-    let Some(hash_table) = partition.hash_table.as_ref() else {
-        return;
-    };
-    let sector_idx = part_sector as usize;
-    let h0_hashes: &[u8; 0x26C] =
-        transmute_ref!(array_ref![hash_table.h0_hashes, sector_idx * 31, 31]);
-    out[0..0x26C].copy_from_slice(h0_hashes);
-    let h1_hashes: &[u8; 0xA0] =
-        transmute_ref!(array_ref![hash_table.h1_hashes, sector_idx & !7, 8]);
-    out[0x280..0x320].copy_from_slice(h1_hashes);
-    let h2_hashes: &[u8; 0xA0] =
-        transmute_ref!(array_ref![hash_table.h2_hashes, (sector_idx / 8) & !7, 8]);
-    out[0x340..0x3E0].copy_from_slice(h2_hashes);
-}
-
-fn encrypt_sector(out: &mut [u8; SECTOR_SIZE], partition: &PartitionInfo) {
-    aes_cbc_encrypt(&partition.key, &[0u8; 16], &mut out[..HASHES_SIZE]);
-    // Data IV from encrypted hash block
-    let iv = *array_ref![out, 0x3D0, 16];
-    aes_cbc_encrypt(&partition.key, &iv, &mut out[HASHES_SIZE..]);
-}
-
-fn decrypt_sector(out: &mut [u8; SECTOR_SIZE], partition: &PartitionInfo) {
-    // Data IV from encrypted hash block
-    let iv = *array_ref![out, 0x3D0, 16];
-    aes_cbc_decrypt(&partition.key, &[0u8; 16], &mut out[..HASHES_SIZE]);
-    aes_cbc_decrypt(&partition.key, &iv, &mut out[HASHES_SIZE..]);
-}

nod/src/io/ciso.rs

@@ -2,20 +2,36 @@ use std::{
     io,
     io::{Read, Seek, SeekFrom},
     mem::size_of,
+    sync::Arc,
 };
 
-use zerocopy::{little_endian::*, FromBytes, Immutable, IntoBytes, KnownLayout};
+use bytes::{BufMut, Bytes, BytesMut};
+use zerocopy::{little_endian::*, FromBytes, FromZeros, Immutable, IntoBytes, KnownLayout};
 
 use crate::{
-    disc::SECTOR_SIZE,
-    io::{
-        block::{Block, BlockIO, DiscStream, PartitionInfo, CISO_MAGIC},
-        nkit::NKitHeader,
-        Format, MagicBytes,
+    common::{Compression, Format, MagicBytes},
+    disc::{
+        reader::DiscReader,
+        writer::{
+            check_block, par_process, read_block, BlockProcessor, BlockResult, CheckBlockResult,
+            DataCallback, DiscWriter,
         },
+        SECTOR_SIZE,
+    },
+    io::{
+        block::{Block, BlockKind, BlockReader, CISO_MAGIC},
+        nkit::{JunkBits, NKitHeader},
+    },
+    read::{DiscMeta, DiscStream},
+    util::{
+        array_ref,
+        digest::DigestManager,
+        lfg::LaggedFibonacci,
+        read::{box_to_bytes, read_arc},
         static_assert,
-    util::read::read_from,
-    DiscMeta, Error, Result, ResultContext,
+    },
+    write::{DiscFinalization, DiscWriterWeight, FormatOptions, ProcessOptions},
+    Error, Result, ResultContext,
 };
 
 pub const CISO_MAP_SIZE: usize = SECTOR_SIZE - 8;
@@ -32,18 +48,18 @@ struct CISOHeader {
 static_assert!(size_of::<CISOHeader>() == SECTOR_SIZE);
 
 #[derive(Clone)]
-pub struct DiscIOCISO {
+pub struct BlockReaderCISO {
     inner: Box<dyn DiscStream>,
-    header: CISOHeader,
-    block_map: [u16; CISO_MAP_SIZE],
+    header: Arc<CISOHeader>,
+    block_map: Arc<[u16; CISO_MAP_SIZE]>,
     nkit_header: Option<NKitHeader>,
 }
 
-impl DiscIOCISO {
+impl BlockReaderCISO {
     pub fn new(mut inner: Box<dyn DiscStream>) -> Result<Box<Self>> {
         // Read header
         inner.seek(SeekFrom::Start(0)).context("Seeking to start")?;
-        let header: CISOHeader = read_from(inner.as_mut()).context("Reading CISO header")?;
+        let header: Arc<CISOHeader> = read_arc(inner.as_mut()).context("Reading CISO header")?;
         if header.magic != CISO_MAGIC {
             return Err(Error::DiscFormat("Invalid CISO magic".to_string()));
         }
@@ -69,54 +85,47 @@ impl DiscIOCISO {
         }
 
         // Read NKit header if present (after CISO data)
-        let nkit_header = if len > file_size + 4 {
+        let nkit_header = if len > file_size + 12 {
             inner.seek(SeekFrom::Start(file_size)).context("Seeking to NKit header")?;
             NKitHeader::try_read_from(inner.as_mut(), header.block_size.get(), true)
         } else {
             None
         };
 
-        Ok(Box::new(Self { inner, header, block_map, nkit_header }))
+        Ok(Box::new(Self { inner, header, block_map: Arc::new(block_map), nkit_header }))
     }
 }
 
-impl BlockIO for DiscIOCISO {
-    fn read_block_internal(
-        &mut self,
-        out: &mut [u8],
-        block: u32,
-        partition: Option<&PartitionInfo>,
-    ) -> io::Result<Block> {
-        if block >= CISO_MAP_SIZE as u32 {
+impl BlockReader for BlockReaderCISO {
+    fn read_block(&mut self, out: &mut [u8], sector: u32) -> io::Result<Block> {
+        let block_size = self.header.block_size.get();
+        let block_idx = ((sector as u64 * SECTOR_SIZE as u64) / block_size as u64) as u32;
+        if block_idx >= CISO_MAP_SIZE as u32 {
             // Out of bounds
-            return Ok(Block::Zero);
+            return Ok(Block::new(block_idx, block_size, BlockKind::None));
         }
 
         // Find the block in the map
-        let phys_block = self.block_map[block as usize];
+        let phys_block = self.block_map[block_idx as usize];
         if phys_block == u16::MAX {
             // Check if block is junk data
-            if self.nkit_header.as_ref().and_then(|h| h.is_junk_block(block)).unwrap_or(false) {
-                return Ok(Block::Junk);
+            if self.nkit_header.as_ref().and_then(|h| h.is_junk_block(block_idx)).unwrap_or(false) {
+                return Ok(Block::new(block_idx, block_size, BlockKind::Junk));
             };
 
             // Otherwise, read zeroes
-            return Ok(Block::Zero);
+            return Ok(Block::new(block_idx, block_size, BlockKind::Zero));
         }
 
         // Read block
-        let file_offset = size_of::<CISOHeader>() as u64
-            + phys_block as u64 * self.header.block_size.get() as u64;
+        let file_offset = size_of::<CISOHeader>() as u64 + phys_block as u64 * block_size as u64;
         self.inner.seek(SeekFrom::Start(file_offset))?;
         self.inner.read_exact(out)?;
 
-        match partition {
-            Some(partition) if partition.has_encryption => Ok(Block::PartEncrypted),
-            _ => Ok(Block::Raw),
-        }
+        Ok(Block::new(block_idx, block_size, BlockKind::Raw))
     }
 
-    fn block_size_internal(&self) -> u32 { self.header.block_size.get() }
+    fn block_size(&self) -> u32 { self.header.block_size.get() }
 
     fn meta(&self) -> DiscMeta {
         let mut result = DiscMeta {
@@ -130,3 +139,187 @@ impl BlockIO for DiscIOCISO {
         result
     }
 }
+
+struct BlockProcessorCISO {
+    inner: DiscReader,
+    block_size: u32,
+    decrypted_block: Box<[u8]>,
+    lfg: LaggedFibonacci,
+    disc_id: [u8; 4],
+    disc_num: u8,
+}
+
+impl Clone for BlockProcessorCISO {
+    fn clone(&self) -> Self {
+        Self {
+            inner: self.inner.clone(),
+            block_size: self.block_size,
+            decrypted_block: <[u8]>::new_box_zeroed_with_elems(self.block_size as usize).unwrap(),
+            lfg: LaggedFibonacci::default(),
+            disc_id: self.disc_id,
+            disc_num: self.disc_num,
+        }
+    }
+}
+
+impl BlockProcessor for BlockProcessorCISO {
+    type BlockMeta = CheckBlockResult;
+
+    fn process_block(&mut self, block_idx: u32) -> io::Result<BlockResult<Self::BlockMeta>> {
+        let block_size = self.block_size as usize;
+        let input_position = block_idx as u64 * block_size as u64;
+        self.inner.seek(SeekFrom::Start(input_position))?;
+        let (block_data, disc_data) = read_block(&mut self.inner, block_size)?;
+
+        // Check if block is zeroed or junk
+        let result = match check_block(
+            disc_data.as_ref(),
+            &mut self.decrypted_block,
+            input_position,
+            self.inner.partitions(),
+            &mut self.lfg,
+            self.disc_id,
+            self.disc_num,
+        )? {
+            CheckBlockResult::Normal => {
+                BlockResult { block_idx, disc_data, block_data, meta: CheckBlockResult::Normal }
+            }
+            CheckBlockResult::Zeroed => BlockResult {
+                block_idx,
+                disc_data,
+                block_data: Bytes::new(),
+                meta: CheckBlockResult::Zeroed,
+            },
+            CheckBlockResult::Junk => BlockResult {
+                block_idx,
+                disc_data,
+                block_data: Bytes::new(),
+                meta: CheckBlockResult::Junk,
+            },
+        };
+        Ok(result)
+    }
+}
+
+#[derive(Clone)]
+pub struct DiscWriterCISO {
+    inner: DiscReader,
+    block_size: u32,
+    block_count: u32,
+    disc_size: u64,
+}
+
+pub const DEFAULT_BLOCK_SIZE: u32 = 0x200000; // 2 MiB
+
+impl DiscWriterCISO {
+    pub fn new(inner: DiscReader, options: &FormatOptions) -> Result<Box<dyn DiscWriter>> {
+        if options.format != Format::Ciso {
+            return Err(Error::DiscFormat("Invalid format for CISO writer".to_string()));
+        }
+        if options.compression != Compression::None {
+            return Err(Error::DiscFormat("CISO does not support compression".to_string()));
+        }
+        let block_size = DEFAULT_BLOCK_SIZE;
+
+        let disc_size = inner.disc_size();
+        let block_count = disc_size.div_ceil(block_size as u64) as u32;
+        if block_count > CISO_MAP_SIZE as u32 {
+            return Err(Error::DiscFormat(format!(
+                "CISO block count exceeds maximum: {} > {}",
+                block_count, CISO_MAP_SIZE
+            )));
+        }
+
+        Ok(Box::new(Self { inner, block_size, block_count, disc_size }))
+    }
+}
+
+impl DiscWriter for DiscWriterCISO {
+    fn process(
+        &self,
+        data_callback: &mut DataCallback,
+        options: &ProcessOptions,
+    ) -> Result<DiscFinalization> {
+        data_callback(BytesMut::zeroed(SECTOR_SIZE).freeze(), 0, self.disc_size)
+            .context("Failed to write header")?;
+
+        // Determine junk data values
+        let disc_header = self.inner.header();
+        let disc_id = *array_ref![disc_header.game_id, 0, 4];
+        let disc_num = disc_header.disc_num;
+
+        // Create hashers
+        let digest = DigestManager::new(options);
+        let block_size = self.block_size;
+        let mut junk_bits = JunkBits::new(block_size);
+        let mut input_position = 0;
+
+        let mut block_count = 0;
+        let mut header = CISOHeader::new_box_zeroed()?;
+        header.magic = CISO_MAGIC;
+        header.block_size = block_size.into();
+        par_process(
+            || BlockProcessorCISO {
+                inner: self.inner.clone(),
+                block_size,
+                decrypted_block: <[u8]>::new_box_zeroed_with_elems(block_size as usize).unwrap(),
+                lfg: LaggedFibonacci::default(),
+                disc_id,
+                disc_num,
+            },
+            self.block_count,
+            options.processor_threads,
+            |block| -> Result<()> {
+                // Update hashers
+                let disc_data_len = block.disc_data.len() as u64;
+                digest.send(block.disc_data);
+
+                // Check if block is zeroed or junk
+                match block.meta {
+                    CheckBlockResult::Normal => {
+                        header.block_present[block.block_idx as usize] = 1;
+                        block_count += 1;
+                    }
+                    CheckBlockResult::Zeroed => {}
+                    CheckBlockResult::Junk => {
+                        junk_bits.set(block.block_idx, true);
+                    }
+                }
+
+                input_position += disc_data_len;
+                data_callback(block.block_data, input_position, self.disc_size)
+                    .with_context(|| format!("Failed to write block {}", block.block_idx))?;
+                Ok(())
+            },
+        )?;
+
+        // Collect hash results
+        let digest_results = digest.finish();
+        let mut nkit_header = NKitHeader {
+            version: 2,
+            size: Some(self.disc_size),
+            crc32: None,
+            md5: None,
+            sha1: None,
+            xxh64: None,
+            junk_bits: Some(junk_bits),
+            encrypted: true,
+        };
+        nkit_header.apply_digests(&digest_results);
+
+        // Write NKit header after data
+        let mut buffer = BytesMut::new().writer();
+        nkit_header.write_to(&mut buffer).context("Writing NKit header")?;
+        data_callback(buffer.into_inner().freeze(), self.disc_size, self.disc_size)
+            .context("Failed to write NKit header")?;
+
+        let header = Bytes::from(box_to_bytes(header));
+        let mut finalization = DiscFinalization { header, ..Default::default() };
+        finalization.apply_digests(&digest_results);
+        Ok(finalization)
+    }
+
+    fn progress_bound(&self) -> u64 { self.disc_size }
+
+    fn weight(&self) -> DiscWriterWeight { DiscWriterWeight::Medium }
+}

nod/src/io/gcz.rs

@@ -2,21 +2,30 @@ use std::{
     io,
     io::{Read, Seek, SeekFrom},
     mem::size_of,
+    sync::Arc,
 };
 
 use adler::adler32_slice;
-use miniz_oxide::{inflate, inflate::core::inflate_flags};
+use bytes::{BufMut, Bytes, BytesMut};
 use zerocopy::{little_endian::*, FromBytes, FromZeros, Immutable, IntoBytes, KnownLayout};
-use zstd::zstd_safe::WriteBuf;
 
 use crate::{
-    io::{
-        block::{Block, BlockIO, DiscStream, GCZ_MAGIC},
-        MagicBytes,
+    common::{Compression, Format, MagicBytes},
+    disc::{
+        reader::DiscReader,
+        writer::{par_process, read_block, BlockProcessor, BlockResult, DataCallback, DiscWriter},
+        SECTOR_SIZE,
     },
+    io::block::{Block, BlockKind, BlockReader, GCZ_MAGIC},
+    read::{DiscMeta, DiscStream},
+    util::{
+        compress::{Compressor, DecompressionKind, Decompressor},
+        digest::DigestManager,
+        read::{read_arc_slice, read_from},
         static_assert,
-    util::read::{read_box_slice, read_from},
-    Compression, DiscMeta, Error, Format, PartitionInfo, Result, ResultContext,
+    },
+    write::{DiscFinalization, DiscWriterWeight, FormatOptions, ProcessOptions},
+    Error, Result, ResultContext,
 };
 
 /// GCZ header (little endian)
@@ -33,16 +42,17 @@ struct GCZHeader {
 
 static_assert!(size_of::<GCZHeader>() == 32);
 
-pub struct DiscIOGCZ {
+pub struct BlockReaderGCZ {
     inner: Box<dyn DiscStream>,
     header: GCZHeader,
-    block_map: Box<[U64]>,
-    block_hashes: Box<[U32]>,
+    block_map: Arc<[U64]>,
+    block_hashes: Arc<[U32]>,
     block_buf: Box<[u8]>,
     data_offset: u64,
+    decompressor: Decompressor,
 }
 
-impl Clone for DiscIOGCZ {
+impl Clone for BlockReaderGCZ {
     fn clone(&self) -> Self {
         Self {
             inner: self.inner.clone(),
@@ -51,11 +61,12 @@ impl Clone for DiscIOGCZ {
             block_hashes: self.block_hashes.clone(),
             block_buf: <[u8]>::new_box_zeroed_with_elems(self.block_buf.len()).unwrap(),
             data_offset: self.data_offset,
+            decompressor: self.decompressor.clone(),
         }
     }
 }
 
-impl DiscIOGCZ {
+impl BlockReaderGCZ {
     pub fn new(mut inner: Box<dyn DiscStream>) -> Result<Box<Self>> {
         // Read header
         inner.seek(SeekFrom::Start(0)).context("Seeking to start")?;
@@ -66,39 +77,48 @@ impl DiscIOGCZ {
 
         // Read block map and hashes
         let block_count = header.block_count.get();
-        let block_map = read_box_slice(inner.as_mut(), block_count as usize)
+        let block_map = read_arc_slice(inner.as_mut(), block_count as usize)
             .context("Reading GCZ block map")?;
-        let block_hashes = read_box_slice(inner.as_mut(), block_count as usize)
+        let block_hashes = read_arc_slice(inner.as_mut(), block_count as usize)
             .context("Reading GCZ block hashes")?;
 
         // header + block_count * (u64 + u32)
         let data_offset = size_of::<GCZHeader>() as u64 + block_count as u64 * 12;
         let block_buf = <[u8]>::new_box_zeroed_with_elems(header.block_size.get() as usize)?;
-        Ok(Box::new(Self { inner, header, block_map, block_hashes, block_buf, data_offset }))
+        let decompressor = Decompressor::new(DecompressionKind::Deflate);
+        Ok(Box::new(Self {
+            inner,
+            header,
+            block_map,
+            block_hashes,
+            block_buf,
+            data_offset,
+            decompressor,
+        }))
     }
 }
 
-impl BlockIO for DiscIOGCZ {
-    fn read_block_internal(
-        &mut self,
-        out: &mut [u8],
-        block: u32,
-        partition: Option<&PartitionInfo>,
-    ) -> io::Result<Block> {
-        if block >= self.header.block_count.get() {
+impl BlockReader for BlockReaderGCZ {
+    fn read_block(&mut self, out: &mut [u8], sector: u32) -> io::Result<Block> {
+        let block_size = self.header.block_size.get();
+        let block_idx = ((sector as u64 * SECTOR_SIZE as u64) / block_size as u64) as u32;
+        if block_idx >= self.header.block_count.get() {
             // Out of bounds
-            return Ok(Block::Zero);
+            return Ok(Block::new(block_idx, block_size, BlockKind::None));
         }
 
         // Find block offset and size
-        let mut file_offset = self.block_map[block as usize].get();
+        let mut file_offset = self.block_map[block_idx as usize].get();
         let mut compressed = true;
         if file_offset & (1 << 63) != 0 {
             file_offset &= !(1 << 63);
             compressed = false;
         }
-        let compressed_size =
-            ((self.block_map.get(block as usize + 1).unwrap_or(&self.header.compressed_size).get()
+        let compressed_size = ((self
+            .block_map
+            .get(block_idx as usize + 1)
+            .unwrap_or(&self.header.compressed_size)
+            .get()
             & !(1 << 63))
             - file_offset) as usize;
         if compressed_size > self.block_buf.len() {
@@ -127,58 +147,43 @@ impl BlockIO for DiscIOGCZ {
 
         // Verify block checksum
         let checksum = adler32_slice(&self.block_buf[..compressed_size]);
-        let expected_checksum = self.block_hashes[block as usize].get();
+        let expected_checksum = self.block_hashes[block_idx as usize].get();
         if checksum != expected_checksum {
             return Err(io::Error::new(
                 io::ErrorKind::InvalidData,
                 format!(
-                    "Block checksum mismatch: {:#010x} != {:#010x}",
-                    checksum, expected_checksum
+                    "Block {} checksum mismatch: {:#010x} != {:#010x}",
+                    block_idx, checksum, expected_checksum
                 ),
             ));
         }
 
         if compressed {
             // Decompress block
-            let mut decompressor = inflate::core::DecompressorOxide::new();
-            let input = &self.block_buf[..compressed_size];
-            let (status, in_size, out_size) = inflate::core::decompress(
-                &mut decompressor,
-                input,
-                out,
-                0,
-                inflate_flags::TINFL_FLAG_PARSE_ZLIB_HEADER
-                    | inflate_flags::TINFL_FLAG_USING_NON_WRAPPING_OUTPUT_BUF,
-            );
-            if status != inflate::TINFLStatus::Done
-                || in_size != compressed_size
-                || out_size != self.block_buf.len()
-            {
+            let out_len = self.decompressor.decompress(&self.block_buf[..compressed_size], out)?;
+            if out_len != block_size as usize {
                 return Err(io::Error::new(
                     io::ErrorKind::InvalidData,
                     format!(
-                        "Deflate decompression failed: {:?} (in: {}, out: {})",
-                        status, in_size, out_size
+                        "Block {} decompression failed: in: {}, out: {}",
+                        block_idx, compressed_size, out_len
                     ),
                 ));
             }
         } else {
             // Copy uncompressed block
-            out.copy_from_slice(self.block_buf.as_slice());
+            out.copy_from_slice(self.block_buf.as_ref());
         }
 
-        match partition {
-            Some(partition) if partition.has_encryption => Ok(Block::PartEncrypted),
-            _ => Ok(Block::Raw),
-        }
+        Ok(Block::new(block_idx, block_size, BlockKind::Raw))
     }
 
-    fn block_size_internal(&self) -> u32 { self.header.block_size.get() }
+    fn block_size(&self) -> u32 { self.header.block_size.get() }
 
     fn meta(&self) -> DiscMeta {
         DiscMeta {
             format: Format::Gcz,
-            compression: Compression::Deflate,
+            compression: Compression::Deflate(0),
             block_size: Some(self.header.block_size.get()),
             lossless: true,
             disc_size: Some(self.header.disc_size.get()),
@@ -186,3 +191,174 @@ impl BlockIO for DiscIOGCZ {
         }
     }
 }
+
+struct BlockProcessorGCZ {
+    inner: DiscReader,
+    header: GCZHeader,
+    compressor: Compressor,
+}
+
+impl Clone for BlockProcessorGCZ {
+    fn clone(&self) -> Self {
+        Self {
+            inner: self.inner.clone(),
+            header: self.header.clone(),
+            compressor: self.compressor.clone(),
+        }
+    }
+}
+
+struct BlockMetaGCZ {
+    is_compressed: bool,
+    block_hash: u32,
+}
+
+impl BlockProcessor for BlockProcessorGCZ {
+    type BlockMeta = BlockMetaGCZ;
+
+    fn process_block(&mut self, block_idx: u32) -> io::Result<BlockResult<Self::BlockMeta>> {
+        let block_size = self.header.block_size.get();
+        self.inner.seek(SeekFrom::Start(block_idx as u64 * block_size as u64))?;
+        let (mut block_data, disc_data) = read_block(&mut self.inner, block_size as usize)?;
+
+        // Try to compress block
+        let is_compressed = if self.compressor.compress(&block_data)? {
+            println!("Compressed block {} to {}", block_idx, self.compressor.buffer.len());
+            block_data = Bytes::copy_from_slice(self.compressor.buffer.as_slice());
+            true
+        } else {
+            false
+        };
+
+        let block_hash = adler32_slice(block_data.as_ref());
+        Ok(BlockResult {
+            block_idx,
+            disc_data,
+            block_data,
+            meta: BlockMetaGCZ { is_compressed, block_hash },
+        })
+    }
+}
+
+#[derive(Clone)]
+pub struct DiscWriterGCZ {
+    inner: DiscReader,
+    header: GCZHeader,
+    compression: Compression,
+}
+
+pub const DEFAULT_BLOCK_SIZE: u32 = 0x8000; // 32 KiB
+
+// Level 0 will be converted to the default level in [`Compression::validate_level`]
+pub const DEFAULT_COMPRESSION: Compression = Compression::Deflate(0);
+
+impl DiscWriterGCZ {
+    pub fn new(inner: DiscReader, options: &FormatOptions) -> Result<Box<dyn DiscWriter>> {
+        if options.format != Format::Gcz {
+            return Err(Error::DiscFormat("Invalid format for GCZ writer".to_string()));
+        }
+        if !matches!(options.compression, Compression::Deflate(_)) {
+            return Err(Error::DiscFormat(format!(
+                "Unsupported compression for GCZ: {:?}",
+                options.compression
+            )));
+        }
+
+        let block_size = options.block_size;
+        if block_size < SECTOR_SIZE as u32 || block_size % SECTOR_SIZE as u32 != 0 {
+            return Err(Error::DiscFormat("Invalid block size for GCZ".to_string()));
+        }
+
+        let disc_header = inner.header();
+        let disc_size = inner.disc_size();
+        let block_count = disc_size.div_ceil(block_size as u64) as u32;
+
+        // Generate header
+        let header = GCZHeader {
+            magic: GCZ_MAGIC,
+            disc_type: if disc_header.is_wii() { 1 } else { 0 }.into(),
+            compressed_size: 0.into(), // Written when finalized
+            disc_size: disc_size.into(),
+            block_size: block_size.into(),
+            block_count: block_count.into(),
+        };
+
+        Ok(Box::new(Self { inner, header, compression: options.compression }))
+    }
+}
+
+impl DiscWriter for DiscWriterGCZ {
+    fn process(
+        &self,
+        data_callback: &mut DataCallback,
+        options: &ProcessOptions,
+    ) -> Result<DiscFinalization> {
+        let disc_size = self.header.disc_size.get();
+        let block_size = self.header.block_size.get();
+        let block_count = self.header.block_count.get();
+
+        // Create hashers
+        let digest = DigestManager::new(options);
+
+        // Generate block map and hashes
+        let mut block_map = <[U64]>::new_box_zeroed_with_elems(block_count as usize)?;
+        let mut block_hashes = <[U32]>::new_box_zeroed_with_elems(block_count as usize)?;
+
+        let header_data_size = size_of::<GCZHeader>()
+            + size_of_val(block_map.as_ref())
+            + size_of_val(block_hashes.as_ref());
+        let mut header_data = BytesMut::with_capacity(header_data_size);
+        header_data.put_slice(self.header.as_bytes());
+        header_data.resize(header_data_size, 0);
+        data_callback(header_data.freeze(), 0, disc_size).context("Failed to write GCZ header")?;
+
+        let mut input_position = 0;
+        let mut data_position = 0;
+        par_process(
+            || BlockProcessorGCZ {
+                inner: self.inner.clone(),
+                header: self.header.clone(),
+                compressor: Compressor::new(self.compression, block_size as usize),
+            },
+            block_count,
+            options.processor_threads,
+            |block| {
+                // Update hashers
+                let disc_data_len = block.disc_data.len() as u64;
+                digest.send(block.disc_data);
+
+                // Update block map and hash
+                if block.meta.is_compressed {
+                    block_map[block.block_idx as usize] = data_position.into();
+                } else {
+                    block_map[block.block_idx as usize] = (data_position | (1 << 63)).into();
+                }
+                block_hashes[block.block_idx as usize] = block.meta.block_hash.into();
+
+                // Write block data
+                input_position += disc_data_len;
+                data_position += block.block_data.len() as u64;
+                data_callback(block.block_data, input_position, disc_size)
+                    .with_context(|| format!("Failed to write block {}", block.block_idx))?;
+                Ok(())
+            },
+        )?;
+
+        // Write updated header, block map and hashes
+        let mut header = self.header.clone();
+        header.compressed_size = data_position.into();
+        let mut header_data = BytesMut::with_capacity(header_data_size);
+        header_data.extend_from_slice(header.as_bytes());
+        header_data.extend_from_slice(block_map.as_bytes());
+        header_data.extend_from_slice(block_hashes.as_bytes());
+
+        let mut finalization =
+            DiscFinalization { header: header_data.freeze(), ..Default::default() };
+        finalization.apply_digests(&digest.finish());
+        Ok(finalization)
+    }
+
+    fn progress_bound(&self) -> u64 { self.header.disc_size.get() }
+
+    fn weight(&self) -> DiscWriterWeight { DiscWriterWeight::Heavy }
+}

nod/src/io/iso.rs

@@ -1,68 +1,97 @@
 use std::{
     io,
-    io::{Read, Seek, SeekFrom},
+    io::{BufRead, Read, Seek, SeekFrom},
 };
 
 use crate::{
-    disc::SECTOR_SIZE,
-    io::{
-        block::{Block, BlockIO, DiscStream, PartitionInfo},
-        Format,
+    common::Format,
+    disc::{
+        reader::DiscReader,
+        writer::{DataCallback, DiscWriter},
+        SECTOR_SIZE,
     },
-    DiscMeta, Result, ResultContext,
+    io::block::{Block, BlockKind, BlockReader},
+    read::{DiscMeta, DiscStream},
+    util::digest::DigestManager,
+    write::{DiscFinalization, DiscWriterWeight, ProcessOptions},
+    Result, ResultContext,
 };
 
 #[derive(Clone)]
-pub struct DiscIOISO {
+pub struct BlockReaderISO {
     inner: Box<dyn DiscStream>,
-    stream_len: u64,
+    disc_size: u64,
 }
 
-impl DiscIOISO {
+impl BlockReaderISO {
     pub fn new(mut inner: Box<dyn DiscStream>) -> Result<Box<Self>> {
-        let stream_len = inner.seek(SeekFrom::End(0)).context("Determining stream length")?;
-        inner.seek(SeekFrom::Start(0)).context("Seeking to start")?;
-        Ok(Box::new(Self { inner, stream_len }))
+        let disc_size = inner.seek(SeekFrom::End(0)).context("Determining stream length")?;
+        Ok(Box::new(Self { inner, disc_size }))
     }
 }
 
-impl BlockIO for DiscIOISO {
-    fn read_block_internal(
-        &mut self,
-        out: &mut [u8],
-        block: u32,
-        partition: Option<&PartitionInfo>,
-    ) -> io::Result<Block> {
-        let offset = block as u64 * SECTOR_SIZE as u64;
-        if offset >= self.stream_len {
+impl BlockReader for BlockReaderISO {
+    fn read_block(&mut self, out: &mut [u8], sector: u32) -> io::Result<Block> {
+        let pos = sector as u64 * SECTOR_SIZE as u64;
+        if pos >= self.disc_size {
             // End of file
-            return Ok(Block::Zero);
+            return Ok(Block::sector(sector, BlockKind::None));
         }
 
-        self.inner.seek(SeekFrom::Start(offset))?;
-        if offset + SECTOR_SIZE as u64 > self.stream_len {
+        self.inner.seek(SeekFrom::Start(pos))?;
+        if pos + SECTOR_SIZE as u64 > self.disc_size {
             // If the last block is not a full sector, fill the rest with zeroes
-            let read = (self.stream_len - offset) as usize;
+            let read = (self.disc_size - pos) as usize;
             self.inner.read_exact(&mut out[..read])?;
             out[read..].fill(0);
         } else {
             self.inner.read_exact(out)?;
         }
 
-        match partition {
-            Some(partition) if partition.has_encryption => Ok(Block::PartEncrypted),
-            _ => Ok(Block::Raw),
-        }
+        Ok(Block::sector(sector, BlockKind::Raw))
     }
 
-    fn block_size_internal(&self) -> u32 { SECTOR_SIZE as u32 }
+    fn block_size(&self) -> u32 { SECTOR_SIZE as u32 }
 
     fn meta(&self) -> DiscMeta {
         DiscMeta {
             format: Format::Iso,
             lossless: true,
-            disc_size: Some(self.stream_len),
+            disc_size: Some(self.disc_size),
             ..Default::default()
         }
     }
 }
+
+impl DiscWriter for DiscReader {
+    fn process(
+        &self,
+        data_callback: &mut DataCallback,
+        options: &ProcessOptions,
+    ) -> Result<DiscFinalization> {
+        let mut reader = self.clone();
+        let digest = DigestManager::new(options);
+        loop {
+            let pos = reader.position();
+            let data = reader
+                .fill_buf_internal()
+                .with_context(|| format!("Reading disc data at offset {pos}"))?;
+            let len = data.len();
+            if len == 0 {
+                break;
+            }
+            // Update hashers
+            digest.send(data.clone());
+            data_callback(data, pos + len as u64, reader.disc_size())
+                .context("Failed to write disc data")?;
+            reader.consume(len);
+        }
+        let mut finalization = DiscFinalization::default();
+        finalization.apply_digests(&digest.finish());
+        Ok(finalization)
+    }
+
+    fn progress_bound(&self) -> u64 { self.disc_size() }
+
+    fn weight(&self) -> DiscWriterWeight { DiscWriterWeight::Light }
+}

nod/src/io/mapped.rs

@@ -0,0 +1,51 @@
+use std::{io, path::Path, sync::Arc};
+
+use memmap2::Mmap;
+
+use crate::{util::impl_read_for_bufread, Result, ResultContext};
+
+pub struct MappedFileReader {
+    inner: Arc<Mmap>,
+    pos: usize,
+}
+
+impl Clone for MappedFileReader {
+    fn clone(&self) -> Self { Self { inner: self.inner.clone(), pos: 0 } }
+}
+
+impl MappedFileReader {
+    #[expect(unused)]
+    pub fn new(path: &Path) -> Result<Self> {
+        let file = std::fs::File::open(path)
+            .with_context(|| format!("Failed to open file {}", path.display()))?;
+        let inner = unsafe { Mmap::map(&file) }
+            .with_context(|| format!("Failed to map file {}", path.display()))?;
+        Ok(Self { inner: Arc::new(inner), pos: 0 })
+    }
+}
+
+impl io::BufRead for MappedFileReader {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> {
+        if self.pos < self.inner.len() {
+            Ok(&self.inner[self.pos..])
+        } else {
+            Ok(&[])
+        }
+    }
+
+    fn consume(&mut self, amt: usize) { self.pos = self.pos.saturating_add(amt); }
+}
+
+impl_read_for_bufread!(MappedFileReader);
+
+impl io::Seek for MappedFileReader {
+    fn seek(&mut self, pos: io::SeekFrom) -> io::Result<u64> {
+        let pos = match pos {
+            io::SeekFrom::Start(pos) => pos,
+            io::SeekFrom::End(pos) => (self.inner.len() as u64).saturating_add_signed(pos),
+            io::SeekFrom::Current(off) => (self.pos as u64).saturating_add_signed(off),
+        };
+        self.pos = pos.try_into().map_err(|_| io::ErrorKind::UnexpectedEof)?;
+        Ok(pos)
+    }
+}

nod/src/io/mod.rs

@@ -1,142 +1,14 @@
 //! Disc file format related logic (CISO, NFS, WBFS, WIA, etc.)
 
-use std::fmt;
-
 pub(crate) mod block;
 pub(crate) mod ciso;
 #[cfg(feature = "compress-zlib")]
 pub(crate) mod gcz;
 pub(crate) mod iso;
+pub(crate) mod mapped;
 pub(crate) mod nfs;
 pub(crate) mod nkit;
 pub(crate) mod split;
 pub(crate) mod tgc;
 pub(crate) mod wbfs;
 pub(crate) mod wia;
-
-/// SHA-1 hash bytes
-pub type HashBytes = [u8; 20];
-
-/// AES key bytes
-pub type KeyBytes = [u8; 16];
-
-/// Magic bytes
-pub type MagicBytes = [u8; 4];
-
-/// The disc file format.
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
-pub enum Format {
-    /// ISO / GCM (GameCube master disc)
-    #[default]
-    Iso,
-    /// CISO (Compact ISO)
-    Ciso,
-    /// GCZ
-    Gcz,
-    /// NFS (Wii U VC)
-    Nfs,
-    /// RVZ
-    Rvz,
-    /// WBFS
-    Wbfs,
-    /// WIA
-    Wia,
-    /// TGC
-    Tgc,
-}
-
-impl fmt::Display for Format {
-    #[inline]
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self {
-            Format::Iso => write!(f, "ISO"),
-            Format::Ciso => write!(f, "CISO"),
-            Format::Gcz => write!(f, "GCZ"),
-            Format::Nfs => write!(f, "NFS"),
-            Format::Rvz => write!(f, "RVZ"),
-            Format::Wbfs => write!(f, "WBFS"),
-            Format::Wia => write!(f, "WIA"),
-            Format::Tgc => write!(f, "TGC"),
-        }
-    }
-}
-
-/// The disc file format's compression algorithm.
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
-pub enum Compression {
-    /// No compression
-    #[default]
-    None,
-    /// BZIP2
-    Bzip2,
-    /// Deflate (GCZ only)
-    Deflate,
-    /// LZMA
-    Lzma,
-    /// LZMA2
-    Lzma2,
-    /// Purge (WIA only)
-    Purge,
-    /// Zstandard
-    Zstandard,
-}
-
-impl fmt::Display for Compression {
-    #[inline]
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self {
-            Compression::None => write!(f, "None"),
-            Compression::Bzip2 => write!(f, "BZIP2"),
-            Compression::Deflate => write!(f, "Deflate"),
-            Compression::Lzma => write!(f, "LZMA"),
-            Compression::Lzma2 => write!(f, "LZMA2"),
-            Compression::Purge => write!(f, "Purge"),
-            Compression::Zstandard => write!(f, "Zstandard"),
-        }
-    }
-}
-
-/// Extra metadata about the underlying disc file format.
-#[derive(Debug, Clone, Default)]
-pub struct DiscMeta {
-    /// The disc file format.
-    pub format: Format,
-    /// The format's compression algorithm.
-    pub compression: Compression,
-    /// If the format uses blocks, the block size in bytes.
-    pub block_size: Option<u32>,
-    /// Whether Wii partitions are stored decrypted in the format.
-    pub decrypted: bool,
-    /// Whether the format omits Wii partition data hashes.
-    pub needs_hash_recovery: bool,
-    /// Whether the format supports recovering the original disc data losslessly.
-    pub lossless: bool,
-    /// The original disc's size in bytes, if stored by the format.
-    pub disc_size: Option<u64>,
-    /// The original disc's CRC32 hash, if stored by the format.
-    pub crc32: Option<u32>,
-    /// The original disc's MD5 hash, if stored by the format.
-    pub md5: Option<[u8; 16]>,
-    /// The original disc's SHA-1 hash, if stored by the format.
-    pub sha1: Option<[u8; 20]>,
-    /// The original disc's XXH64 hash, if stored by the format.
-    pub xxhash64: Option<u64>,
-}
-
-/// Encrypts data in-place using AES-128-CBC with the given key and IV.
-/// Requires the data length to be a multiple of the AES block size (16 bytes).
-pub fn aes_cbc_encrypt(key: &KeyBytes, iv: &KeyBytes, data: &mut [u8]) {
-    use aes::cipher::{block_padding::NoPadding, BlockEncryptMut, KeyIvInit};
-    <cbc::Encryptor<aes::Aes128>>::new(key.into(), iv.into())
-        .encrypt_padded_mut::<NoPadding>(data, data.len())
-        .unwrap();
-}
-
-/// Decrypts data in-place using AES-128-CBC with the given key and IV.
-/// Requires the data length to be a multiple of the AES block size (16 bytes).
-pub fn aes_cbc_decrypt(key: &KeyBytes, iv: &KeyBytes, data: &mut [u8]) {
-    use aes::cipher::{block_padding::NoPadding, BlockDecryptMut, KeyIvInit};
-    <cbc::Decryptor<aes::Aes128>>::new(key.into(), iv.into())
-        .decrypt_padded_mut::<NoPadding>(data)
-        .unwrap();
-}

nod/src/io/nfs.rs

@@ -4,22 +4,21 @@ use std::{
     io::{BufReader, Read, Seek, SeekFrom},
     mem::size_of,
     path::{Component, Path, PathBuf},
+    sync::Arc,
 };
 
 use zerocopy::{big_endian::U32, FromBytes, FromZeros, Immutable, IntoBytes, KnownLayout};
 
 use crate::{
-    array_ref_mut,
+    common::{Format, KeyBytes, MagicBytes},
     disc::SECTOR_SIZE,
     io::{
-        aes_cbc_decrypt,
-        block::{Block, BlockIO, PartitionInfo, NFS_MAGIC},
+        block::{Block, BlockKind, BlockReader, NFS_MAGIC},
         split::SplitFileReader,
-        Format, KeyBytes, MagicBytes,
     },
-    static_assert,
-    util::read::read_from,
-    DiscMeta, Error, Result, ResultContext,
+    read::DiscMeta,
+    util::{aes::aes_cbc_decrypt, array_ref_mut, read::read_arc, static_assert},
+    Error, Result, ResultContext,
 };
 
 pub const NFS_END_MAGIC: MagicBytes = *b"SGGE";
@@ -84,19 +83,19 @@ impl NFSHeader {
 }
 
 #[derive(Clone)]
-pub struct DiscIONFS {
+pub struct BlockReaderNFS {
     inner: SplitFileReader,
-    header: NFSHeader,
+    header: Arc<NFSHeader>,
     raw_size: u64,
     disc_size: u64,
     key: KeyBytes,
 }
 
-impl DiscIONFS {
+impl BlockReaderNFS {
     pub fn new(directory: &Path) -> Result<Box<Self>> {
         let mut disc_io = Box::new(Self {
             inner: SplitFileReader::empty(),
-            header: NFSHeader::new_zeroed(),
+            header: Arc::new(NFSHeader::new_zeroed()),
             raw_size: 0,
             disc_size: 0,
             key: [0; 16],
@@ -106,18 +105,13 @@ impl DiscIONFS {
     }
 }
 
-impl BlockIO for DiscIONFS {
-    fn read_block_internal(
-        &mut self,
-        out: &mut [u8],
-        sector: u32,
-        partition: Option<&PartitionInfo>,
-    ) -> io::Result<Block> {
+impl BlockReader for BlockReaderNFS {
+    fn read_block(&mut self, out: &mut [u8], sector: u32) -> io::Result<Block> {
         // Calculate physical sector
         let phys_sector = self.header.phys_sector(sector);
         if phys_sector == u32::MAX {
             // Logical zero sector
-            return Ok(Block::Zero);
+            return Ok(Block::sector(sector, BlockKind::Raw));
         }
 
         // Read sector
@@ -130,15 +124,10 @@ impl BlockIO for DiscIONFS {
         *array_ref_mut!(iv, 12, 4) = sector.to_be_bytes();
         aes_cbc_decrypt(&self.key, &iv, out);
 
-        match partition {
-            Some(partition) if partition.has_encryption => {
-                Ok(Block::PartDecrypted { has_hashes: true })
-            }
-            _ => Ok(Block::Raw),
-        }
+        Ok(Block::sector(sector, BlockKind::PartDecrypted { hash_block: true }))
     }
 
-    fn block_size_internal(&self) -> u32 { SECTOR_SIZE as u32 }
+    fn block_size(&self) -> u32 { SECTOR_SIZE as u32 }
 
     fn meta(&self) -> DiscMeta {
         DiscMeta { format: Format::Nfs, decrypted: true, ..Default::default() }
@@ -168,7 +157,7 @@ fn get_nfs(directory: &Path, num: u32) -> Result<PathBuf> {
     }
 }
 
-impl DiscIONFS {
+impl BlockReaderNFS {
     pub fn load_files(&mut self, directory: &Path) -> Result<()> {
         {
             // Load key file
@@ -201,7 +190,7 @@ impl DiscIONFS {
             let mut file = BufReader::new(
                 File::open(&path).with_context(|| format!("Opening file {}", path.display()))?,
             );
-            let header: NFSHeader = read_from(&mut file)
+            let header: Arc<NFSHeader> = read_arc(&mut file)
                 .with_context(|| format!("Reading NFS header from file {}", path.display()))?;
             header.validate()?;
             // log::debug!("{:?}", header);

nod/src/io/nkit.rs

@@ -1,13 +1,15 @@
 use std::{
     io,
-    io::{Read, Seek, SeekFrom},
+    io::{Read, Seek, SeekFrom, Write},
 };
 
+use tracing::warn;
+
 use crate::{
+    common::MagicBytes,
     disc::DL_DVD_SIZE,
-    io::MagicBytes,
+    read::DiscMeta,
     util::read::{read_from, read_u16_be, read_u32_be, read_u64_be, read_vec},
-    DiscMeta,
 };
 
 #[allow(unused)]
@@ -56,19 +58,32 @@ const fn calc_header_size(version: u8, flags: u16, key_len: u32) -> usize {
     size
 }
 
-#[allow(unused)]
 #[derive(Debug, Clone)]
 pub struct NKitHeader {
     pub version: u8,
-    pub flags: u16,
     pub size: Option<u64>,
     pub crc32: Option<u32>,
     pub md5: Option<[u8; 16]>,
     pub sha1: Option<[u8; 20]>,
-    pub xxhash64: Option<u64>,
+    pub xxh64: Option<u64>,
     /// Bitstream of blocks that are junk data
-    pub junk_bits: Option<Vec<u8>>,
-    pub block_size: u32,
+    pub junk_bits: Option<JunkBits>,
+    pub encrypted: bool,
+}
+
+impl Default for NKitHeader {
+    fn default() -> Self {
+        Self {
+            version: 2,
+            size: None,
+            crc32: None,
+            md5: None,
+            sha1: None,
+            xxh64: None,
+            junk_bits: None,
+            encrypted: false,
+        }
+    }
 }
 
 const VERSION_PREFIX: [u8; 7] = *b"NKIT  v";
@@ -82,7 +97,7 @@ impl NKitHeader {
             match NKitHeader::read_from(reader, block_size, has_junk_bits) {
                 Ok(header) => Some(header),
                 Err(e) => {
-                    log::warn!("Failed to read NKit header: {}", e);
+                    warn!("Failed to read NKit header: {}", e);
                     None
                 }
             }
@@ -136,25 +151,20 @@ impl NKitHeader {
         let sha1 = (flags & NKitHeaderFlags::Sha1 as u16 != 0)
             .then(|| read_from::<[u8; 20], _>(&mut inner))
             .transpose()?;
-        let xxhash64 = (flags & NKitHeaderFlags::Xxhash64 as u16 != 0)
+        let xxh64 = (flags & NKitHeaderFlags::Xxhash64 as u16 != 0)
             .then(|| read_u64_be(&mut inner))
             .transpose()?;
 
-        let junk_bits = if has_junk_bits {
-            let n = DL_DVD_SIZE.div_ceil(block_size as u64).div_ceil(8);
-            Some(read_vec(reader, n as usize)?)
-        } else {
-            None
-        };
+        let junk_bits =
+            if has_junk_bits { Some(JunkBits::read_from(reader, block_size)?) } else { None };
 
-        Ok(Self { version, flags, size, crc32, md5, sha1, xxhash64, junk_bits, block_size })
+        let encrypted = flags & NKitHeaderFlags::Encrypted as u16 != 0;
+
+        Ok(Self { version, size, crc32, md5, sha1, xxh64, junk_bits, encrypted })
     }
 
     pub fn is_junk_block(&self, block: u32) -> Option<bool> {
-        self.junk_bits
-            .as_ref()
-            .and_then(|v| v.get((block / 8) as usize))
-            .map(|&b| b & (1 << (7 - (block & 7))) != 0)
+        self.junk_bits.as_ref().map(|v| v.get(block))
     }
 
     pub fn apply(&self, meta: &mut DiscMeta) {
@@ -164,6 +174,128 @@ impl NKitHeader {
         meta.crc32 = self.crc32;
         meta.md5 = self.md5;
         meta.sha1 = self.sha1;
-        meta.xxhash64 = self.xxhash64;
+        meta.xxh64 = self.xxh64;
+    }
+
+    fn calc_flags(&self) -> u16 {
+        let mut flags = 0;
+        if self.size.is_some() {
+            flags |= NKitHeaderFlags::Size as u16;
+        }
+        if self.crc32.is_some() {
+            flags |= NKitHeaderFlags::Crc32 as u16;
+        }
+        if self.md5.is_some() {
+            flags |= NKitHeaderFlags::Md5 as u16;
+        }
+        if self.sha1.is_some() {
+            flags |= NKitHeaderFlags::Sha1 as u16;
+        }
+        if self.xxh64.is_some() {
+            flags |= NKitHeaderFlags::Xxhash64 as u16;
+        }
+        if self.encrypted {
+            flags |= NKitHeaderFlags::Encrypted as u16;
+        }
+        flags
+    }
+
+    pub fn write_to<W>(&self, w: &mut W) -> io::Result<()>
+    where W: Write + ?Sized {
+        w.write_all(&VERSION_PREFIX)?;
+        w.write_all(&[b'0' + self.version])?;
+        let flags = self.calc_flags();
+        match self.version {
+            1 => {}
+            2 => {
+                let header_size = calc_header_size(self.version, flags, 0) as u16;
+                w.write_all(&header_size.to_be_bytes())?;
+                w.write_all(&flags.to_be_bytes())?;
+            }
+            version => {
+                return Err(io::Error::new(
+                    io::ErrorKind::InvalidData,
+                    format!("Unsupported NKit header version: {}", version),
+                ));
+            }
+        };
+        if let Some(size) = self.size {
+            w.write_all(&size.to_be_bytes())?;
+        }
+        if let Some(crc32) = self.crc32 {
+            w.write_all(&crc32.to_be_bytes())?;
+        } else if self.version == 1 {
+            return Err(io::Error::new(
+                io::ErrorKind::InvalidData,
+                "Missing CRC32 in NKit v1 header",
+            ));
+        }
+        if let Some(md5) = self.md5 {
+            w.write_all(&md5)?;
+        } else if self.version == 1 {
+            return Err(io::Error::new(
+                io::ErrorKind::InvalidData,
+                "Missing MD5 in NKit v1 header",
+            ));
+        }
+        if let Some(sha1) = self.sha1 {
+            w.write_all(&sha1)?;
+        } else if self.version == 1 {
+            return Err(io::Error::new(
+                io::ErrorKind::InvalidData,
+                "Missing SHA1 in NKit v1 header",
+            ));
+        }
+        if let Some(xxh64) = self.xxh64 {
+            w.write_all(&xxh64.to_be_bytes())?;
+        } else if self.version == 1 {
+            return Err(io::Error::new(
+                io::ErrorKind::InvalidData,
+                "Missing XXHash64 in NKit header",
+            ));
+        }
+        if let Some(junk_bits) = &self.junk_bits {
+            junk_bits.write_to(w)?;
+        }
+        Ok(())
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct JunkBits(Vec<u8>);
+
+impl JunkBits {
+    pub fn new(block_size: u32) -> Self { Self(vec![0; Self::len(block_size)]) }
+
+    pub fn read_from<R>(reader: &mut R, block_size: u32) -> io::Result<Self>
+    where R: Read + ?Sized {
+        Ok(Self(read_vec(reader, Self::len(block_size))?))
+    }
+
+    pub fn write_to<W>(&self, w: &mut W) -> io::Result<()>
+    where W: Write + ?Sized {
+        w.write_all(&self.0)
+    }
+
+    pub fn set(&mut self, block: u32, is_junk: bool) {
+        let Some(byte) = self.0.get_mut((block / 8) as usize) else {
+            return;
+        };
+        if is_junk {
+            *byte |= 1 << (7 - (block & 7));
+        } else {
+            *byte &= !(1 << (7 - (block & 7)));
+        }
+    }
+
+    pub fn get(&self, block: u32) -> bool {
+        let Some(&byte) = self.0.get((block / 8) as usize) else {
+            return false;
+        };
+        byte & (1 << (7 - (block & 7))) != 0
+    }
+
+    fn len(block_size: u32) -> usize {
+        DL_DVD_SIZE.div_ceil(block_size as u64).div_ceil(8) as usize
     }
 }

nod/src/io/split.rs

@@ -1,11 +1,12 @@
 use std::{
-    cmp::min,
     fs::File,
     io,
     io::{BufReader, Read, Seek, SeekFrom},
     path::{Path, PathBuf},
 };
 
+use tracing::instrument;
+
 use crate::{ErrorContext, Result, ResultContext};
 
 #[derive(Debug)]
@@ -101,10 +102,9 @@ impl SplitFileReader {
     }
 
     pub fn len(&self) -> u64 { self.files.last().map_or(0, |f| f.begin + f.size) }
-}
 
-impl Read for SplitFileReader {
-    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+    #[instrument(name = "SplitFileReader::check_open_file", skip_all)]
+    fn check_open_file(&mut self) -> io::Result<Option<&mut Split<BufReader<File>>>> {
         if self.open_file.is_none() || !self.open_file.as_ref().unwrap().contains(self.pos) {
             self.open_file = if let Some(split) = self.files.iter().find(|f| f.contains(self.pos)) {
                 let mut file = BufReader::new(File::open(&split.inner)?);
@@ -115,10 +115,18 @@ impl Read for SplitFileReader {
                 None
             };
         }
-        let Some(split) = self.open_file.as_mut() else {
+        Ok(self.open_file.as_mut())
+    }
+}
+
+impl Read for SplitFileReader {
+    #[instrument(name = "SplitFileReader::read", skip_all)]
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        let pos = self.pos;
+        let Some(split) = self.check_open_file()? else {
             return Ok(0);
         };
-        let to_read = min(buf.len(), (split.begin + split.size - self.pos) as usize);
+        let to_read = buf.len().min((split.begin + split.size - pos) as usize);
         let read = split.inner.read(&mut buf[..to_read])?;
         self.pos += read as u64;
         Ok(read)
@@ -126,6 +134,7 @@ impl Read for SplitFileReader {
 }
 
 impl Seek for SplitFileReader {
+    #[instrument(name = "SplitFileReader::seek", skip_all)]
     fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
         self.pos = match pos {
             SeekFrom::Start(pos) => pos,

nod/src/io/tgc.rs

@@ -1,19 +1,31 @@
 use std::{
     io,
-    io::{Read, Seek, SeekFrom},
-    mem::size_of,
+    io::{BufRead, Read, Seek, SeekFrom},
+    sync::Arc,
 };
 
-use zerocopy::{big_endian::U32, FromBytes, Immutable, IntoBytes, KnownLayout};
+use bytes::{BufMut, Bytes, BytesMut};
+use zerocopy::{big_endian::U32, FromBytes, FromZeros, Immutable, IntoBytes, KnownLayout};
 
 use crate::{
-    disc::SECTOR_SIZE,
-    io::{
-        block::{Block, BlockIO, DiscStream, PartitionInfo, TGC_MAGIC},
-        Format, MagicBytes,
+    build::gc::{insert_junk_data, FileCallback, GCPartitionStream, WriteInfo, WriteKind},
+    common::{Compression, Format, MagicBytes, PartitionKind},
+    disc::{
+        fst::Fst,
+        gcn::{read_dol, read_fst},
+        reader::DiscReader,
+        writer::{DataCallback, DiscWriter},
+        DiscHeader, PartitionHeader, SECTOR_SIZE,
     },
-    util::read::{read_box_slice, read_from},
-    DiscHeader, DiscMeta, Error, Node, PartitionHeader, Result, ResultContext,
+    io::block::{Block, BlockKind, BlockReader, TGC_MAGIC},
+    read::{DiscMeta, DiscStream, PartitionOptions, PartitionReader},
+    util::{
+        align_up_32, array_ref,
+        read::{read_arc, read_arc_slice, read_from, read_with_zero_fill},
+        static_assert,
+    },
+    write::{DiscFinalization, DiscWriterWeight, FormatOptions, ProcessOptions},
+    Error, Result, ResultContext,
 };
 
 /// TGC header (big endian)
@@ -46,21 +58,21 @@ struct TGCHeader {
     banner_offset: U32,
     /// Size of the banner
     banner_size: U32,
-    /// Original user data offset in the GCM
-    gcm_user_offset: U32,
+    /// Start of user files in the original GCM
+    gcm_files_start: U32,
 }
 
+static_assert!(size_of::<TGCHeader>() == 0x38);
+
+const GCM_HEADER_SIZE: usize = 0x100000;
+
 #[derive(Clone)]
-pub struct DiscIOTGC {
-    inner: Box<dyn DiscStream>,
-    stream_len: u64,
-    header: TGCHeader,
-    fst: Box<[u8]>,
+pub struct BlockReaderTGC {
+    inner: GCPartitionStream<FileCallbackTGC>,
 }
 
-impl DiscIOTGC {
-    pub fn new(mut inner: Box<dyn DiscStream>) -> Result<Box<Self>> {
-        let stream_len = inner.seek(SeekFrom::End(0)).context("Determining stream length")?;
+impl BlockReaderTGC {
+    pub fn new(mut inner: Box<dyn DiscStream>) -> Result<Box<dyn BlockReader>> {
         inner.seek(SeekFrom::Start(0)).context("Seeking to start")?;
 
         // Read header
@@ -68,89 +80,253 @@ impl DiscIOTGC {
         if header.magic != TGC_MAGIC {
             return Err(Error::DiscFormat("Invalid TGC magic".to_string()));
         }
+        let disc_size = (header.gcm_files_start.get() + header.user_size.get()) as u64;
 
-        // Read FST and adjust offsets
+        // Read disc header and partition header
         inner
-            .seek(SeekFrom::Start(header.fst_offset.get() as u64))
-            .context("Seeking to TGC FST")?;
-        let mut fst = read_box_slice(inner.as_mut(), header.fst_size.get() as usize)
-            .context("Reading TGC FST")?;
-        let (root_node, _) = Node::ref_from_prefix(&fst)
-            .map_err(|_| Error::DiscFormat("Invalid TGC FST".to_string()))?;
-        let node_count = root_node.length() as usize;
-        let (nodes, _) = <[Node]>::mut_from_prefix_with_elems(&mut fst, node_count)
-            .map_err(|_| Error::DiscFormat("Invalid TGC FST".to_string()))?;
-        for node in nodes {
-            if node.is_file() {
-                node.offset = node.offset - header.gcm_user_offset
-                    + (header.user_offset - header.header_offset);
-            }
-        }
+            .seek(SeekFrom::Start(header.header_offset.get() as u64))
+            .context("Seeking to GCM header")?;
+        let raw_header =
+            read_arc::<[u8; GCM_HEADER_SIZE], _>(inner.as_mut()).context("Reading GCM header")?;
 
-        Ok(Box::new(Self { inner, stream_len, header, fst }))
+        let (disc_header, remain) = DiscHeader::ref_from_prefix(raw_header.as_ref())
+            .expect("Invalid disc header alignment");
+        let disc_header = disc_header.clone();
+        let (partition_header, _) =
+            PartitionHeader::ref_from_prefix(remain).expect("Invalid partition header alignment");
+        let partition_header = partition_header.clone();
+
+        // Read DOL
+        inner.seek(SeekFrom::Start(header.dol_offset.get() as u64)).context("Seeking to DOL")?;
+        let raw_dol = read_arc_slice::<u8, _>(inner.as_mut(), header.dol_size.get() as usize)
+            .context("Reading DOL")?;
+
+        // Read FST
+        inner.seek(SeekFrom::Start(header.fst_offset.get() as u64)).context("Seeking to FST")?;
+        let raw_fst = read_arc_slice::<u8, _>(inner.as_mut(), header.fst_size.get() as usize)
+            .context("Reading FST")?;
+        let fst = Fst::new(&raw_fst)?;
+
+        let mut write_info = Vec::with_capacity(5 + fst.num_files());
+        write_info.push(WriteInfo {
+            kind: WriteKind::Static(raw_header, "sys/header.bin"),
+            size: GCM_HEADER_SIZE as u64,
+            offset: 0,
+        });
+        write_info.push(WriteInfo {
+            kind: WriteKind::Static(raw_dol, "sys/main.dol"),
+            size: header.dol_size.get() as u64,
+            offset: partition_header.dol_offset(false),
+        });
+        write_info.push(WriteInfo {
+            kind: WriteKind::Static(raw_fst.clone(), "sys/fst.bin"),
+            size: header.fst_size.get() as u64,
+            offset: partition_header.fst_offset(false),
+        });
+
+        // Collect files
+        for (_, node, path) in fst.iter() {
+            if node.is_dir() {
+                continue;
+            }
+            write_info.push(WriteInfo {
+                kind: WriteKind::File(path),
+                size: node.length() as u64,
+                offset: node.offset(false),
+            });
+        }
+        write_info.sort_unstable_by(|a, b| a.offset.cmp(&b.offset).then(a.size.cmp(&b.size)));
+        let write_info = insert_junk_data(write_info, &partition_header);
+
+        let file_callback = FileCallbackTGC::new(inner, raw_fst, header);
+        let disc_id = *array_ref![disc_header.game_id, 0, 4];
+        let disc_num = disc_header.disc_num;
+        Ok(Box::new(Self {
+            inner: GCPartitionStream::new(
+                file_callback,
+                Arc::from(write_info),
+                disc_size,
+                disc_id,
+                disc_num,
+            ),
+        }))
     }
 }
 
-impl BlockIO for DiscIOTGC {
-    fn read_block_internal(
-        &mut self,
-        out: &mut [u8],
-        block: u32,
-        partition: Option<&PartitionInfo>,
-    ) -> io::Result<Block> {
-        let offset = self.header.header_offset.get() as u64 + block as u64 * SECTOR_SIZE as u64;
-        if offset >= self.stream_len {
-            // End of file
-            return Ok(Block::Zero);
+impl BlockReader for BlockReaderTGC {
+    fn read_block(&mut self, out: &mut [u8], sector: u32) -> io::Result<Block> {
+        let count = (out.len() / SECTOR_SIZE) as u32;
+        self.inner.set_position(sector as u64 * SECTOR_SIZE as u64);
+        let read = read_with_zero_fill(&mut self.inner, out)?;
+        Ok(Block::sectors(sector, count, if read == 0 { BlockKind::None } else { BlockKind::Raw }))
     }
 
-        self.inner.seek(SeekFrom::Start(offset))?;
-        if offset + SECTOR_SIZE as u64 > self.stream_len {
-            // If the last block is not a full sector, fill the rest with zeroes
-            let read = (self.stream_len - offset) as usize;
-            self.inner.read_exact(&mut out[..read])?;
-            out[read..].fill(0);
-        } else {
-            self.inner.read_exact(out)?;
-        }
-
-        // Adjust internal GCM header
-        if block == 0 {
-            let partition_header = PartitionHeader::mut_from_bytes(
-                &mut out[size_of::<DiscHeader>()
-                    ..size_of::<DiscHeader>() + size_of::<PartitionHeader>()],
-            )
-            .unwrap();
-            partition_header.dol_offset = self.header.dol_offset - self.header.header_offset;
-            partition_header.fst_offset = self.header.fst_offset - self.header.header_offset;
-        }
-
-        // Copy modified FST to output
-        if offset + out.len() as u64 > self.header.fst_offset.get() as u64
-            && offset < self.header.fst_offset.get() as u64 + self.header.fst_size.get() as u64
-        {
-            let out_offset = (self.header.fst_offset.get() as u64).saturating_sub(offset) as usize;
-            let fst_offset = offset.saturating_sub(self.header.fst_offset.get() as u64) as usize;
-            let copy_len =
-                (out.len() - out_offset).min(self.header.fst_size.get() as usize - fst_offset);
-            out[out_offset..out_offset + copy_len]
-                .copy_from_slice(&self.fst[fst_offset..fst_offset + copy_len]);
-        }
-
-        match partition {
-            Some(partition) if partition.has_encryption => Ok(Block::PartEncrypted),
-            _ => Ok(Block::Raw),
-        }
-    }
-
-    fn block_size_internal(&self) -> u32 { SECTOR_SIZE as u32 }
+    fn block_size(&self) -> u32 { SECTOR_SIZE as u32 }
 
     fn meta(&self) -> DiscMeta {
-        DiscMeta {
-            format: Format::Tgc,
-            lossless: true,
-            disc_size: Some(self.stream_len - self.header.header_offset.get() as u64),
-            ..Default::default()
-        }
+        DiscMeta { format: Format::Tgc, disc_size: Some(self.inner.len()), ..Default::default() }
     }
 }
+
+#[derive(Clone)]
+struct FileCallbackTGC {
+    inner: Box<dyn DiscStream>,
+    fst: Arc<[u8]>,
+    header: TGCHeader,
+}
+
+impl FileCallbackTGC {
+    fn new(inner: Box<dyn DiscStream>, fst: Arc<[u8]>, header: TGCHeader) -> Self {
+        Self { inner, fst, header }
+    }
+}
+
+impl FileCallback for FileCallbackTGC {
+    fn read_file(&mut self, out: &mut [u8], name: &str, offset: u64) -> io::Result<()> {
+        let fst = Fst::new(&self.fst).map_err(|e| io::Error::new(io::ErrorKind::Other, e))?;
+        let (_, node) = fst.find(name).ok_or_else(|| {
+            io::Error::new(io::ErrorKind::NotFound, format!("File not found in FST: {}", name))
+        })?;
+        if !node.is_file() {
+            return Err(io::Error::new(
+                io::ErrorKind::InvalidData,
+                format!("Path is a directory: {}", name),
+            ));
+        }
+        // Calculate file offset in TGC
+        let file_start = (node.offset(false) as u32 - self.header.gcm_files_start.get())
+            + self.header.user_offset.get();
+        self.inner.seek(SeekFrom::Start(file_start as u64 + offset))?;
+        self.inner.read_exact(out)?;
+        Ok(())
+    }
+}
+
+#[derive(Clone)]
+pub struct DiscWriterTGC {
+    inner: Box<dyn PartitionReader>,
+    header: TGCHeader,
+    header_data: Bytes,
+    output_size: u64,
+}
+
+impl DiscWriterTGC {
+    pub fn new(reader: DiscReader, options: &FormatOptions) -> Result<Box<dyn DiscWriter>> {
+        if options.format != Format::Tgc {
+            return Err(Error::DiscFormat("Invalid format for TGC writer".to_string()));
+        }
+        if options.compression != Compression::None {
+            return Err(Error::DiscFormat("TGC does not support compression".to_string()));
+        }
+
+        let mut inner =
+            reader.open_partition_kind(PartitionKind::Data, &PartitionOptions::default())?;
+
+        // Read GCM header
+        let mut raw_header = <[u8; GCM_HEADER_SIZE]>::new_box_zeroed()?;
+        inner.read_exact(raw_header.as_mut()).context("Reading GCM header")?;
+        let (_, remain) = DiscHeader::ref_from_prefix(raw_header.as_ref())
+            .expect("Invalid disc header alignment");
+        let (partition_header, _) =
+            PartitionHeader::ref_from_prefix(remain).expect("Invalid partition header alignment");
+
+        // Read DOL
+        let raw_dol = read_dol(inner.as_mut(), partition_header, false)?;
+        let raw_fst = read_fst(inner.as_mut(), partition_header, false)?;
+
+        // Parse FST
+        let fst = Fst::new(&raw_fst)?;
+        let mut gcm_files_start = u32::MAX;
+        for (_, node, _) in fst.iter() {
+            if node.is_file() {
+                let start = node.offset(false) as u32;
+                if start < gcm_files_start {
+                    gcm_files_start = start;
+                }
+            }
+        }
+
+        // Layout system files
+        let gcm_header_offset = SECTOR_SIZE as u32;
+        let fst_offset = gcm_header_offset + GCM_HEADER_SIZE as u32;
+        let dol_offset = align_up_32(fst_offset + partition_header.fst_size.get(), 32);
+        let user_size =
+            partition_header.user_offset.get() + partition_header.user_size.get() - gcm_files_start;
+        let user_end =
+            align_up_32(dol_offset + raw_dol.len() as u32 + user_size, SECTOR_SIZE as u32);
+        let user_offset = user_end - user_size;
+
+        let header = TGCHeader {
+            magic: TGC_MAGIC,
+            version: 0.into(),
+            header_offset: gcm_header_offset.into(),
+            header_size: (GCM_HEADER_SIZE as u32).into(),
+            fst_offset: fst_offset.into(),
+            fst_size: partition_header.fst_size,
+            fst_max_size: partition_header.fst_max_size,
+            dol_offset: dol_offset.into(),
+            dol_size: (raw_dol.len() as u32).into(),
+            user_offset: user_offset.into(),
+            user_size: user_size.into(),
+            banner_offset: 0.into(),
+            banner_size: 0.into(),
+            gcm_files_start: gcm_files_start.into(),
+        };
+        let mut buffer = BytesMut::with_capacity(user_offset as usize);
+        buffer.put_slice(header.as_bytes());
+        buffer.put_bytes(0, gcm_header_offset as usize - buffer.len());
+
+        // Write GCM header
+        buffer.put_slice(raw_header.as_ref());
+        buffer.put_bytes(0, fst_offset as usize - buffer.len());
+
+        // Write FST
+        buffer.put_slice(raw_fst.as_ref());
+        buffer.put_bytes(0, dol_offset as usize - buffer.len());
+
+        // Write DOL
+        buffer.put_slice(raw_dol.as_ref());
+        buffer.put_bytes(0, user_offset as usize - buffer.len());
+
+        let header_data = buffer.freeze();
+        Ok(Box::new(Self { inner, header, header_data, output_size: user_end as u64 }))
+    }
+}
+
+impl DiscWriter for DiscWriterTGC {
+    fn process(
+        &self,
+        data_callback: &mut DataCallback,
+        _options: &ProcessOptions,
+    ) -> Result<DiscFinalization> {
+        let mut data_position = self.header.user_offset.get() as u64;
+        data_callback(self.header_data.clone(), data_position, self.output_size)
+            .context("Failed to write TGC header")?;
+
+        // Write user data serially
+        let mut inner = self.inner.clone();
+        inner
+            .seek(SeekFrom::Start(self.header.gcm_files_start.get() as u64))
+            .context("Seeking to GCM files start")?;
+        loop {
+            // TODO use DiscReader::fill_buf_internal
+            let buf = inner
+                .fill_buf()
+                .with_context(|| format!("Reading disc data at offset {data_position}"))?;
+            let len = buf.len();
+            if len == 0 {
+                break;
+            }
+            data_position += len as u64;
+            data_callback(Bytes::copy_from_slice(buf), data_position, self.output_size)
+                .context("Failed to write disc data")?;
+            inner.consume(len);
+        }
+
+        Ok(DiscFinalization::default())
+    }
+
+    fn progress_bound(&self) -> u64 { self.output_size }
+
+    fn weight(&self) -> DiscWriterWeight { DiscWriterWeight::Light }
+}

nod/src/io/wbfs.rs

@@ -2,17 +2,34 @@ use std::{
     io,
     io::{Read, Seek, SeekFrom},
     mem::size_of,
+    sync::Arc,
 };
 
-use zerocopy::{big_endian::*, FromBytes, Immutable, IntoBytes, KnownLayout};
+use bytes::{BufMut, Bytes, BytesMut};
+use zerocopy::{big_endian::*, FromBytes, FromZeros, Immutable, IntoBytes, KnownLayout};
 
 use crate::{
-    io::{
-        block::{Block, BlockIO, DiscStream, PartitionInfo, WBFS_MAGIC},
-        nkit::NKitHeader,
-        DiscMeta, Format, MagicBytes,
+    common::{Compression, Format, MagicBytes},
+    disc::{
+        reader::DiscReader,
+        writer::{
+            check_block, par_process, read_block, BlockProcessor, BlockResult, CheckBlockResult,
+            DataCallback, DiscWriter,
         },
-    util::read::{read_box_slice, read_from},
+        SECTOR_SIZE,
+    },
+    io::{
+        block::{Block, BlockKind, BlockReader, WBFS_MAGIC},
+        nkit::{JunkBits, NKitHeader},
+    },
+    read::{DiscMeta, DiscStream},
+    util::{
+        array_ref,
+        digest::DigestManager,
+        lfg::LaggedFibonacci,
+        read::{read_arc_slice, read_box_slice, read_from},
+    },
+    write::{DiscFinalization, DiscWriterWeight, FormatOptions, ProcessOptions},
     Error, Result, ResultContext,
 };
 
@@ -23,7 +40,8 @@ struct WBFSHeader {
     num_sectors: U32,
     sector_size_shift: u8,
     block_size_shift: u8,
-    _pad: [u8; 2],
+    version: u8,
+    _pad: u8,
 }
 
 impl WBFSHeader {
@@ -36,19 +54,20 @@ impl WBFSHeader {
 
 const DISC_HEADER_SIZE: usize = 0x100;
 const NUM_WII_SECTORS: u32 = 143432 * 2; // Double layer discs
+const NKIT_HEADER_OFFSET: u64 = 0x10000;
 
 #[derive(Clone)]
-pub struct DiscIOWBFS {
+pub struct BlockReaderWBFS {
     inner: Box<dyn DiscStream>,
     /// WBFS header
     header: WBFSHeader,
     /// Map of Wii LBAs to WBFS LBAs
-    block_map: Box<[U16]>,
+    block_map: Arc<[U16]>,
     /// Optional NKit header
     nkit_header: Option<NKitHeader>,
 }
 
-impl DiscIOWBFS {
+impl BlockReaderWBFS {
     pub fn new(mut inner: Box<dyn DiscStream>) -> Result<Box<Self>> {
         inner.seek(SeekFrom::Start(0)).context("Seeking to start")?;
         let header: WBFSHeader = read_from(inner.as_mut()).context("Reading WBFS header")?;
@@ -81,39 +100,36 @@ impl DiscIOWBFS {
         inner
             .seek(SeekFrom::Start(header.sector_size() as u64 + DISC_HEADER_SIZE as u64))
             .context("Seeking to WBFS LBA table")?; // Skip header
-        let block_map: Box<[U16]> = read_box_slice(inner.as_mut(), header.max_blocks() as usize)
+        let block_map: Arc<[U16]> = read_arc_slice(inner.as_mut(), header.max_blocks() as usize)
             .context("Reading WBFS LBA table")?;
 
         // Read NKit header if present (always at 0x10000)
-        inner.seek(SeekFrom::Start(0x10000)).context("Seeking to NKit header")?;
+        inner.seek(SeekFrom::Start(NKIT_HEADER_OFFSET)).context("Seeking to NKit header")?;
         let nkit_header = NKitHeader::try_read_from(inner.as_mut(), header.block_size(), true);
 
         Ok(Box::new(Self { inner, header, block_map, nkit_header }))
     }
 }
 
-impl BlockIO for DiscIOWBFS {
-    fn read_block_internal(
-        &mut self,
-        out: &mut [u8],
-        block: u32,
-        partition: Option<&PartitionInfo>,
-    ) -> io::Result<Block> {
+impl BlockReader for BlockReaderWBFS {
+    fn read_block(&mut self, out: &mut [u8], sector: u32) -> io::Result<Block> {
         let block_size = self.header.block_size();
-        if block >= self.header.max_blocks() {
-            return Ok(Block::Zero);
+        let block_idx = ((sector as u64 * SECTOR_SIZE as u64) / block_size as u64) as u32;
+        if block_idx >= self.header.max_blocks() {
+            // Out of bounds
+            return Ok(Block::new(block_idx, block_size, BlockKind::None));
         }
 
         // Find the block in the map
-        let phys_block = self.block_map[block as usize].get();
+        let phys_block = self.block_map[block_idx as usize].get();
         if phys_block == 0 {
             // Check if block is junk data
-            if self.nkit_header.as_ref().and_then(|h| h.is_junk_block(block)).unwrap_or(false) {
-                return Ok(Block::Junk);
+            if self.nkit_header.as_ref().and_then(|h| h.is_junk_block(block_idx)).unwrap_or(false) {
+                return Ok(Block::new(block_idx, block_size, BlockKind::Junk));
             }
 
             // Otherwise, read zeroes
-            return Ok(Block::Zero);
+            return Ok(Block::new(block_idx, block_size, BlockKind::Zero));
         }
 
         // Read block
@@ -121,13 +137,10 @@ impl BlockIO for DiscIOWBFS {
         self.inner.seek(SeekFrom::Start(block_start))?;
         self.inner.read_exact(out)?;
 
-        match partition {
-            Some(partition) if partition.has_encryption => Ok(Block::PartEncrypted),
-            _ => Ok(Block::Raw),
-        }
+        Ok(Block::new(block_idx, block_size, BlockKind::Raw))
     }
 
-    fn block_size_internal(&self) -> u32 { self.header.block_size() }
+    fn block_size(&self) -> u32 { self.header.block_size() }
 
     fn meta(&self) -> DiscMeta {
         let mut result = DiscMeta {
@@ -141,3 +154,228 @@ impl BlockIO for DiscIOWBFS {
         result
     }
 }
+
+struct BlockProcessorWBFS {
+    inner: DiscReader,
+    header: WBFSHeader,
+    decrypted_block: Box<[u8]>,
+    lfg: LaggedFibonacci,
+    disc_id: [u8; 4],
+    disc_num: u8,
+}
+
+impl Clone for BlockProcessorWBFS {
+    fn clone(&self) -> Self {
+        let block_size = self.header.block_size() as usize;
+        Self {
+            inner: self.inner.clone(),
+            header: self.header.clone(),
+            decrypted_block: <[u8]>::new_box_zeroed_with_elems(block_size).unwrap(),
+            lfg: LaggedFibonacci::default(),
+            disc_id: self.disc_id,
+            disc_num: self.disc_num,
+        }
+    }
+}
+
+impl BlockProcessor for BlockProcessorWBFS {
+    type BlockMeta = CheckBlockResult;
+
+    fn process_block(&mut self, block_idx: u32) -> io::Result<BlockResult<Self::BlockMeta>> {
+        let block_size = self.header.block_size() as usize;
+        let input_position = block_idx as u64 * block_size as u64;
+        self.inner.seek(SeekFrom::Start(input_position))?;
+        let (block_data, disc_data) = read_block(&mut self.inner, block_size)?;
+
+        // Check if block is zeroed or junk
+        let result = match check_block(
+            disc_data.as_ref(),
+            &mut self.decrypted_block,
+            input_position,
+            self.inner.partitions(),
+            &mut self.lfg,
+            self.disc_id,
+            self.disc_num,
+        )? {
+            CheckBlockResult::Normal => {
+                BlockResult { block_idx, disc_data, block_data, meta: CheckBlockResult::Normal }
+            }
+            CheckBlockResult::Zeroed => BlockResult {
+                block_idx,
+                disc_data,
+                block_data: Bytes::new(),
+                meta: CheckBlockResult::Zeroed,
+            },
+            CheckBlockResult::Junk => BlockResult {
+                block_idx,
+                disc_data,
+                block_data: Bytes::new(),
+                meta: CheckBlockResult::Junk,
+            },
+        };
+        Ok(result)
+    }
+}
+
+#[derive(Clone)]
+pub struct DiscWriterWBFS {
+    inner: DiscReader,
+    header: WBFSHeader,
+    disc_table: Box<[u8]>,
+    block_count: u16,
+}
+
+pub const DEFAULT_BLOCK_SIZE: u32 = 0x200000; // 2 MiB
+
+impl DiscWriterWBFS {
+    pub fn new(mut inner: DiscReader, options: &FormatOptions) -> Result<Box<dyn DiscWriter>> {
+        if options.format != Format::Wbfs {
+            return Err(Error::DiscFormat("Invalid format for WBFS writer".to_string()));
+        }
+        if options.compression != Compression::None {
+            return Err(Error::DiscFormat("WBFS does not support compression".to_string()));
+        }
+        let block_size = options.block_size;
+        if block_size < SECTOR_SIZE as u32 || block_size % SECTOR_SIZE as u32 != 0 {
+            return Err(Error::DiscFormat("Invalid block size for WBFS".to_string()));
+        }
+        let sector_size = 512u32;
+
+        let disc_size = inner.disc_size();
+        let block_count = disc_size.div_ceil(block_size as u64);
+        if block_count > u16::MAX as u64 {
+            return Err(Error::DiscFormat("Block size too small".to_string()));
+        }
+        let block_count = block_count as u16;
+
+        // Create header
+        let header = WBFSHeader {
+            magic: WBFS_MAGIC,
+            num_sectors: 0.into(), // Written during finalization
+            sector_size_shift: sector_size.trailing_zeros() as u8,
+            block_size_shift: block_size.trailing_zeros() as u8,
+            version: 1,
+            _pad: 0,
+        };
+
+        // Create disc table
+        let mut disc_table =
+            <[u8]>::new_box_zeroed_with_elems(sector_size as usize - size_of::<WBFSHeader>())?;
+        disc_table[0] = 1;
+
+        let mut header_size = size_of::<WBFSHeader>();
+        header_size += size_of_val(disc_table.as_ref());
+        header_size += DISC_HEADER_SIZE;
+        header_size += header.max_blocks() as usize * size_of::<U16>();
+        if header_size > block_size as usize {
+            return Err(Error::Other("WBFS info too large for block".to_string()));
+        }
+
+        inner.seek(SeekFrom::Start(0)).context("Seeking to start")?;
+        Ok(Box::new(Self { inner, header, disc_table, block_count }))
+    }
+}
+
+impl DiscWriter for DiscWriterWBFS {
+    fn process(
+        &self,
+        data_callback: &mut DataCallback,
+        options: &ProcessOptions,
+    ) -> Result<DiscFinalization> {
+        let block_size = self.header.block_size();
+        let max_blocks = self.header.max_blocks();
+        let mut block_map = <[U16]>::new_box_zeroed_with_elems(max_blocks as usize)?;
+
+        let disc_size = self.inner.disc_size();
+        let mut header_data = BytesMut::with_capacity(block_size as usize);
+        header_data.put_slice(self.header.as_bytes());
+        header_data.put_slice(self.disc_table.as_ref());
+        header_data.put_slice(&self.inner.header().as_bytes()[..DISC_HEADER_SIZE]);
+        header_data.put_slice(block_map.as_bytes());
+        header_data.resize(block_size as usize, 0);
+        data_callback(header_data.freeze(), 0, disc_size).context("Failed to write header")?;
+
+        // Determine junk data values
+        let disc_header = self.inner.header();
+        let disc_id = *array_ref![disc_header.game_id, 0, 4];
+        let disc_num = disc_header.disc_num;
+
+        // Create hashers
+        let digest = DigestManager::new(options);
+        let mut junk_bits = JunkBits::new(block_size);
+        let mut input_position = 0;
+
+        let mut phys_block = 1;
+        par_process(
+            || BlockProcessorWBFS {
+                inner: self.inner.clone(),
+                header: self.header.clone(),
+                decrypted_block: <[u8]>::new_box_zeroed_with_elems(block_size as usize).unwrap(),
+                lfg: LaggedFibonacci::default(),
+                disc_id,
+                disc_num,
+            },
+            self.block_count as u32,
+            options.processor_threads,
+            |block| -> Result<()> {
+                // Update hashers
+                let disc_data_len = block.disc_data.len() as u64;
+                digest.send(block.disc_data);
+
+                // Check if block is zeroed or junk
+                match block.meta {
+                    CheckBlockResult::Normal => {
+                        block_map[block.block_idx as usize] = phys_block.into();
+                        phys_block += 1;
+                    }
+                    CheckBlockResult::Zeroed => {}
+                    CheckBlockResult::Junk => {
+                        junk_bits.set(block.block_idx, true);
+                    }
+                }
+
+                input_position += disc_data_len;
+                data_callback(block.block_data.clone(), input_position, disc_size)
+                    .with_context(|| format!("Failed to write block {}", block.block_idx))?;
+                Ok(())
+            },
+        )?;
+
+        // Collect hash results
+        let digest_results = digest.finish();
+        let mut nkit_header = NKitHeader {
+            version: 2,
+            size: Some(disc_size),
+            crc32: None,
+            md5: None,
+            sha1: None,
+            xxh64: None,
+            junk_bits: Some(junk_bits),
+            encrypted: true,
+        };
+        nkit_header.apply_digests(&digest_results);
+
+        // Update header
+        let mut header = self.header.clone();
+        header.num_sectors = (((phys_block as u64 * header.block_size() as u64)
+            / header.sector_size() as u64) as u32)
+            .into();
+        let mut header_data = BytesMut::with_capacity(block_size as usize);
+        header_data.put_slice(header.as_bytes());
+        header_data.put_slice(&self.disc_table);
+        header_data.put_slice(&self.inner.header().as_bytes()[..DISC_HEADER_SIZE]);
+        header_data.put_slice(block_map.as_bytes());
+        header_data.resize(NKIT_HEADER_OFFSET as usize, 0);
+        let mut w = header_data.writer();
+        nkit_header.write_to(&mut w).context("Writing NKit header")?;
+        let header_data = w.into_inner().freeze();
+
+        let mut finalization = DiscFinalization { header: header_data, ..Default::default() };
+        finalization.apply_digests(&digest_results);
+        Ok(finalization)
+    }
+
+    fn progress_bound(&self) -> u64 { self.inner.disc_size() }
+
+    fn weight(&self) -> DiscWriterWeight { DiscWriterWeight::Medium }
+}

nod/src/lib.rs

@@ -1,4 +1,5 @@
-#![warn(missing_docs, clippy::missing_inline_in_public_items)]
+#![allow(clippy::new_ret_no_self)]
+#![warn(missing_docs)]
 //! Library for traversing & reading Nintendo Optical Disc (GameCube and Wii) images.
 //!
 //! Originally based on the C++ library [nod](https://github.com/AxioDL/nod),
@@ -11,6 +12,7 @@
 //! - CISO (+ NKit 2 lossless)
 //! - NFS (Wii U VC)
 //! - GCZ
+//! - TGC
 //!
 //! # Examples
 //!
@@ -19,17 +21,21 @@
 //! ```no_run
 //! use std::io::Read;
 //!
+//! use nod::{
+//!     common::PartitionKind,
+//!     read::{DiscOptions, DiscReader, PartitionOptions},
+//! };
+//!
 //! // Open a disc image and the first data partition.
-//! let disc = nod::Disc::new("path/to/file.iso")
-//!     .expect("Failed to open disc");
-//! let mut partition = disc.open_partition_kind(nod::PartitionKind::Data)
+//! let disc =
+//!     DiscReader::new("path/to/file.iso", &DiscOptions::default()).expect("Failed to open disc");
+//! let mut partition = disc
+//!     .open_partition_kind(PartitionKind::Data, &PartitionOptions::default())
 //!     .expect("Failed to open data partition");
 //!
 //! // Read partition metadata and the file system table.
-//! let meta = partition.meta()
-//!     .expect("Failed to read partition metadata");
-//! let fst = meta.fst()
-//!     .expect("File system table is invalid");
+//! let meta = partition.meta().expect("Failed to read partition metadata");
+//! let fst = meta.fst().expect("File system table is invalid");
 //!
 //! // Find a file by path and read it into a string.
 //! if let Some((_, node)) = fst.find("/MP3/Worlds.txt") {
@@ -46,38 +52,106 @@
 //! Converting a disc image to raw ISO:
 //!
 //! ```no_run
-//! // Enable `PartitionEncryptionMode::Original` to ensure the output is a valid ISO.
-//! let options = nod::OpenOptions { partition_encryption: nod::PartitionEncryptionMode::Original };
-//! let mut disc = nod::Disc::new_with_options("path/to/file.rvz", &options)
-//!     .expect("Failed to open disc");
+//! use nod::read::{DiscOptions, DiscReader, PartitionEncryption};
 //!
-//! // Read directly from the open disc and write to the output file.
-//! let mut out = std::fs::File::create("output.iso")
-//!     .expect("Failed to create output file");
-//! std::io::copy(&mut disc, &mut out)
-//!     .expect("Failed to write data");
+//! let options = DiscOptions {
+//!     partition_encryption: PartitionEncryption::Original,
+//!     // Use 4 threads to preload data as the disc is read. This can speed up sequential reads,
+//!     // especially when the disc image format uses compression.
+//!     preloader_threads: 4,
+//! };
+//! // Open a disc image.
+//! let mut disc = DiscReader::new("path/to/file.rvz", &options).expect("Failed to open disc");
+//!
+//! // Create a new output file.
+//! let mut out = std::fs::File::create("output.iso").expect("Failed to create output file");
+//! // Read directly from the DiscReader and write to the output file.
+//! // NOTE: Any copy method that accepts `Read` and `Write` can be used here,
+//! // such as `std::io::copy`. This example utilizes `BufRead` for efficiency,
+//! // since `DiscReader` has its own internal buffer.
+//! nod::util::buf_copy(&mut disc, &mut out).expect("Failed to write data");
 //! ```
+//!
+//! Converting a disc image to RVZ:
+//!
+//! ```no_run
+//! use std::fs::File;
+//! use std::io::{Seek, Write};
+//! use nod::common::{Compression, Format};
+//! use nod::read::{DiscOptions, DiscReader, PartitionEncryption};
+//! use nod::write::{DiscWriter, DiscWriterWeight, FormatOptions, ProcessOptions};
+//!
+//! let open_options = DiscOptions {
+//!     partition_encryption: PartitionEncryption::Original,
+//!     // Use 4 threads to preload data as the disc is read. This can speed up sequential reads,
+//!     // especially when the disc image format uses compression.
+//!     preloader_threads: 4,
+//! };
+//! // Open a disc image.
+//! let disc = DiscReader::new("path/to/file.iso", &open_options)
+//!     .expect("Failed to open disc");
+//! // Create a new output file.
+//! let mut output_file = File::create("output.rvz")
+//!     .expect("Failed to create output file");
+//!
+//! let options = FormatOptions {
+//!     format: Format::Rvz,
+//!     compression: Compression::Zstandard(19),
+//!     block_size: Format::Rvz.default_block_size(),
+//! };
+//! // Create a disc writer with the desired output format.
+//! let mut writer = DiscWriter::new(disc, &options)
+//!     .expect("Failed to create writer");
+//!
+//! // Ideally we'd base this on the actual number of CPUs available.
+//! // This is just an example.
+//! let num_threads = match writer.weight() {
+//!     DiscWriterWeight::Light => 0,
+//!     DiscWriterWeight::Medium => 4,
+//!     DiscWriterWeight::Heavy => 12,
+//! };
+//! let process_options = ProcessOptions {
+//!     processor_threads: num_threads,
+//!     // Enable checksum calculation for the _original_ disc data.
+//!     // Digests will be stored in the output file for verification, if supported.
+//!     // They will also be returned in the finalization result.
+//!     digest_crc32: true,
+//!     digest_md5: false, // MD5 is slow, skip it
+//!     digest_sha1: true,
+//!     digest_xxh64: true,
+//! };
+//! // Start processing the disc image.
+//! let finalization = writer.process(
+//!     |data, _progress, _total| {
+//!         output_file.write_all(data.as_ref())?;
+//!         // One could display progress here, if desired.
+//!         Ok(())
+//!     },
+//!     &process_options
+//! )
+//! .expect("Failed to process disc image");
+//!
+//! // Some disc writers calculate data during processing.
+//! // If the finalization returns header data, seek to the beginning of the file and write it.
+//! if !finalization.header.is_empty() {
+//!     output_file.seek(std::io::SeekFrom::Start(0))
+//!         .expect("Failed to seek");
+//!     output_file.write_all(finalization.header.as_ref())
+//!         .expect("Failed to write header");
+//! }
+//! output_file.flush().expect("Failed to flush output file");
+//!
+//! // Display the calculated digests.
+//! println!("CRC32: {:08X}", finalization.crc32.unwrap());
+//! // ...
 
-use std::{
-    io::{BufRead, Read, Seek},
-    path::Path,
-};
-
-pub use disc::{
-    ApploaderHeader, ContentMetadata, DiscHeader, DolHeader, FileStream, Fst, Node, NodeKind,
-    OwnedFileStream, PartitionBase, PartitionHeader, PartitionKind, PartitionMeta, SignedHeader,
-    Ticket, TicketLimit, TmdHeader, WindowedStream, BI2_SIZE, BOOT_SIZE, DL_DVD_SIZE, GCN_MAGIC,
-    MINI_DVD_SIZE, REGION_SIZE, SECTOR_SIZE, SL_DVD_SIZE, WII_MAGIC,
-};
-pub use io::{
-    block::{DiscStream, PartitionInfo},
-    Compression, DiscMeta, Format, KeyBytes, MagicBytes,
-};
-pub use util::lfg::LaggedFibonacci;
-
-mod disc;
-mod io;
-mod util;
+pub mod build;
+pub mod common;
+pub mod disc;
+pub(crate) mod io;
+pub mod read;
+pub mod util;
+pub mod write;
 
 /// Error types for nod.
 #[derive(thiserror::Error, Debug)]
@@ -91,9 +165,6 @@ pub enum Error {
     /// An unknown error.
     #[error("error: {0}")]
     Other(String),
-    /// An error occurred while allocating memory.
-    #[error("allocation failed")]
-    Alloc(zerocopy::AllocError),
 }
 
 impl From<&str> for Error {
@@ -108,7 +179,12 @@ impl From<String> for Error {
 
 impl From<zerocopy::AllocError> for Error {
     #[inline]
-    fn from(e: zerocopy::AllocError) -> Error { Error::Alloc(e) }
+    fn from(_: zerocopy::AllocError) -> Error {
+        Error::Io(
+            "allocation failed".to_string(),
+            std::io::Error::from(std::io::ErrorKind::OutOfMemory),
+        )
+    }
 }
 
 /// Helper result type for [`Error`].
@@ -149,178 +225,3 @@ where E: ErrorContext
         self.map_err(|e| e.context(f()))
     }
 }
-
-/// Wii partition encryption mode.
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
-pub enum PartitionEncryptionMode {
-    /// Partition data is read as it's stored in the underlying disc format.
-    /// For example, WIA/RVZ partitions are stored decrypted, so this avoids
-    /// rebuilding the partition encryption and hash data if it will only be
-    /// read via [`PartitionBase`]. If it's desired to read a full disc image
-    /// via [`Disc`], use [`PartitionEncryptionMode::Original`] instead.
-    #[default]
-    AsIs,
-    /// Partition encryption and hashes are rebuilt to match its original state,
-    /// if necessary. This is used for converting or verifying a disc image.
-    Original,
-    /// Partition data will be encrypted if reading a decrypted disc image.
-    /// Modifies the disc header to mark partition data as encrypted.
-    ForceEncrypted,
-    /// Partition data will be decrypted if reading an encrypted disc image.
-    /// Modifies the disc header to mark partition data as decrypted.
-    ForceDecrypted,
-}
-
-/// Options for opening a disc image.
-#[derive(Default, Debug, Clone)]
-pub struct OpenOptions {
-    /// Wii: Partition encryption mode. By default, partitions are read as they
-    /// are stored in the underlying disc format, avoiding extra work when the
-    /// underlying format stores them decrypted (e.g. WIA/RVZ).
-    ///
-    /// This can be changed to [`PartitionEncryptionMode::Original`] to rebuild
-    /// partition encryption and hashes to match its original state for conversion
-    /// or verification.
-    pub partition_encryption: PartitionEncryptionMode,
-}
-
-/// Options for opening a partition.
-#[derive(Default, Debug, Clone)]
-pub struct PartitionOptions {
-    /// Wii: Validate data hashes while reading the partition, if available.
-    /// To ensure hashes are present, regardless of the underlying disc format,
-    /// set [`OpenOptions::partition_encryption`] to [`PartitionEncryptionMode::Original`].
-    pub validate_hashes: bool,
-}
-
-/// An open disc image and read stream.
-///
-/// This is the primary entry point for reading disc images.
-pub struct Disc {
-    reader: disc::reader::DiscReader,
-}
-
-impl Disc {
-    /// Opens a disc image from a file path.
-    #[inline]
-    pub fn new<P: AsRef<Path>>(path: P) -> Result<Disc> {
-        Disc::new_with_options(path, &OpenOptions::default())
-    }
-
-    /// Opens a disc image from a file path with custom options.
-    #[inline]
-    pub fn new_with_options<P: AsRef<Path>>(path: P, options: &OpenOptions) -> Result<Disc> {
-        let io = io::block::open(path.as_ref())?;
-        let reader = disc::reader::DiscReader::new(io, options)?;
-        Ok(Disc { reader })
-    }
-
-    /// Opens a disc image from a read stream.
-    #[inline]
-    pub fn new_stream(stream: Box<dyn DiscStream>) -> Result<Disc> {
-        Disc::new_stream_with_options(stream, &OpenOptions::default())
-    }
-
-    /// Opens a disc image from a read stream with custom options.
-    #[inline]
-    pub fn new_stream_with_options(
-        stream: Box<dyn DiscStream>,
-        options: &OpenOptions,
-    ) -> Result<Disc> {
-        let io = io::block::new(stream)?;
-        let reader = disc::reader::DiscReader::new(io, options)?;
-        Ok(Disc { reader })
-    }
-
-    /// Detects the format of a disc image from a read stream.
-    #[inline]
-    pub fn detect<R>(stream: &mut R) -> std::io::Result<Option<Format>>
-    where R: Read + ?Sized {
-        io::block::detect(stream)
-    }
-
-    /// The disc's primary header.
-    #[inline]
-    pub fn header(&self) -> &DiscHeader { self.reader.header() }
-
-    /// The Wii disc's region information.
-    ///
-    /// **GameCube**: This will return `None`.
-    #[inline]
-    pub fn region(&self) -> Option<&[u8; REGION_SIZE]> { self.reader.region() }
-
-    /// Returns extra metadata included in the disc file format, if any.
-    #[inline]
-    pub fn meta(&self) -> DiscMeta { self.reader.meta() }
-
-    /// The disc's size in bytes, or an estimate if not stored by the format.
-    #[inline]
-    pub fn disc_size(&self) -> u64 { self.reader.disc_size() }
-
-    /// A list of Wii partitions on the disc.
-    ///
-    /// **GameCube**: This will return an empty slice.
-    #[inline]
-    pub fn partitions(&self) -> &[PartitionInfo] { self.reader.partitions() }
-
-    /// Opens a decrypted partition read stream for the specified partition index.
-    ///
-    /// **GameCube**: `index` must always be 0.
-    #[inline]
-    pub fn open_partition(&self, index: usize) -> Result<Box<dyn PartitionBase>> {
-        self.open_partition_with_options(index, &PartitionOptions::default())
-    }
-
-    /// Opens a decrypted partition read stream for the specified partition index
-    /// with custom options.
-    ///
-    /// **GameCube**: `index` must always be 0.
-    #[inline]
-    pub fn open_partition_with_options(
-        &self,
-        index: usize,
-        options: &PartitionOptions,
-    ) -> Result<Box<dyn PartitionBase>> {
-        self.reader.open_partition(index, options)
-    }
-
-    /// Opens a decrypted partition read stream for the first partition matching
-    /// the specified kind.
-    ///
-    /// **GameCube**: `kind` must always be [`PartitionKind::Data`].
-    #[inline]
-    pub fn open_partition_kind(&self, kind: PartitionKind) -> Result<Box<dyn PartitionBase>> {
-        self.reader.open_partition_kind(kind, &PartitionOptions::default())
-    }
-
-    /// Opens a decrypted partition read stream for the first partition matching
-    /// the specified kind with custom options.
-    ///
-    /// **GameCube**: `kind` must always be [`PartitionKind::Data`].
-    #[inline]
-    pub fn open_partition_kind_with_options(
-        &self,
-        kind: PartitionKind,
-        options: &PartitionOptions,
-    ) -> Result<Box<dyn PartitionBase>> {
-        self.reader.open_partition_kind(kind, options)
-    }
-}
-
-impl BufRead for Disc {
-    #[inline]
-    fn fill_buf(&mut self) -> std::io::Result<&[u8]> { self.reader.fill_buf() }
-
-    #[inline]
-    fn consume(&mut self, amt: usize) { self.reader.consume(amt) }
-}
-
-impl Read for Disc {
-    #[inline]
-    fn read(&mut self, buf: &mut [u8]) -> std::io::Result<usize> { self.reader.read(buf) }
-}
-
-impl Seek for Disc {
-    #[inline]
-    fn seek(&mut self, pos: std::io::SeekFrom) -> std::io::Result<u64> { self.reader.seek(pos) }
-}

nod/src/read.rs

@@ -0,0 +1,376 @@
+//! [`DiscReader`] and associated types.
+use std::{
+    io::{BufRead, Read, Seek},
+    path::Path,
+    sync::Arc,
+};
+
+use dyn_clone::DynClone;
+use zerocopy::FromBytes;
+
+use crate::{
+    common::{Compression, Format, PartitionInfo, PartitionKind},
+    disc,
+    disc::{
+        fst::{Fst, Node},
+        wii::{ContentMetadata, Ticket, TmdHeader, H3_TABLE_SIZE, REGION_SIZE},
+        ApploaderHeader, DiscHeader, DolHeader, PartitionHeader, BI2_SIZE, BOOT_SIZE,
+    },
+    io::block,
+    util::WindowedReader,
+    Result,
+};
+
+/// Wii partition encryption mode.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Default, Hash)]
+pub enum PartitionEncryption {
+    /// Partition encryption and hashes are rebuilt to match its original state,
+    /// if necessary. This is used for converting or verifying a disc image.
+    #[default]
+    Original,
+    /// Partition data will be encrypted if reading a decrypted disc image.
+    /// Modifies the disc header to mark partition data as encrypted.
+    ForceEncrypted,
+    /// Partition data will be decrypted if reading an encrypted disc image.
+    /// Modifies the disc header to mark partition data as decrypted.
+    ForceDecrypted,
+    /// Partition data will be decrypted if reading an encrypted disc image.
+    /// Modifies the disc header to mark partition data as decrypted.
+    /// Hashes are removed from the partition data.
+    ForceDecryptedNoHashes,
+}
+
+/// Options for opening a disc image.
+#[derive(Default, Debug, Clone)]
+pub struct DiscOptions {
+    /// Wii: Partition encryption mode. This affects how partition data appears when
+    /// reading directly from [`DiscReader`], and can be used to convert between
+    /// encrypted and decrypted disc images.
+    pub partition_encryption: PartitionEncryption,
+    /// Number of threads to use for preloading data as the disc is read. This
+    /// is particularly useful when reading the disc image sequentially, as it
+    /// can perform decompression and rebuilding in parallel with the main
+    /// read thread. The default value of 0 disables preloading.
+    pub preloader_threads: usize,
+}
+
+/// Options for opening a partition.
+#[derive(Default, Debug, Clone)]
+pub struct PartitionOptions {
+    /// Wii: Validate data hashes while reading the partition, if available.
+    pub validate_hashes: bool,
+}
+
+/// Required trait bounds for reading disc images.
+pub trait DiscStream: Read + Seek + DynClone + Send + Sync {}
+
+impl<T> DiscStream for T where T: Read + Seek + DynClone + Send + Sync + ?Sized {}
+
+dyn_clone::clone_trait_object!(DiscStream);
+
+/// An open disc image and read stream.
+///
+/// This is the primary entry point for reading disc images.
+#[derive(Clone)]
+pub struct DiscReader {
+    inner: disc::reader::DiscReader,
+}
+
+impl DiscReader {
+    /// Opens a disc image from a file path.
+    #[inline]
+    pub fn new<P: AsRef<Path>>(path: P, options: &DiscOptions) -> Result<DiscReader> {
+        let io = block::open(path.as_ref())?;
+        let inner = disc::reader::DiscReader::new(io, options)?;
+        Ok(DiscReader { inner })
+    }
+
+    /// Opens a disc image from a read stream.
+    #[inline]
+    pub fn new_stream(stream: Box<dyn DiscStream>, options: &DiscOptions) -> Result<DiscReader> {
+        let io = block::new(stream)?;
+        let reader = disc::reader::DiscReader::new(io, options)?;
+        Ok(DiscReader { inner: reader })
+    }
+
+    /// Detects the format of a disc image from a read stream.
+    #[inline]
+    pub fn detect<R>(stream: &mut R) -> std::io::Result<Option<Format>>
+    where R: Read + ?Sized {
+        block::detect(stream)
+    }
+
+    /// The disc's primary header.
+    #[inline]
+    pub fn header(&self) -> &DiscHeader { self.inner.header() }
+
+    /// The Wii disc's region information.
+    ///
+    /// **GameCube**: This will return `None`.
+    #[inline]
+    pub fn region(&self) -> Option<&[u8; REGION_SIZE]> { self.inner.region() }
+
+    /// Returns extra metadata included in the disc file format, if any.
+    #[inline]
+    pub fn meta(&self) -> DiscMeta { self.inner.meta() }
+
+    /// The disc's size in bytes, or an estimate if not stored by the format.
+    #[inline]
+    pub fn disc_size(&self) -> u64 { self.inner.disc_size() }
+
+    /// A list of Wii partitions on the disc.
+    ///
+    /// **GameCube**: This will return an empty slice.
+    #[inline]
+    pub fn partitions(&self) -> &[PartitionInfo] { self.inner.partitions() }
+
+    /// Opens a decrypted partition read stream for the specified partition index.
+    ///
+    /// **GameCube**: `index` must always be 0.
+    #[inline]
+    pub fn open_partition(
+        &self,
+        index: usize,
+        options: &PartitionOptions,
+    ) -> Result<Box<dyn PartitionReader>> {
+        self.inner.open_partition(index, options)
+    }
+
+    /// Opens a decrypted partition read stream for the first partition matching
+    /// the specified kind.
+    ///
+    /// **GameCube**: `kind` must always be [`PartitionKind::Data`].
+    #[inline]
+    pub fn open_partition_kind(
+        &self,
+        kind: PartitionKind,
+        options: &PartitionOptions,
+    ) -> Result<Box<dyn PartitionReader>> {
+        self.inner.open_partition_kind(kind, options)
+    }
+
+    pub(crate) fn into_inner(self) -> disc::reader::DiscReader { self.inner }
+}
+
+impl BufRead for DiscReader {
+    #[inline]
+    fn fill_buf(&mut self) -> std::io::Result<&[u8]> { self.inner.fill_buf() }
+
+    #[inline]
+    fn consume(&mut self, amt: usize) { self.inner.consume(amt) }
+}
+
+impl Read for DiscReader {
+    #[inline]
+    fn read(&mut self, buf: &mut [u8]) -> std::io::Result<usize> { self.inner.read(buf) }
+}
+
+impl Seek for DiscReader {
+    #[inline]
+    fn seek(&mut self, pos: std::io::SeekFrom) -> std::io::Result<u64> { self.inner.seek(pos) }
+}
+
+/// Extra metadata about the underlying disc file format.
+#[derive(Debug, Clone, Default)]
+pub struct DiscMeta {
+    /// The disc file format.
+    pub format: Format,
+    /// The format's compression algorithm.
+    pub compression: Compression,
+    /// If the format uses blocks, the block size in bytes.
+    pub block_size: Option<u32>,
+    /// Whether Wii partitions are stored decrypted in the format.
+    pub decrypted: bool,
+    /// Whether the format omits Wii partition data hashes.
+    pub needs_hash_recovery: bool,
+    /// Whether the format supports recovering the original disc data losslessly.
+    pub lossless: bool,
+    /// The original disc's size in bytes, if stored by the format.
+    pub disc_size: Option<u64>,
+    /// The original disc's CRC32 hash, if stored by the format.
+    pub crc32: Option<u32>,
+    /// The original disc's MD5 hash, if stored by the format.
+    pub md5: Option<[u8; 16]>,
+    /// The original disc's SHA-1 hash, if stored by the format.
+    pub sha1: Option<[u8; 20]>,
+    /// The original disc's XXH64 hash, if stored by the format.
+    pub xxh64: Option<u64>,
+}
+
+/// An open disc partition.
+pub trait PartitionReader: DynClone + BufRead + Seek + Send + Sync {
+    /// Whether this is a Wii partition. (GameCube otherwise)
+    fn is_wii(&self) -> bool;
+
+    /// Reads the partition header and file system table.
+    fn meta(&mut self) -> Result<PartitionMeta>;
+}
+
+/// A file reader borrowing a [`PartitionReader`].
+pub type FileReader<'a> = WindowedReader<&'a mut dyn PartitionReader>;
+
+/// A file reader owning a [`PartitionReader`].
+pub type OwnedFileReader = WindowedReader<Box<dyn PartitionReader>>;
+
+impl<'a> dyn PartitionReader + 'a {
+    /// Seeks the partition stream to the specified file system node
+    /// and returns a windowed stream.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    /// ```no_run
+    /// use std::io::Read;
+    ///
+    /// use nod::read::{DiscOptions, DiscReader, PartitionKind, PartitionOptions};
+    ///
+    /// fn main() -> nod::Result<()> {
+    ///     let disc = DiscReader::new("path/to/file.iso", &DiscOptions::default())?;
+    ///     let mut partition =
+    ///         disc.open_partition_kind(PartitionKind::Data, &PartitionOptions::default())?;
+    ///     let meta = partition.meta()?;
+    ///     let fst = meta.fst()?;
+    ///     if let Some((_, node)) = fst.find("/MP3/Worlds.txt") {
+    ///         let mut s = String::new();
+    ///         partition
+    ///             .open_file(node)
+    ///             .expect("Failed to open file stream")
+    ///             .read_to_string(&mut s)
+    ///             .expect("Failed to read file");
+    ///         println!("{}", s);
+    ///     }
+    ///     Ok(())
+    /// }
+    /// ```
+    pub fn open_file(&mut self, node: Node) -> std::io::Result<FileReader> {
+        if !node.is_file() {
+            return Err(std::io::Error::new(
+                std::io::ErrorKind::InvalidInput,
+                "Node is not a file".to_string(),
+            ));
+        }
+        let is_wii = self.is_wii();
+        FileReader::new(self, node.offset(is_wii), node.length() as u64)
+    }
+}
+
+impl dyn PartitionReader {
+    /// Consumes the partition instance and returns a windowed stream.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::Read;
+    ///
+    /// use nod::read::{DiscOptions, DiscReader, OwnedFileReader, PartitionKind, PartitionOptions};
+    ///
+    /// fn main() -> nod::Result<()> {
+    ///     let disc = DiscReader::new("path/to/file.iso", &DiscOptions::default())?;
+    ///     let mut partition =
+    ///         disc.open_partition_kind(PartitionKind::Data, &PartitionOptions::default())?;
+    ///     let meta = partition.meta()?;
+    ///     let fst = meta.fst()?;
+    ///     if let Some((_, node)) = fst.find("/disc.tgc") {
+    ///         let file: OwnedFileReader = partition
+    ///             .clone() // Clone the Box<dyn PartitionBase>
+    ///             .into_open_file(node) // Get an OwnedFileStream
+    ///             .expect("Failed to open file stream");
+    ///         // Open the inner disc image using the owned stream
+    ///         let inner_disc = DiscReader::new_stream(Box::new(file), &DiscOptions::default())
+    ///             .expect("Failed to open inner disc");
+    ///         // ...
+    ///     }
+    ///     Ok(())
+    /// }
+    /// ```
+    pub fn into_open_file(self: Box<Self>, node: Node) -> std::io::Result<OwnedFileReader> {
+        if !node.is_file() {
+            return Err(std::io::Error::new(
+                std::io::ErrorKind::InvalidInput,
+                "Node is not a file".to_string(),
+            ));
+        }
+        let is_wii = self.is_wii();
+        OwnedFileReader::new(self, node.offset(is_wii), node.length() as u64)
+    }
+}
+
+dyn_clone::clone_trait_object!(PartitionReader);
+
+/// Extra disc partition data. (DOL, FST, etc.)
+#[derive(Clone, Debug)]
+pub struct PartitionMeta {
+    /// Disc and partition header (boot.bin)
+    pub raw_boot: Arc<[u8; BOOT_SIZE]>,
+    /// Debug and region information (bi2.bin)
+    pub raw_bi2: Arc<[u8; BI2_SIZE]>,
+    /// Apploader (apploader.bin)
+    pub raw_apploader: Arc<[u8]>,
+    /// Main binary (main.dol)
+    pub raw_dol: Arc<[u8]>,
+    /// File system table (fst.bin)
+    pub raw_fst: Arc<[u8]>,
+    /// Ticket (ticket.bin, Wii only)
+    pub raw_ticket: Option<Arc<[u8]>>,
+    /// TMD (tmd.bin, Wii only)
+    pub raw_tmd: Option<Arc<[u8]>>,
+    /// Certificate chain (cert.bin, Wii only)
+    pub raw_cert_chain: Option<Arc<[u8]>>,
+    /// H3 hash table (h3.bin, Wii only)
+    pub raw_h3_table: Option<Arc<[u8; H3_TABLE_SIZE]>>,
+}
+
+impl PartitionMeta {
+    /// A view into the disc header.
+    #[inline]
+    pub fn header(&self) -> &DiscHeader {
+        DiscHeader::ref_from_bytes(&self.raw_boot[..size_of::<DiscHeader>()])
+            .expect("Invalid header alignment")
+    }
+
+    /// A view into the partition header.
+    #[inline]
+    pub fn partition_header(&self) -> &PartitionHeader {
+        PartitionHeader::ref_from_bytes(&self.raw_boot[size_of::<DiscHeader>()..])
+            .expect("Invalid partition header alignment")
+    }
+
+    /// A view into the apploader header.
+    #[inline]
+    pub fn apploader_header(&self) -> &ApploaderHeader {
+        ApploaderHeader::ref_from_prefix(&self.raw_apploader)
+            .expect("Invalid apploader alignment")
+            .0
+    }
+
+    /// A view into the file system table (FST).
+    #[inline]
+    pub fn fst(&self) -> Result<Fst, &'static str> { Fst::new(&self.raw_fst) }
+
+    /// A view into the DOL header.
+    #[inline]
+    pub fn dol_header(&self) -> &DolHeader {
+        DolHeader::ref_from_prefix(&self.raw_dol).expect("Invalid DOL alignment").0
+    }
+
+    /// A view into the ticket. (Wii only)
+    #[inline]
+    pub fn ticket(&self) -> Option<&Ticket> {
+        let raw_ticket = self.raw_ticket.as_deref()?;
+        Some(Ticket::ref_from_bytes(raw_ticket).expect("Invalid ticket alignment"))
+    }
+
+    /// A view into the TMD. (Wii only)
+    #[inline]
+    pub fn tmd_header(&self) -> Option<&TmdHeader> {
+        let raw_tmd = self.raw_tmd.as_deref()?;
+        Some(TmdHeader::ref_from_prefix(raw_tmd).expect("Invalid TMD alignment").0)
+    }
+
+    /// A view into the TMD content metadata. (Wii only)
+    #[inline]
+    pub fn content_metadata(&self) -> Option<&[ContentMetadata]> {
+        let raw_cmd = &self.raw_tmd.as_deref()?[size_of::<TmdHeader>()..];
+        Some(<[ContentMetadata]>::ref_from_bytes(raw_cmd).expect("Invalid CMD alignment"))
+    }
+}

nod/src/util/aes.rs

@@ -0,0 +1,136 @@
+use tracing::instrument;
+
+use crate::{
+    common::KeyBytes,
+    disc::{
+        wii::{HASHES_SIZE, SECTOR_DATA_SIZE},
+        SECTOR_SIZE,
+    },
+    util::array_ref,
+};
+
+#[cfg(feature = "openssl")]
+thread_local! {
+    static ENC_CIPHER_CTX: std::cell::RefCell<openssl::cipher_ctx::CipherCtx> = {
+        let cipher = openssl::cipher::Cipher::fetch(None, "AES-128-CBC", None).unwrap();
+        let mut ctx = openssl::cipher_ctx::CipherCtx::new().unwrap();
+        ctx.set_padding(false);
+        ctx.encrypt_init(Some(&cipher), None, None).unwrap();
+        std::cell::RefCell::new(ctx)
+    };
+    static DEC_CIPHER_CTX: std::cell::RefCell<openssl::cipher_ctx::CipherCtx> = {
+        let cipher = openssl::cipher::Cipher::fetch(None, "AES-128-CBC", None).unwrap();
+        let mut ctx = openssl::cipher_ctx::CipherCtx::new().unwrap();
+        ctx.set_padding(false);
+        ctx.decrypt_init(Some(&cipher), None, None).unwrap();
+        std::cell::RefCell::new(ctx)
+    };
+}
+
+/// Encrypts data in-place using AES-128-CBC with the given key and IV.
+pub fn aes_cbc_encrypt(key: &KeyBytes, iv: &KeyBytes, data: &mut [u8]) {
+    assert_eq!(data.len() % 16, 0);
+    #[cfg(not(feature = "openssl"))]
+    {
+        use aes::cipher::{block_padding::NoPadding, BlockModeEncrypt, KeyIvInit};
+        <cbc::Encryptor<aes::Aes128>>::new(key.into(), iv.into())
+            .encrypt_padded::<NoPadding>(data, data.len())
+            .unwrap();
+    }
+    #[cfg(feature = "openssl")]
+    ENC_CIPHER_CTX.with_borrow_mut(|ctx| {
+        ctx.encrypt_init(None, Some(key), Some(iv)).unwrap();
+        let len = unsafe {
+            // The openssl crate doesn't provide a safe API for using the same inbuf/outbuf.
+            // However, this is valid with AES-CBC and no padding. Create a copy of the input
+            // slice to appease the borrow checker.
+            let input = std::slice::from_raw_parts(data.as_ptr(), data.len());
+            ctx.cipher_update_unchecked(input, Some(data))
+        }
+        .unwrap();
+        assert_eq!(len, data.len());
+    });
+}
+
+/// Decrypts data in-place using AES-128-CBC with the given key and IV.
+pub fn aes_cbc_decrypt(key: &KeyBytes, iv: &KeyBytes, data: &mut [u8]) {
+    assert_eq!(data.len() % 16, 0);
+    #[cfg(not(feature = "openssl"))]
+    {
+        use aes::cipher::{block_padding::NoPadding, BlockModeDecrypt, KeyIvInit};
+        <cbc::Decryptor<aes::Aes128>>::new(key.into(), iv.into())
+            .decrypt_padded::<NoPadding>(data)
+            .unwrap();
+    }
+    #[cfg(feature = "openssl")]
+    DEC_CIPHER_CTX.with_borrow_mut(|ctx| {
+        ctx.decrypt_init(None, Some(key), Some(iv)).unwrap();
+        let len = unsafe {
+            // The openssl crate doesn't provide a safe API for using the same inbuf/outbuf.
+            // However, this is valid with AES-CBC and no padding. Create a copy of the input
+            // slice to appease the borrow checker.
+            let input = std::slice::from_raw_parts(data.as_ptr(), data.len());
+            ctx.cipher_update_unchecked(input, Some(data))
+        }
+        .unwrap();
+        assert_eq!(len, data.len());
+    });
+}
+
+/// Decrypts data buffer-to-buffer using AES-128-CBC with the given key and IV.
+pub fn aes_cbc_decrypt_b2b(key: &KeyBytes, iv: &KeyBytes, data: &[u8], out: &mut [u8]) {
+    assert_eq!(data.len() % 16, 0);
+    assert_eq!(data.len(), out.len());
+    #[cfg(not(feature = "openssl"))]
+    {
+        use aes::cipher::{block_padding::NoPadding, BlockModeDecrypt, KeyIvInit};
+        <cbc::Decryptor<aes::Aes128>>::new(key.into(), iv.into())
+            .decrypt_padded_b2b::<NoPadding>(data, out)
+            .unwrap();
+    }
+    #[cfg(feature = "openssl")]
+    DEC_CIPHER_CTX.with_borrow_mut(|ctx| {
+        ctx.decrypt_init(None, Some(key), Some(iv)).unwrap();
+        let len = unsafe { ctx.cipher_update_unchecked(data, Some(out)) }.unwrap();
+        assert_eq!(len, out.len());
+    });
+}
+
+/// Encrypts a Wii partition sector in-place.
+#[instrument(skip_all)]
+pub fn encrypt_sector(out: &mut [u8; SECTOR_SIZE], key: &KeyBytes) {
+    aes_cbc_encrypt(key, &[0u8; 16], &mut out[..HASHES_SIZE]);
+    // Data IV from encrypted hash block
+    let iv = *array_ref![out, 0x3D0, 16];
+    aes_cbc_encrypt(key, &iv, &mut out[HASHES_SIZE..]);
+}
+
+/// Decrypts a Wii partition sector in-place.
+#[instrument(skip_all)]
+pub fn decrypt_sector(out: &mut [u8; SECTOR_SIZE], key: &KeyBytes) {
+    // Data IV from encrypted hash block
+    let iv = *array_ref![out, 0x3D0, 16];
+    aes_cbc_decrypt(key, &[0u8; 16], &mut out[..HASHES_SIZE]);
+    aes_cbc_decrypt(key, &iv, &mut out[HASHES_SIZE..]);
+}
+
+/// Decrypts a Wii partition sector buffer-to-buffer.
+#[instrument(skip_all)]
+pub fn decrypt_sector_b2b(data: &[u8; SECTOR_SIZE], out: &mut [u8; SECTOR_SIZE], key: &KeyBytes) {
+    // Data IV from encrypted hash block
+    let iv = *array_ref![data, 0x3D0, 16];
+    aes_cbc_decrypt_b2b(key, &[0u8; 16], &data[..HASHES_SIZE], &mut out[..HASHES_SIZE]);
+    aes_cbc_decrypt_b2b(key, &iv, &data[HASHES_SIZE..], &mut out[HASHES_SIZE..]);
+}
+
+/// Decrypts a Wii partition sector data (excluding hashes) buffer-to-buffer.
+#[instrument(skip_all)]
+pub fn decrypt_sector_data_b2b(
+    data: &[u8; SECTOR_SIZE],
+    out: &mut [u8; SECTOR_DATA_SIZE],
+    key: &KeyBytes,
+) {
+    // Data IV from encrypted hash block
+    let iv = *array_ref![data, 0x3D0, 16];
+    aes_cbc_decrypt_b2b(key, &iv, &data[HASHES_SIZE..], out);
+}

nod/src/util/compress.rs

@@ -1,14 +1,333 @@
-/// Decodes the LZMA Properties byte (lc/lp/pb).
-/// See `lzma_lzma_lclppb_decode` in `liblzma/lzma/lzma_decoder.c`.
+use std::{io, io::Read};
+
+use tracing::instrument;
+
+use crate::{
+    common::Compression,
+    io::wia::{WIACompression, WIADisc},
+    Error, Result,
+};
+
+pub struct Decompressor {
+    pub kind: DecompressionKind,
+    pub cache: DecompressorCache,
+}
+
+impl Clone for Decompressor {
+    fn clone(&self) -> Self {
+        Self { kind: self.kind.clone(), cache: DecompressorCache::default() }
+    }
+}
+
+#[derive(Default)]
+pub enum DecompressorCache {
+    #[default]
+    None,
+    #[cfg(feature = "compress-zlib")]
+    Deflate(Box<miniz_oxide::inflate::core::DecompressorOxide>),
+    #[cfg(feature = "compress-zstd")]
+    Zstandard(zstd_safe::DCtx<'static>),
+}
+
+impl Decompressor {
+    pub fn new(kind: DecompressionKind) -> Self {
+        Self { kind, cache: DecompressorCache::default() }
+    }
+
+    #[instrument(name = "Decompressor::decompress", skip_all)]
+    pub fn decompress(&mut self, buf: &[u8], out: &mut [u8]) -> io::Result<usize> {
+        match &self.kind {
+            DecompressionKind::None => {
+                out.copy_from_slice(buf);
+                Ok(buf.len())
+            }
+            #[cfg(feature = "compress-zlib")]
+            DecompressionKind::Deflate => {
+                let decompressor = match &mut self.cache {
+                    DecompressorCache::Deflate(decompressor) => decompressor,
+                    _ => {
+                        self.cache = DecompressorCache::Deflate(Box::new(
+                            miniz_oxide::inflate::core::DecompressorOxide::new(),
+                        ));
+                        match &mut self.cache {
+                            DecompressorCache::Deflate(decompressor) => decompressor,
+                            _ => unreachable!(),
+                        }
+                    }
+                };
+                decompressor.init();
+                let (status, in_size, out_size) = miniz_oxide::inflate::core::decompress(
+                    decompressor.as_mut(),
+                    buf,
+                    out,
+                    0,
+                    miniz_oxide::inflate::core::inflate_flags::TINFL_FLAG_PARSE_ZLIB_HEADER
+                        | miniz_oxide::inflate::core::inflate_flags::TINFL_FLAG_USING_NON_WRAPPING_OUTPUT_BUF,
+                );
+                match status {
+                    miniz_oxide::inflate::TINFLStatus::Done => Ok(out_size),
+                    _ => Err(io::Error::new(
+                        io::ErrorKind::InvalidData,
+                        format!(
+                            "Deflate decompression status {:?} (in: {}, out: {})",
+                            status, in_size, out_size
+                        ),
+                    )),
+                }
+            }
+            #[cfg(feature = "compress-bzip2")]
+            DecompressionKind::Bzip2 => {
+                let mut decoder = bzip2::Decompress::new(false);
+                let status = decoder.decompress(buf, out)?;
+                match status {
+                    bzip2::Status::StreamEnd => Ok(decoder.total_out() as usize),
+                    _ => Err(io::Error::new(
+                        io::ErrorKind::InvalidData,
+                        format!("Bzip2 decompression status {:?}", status),
+                    )),
+                }
+            }
+            #[cfg(feature = "compress-lzma")]
+            DecompressionKind::Lzma(data) => {
+                use lzma_util::{lzma_props_decode, new_lzma_decoder};
+                let mut decoder = new_lzma_decoder(&lzma_props_decode(data)?)?;
+                let status = decoder.process(buf, out, liblzma::stream::Action::Finish)?;
+                match status {
+                    liblzma::stream::Status::StreamEnd => Ok(decoder.total_out() as usize),
+                    _ => Err(io::Error::new(
+                        io::ErrorKind::InvalidData,
+                        format!("LZMA decompression status {:?}", status),
+                    )),
+                }
+            }
+            #[cfg(feature = "compress-lzma")]
+            DecompressionKind::Lzma2(data) => {
+                use lzma_util::{lzma2_props_decode, new_lzma2_decoder};
+                let mut decoder = new_lzma2_decoder(&lzma2_props_decode(data)?)?;
+                let status = decoder.process(buf, out, liblzma::stream::Action::Finish)?;
+                match status {
+                    liblzma::stream::Status::StreamEnd => Ok(decoder.total_out() as usize),
+                    _ => Err(io::Error::new(
+                        io::ErrorKind::InvalidData,
+                        format!("LZMA2 decompression status {:?}", status),
+                    )),
+                }
+            }
+            #[cfg(feature = "compress-zstd")]
+            DecompressionKind::Zstandard => {
+                let ctx = match &mut self.cache {
+                    DecompressorCache::Zstandard(ctx) => ctx,
+                    _ => {
+                        let ctx = zstd_safe::DCtx::create();
+                        self.cache = DecompressorCache::Zstandard(ctx);
+                        match &mut self.cache {
+                            DecompressorCache::Zstandard(ctx) => ctx,
+                            _ => unreachable!(),
+                        }
+                    }
+                };
+                ctx.decompress(out, buf).map_err(zstd_util::map_error_code)
+            }
+        }
+    }
+}
+
+#[derive(Debug, Clone)]
+pub enum DecompressionKind {
+    None,
+    #[cfg(feature = "compress-zlib")]
+    Deflate,
+    #[cfg(feature = "compress-bzip2")]
+    Bzip2,
+    #[cfg(feature = "compress-lzma")]
+    Lzma(Box<[u8]>),
+    #[cfg(feature = "compress-lzma")]
+    Lzma2(Box<[u8]>),
+    #[cfg(feature = "compress-zstd")]
+    Zstandard,
+}
+
+impl DecompressionKind {
+    pub fn from_wia(disc: &WIADisc) -> Result<Self> {
+        let _data = &disc.compr_data[..disc.compr_data_len as usize];
+        match disc.compression() {
+            WIACompression::None => Ok(Self::None),
+            #[cfg(feature = "compress-bzip2")]
+            WIACompression::Bzip2 => Ok(Self::Bzip2),
+            #[cfg(feature = "compress-lzma")]
+            WIACompression::Lzma => Ok(Self::Lzma(Box::from(_data))),
+            #[cfg(feature = "compress-lzma")]
+            WIACompression::Lzma2 => Ok(Self::Lzma2(Box::from(_data))),
+            #[cfg(feature = "compress-zstd")]
+            WIACompression::Zstandard => Ok(Self::Zstandard),
+            comp => Err(Error::DiscFormat(format!("Unsupported WIA/RVZ compression: {:?}", comp))),
+        }
+    }
+
+    pub fn wrap<'a, R>(&mut self, reader: R) -> io::Result<Box<dyn Read + 'a>>
+    where R: Read + 'a {
+        Ok(match self {
+            DecompressionKind::None => Box::new(reader),
+            #[cfg(feature = "compress-zlib")]
+            DecompressionKind::Deflate => unimplemented!("DecompressionKind::Deflate.wrap"),
+            #[cfg(feature = "compress-bzip2")]
+            DecompressionKind::Bzip2 => Box::new(bzip2::read::BzDecoder::new(reader)),
+            #[cfg(feature = "compress-lzma")]
+            DecompressionKind::Lzma(data) => {
+                use lzma_util::{lzma_props_decode, new_lzma_decoder};
+                let stream = new_lzma_decoder(&lzma_props_decode(data)?)?;
+                Box::new(liblzma::read::XzDecoder::new_stream(reader, stream))
+            }
+            #[cfg(feature = "compress-lzma")]
+            DecompressionKind::Lzma2(data) => {
+                use lzma_util::{lzma2_props_decode, new_lzma2_decoder};
+                let stream = new_lzma2_decoder(&lzma2_props_decode(data)?)?;
+                Box::new(liblzma::read::XzDecoder::new_stream(reader, stream))
+            }
+            #[cfg(feature = "compress-zstd")]
+            DecompressionKind::Zstandard => Box::new(zstd::stream::Decoder::new(reader)?),
+        })
+    }
+}
+
+pub struct Compressor {
+    pub kind: Compression,
+    pub cache: CompressorCache,
+    pub buffer: Vec<u8>,
+}
+
+impl Clone for Compressor {
+    fn clone(&self) -> Self {
+        Self {
+            kind: self.kind,
+            cache: CompressorCache::default(),
+            buffer: Vec::with_capacity(self.buffer.capacity()),
+        }
+    }
+}
+
+#[derive(Default)]
+pub enum CompressorCache {
+    #[default]
+    None,
+    #[cfg(feature = "compress-zlib")]
+    Deflate(Box<miniz_oxide::deflate::core::CompressorOxide>),
+    #[cfg(feature = "compress-zstd")]
+    Zstandard(zstd_safe::CCtx<'static>),
+}
+
+impl Compressor {
+    pub fn new(kind: Compression, buffer_size: usize) -> Self {
+        Self { kind, cache: CompressorCache::default(), buffer: Vec::with_capacity(buffer_size) }
+    }
+
+    /// Compresses the given buffer into `out`. `out`'s capacity will not be extended. Instead, if
+    /// the compressed data is larger than `out`, this function will bail and return `false`.
+    #[instrument(name = "Compressor::compress", skip_all)]
+    pub fn compress(&mut self, buf: &[u8]) -> io::Result<bool> {
+        self.buffer.clear();
+        match self.kind {
+            #[cfg(feature = "compress-zlib")]
+            Compression::Deflate(level) => {
+                let compressor = match &mut self.cache {
+                    CompressorCache::Deflate(compressor) => compressor,
+                    _ => {
+                        self.cache = CompressorCache::Deflate(Box::new(
+                            miniz_oxide::deflate::core::CompressorOxide::new(
+                                miniz_oxide::deflate::core::create_comp_flags_from_zip_params(
+                                    level as i32,
+                                    15,
+                                    0,
+                                ),
+                            ),
+                        ));
+                        match &mut self.cache {
+                            CompressorCache::Deflate(compressor) => compressor,
+                            _ => unreachable!(),
+                        }
+                    }
+                };
+                self.buffer.resize(self.buffer.capacity(), 0);
+                compressor.reset();
+                let (status, _, out_size) = miniz_oxide::deflate::core::compress(
+                    compressor.as_mut(),
+                    buf,
+                    self.buffer.as_mut_slice(),
+                    miniz_oxide::deflate::core::TDEFLFlush::Finish,
+                );
+                self.buffer.truncate(out_size);
+                Ok(status == miniz_oxide::deflate::core::TDEFLStatus::Done)
+            }
+            #[cfg(feature = "compress-bzip2")]
+            Compression::Bzip2(level) => {
+                let compression = bzip2::Compression::new(level as u32);
+                let mut compress = bzip2::Compress::new(compression, 30);
+                let status = compress.compress_vec(buf, &mut self.buffer, bzip2::Action::Finish)?;
+                Ok(status == bzip2::Status::StreamEnd)
+            }
+            #[cfg(feature = "compress-lzma")]
+            Compression::Lzma(level) => {
+                let options = liblzma::stream::LzmaOptions::new_preset(level as u32)?;
+                let mut encoder = lzma_util::new_lzma_encoder(&options)?;
+                let status =
+                    encoder.process_vec(buf, &mut self.buffer, liblzma::stream::Action::Finish)?;
+                Ok(status == liblzma::stream::Status::StreamEnd)
+            }
+            #[cfg(feature = "compress-lzma")]
+            Compression::Lzma2(level) => {
+                let options = liblzma::stream::LzmaOptions::new_preset(level as u32)?;
+                let mut encoder = lzma_util::new_lzma2_encoder(&options)?;
+                let status =
+                    encoder.process_vec(buf, &mut self.buffer, liblzma::stream::Action::Finish)?;
+                Ok(status == liblzma::stream::Status::StreamEnd)
+            }
+            #[cfg(feature = "compress-zstd")]
+            Compression::Zstandard(level) => {
+                let ctx = match &mut self.cache {
+                    CompressorCache::Zstandard(compressor) => compressor,
+                    _ => {
+                        let mut ctx = zstd_safe::CCtx::create();
+                        ctx.init(level as i32).map_err(zstd_util::map_error_code)?;
+                        self.cache = CompressorCache::Zstandard(ctx);
+                        match &mut self.cache {
+                            CompressorCache::Zstandard(compressor) => compressor,
+                            _ => unreachable!(),
+                        }
+                    }
+                };
+                match ctx.compress2(&mut self.buffer, buf) {
+                    Ok(_) => Ok(true),
+                    // dstSize_tooSmall
+                    Err(e) if e == -70isize as usize => Ok(false),
+                    Err(e) => Err(zstd_util::map_error_code(e)),
+                }
+            }
+            _ => Err(io::Error::new(
+                io::ErrorKind::Other,
+                format!("Unsupported compression: {:?}", self.kind),
+            )),
+        }
+    }
+}
+
 #[cfg(feature = "compress-lzma")]
-pub fn lzma_lclppb_decode(
-    options: &mut liblzma::stream::LzmaOptions,
-    byte: u8,
-) -> std::io::Result<()> {
+pub mod lzma_util {
+    use std::{
+        cmp::Ordering,
+        io::{Error, ErrorKind, Result},
+    };
+
+    use liblzma::stream::{Filters, LzmaOptions, Stream};
+
+    use crate::util::{array_ref, array_ref_mut, static_assert};
+
+    /// Decodes the LZMA Properties byte (lc/lp/pb).
+    /// See `lzma_lzma_lclppb_decode` in `liblzma/lzma/lzma_decoder.c`.
+    pub fn lzma_lclppb_decode(options: &mut LzmaOptions, byte: u8) -> Result<()> {
         let mut d = byte as u32;
         if d >= (9 * 5 * 5) {
-        return Err(std::io::Error::new(
-            std::io::ErrorKind::InvalidData,
+            return Err(Error::new(
+                ErrorKind::InvalidData,
                 format!("Invalid LZMA props byte: {}", d),
             ));
         }
@@ -17,42 +336,61 @@ pub fn lzma_lclppb_decode(
         options.position_bits(d / 5);
         options.literal_position_bits(d % 5);
         Ok(())
-}
+    }
 
-/// Decodes LZMA properties.
-/// See `lzma_lzma_props_decode` in `liblzma/lzma/lzma_decoder.c`.
-#[cfg(feature = "compress-lzma")]
-pub fn lzma_props_decode(props: &[u8]) -> std::io::Result<liblzma::stream::LzmaOptions> {
-    use crate::array_ref;
+    /// Encodes the LZMA Properties byte (lc/lp/pb).
+    /// See `lzma_lzma_lclppb_encode` in `liblzma/lzma/lzma_encoder.c`.
+    pub fn lzma_lclppb_encode(options: &LzmaOptions) -> Result<u8> {
+        let options = get_options_sys(options);
+        let byte = (options.pb * 5 + options.lp) * 9 + options.lc;
+        if byte >= (9 * 5 * 5) {
+            return Err(Error::new(
+                ErrorKind::InvalidData,
+                format!("Invalid LZMA props byte: {}", byte),
+            ));
+        }
+        Ok(byte as u8)
+    }
+
+    /// Decodes LZMA properties.
+    /// See `lzma_lzma_props_decode` in `liblzma/lzma/lzma_decoder.c`.
+    pub fn lzma_props_decode(props: &[u8]) -> Result<LzmaOptions> {
         if props.len() != 5 {
-        return Err(std::io::Error::new(
-            std::io::ErrorKind::InvalidData,
+            return Err(Error::new(
+                ErrorKind::InvalidData,
                 format!("Invalid LZMA props length: {}", props.len()),
             ));
         }
-    let mut options = liblzma::stream::LzmaOptions::new();
+        let mut options = LzmaOptions::new();
         lzma_lclppb_decode(&mut options, props[0])?;
-    options.dict_size(u32::from_le_bytes(*array_ref!(props, 1, 4)));
+        options.dict_size(u32::from_le_bytes(*array_ref![props, 1, 4]));
         Ok(options)
-}
+    }
 
-/// Decodes LZMA2 properties.
-/// See `lzma_lzma2_props_decode` in `liblzma/lzma/lzma2_decoder.c`.
-#[cfg(feature = "compress-lzma")]
-pub fn lzma2_props_decode(props: &[u8]) -> std::io::Result<liblzma::stream::LzmaOptions> {
-    use std::cmp::Ordering;
+    /// Encodes LZMA properties.
+    /// See `lzma_lzma_props_encode` in `liblzma/lzma/lzma_encoder.c`.
+    pub fn lzma_props_encode(options: &LzmaOptions) -> Result<[u8; 5]> {
+        let mut props = [0u8; 5];
+        props[0] = lzma_lclppb_encode(options)?;
+        *array_ref_mut![props, 1, 4] = get_options_sys(options).dict_size.to_le_bytes();
+        Ok(props)
+    }
+
+    /// Decodes LZMA2 properties.
+    /// See `lzma_lzma2_props_decode` in `liblzma/lzma/lzma2_decoder.c`.
+    pub fn lzma2_props_decode(props: &[u8]) -> Result<LzmaOptions> {
         if props.len() != 1 {
-        return Err(std::io::Error::new(
-            std::io::ErrorKind::InvalidData,
+            return Err(Error::new(
+                ErrorKind::InvalidData,
                 format!("Invalid LZMA2 props length: {}", props.len()),
             ));
         }
         let d = props[0] as u32;
-    let mut options = liblzma::stream::LzmaOptions::new();
+        let mut options = LzmaOptions::new();
         options.dict_size(match d.cmp(&40) {
             Ordering::Greater => {
-            return Err(std::io::Error::new(
-                std::io::ErrorKind::InvalidData,
+                return Err(Error::new(
+                    ErrorKind::InvalidData,
                     format!("Invalid LZMA2 props byte: {}", d),
                 ));
             }
@@ -60,36 +398,86 @@ pub fn lzma2_props_decode(props: &[u8]) -> std::io::Result<liblzma::stream::Lzma
             Ordering::Less => (2 | (d & 1)) << (d / 2 + 11),
         });
         Ok(options)
-}
+    }
 
-/// Creates a new raw LZMA decoder with the given options.
-#[cfg(feature = "compress-lzma")]
-pub fn new_lzma_decoder<R>(
-    reader: R,
-    options: &liblzma::stream::LzmaOptions,
-) -> std::io::Result<liblzma::read::XzDecoder<R>>
-where
-    R: std::io::Read,
-{
-    let mut filters = liblzma::stream::Filters::new();
+    /// Encodes LZMA2 properties.
+    /// See `lzma_lzma2_props_encode` in `liblzma/lzma/lzma2_encoder.c`.
+    pub fn lzma2_props_encode(options: &LzmaOptions) -> Result<[u8; 1]> {
+        let options = get_options_sys(options);
+        let mut d = options.dict_size.max(liblzma_sys::LZMA_DICT_SIZE_MIN);
+
+        // Round up to the next 2^n - 1 or 2^n + 2^(n - 1) - 1 depending
+        // on which one is the next:
+        d -= 1;
+        d |= d >> 2;
+        d |= d >> 3;
+        d |= d >> 4;
+        d |= d >> 8;
+        d |= d >> 16;
+
+        // Get the highest two bits using the proper encoding:
+        if d == u32::MAX {
+            d = 40;
+        } else {
+            d = get_dist_slot(d + 1) - 24;
+        }
+
+        Ok([d as u8])
+    }
+
+    /// Creates a new raw LZMA decoder with the given options.
+    pub fn new_lzma_decoder(options: &LzmaOptions) -> Result<Stream> {
+        let mut filters = Filters::new();
         filters.lzma1(options);
-    let stream =
-        liblzma::stream::Stream::new_raw_decoder(&filters).map_err(std::io::Error::from)?;
-    Ok(liblzma::read::XzDecoder::new_stream(reader, stream))
+        Stream::new_raw_decoder(&filters).map_err(Error::from)
+    }
+
+    /// Creates a new raw LZMA encoder with the given options.
+    pub fn new_lzma_encoder(options: &LzmaOptions) -> Result<Stream> {
+        let mut filters = Filters::new();
+        filters.lzma1(options);
+        Stream::new_raw_encoder(&filters).map_err(Error::from)
+    }
+
+    /// Creates a new raw LZMA2 decoder with the given options.
+    pub fn new_lzma2_decoder(options: &LzmaOptions) -> Result<Stream> {
+        let mut filters = Filters::new();
+        filters.lzma2(options);
+        Stream::new_raw_decoder(&filters).map_err(Error::from)
+    }
+
+    /// Creates a new raw LZMA2 encoder with the given options.
+    pub fn new_lzma2_encoder(options: &LzmaOptions) -> Result<Stream> {
+        let mut filters = Filters::new();
+        filters.lzma2(options);
+        Stream::new_raw_encoder(&filters).map_err(Error::from)
+    }
+
+    /// liblzma does not expose any accessors for `LzmaOptions`, so we have to
+    /// cast it into the internal `lzma_options_lzma` struct.
+    #[inline]
+    fn get_options_sys(options: &LzmaOptions) -> &liblzma_sys::lzma_options_lzma {
+        static_assert!(size_of::<LzmaOptions>() == size_of::<liblzma_sys::lzma_options_lzma>());
+        unsafe { &*(options as *const LzmaOptions as *const liblzma_sys::lzma_options_lzma) }
+    }
+
+    /// See `get_dist_slot` in `liblzma/lzma/fastpos.h`.
+    fn get_dist_slot(dist: u32) -> u32 {
+        if dist <= 4 {
+            dist
+        } else {
+            let i = dist.leading_zeros() ^ 31;
+            (i + i) + ((dist >> (i - 1)) & 1)
+        }
+    }
 }
 
-/// Creates a new raw LZMA2 decoder with the given options.
-#[cfg(feature = "compress-lzma")]
-pub fn new_lzma2_decoder<R>(
-    reader: R,
-    options: &liblzma::stream::LzmaOptions,
-) -> std::io::Result<liblzma::read::XzDecoder<R>>
-where
-    R: std::io::Read,
-{
-    let mut filters = liblzma::stream::Filters::new();
-    filters.lzma2(options);
-    let stream =
-        liblzma::stream::Stream::new_raw_decoder(&filters).map_err(std::io::Error::from)?;
-    Ok(liblzma::read::XzDecoder::new_stream(reader, stream))
+#[cfg(feature = "compress-zstd")]
+mod zstd_util {
+    use std::io;
+
+    pub fn map_error_code(code: usize) -> io::Error {
+        let msg = zstd_safe::get_error_name(code);
+        io::Error::new(io::ErrorKind::Other, msg.to_string())
+    }
 }

nod/src/util/digest.rs

@@ -0,0 +1,253 @@
+use std::{thread, thread::JoinHandle};
+
+use bytes::Bytes;
+use crossbeam_channel::Sender;
+use digest::Digest;
+use tracing::instrument;
+
+use crate::{
+    io::nkit::NKitHeader,
+    write::{DiscFinalization, ProcessOptions},
+};
+
+pub type DigestThread = (Sender<Bytes>, JoinHandle<DigestResult>);
+
+pub fn digest_thread<H>() -> DigestThread
+where H: Hasher + Send + 'static {
+    let (tx, rx) = crossbeam_channel::bounded::<Bytes>(1);
+    let handle = thread::Builder::new()
+        .name(format!("Digest {}", H::NAME))
+        .spawn(move || {
+            let mut hasher = H::new();
+            while let Ok(data) = rx.recv() {
+                hasher.update(data.as_ref());
+            }
+            hasher.finalize()
+        })
+        .expect("Failed to spawn digest thread");
+    (tx, handle)
+}
+
+pub struct DigestManager {
+    threads: Vec<DigestThread>,
+}
+
+impl DigestManager {
+    pub fn new(options: &ProcessOptions) -> Self {
+        let mut threads = Vec::new();
+        if options.digest_crc32 {
+            threads.push(digest_thread::<crc32fast::Hasher>());
+        }
+        if options.digest_md5 {
+            #[cfg(feature = "openssl")]
+            threads.push(digest_thread::<ossl::HasherMD5>());
+            #[cfg(not(feature = "openssl"))]
+            threads.push(digest_thread::<md5::Md5>());
+        }
+        if options.digest_sha1 {
+            #[cfg(feature = "openssl")]
+            threads.push(digest_thread::<ossl::HasherSHA1>());
+            #[cfg(not(feature = "openssl"))]
+            threads.push(digest_thread::<sha1::Sha1>());
+        }
+        if options.digest_xxh64 {
+            threads.push(digest_thread::<xxhash_rust::xxh64::Xxh64>());
+        }
+        DigestManager { threads }
+    }
+
+    #[instrument(name = "DigestManager::send", skip_all)]
+    pub fn send(&self, data: Bytes) {
+        let mut sent = 0usize;
+        // Non-blocking send to all threads
+        for (idx, (tx, _)) in self.threads.iter().enumerate() {
+            if tx.try_send(data.clone()).is_ok() {
+                sent |= 1 << idx;
+            }
+        }
+        // Blocking send to any remaining threads
+        for (idx, (tx, _)) in self.threads.iter().enumerate() {
+            if sent & (1 << idx) == 0 {
+                tx.send(data.clone()).expect("Failed to send data to digest thread");
+            }
+        }
+    }
+
+    #[instrument(name = "DigestManager::finish", skip_all)]
+    pub fn finish(self) -> DigestResults {
+        let mut results = DigestResults { crc32: None, md5: None, sha1: None, xxh64: None };
+        for (tx, handle) in self.threads {
+            drop(tx); // Close channel
+            match handle.join().unwrap() {
+                DigestResult::Crc32(v) => results.crc32 = Some(v),
+                DigestResult::Md5(v) => results.md5 = Some(v),
+                DigestResult::Sha1(v) => results.sha1 = Some(v),
+                DigestResult::Xxh64(v) => results.xxh64 = Some(v),
+            }
+        }
+        results
+    }
+}
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum DigestResult {
+    Crc32(u32),
+    Md5([u8; 16]),
+    Sha1([u8; 20]),
+    Xxh64(u64),
+}
+
+pub trait Hasher {
+    const NAME: &'static str;
+
+    fn new() -> Self;
+    fn finalize(self) -> DigestResult;
+    fn update(&mut self, data: &[u8]);
+}
+
+impl Hasher for md5::Md5 {
+    const NAME: &'static str = "MD5";
+
+    fn new() -> Self { Digest::new() }
+
+    fn finalize(self) -> DigestResult { DigestResult::Md5(Digest::finalize(self).into()) }
+
+    #[allow(unused_braces)] // https://github.com/rust-lang/rust/issues/116347
+    #[instrument(name = "md5::Md5::update", skip_all)]
+    fn update(&mut self, data: &[u8]) { Digest::update(self, data) }
+}
+
+impl Hasher for sha1::Sha1 {
+    const NAME: &'static str = "SHA-1";
+
+    fn new() -> Self { Digest::new() }
+
+    fn finalize(self) -> DigestResult { DigestResult::Sha1(Digest::finalize(self).into()) }
+
+    #[allow(unused_braces)] // https://github.com/rust-lang/rust/issues/116347
+    #[instrument(name = "sha1::Sha1::update", skip_all)]
+    fn update(&mut self, data: &[u8]) { Digest::update(self, data) }
+}
+
+impl Hasher for crc32fast::Hasher {
+    const NAME: &'static str = "CRC32";
+
+    fn new() -> Self { crc32fast::Hasher::new() }
+
+    fn finalize(self) -> DigestResult { DigestResult::Crc32(crc32fast::Hasher::finalize(self)) }
+
+    #[allow(unused_braces)] // https://github.com/rust-lang/rust/issues/116347
+    #[instrument(name = "crc32fast::Hasher::update", skip_all)]
+    fn update(&mut self, data: &[u8]) { crc32fast::Hasher::update(self, data) }
+}
+
+impl Hasher for xxhash_rust::xxh64::Xxh64 {
+    const NAME: &'static str = "XXH64";
+
+    fn new() -> Self { xxhash_rust::xxh64::Xxh64::new(0) }
+
+    fn finalize(self) -> DigestResult {
+        DigestResult::Xxh64(xxhash_rust::xxh64::Xxh64::digest(&self))
+    }
+
+    #[allow(unused_braces)] // https://github.com/rust-lang/rust/issues/116347
+    #[instrument(name = "xxhash_rust::xxh64::Xxh64::update", skip_all)]
+    fn update(&mut self, data: &[u8]) { xxhash_rust::xxh64::Xxh64::update(self, data) }
+}
+
+#[cfg(feature = "openssl")]
+mod ossl {
+    use tracing::instrument;
+
+    use super::{DigestResult, Hasher};
+
+    pub type HasherMD5 = HashWrapper<MessageDigestMD5>;
+    pub type HasherSHA1 = HashWrapper<MessageDigestSHA1>;
+
+    pub struct HashWrapper<T>
+    where T: MessageDigest
+    {
+        hasher: openssl::hash::Hasher,
+        _marker: std::marker::PhantomData<T>,
+    }
+
+    impl<T> HashWrapper<T>
+    where T: MessageDigest
+    {
+        fn new() -> Self {
+            Self {
+                hasher: openssl::hash::Hasher::new(T::new()).unwrap(),
+                _marker: Default::default(),
+            }
+        }
+    }
+
+    pub trait MessageDigest {
+        fn new() -> openssl::hash::MessageDigest;
+    }
+
+    pub struct MessageDigestMD5;
+
+    impl MessageDigest for MessageDigestMD5 {
+        fn new() -> openssl::hash::MessageDigest { openssl::hash::MessageDigest::md5() }
+    }
+
+    pub struct MessageDigestSHA1;
+
+    impl MessageDigest for MessageDigestSHA1 {
+        fn new() -> openssl::hash::MessageDigest { openssl::hash::MessageDigest::sha1() }
+    }
+
+    impl Hasher for HasherMD5 {
+        const NAME: &'static str = "MD5";
+
+        fn new() -> Self { Self::new() }
+
+        fn finalize(mut self) -> DigestResult {
+            DigestResult::Md5((*self.hasher.finish().unwrap()).try_into().unwrap())
+        }
+
+        #[allow(unused_braces)] // https://github.com/rust-lang/rust/issues/116347
+        #[instrument(name = "ossl::HasherMD5::update", skip_all)]
+        fn update(&mut self, data: &[u8]) { self.hasher.update(data).unwrap() }
+    }
+
+    impl Hasher for HasherSHA1 {
+        const NAME: &'static str = "SHA-1";
+
+        fn new() -> Self { Self::new() }
+
+        fn finalize(mut self) -> DigestResult {
+            DigestResult::Sha1((*self.hasher.finish().unwrap()).try_into().unwrap())
+        }
+
+        #[allow(unused_braces)] // https://github.com/rust-lang/rust/issues/116347
+        #[instrument(name = "ossl::HasherSHA1::update", skip_all)]
+        fn update(&mut self, data: &[u8]) { self.hasher.update(data).unwrap() }
+    }
+}
+
+pub struct DigestResults {
+    pub crc32: Option<u32>,
+    pub md5: Option<[u8; 16]>,
+    pub sha1: Option<[u8; 20]>,
+    pub xxh64: Option<u64>,
+}
+
+impl DiscFinalization {
+    pub(crate) fn apply_digests(&mut self, results: &DigestResults) {
+        self.crc32 = results.crc32;
+        self.md5 = results.md5;
+        self.sha1 = results.sha1;
+        self.xxh64 = results.xxh64;
+    }
+}
+
+impl NKitHeader {
+    pub(crate) fn apply_digests(&mut self, results: &DigestResults) {
+        self.crc32 = results.crc32;
+        self.md5 = results.md5;
+        self.sha1 = results.sha1;
+        self.xxh64 = results.xxh64;
+    }
+}

nod/src/util/lfg.rs

@@ -1,22 +1,30 @@
+//! Lagged Fibonacci generator for GC / Wii partition junk data.
+
 use std::{
     cmp::min,
     io,
     io::{Read, Write},
 };
 
+use bytes::Buf;
 use zerocopy::{transmute_ref, IntoBytes};
 
 use crate::disc::SECTOR_SIZE;
 
+/// Value of `k` for the LFG.
 pub const LFG_K: usize = 521;
+
+/// Value of `j` for the LFG.
 pub const LFG_J: usize = 32;
+
+/// Number of 32-bit words in the seed.
 pub const SEED_SIZE: usize = 17;
 
 /// Lagged Fibonacci generator for GC / Wii partition junk data.
 ///
 /// References (license CC0-1.0):
-/// https://github.com/dolphin-emu/dolphin/blob/a0f555648c27ec0c928f6b1e1fcad5e2d7c4d0c4/docs/WiaAndRvz.md
-/// https://github.com/dolphin-emu/dolphin/blob/a0f555648c27ec0c928f6b1e1fcad5e2d7c4d0c4/Source/Core/DiscIO/LaggedFibonacciGenerator.cpp
+/// - [WiaAndRvz.md](https://github.com/dolphin-emu/dolphin/blob/a0f555648c27ec0c928f6b1e1fcad5e2d7c4d0c4/docs/WiaAndRvz.md)
+/// - [LaggedFibonacciGenerator.cpp](https://github.com/dolphin-emu/dolphin/blob/a0f555648c27ec0c928f6b1e1fcad5e2d7c4d0c4/Source/Core/DiscIO/LaggedFibonacciGenerator.cpp)
 pub struct LaggedFibonacci {
     buffer: [u32; LFG_K],
     position: usize,
@@ -46,7 +54,6 @@ impl LaggedFibonacci {
     /// Initializes the LFG with the standard seed for a given disc ID, disc number, and sector.
     /// The partition offset is used to determine the sector and how many bytes to skip within the
     /// sector.
-    #[allow(clippy::missing_inline_in_public_items)]
     pub fn init_with_seed(&mut self, disc_id: [u8; 4], disc_num: u8, partition_offset: u64) {
         let seed = u32::from_be_bytes([
             disc_id[2],
@@ -73,7 +80,6 @@ impl LaggedFibonacci {
 
     /// Initializes the LFG with the seed read from a reader. The seed is assumed to be big-endian.
     /// This is used for rebuilding junk data in WIA/RVZ files.
-    #[allow(clippy::missing_inline_in_public_items)]
     pub fn init_with_reader<R>(&mut self, reader: &mut R) -> io::Result<()>
     where R: Read + ?Sized {
         reader.read_exact(self.buffer[..SEED_SIZE].as_mut_bytes())?;
@@ -85,6 +91,22 @@ impl LaggedFibonacci {
         Ok(())
     }
 
+    /// Initializes the LFG with the seed read from a [`Buf`]. The seed is assumed to be big-endian.
+    /// This is used for rebuilding junk data in WIA/RVZ files.
+    pub fn init_with_buf(&mut self, reader: &mut impl Buf) -> io::Result<()> {
+        let out = self.buffer[..SEED_SIZE].as_mut_bytes();
+        if reader.remaining() < out.len() {
+            return Err(io::Error::new(io::ErrorKind::UnexpectedEof, "Filling LFG seed"));
+        }
+        reader.copy_to_slice(out);
+        for x in self.buffer[..SEED_SIZE].iter_mut() {
+            *x = u32::from_be(*x);
+        }
+        self.position = 0;
+        self.init();
+        Ok(())
+    }
+
     /// Advances the LFG by one step.
     fn forward(&mut self) {
         for i in 0..LFG_J {
@@ -96,7 +118,6 @@ impl LaggedFibonacci {
     }
 
     /// Skips `n` bytes of junk data.
-    #[allow(clippy::missing_inline_in_public_items)]
     pub fn skip(&mut self, n: usize) {
         self.position += n;
         while self.position >= LFG_K * 4 {
@@ -105,8 +126,22 @@ impl LaggedFibonacci {
         }
     }
 
+    // pub fn backward(&mut self) {
+    //     for i in (LFG_J..LFG_K).rev() {
+    //         self.buffer[i] ^= self.buffer[i - LFG_J];
+    //     }
+    //     for i in (0..LFG_J).rev() {
+    //         self.buffer[i] ^= self.buffer[i + LFG_K - LFG_J];
+    //     }
+    // }
+
+    // pub fn get_seed(&mut self, seed: &mut [u8; SEED_SIZE]) {
+    //     for i in 0..SEED_SIZE {
+    //         seed[i] = self.buffer[i].to_be_bytes()[3];
+    //     }
+    // }
+
     /// Fills the buffer with junk data.
-    #[allow(clippy::missing_inline_in_public_items)]
     pub fn fill(&mut self, mut buf: &mut [u8]) {
         while !buf.is_empty() {
             let len = min(buf.len(), LFG_K * 4 - self.position);
@@ -122,7 +157,6 @@ impl LaggedFibonacci {
     }
 
     /// Writes junk data to the output stream.
-    #[allow(clippy::missing_inline_in_public_items)]
     pub fn write<W>(&mut self, w: &mut W, mut len: u64) -> io::Result<()>
     where W: Write + ?Sized {
         while len > 0 {
@@ -141,7 +175,6 @@ impl LaggedFibonacci {
 
     /// The junk data on GC / Wii discs is reinitialized every 32KB. This functions handles the
     /// wrapping logic and reinitializes the LFG at sector boundaries.
-    #[allow(clippy::missing_inline_in_public_items)]
     pub fn fill_sector_chunked(
         &mut self,
         mut buf: &mut [u8],
@@ -161,7 +194,6 @@ impl LaggedFibonacci {
 
     /// The junk data on GC / Wii discs is reinitialized every 32KB. This functions handles the
     /// wrapping logic and reinitializes the LFG at sector boundaries.
-    #[allow(clippy::missing_inline_in_public_items)]
     pub fn write_sector_chunked<W>(
         &mut self,
         w: &mut W,
@@ -182,6 +214,33 @@ impl LaggedFibonacci {
         }
         Ok(())
     }
+
+    /// Checks if the data matches the junk data generated by the LFG. This function handles the
+    /// wrapping logic and reinitializes the LFG at sector boundaries.
+    pub fn check_sector_chunked(
+        &mut self,
+        mut buf: &[u8],
+        disc_id: [u8; 4],
+        disc_num: u8,
+        mut partition_offset: u64,
+    ) -> bool {
+        if buf.is_empty() {
+            return false;
+        }
+        let mut lfg_buf = [0u8; SECTOR_SIZE];
+        while !buf.is_empty() {
+            self.init_with_seed(disc_id, disc_num, partition_offset);
+            let len =
+                (SECTOR_SIZE - (partition_offset % SECTOR_SIZE as u64) as usize).min(buf.len());
+            self.fill(&mut lfg_buf[..len]);
+            if buf[..len] != lfg_buf[..len] {
+                return false;
+            }
+            buf = &buf[len..];
+            partition_offset += len as u64;
+        }
+        true
+    }
 }
 
 #[cfg(test)]

nod/src/util/mod.rs

@@ -1,20 +1,139 @@
-use std::ops::{Div, Rem};
+//! Utility functions and types.
 
+use std::{
+    io,
+    io::{Read, Seek, SeekFrom},
+    ops::{Div, Rem},
+};
+
+use io::{BufRead, Write};
+
+pub(crate) mod aes;
 pub(crate) mod compress;
-pub(crate) mod lfg;
+pub(crate) mod digest;
+pub mod lfg;
 pub(crate) mod read;
-pub(crate) mod take_seek;
+
+/// Copies from a buffered reader to a writer without extra allocations.
+pub fn buf_copy<R, W>(reader: &mut R, writer: &mut W) -> io::Result<u64>
+where
+    R: BufRead + ?Sized,
+    W: Write + ?Sized,
+{
+    let mut copied = 0;
+    loop {
+        let buf = reader.fill_buf()?;
+        let len = buf.len();
+        if len == 0 {
+            break;
+        }
+        writer.write_all(buf)?;
+        reader.consume(len);
+        copied += len as u64;
+    }
+    Ok(copied)
+}
+
+/// A reader with a fixed window.
+#[derive(Clone)]
+pub struct WindowedReader<T>
+where T: BufRead + Seek
+{
+    base: T,
+    pos: u64,
+    begin: u64,
+    end: u64,
+}
+
+impl<T> WindowedReader<T>
+where T: BufRead + Seek
+{
+    /// Creates a new windowed stream with offset and size.
+    ///
+    /// Seeks underlying stream immediately.
+    #[inline]
+    pub fn new(mut base: T, offset: u64, size: u64) -> io::Result<Self> {
+        base.seek(SeekFrom::Start(offset))?;
+        Ok(Self { base, pos: offset, begin: offset, end: offset + size })
+    }
+
+    /// Returns the length of the window.
+    #[inline]
+    #[allow(clippy::len_without_is_empty)]
+    pub fn len(&self) -> u64 { self.end - self.begin }
+}
+
+impl<T> Read for WindowedReader<T>
+where T: BufRead + Seek
+{
+    #[inline]
+    fn read(&mut self, out: &mut [u8]) -> io::Result<usize> {
+        let buf = self.fill_buf()?;
+        let len = buf.len().min(out.len());
+        out[..len].copy_from_slice(&buf[..len]);
+        self.consume(len);
+        Ok(len)
+    }
+}
+
+impl<T> BufRead for WindowedReader<T>
+where T: BufRead + Seek
+{
+    #[inline]
+    fn fill_buf(&mut self) -> io::Result<&[u8]> {
+        let limit = self.end.saturating_sub(self.pos);
+        if limit == 0 {
+            return Ok(&[]);
+        }
+        let buf = self.base.fill_buf()?;
+        let max = (buf.len() as u64).min(limit) as usize;
+        Ok(&buf[..max])
+    }
+
+    #[inline]
+    fn consume(&mut self, amt: usize) {
+        self.base.consume(amt);
+        self.pos += amt as u64;
+    }
+}
+
+impl<T> Seek for WindowedReader<T>
+where T: BufRead + Seek
+{
+    #[inline]
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+        let mut pos = match pos {
+            SeekFrom::Start(p) => self.begin + p,
+            SeekFrom::End(p) => self.end.saturating_add_signed(p),
+            SeekFrom::Current(p) => self.pos.saturating_add_signed(p),
+        };
+        if pos < self.begin {
+            pos = self.begin;
+        } else if pos > self.end {
+            pos = self.end;
+        }
+        let result = self.base.seek(SeekFrom::Start(pos))?;
+        self.pos = result;
+        Ok(result - self.begin)
+    }
+
+    #[inline]
+    fn stream_position(&mut self) -> io::Result<u64> { Ok(self.pos) }
+}
 
 #[inline(always)]
 pub(crate) fn div_rem<T>(x: T, y: T) -> (T, T)
 where T: Div<Output = T> + Rem<Output = T> + Copy {
-    let quot = x / y;
-    let rem = x % y;
-    (quot, rem)
+    (x / y, x % y)
 }
 
+#[inline]
+pub(crate) fn align_up_32(n: u32, align: u32) -> u32 { (n + align - 1) & !(align - 1) }
+
+#[inline]
+pub(crate) fn align_up_64(n: u64, align: u64) -> u64 { (n + align - 1) & !(align - 1) }
+
 /// Creates a fixed-size array reference from a slice.
-#[macro_export]
 macro_rules! array_ref {
     ($slice:expr, $offset:expr, $size:expr) => {{
         #[inline(always)]
@@ -24,9 +143,9 @@ macro_rules! array_ref {
         to_array(&$slice[$offset..$offset + $size])
     }};
 }
+pub(crate) use array_ref;
 
 /// Creates a mutable fixed-size array reference from a slice.
-#[macro_export]
 macro_rules! array_ref_mut {
     ($slice:expr, $offset:expr, $size:expr) => {{
         #[inline(always)]
@@ -36,11 +155,28 @@ macro_rules! array_ref_mut {
         to_array(&mut $slice[$offset..$offset + $size])
     }};
 }
+pub(crate) use array_ref_mut;
 
 /// Compile-time assertion.
-#[macro_export]
 macro_rules! static_assert {
     ($condition:expr) => {
         const _: () = core::assert!($condition);
     };
 }
+pub(crate) use static_assert;
+
+macro_rules! impl_read_for_bufread {
+    ($ty:ident) => {
+        impl std::io::Read for $ty {
+            fn read(&mut self, out: &mut [u8]) -> std::io::Result<usize> {
+                use std::io::BufRead;
+                let buf = self.fill_buf()?;
+                let len = buf.len().min(out.len());
+                out[..len].copy_from_slice(&buf[..len]);
+                self.consume(len);
+                Ok(len)
+            }
+        }
+    };
+}
+pub(crate) use impl_read_for_bufread;

nod/src/util/read.rs

@@ -1,4 +1,4 @@
-use std::{io, io::Read};
+use std::{io, io::Read, sync::Arc};
 
 use zerocopy::{FromBytes, FromZeros, IntoBytes};
 
@@ -36,6 +36,16 @@ where
     Ok(ret)
 }
 
+#[inline(always)]
+pub fn read_arc<T, R>(reader: &mut R) -> io::Result<Arc<T>>
+where
+    T: FromBytes + IntoBytes,
+    R: Read + ?Sized,
+{
+    // TODO use Arc::new_zeroed once it's stable
+    read_box(reader).map(Arc::from)
+}
+
 #[inline(always)]
 pub fn read_box_slice<T, R>(reader: &mut R, count: usize) -> io::Result<Box<[T]>>
 where
@@ -48,6 +58,16 @@ where
     Ok(ret)
 }
 
+#[inline(always)]
+pub fn read_arc_slice<T, R>(reader: &mut R, count: usize) -> io::Result<Arc<[T]>>
+where
+    T: FromBytes + IntoBytes,
+    R: Read + ?Sized,
+{
+    // TODO use Arc::new_zeroed once it's stable
+    read_box_slice(reader, count).map(Arc::from)
+}
+
 #[inline(always)]
 pub fn read_u16_be<R>(reader: &mut R) -> io::Result<u16>
 where R: Read + ?Sized {
@@ -71,3 +91,26 @@ where R: Read + ?Sized {
     reader.read_exact(&mut buf)?;
     Ok(u64::from_be_bytes(buf))
 }
+
+pub fn read_with_zero_fill<R>(r: &mut R, mut buf: &mut [u8]) -> io::Result<usize>
+where R: Read + ?Sized {
+    let mut total = 0;
+    while !buf.is_empty() {
+        let read = r.read(buf)?;
+        if read == 0 {
+            // Fill remaining block with zeroes
+            buf.fill(0);
+            break;
+        }
+        buf = &mut buf[read..];
+        total += read;
+    }
+    Ok(total)
+}
+
+pub fn box_to_bytes<T>(b: Box<T>) -> Box<[u8]>
+where T: IntoBytes {
+    let p = Box::into_raw(b);
+    let sp = unsafe { std::slice::from_raw_parts_mut(p as *mut u8, size_of::<T>()) };
+    unsafe { Box::from_raw(sp) }
+}

nod/src/util/take_seek.rs

@@ -1,127 +0,0 @@
-// From https://github.com/jam1garner/binrw/blob/e96a1320287ec83d1f471525ffa380800ec9e124/binrw/src/io/take_seek.rs
-// MIT License
-//
-// Copyright (c) jam1garner and other contributors
-//
-// Permission is hereby granted, free of charge, to any person obtaining a copy
-// of this software and associated documentation files (the "Software"), to deal
-// in the Software without restriction, including without limitation the rights
-// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-// copies of the Software, and to permit persons to whom the Software is
-// furnished to do so, subject to the following conditions:
-//
-// The above copyright notice and this permission notice shall be included in all
-// copies or substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-// SOFTWARE.
-#![allow(dead_code)]
-//! Types for seekable reader adapters which limit the number of bytes read from
-//! the underlying reader.
-
-use std::io::{Read, Result, Seek, SeekFrom};
-
-/// Read adapter which limits the bytes read from an underlying reader, with
-/// seek support.
-///
-/// This struct is generally created by importing the [`TakeSeekExt`] extension
-/// and calling [`take_seek`] on a reader.
-///
-/// [`take_seek`]: TakeSeekExt::take_seek
-#[derive(Debug)]
-pub struct TakeSeek<T> {
-    inner: T,
-    pos: u64,
-    end: u64,
-}
-
-impl<T> TakeSeek<T> {
-    /// Gets a reference to the underlying reader.
-    pub fn get_ref(&self) -> &T { &self.inner }
-
-    /// Gets a mutable reference to the underlying reader.
-    ///
-    /// Care should be taken to avoid modifying the internal I/O state of the
-    /// underlying reader as doing so may corrupt the internal limit of this
-    /// `TakeSeek`.
-    pub fn get_mut(&mut self) -> &mut T { &mut self.inner }
-
-    /// Consumes this wrapper, returning the wrapped value.
-    pub fn into_inner(self) -> T { self.inner }
-
-    /// Returns the number of bytes that can be read before this instance will
-    /// return EOF.
-    ///
-    /// # Note
-    ///
-    /// This instance may reach EOF after reading fewer bytes than indicated by
-    /// this method if the underlying [`Read`] instance reaches EOF.
-    pub fn limit(&self) -> u64 { self.end.saturating_sub(self.pos) }
-}
-
-impl<T: Seek> TakeSeek<T> {
-    /// Sets the number of bytes that can be read before this instance will
-    /// return EOF. This is the same as constructing a new `TakeSeek` instance,
-    /// so the amount of bytes read and the previous limit value don’t matter
-    /// when calling this method.
-    ///
-    /// # Panics
-    ///
-    /// Panics if the inner stream returns an error from `stream_position`.
-    pub fn set_limit(&mut self, limit: u64) {
-        let pos = self.inner.stream_position().expect("cannot get position for `set_limit`");
-        self.pos = pos;
-        self.end = pos + limit;
-    }
-}
-
-impl<T: Read> Read for TakeSeek<T> {
-    fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
-        let limit = self.limit();
-
-        // Don't call into inner reader at all at EOF because it may still block
-        if limit == 0 {
-            return Ok(0);
-        }
-
-        // Lint: It is impossible for this cast to truncate because the value
-        // being cast is the minimum of two values, and one of the value types
-        // is already `usize`.
-        #[allow(clippy::cast_possible_truncation)]
-        let max = (buf.len() as u64).min(limit) as usize;
-        let n = self.inner.read(&mut buf[0..max])?;
-        self.pos += n as u64;
-        Ok(n)
-    }
-}
-
-impl<T: Seek> Seek for TakeSeek<T> {
-    fn seek(&mut self, pos: SeekFrom) -> Result<u64> {
-        self.pos = self.inner.seek(pos)?;
-        Ok(self.pos)
-    }
-
-    fn stream_position(&mut self) -> Result<u64> { Ok(self.pos) }
-}
-
-/// An extension trait that implements `take_seek()` for compatible streams.
-pub trait TakeSeekExt {
-    /// Creates an adapter which will read at most `limit` bytes from the
-    /// wrapped stream.
-    fn take_seek(self, limit: u64) -> TakeSeek<Self>
-    where Self: Sized;
-}
-
-impl<T: Read + Seek> TakeSeekExt for T {
-    fn take_seek(mut self, limit: u64) -> TakeSeek<Self>
-    where Self: Sized {
-        let pos = self.stream_position().expect("cannot get position for `take_seek`");
-
-        TakeSeek { inner: self, pos, end: pos + limit }
-    }
-}

nod/src/write.rs

@@ -0,0 +1,163 @@
+//! [`DiscWriter`] and associated types.
+
+use bytes::Bytes;
+
+use crate::{
+    common::{Compression, Format},
+    disc,
+    read::DiscReader,
+    Error, Result,
+};
+
+/// Options for writing a disc image.
+#[derive(Default, Debug, Clone)]
+pub struct FormatOptions {
+    /// The disc format to write.
+    pub format: Format,
+    /// The compression algorithm to use for the output format, if supported.
+    ///
+    /// If unsure, use [`Format::default_compression`] to get the default compression for the format.
+    pub compression: Compression,
+    /// Block size to use.
+    ///
+    /// If unsure, use [`Format::default_block_size`] to get the default block size for the format.
+    pub block_size: u32,
+}
+
+impl FormatOptions {
+    /// Creates options for the specified format.
+    /// Uses the default compression and block size for the format.
+    #[inline]
+    pub fn new(format: Format) -> FormatOptions {
+        FormatOptions {
+            format,
+            compression: format.default_compression(),
+            block_size: format.default_block_size(),
+        }
+    }
+}
+
+/// Options for processing a disc image writer.
+#[derive(Default, Debug, Clone)]
+pub struct ProcessOptions {
+    /// If the output format supports multithreaded processing, this sets the number of threads to
+    /// use for processing data. This is particularly useful for formats that compress data or
+    /// perform other transformations. The default value of 0 disables multithreading.
+    pub processor_threads: usize,
+    /// Enables CRC32 checksum calculation for the disc data.
+    ///
+    /// If the output format supports it, this will be stored in the disc data. (NKit 2 compatible)
+    /// Each digest calculation will run on a separate thread, unaffected by the processor thread
+    /// count.
+    pub digest_crc32: bool,
+    /// Enables MD5 checksum calculation for the disc data. (Slow!)
+    ///
+    /// If the output format supports it, this will be stored in the disc data. (NKit 2 compatible)
+    /// Each digest calculation will run on a separate thread, unaffected by the processor thread
+    /// count.
+    pub digest_md5: bool,
+    /// Enables SHA-1 checksum calculation for the disc data.
+    ///
+    /// If the output format supports it, this will be stored in the disc data. (NKit 2 compatible)
+    /// Each digest calculation will run on a separate thread, unaffected by the processor thread
+    /// count.
+    pub digest_sha1: bool,
+    /// Enables XXH64 checksum calculation for the disc data.
+    ///
+    /// If the output format supports it, this will be stored in the disc data. (NKit 2 compatible)
+    /// Each digest calculation will run on a separate thread, unaffected by the processor thread
+    /// count.
+    pub digest_xxh64: bool,
+}
+
+/// A constructed disc writer.
+///
+/// This is the primary entry point for writing disc images.
+#[derive(Clone)]
+pub struct DiscWriter {
+    inner: Box<dyn disc::writer::DiscWriter>,
+}
+
+impl DiscWriter {
+    /// Creates a new disc writer with the specified format options.
+    #[inline]
+    pub fn new(disc: DiscReader, options: &FormatOptions) -> Result<DiscWriter> {
+        let mut options = options.clone();
+        options.compression.validate_level()?;
+        let mut reader = disc.into_inner();
+        reader.reset();
+        let inner = match options.format {
+            Format::Iso => {
+                if options.compression != Compression::None {
+                    return Err(Error::Other("ISO/GCM does not support compression".to_string()));
+                }
+                Box::new(reader)
+            }
+            Format::Ciso => crate::io::ciso::DiscWriterCISO::new(reader, &options)?,
+            #[cfg(feature = "compress-zlib")]
+            Format::Gcz => crate::io::gcz::DiscWriterGCZ::new(reader, &options)?,
+            Format::Tgc => crate::io::tgc::DiscWriterTGC::new(reader, &options)?,
+            Format::Wbfs => crate::io::wbfs::DiscWriterWBFS::new(reader, &options)?,
+            Format::Wia | Format::Rvz => crate::io::wia::DiscWriterWIA::new(reader, &options)?,
+            format => return Err(Error::Other(format!("Unsupported write format: {format}"))),
+        };
+        Ok(DiscWriter { inner })
+    }
+
+    /// Processes the disc writer to completion, calling the data callback, in order, for each block
+    /// of data to write to the output file. The callback should write all data before returning, or
+    /// return an error if writing fails.
+    #[inline]
+    pub fn process(
+        &self,
+        mut data_callback: impl FnMut(Bytes, u64, u64) -> std::io::Result<()> + Send,
+        options: &ProcessOptions,
+    ) -> Result<DiscFinalization> {
+        self.inner.process(&mut data_callback, options)
+    }
+
+    /// Returns the progress upper bound for the disc writer. For most formats, this has no
+    /// relation to the written disc size, but can be used to display progress.
+    #[inline]
+    pub fn progress_bound(&self) -> u64 { self.inner.progress_bound() }
+
+    /// Returns the weight of the disc writer, which can help determine the number of threads to
+    /// dedicate for output processing. This may depend on the format's configuration, such as
+    /// whether compression is enabled.
+    #[inline]
+    pub fn weight(&self) -> DiscWriterWeight { self.inner.weight() }
+}
+
+/// Data returned by the disc writer after processing.
+///
+/// If header data is provided, the consumer should seek to the beginning of the output stream and
+/// write the header data, overwriting any existing data. Otherwise, the output disc will be
+/// invalid.
+#[derive(Default, Clone)]
+pub struct DiscFinalization {
+    /// Header data to write to the beginning of the output stream, if any.
+    pub header: Bytes,
+    /// The calculated CRC32 checksum of the input disc data, if any.
+    pub crc32: Option<u32>,
+    /// The calculated MD5 hash of the input disc data, if any.
+    pub md5: Option<[u8; 16]>,
+    /// The calculated SHA-1 hash of the input disc data, if any.
+    pub sha1: Option<[u8; 20]>,
+    /// The calculated SHA-256 hash of the input disc data, if any.
+    pub xxh64: Option<u64>,
+}
+
+/// The weight of a disc writer, which can help determine the number of threads to use for
+/// processing.
+pub enum DiscWriterWeight {
+    /// The writer performs little to no processing of the input data, and is mostly I/O bound.
+    /// This means that this writer does not benefit from parallelization, and will ignore the
+    /// number of threads specified.
+    Light,
+    /// The writer performs some processing of the input data, and is somewhat CPU bound. This means
+    /// that this writer benefits from parallelization, but not as much as a heavy writer.
+    Medium,
+    /// The writer performs significant processing of the input data, and is mostly CPU bound. This
+    /// means that this writer benefits from parallelization.
+    Heavy,
+}

nodtool/Cargo.toml

@@ -16,31 +16,30 @@ categories = ["command-line-utilities", "parser-implementations"]
 build = "build.rs"
 
 [features]
-asm = ["md-5/asm", "nod/asm", "sha1/asm"]
-nightly = ["crc32fast/nightly"]
+openssl = ["nod/openssl"]
+openssl-vendored = ["nod/openssl-vendored"]
+tracy = ["dep:tracing-tracy"]
 
 [dependencies]
 argp = "0.3"
-base16ct = "0.2"
 crc32fast = "1.4"
-digest = "0.10"
+digest = { workspace = true }
 enable-ansi-support = "0.2"
 hex = { version = "0.4", features = ["serde"] }
 indicatif = "0.17"
-itertools = "0.13"
-log = "0.4"
-md-5 = "0.10"
+md-5 = { workspace = true }
 nod = { version = "2.0.0-alpha", path = "../nod" }
-quick-xml = { version = "0.36", features = ["serialize"] }
+num_cpus = "1.16"
+quick-xml = { version = "0.37", features = ["serialize"] }
 serde = { version = "1.0", features = ["derive"] }
-sha1 = "0.10"
+sha1 = { workspace = true }
 size = "0.4"
 supports-color = "3.0"
-tracing = "0.1"
+tracing = { workspace = true }
 tracing-attributes = "0.1"
 tracing-subscriber = { version = "0.3", features = ["env-filter"] }
-xxhash-rust = { version = "0.8", features = ["xxh64"] }
-zerocopy = { version = "0.8", features = ["alloc", "derive"] }
+tracing-tracy = { version = "0.11", features = ["flush-on-exit"], optional = true }
+zerocopy = { workspace = true }
 zstd = "0.13"
 
 [target.'cfg(target_env = "musl")'.dependencies]
@@ -48,7 +47,7 @@ mimalloc = "0.1"
 
 [build-dependencies]
 hex = { version = "0.4", features = ["serde"] }
-quick-xml = { version = "0.36", features = ["serialize"] }
+quick-xml = { version = "0.37", features = ["serialize"] }
 serde = { version = "1.0", features = ["derive"] }
 zerocopy = { version = "0.8", features = ["alloc", "derive"] }
 zstd = "0.13"

nodtool/src/cmd/convert.rs

@@ -1,9 +1,13 @@
-use std::path::PathBuf;
+use std::{ffi::OsStr, path::PathBuf};
 
 use argp::FromArgs;
-use nod::OpenOptions;
+use nod::{
+    common::Format,
+    read::{DiscOptions, PartitionEncryption},
+    write::FormatOptions,
+};
 
-use crate::util::{redump, shared::convert_and_verify};
+use crate::util::{path_display, redump, shared::convert_and_verify};
 
 #[derive(FromArgs, Debug)]
 /// Converts a disc image to ISO.
@@ -27,6 +31,9 @@ pub struct Args {
     #[argp(switch)]
     /// encrypt Wii partition data
     encrypt: bool,
+    #[argp(option, short = 'c')]
+    /// compression format and level (e.g. "zstd:19")
+    compress: Option<String>,
 }
 
 pub fn run(args: Args) -> nod::Result<()> {
@@ -34,15 +41,46 @@ pub fn run(args: Args) -> nod::Result<()> {
         println!("Loading dat files...");
         redump::load_dats(args.dat.iter().map(PathBuf::as_ref))?;
     }
-    let options = OpenOptions {
+    let options = DiscOptions {
         partition_encryption: match (args.decrypt, args.encrypt) {
-            (true, false) => nod::PartitionEncryptionMode::ForceDecrypted,
-            (false, true) => nod::PartitionEncryptionMode::ForceEncrypted,
-            (false, false) => nod::PartitionEncryptionMode::Original,
+            (true, false) => PartitionEncryption::ForceDecrypted,
+            (false, true) => PartitionEncryption::ForceEncrypted,
+            (false, false) => PartitionEncryption::Original,
             (true, true) => {
                 return Err(nod::Error::Other("Both --decrypt and --encrypt specified".to_string()))
             }
         },
+        preloader_threads: 4,
     };
-    convert_and_verify(&args.file, Some(&args.out), args.md5, &options)
+    let format = match args.out.extension() {
+        Some(ext)
+            if ext.eq_ignore_ascii_case(OsStr::new("iso"))
+                || ext.eq_ignore_ascii_case(OsStr::new("gcm")) =>
+        {
+            Format::Iso
+        }
+        Some(ext) if ext.eq_ignore_ascii_case(OsStr::new("ciso")) => Format::Ciso,
+        Some(ext) if ext.eq_ignore_ascii_case(OsStr::new("gcz")) => Format::Gcz,
+        Some(ext) if ext.eq_ignore_ascii_case(OsStr::new("nfs")) => Format::Nfs,
+        Some(ext) if ext.eq_ignore_ascii_case(OsStr::new("rvz")) => Format::Rvz,
+        Some(ext) if ext.eq_ignore_ascii_case(OsStr::new("wbfs")) => Format::Wbfs,
+        Some(ext) if ext.eq_ignore_ascii_case(OsStr::new("wia")) => Format::Wia,
+        Some(ext) if ext.eq_ignore_ascii_case(OsStr::new("tgc")) => Format::Tgc,
+        Some(_) => {
+            return Err(nod::Error::Other(format!(
+                "Unknown file extension: {}",
+                path_display(&args.out)
+            )))
+        }
+        None => Format::Iso,
+    };
+    let mut compression = if let Some(compress) = args.compress {
+        compress.parse()?
+    } else {
+        format.default_compression()
+    };
+    compression.validate_level()?;
+    let format_options =
+        FormatOptions { format, compression, block_size: format.default_block_size() };
+    convert_and_verify(&args.file, Some(&args.out), args.md5, &options, &format_options)
 }

nodtool/src/cmd/dat.rs

@@ -1,24 +1,19 @@
 use std::{
-    cmp::min,
     collections::BTreeMap,
     fmt,
-    io::Read,
     path::{Path, PathBuf},
-    sync::{mpsc::sync_channel, Arc},
-    thread,
 };
 
 use argp::FromArgs;
 use indicatif::{ProgressBar, ProgressState, ProgressStyle};
-use nod::{Disc, OpenOptions, PartitionEncryptionMode, Result, ResultContext};
-use zerocopy::FromZeros;
-
-use crate::util::{
-    digest::{digest_thread, DigestResult},
-    redump,
-    redump::GameResult,
+use nod::{
+    read::{DiscOptions, DiscReader, PartitionEncryption},
+    write::{DiscWriter, FormatOptions, ProcessOptions},
+    Result, ResultContext,
 };
 
+use crate::util::{redump, redump::GameResult};
+
 #[derive(FromArgs, Debug)]
 /// Commands related to DAT files.
 #[argp(subcommand, name = "dat")]
@@ -165,9 +160,9 @@ struct DiscHashes {
 }
 
 fn load_disc(path: &Path, name: &str, full_verify: bool) -> Result<DiscHashes> {
-    let options = OpenOptions { partition_encryption: PartitionEncryptionMode::Original };
-    let mut disc = Disc::new_with_options(path, &options)?;
-    let disc_size = disc.disc_size();
+    let options =
+        DiscOptions { partition_encryption: PartitionEncryption::Original, preloader_threads: 4 };
+    let disc = DiscReader::new(path, &options)?;
     if !full_verify {
         let meta = disc.meta();
         if let (Some(crc32), Some(sha1)) = (meta.crc32, meta.sha1) {
@@ -175,7 +170,8 @@ fn load_disc(path: &Path, name: &str, full_verify: bool) -> Result<DiscHashes> {
         }
     }
 
-    let pb = ProgressBar::new(disc_size).with_message(format!("{}:", name));
+    let disc_writer = DiscWriter::new(disc, &FormatOptions::default())?;
+    let pb = ProgressBar::new(disc_writer.progress_bound()).with_message(format!("{}:", name));
     pb.set_style(ProgressStyle::with_template("{msg} {spinner:.green} [{elapsed_precise}] [{wide_bar:.cyan/blue}] {bytes}/{total_bytes} ({bytes_per_sec}, {eta})")
         .unwrap()
         .with_key("eta", |state: &ProgressState, w: &mut dyn fmt::Write| {
@@ -183,47 +179,22 @@ fn load_disc(path: &Path, name: &str, full_verify: bool) -> Result<DiscHashes> {
         })
         .progress_chars("#>-"));
 
-    const BUFFER_SIZE: usize = 1015808; // LCM(0x8000, 0x7C00)
-    let digest_threads = [digest_thread::<crc32fast::Hasher>(), digest_thread::<sha1::Sha1>()];
-
-    let (w_tx, w_rx) = sync_channel::<Arc<[u8]>>(1);
-    let w_thread = thread::spawn(move || {
     let mut total_written = 0u64;
-        while let Ok(data) = w_rx.recv() {
+    let finalization = disc_writer.process(
+        |data, pos, _| {
             total_written += data.len() as u64;
-            pb.set_position(total_written);
-        }
-        pb.finish_and_clear();
-    });
+            pb.set_position(pos);
+            Ok(())
+        },
+        &ProcessOptions {
+            processor_threads: 12, // TODO
+            digest_crc32: true,
+            digest_md5: false,
+            digest_sha1: true,
+            digest_xxh64: false,
+        },
+    )?;
+    pb.finish();
 
-    let mut total_read = 0u64;
-    let mut buf = <[u8]>::new_box_zeroed_with_elems(BUFFER_SIZE)?;
-    while total_read < disc_size {
-        let read = min(BUFFER_SIZE as u64, disc_size - total_read) as usize;
-        disc.read_exact(&mut buf[..read]).with_context(|| {
-            format!("Reading {} bytes at disc offset {}", BUFFER_SIZE, total_read)
-        })?;
-
-        let arc = Arc::<[u8]>::from(&buf[..read]);
-        for (tx, _) in &digest_threads {
-            tx.send(arc.clone()).map_err(|_| "Sending data to hash thread")?;
-        }
-        w_tx.send(arc).map_err(|_| "Sending data to write thread")?;
-        total_read += read as u64;
-    }
-    drop(w_tx); // Close channel
-    w_thread.join().unwrap();
-
-    let mut crc32 = None;
-    let mut sha1 = None;
-    for (tx, handle) in digest_threads {
-        drop(tx); // Close channel
-        match handle.join().unwrap() {
-            DigestResult::Crc32(v) => crc32 = Some(v),
-            DigestResult::Sha1(v) => sha1 = Some(v),
-            _ => {}
-        }
-    }
-
-    Ok(DiscHashes { crc32: crc32.unwrap(), sha1: sha1.unwrap() })
+    Ok(DiscHashes { crc32: finalization.crc32.unwrap(), sha1: finalization.sha1.unwrap() })
 }

nodtool/src/cmd/extract.rs

@@ -1,5 +1,4 @@
 use std::{
-    borrow::Cow,
     fs,
     fs::File,
     io::{BufRead, Write},
@@ -7,15 +6,16 @@ use std::{
 };
 
 use argp::FromArgs;
-use itertools::Itertools;
 use nod::{
-    Disc, Fst, Node, OpenOptions, PartitionBase, PartitionKind, PartitionMeta, PartitionOptions,
+    common::PartitionKind,
+    disc::fst::{Fst, Node},
+    read::{DiscOptions, DiscReader, PartitionMeta, PartitionOptions, PartitionReader},
     ResultContext,
 };
 use size::{Base, Size};
 use zerocopy::IntoBytes;
 
-use crate::util::{display, has_extension};
+use crate::util::{has_extension, path_display};
 
 #[derive(FromArgs, Debug)]
 /// Extracts a disc image.
@@ -53,77 +53,57 @@ pub fn run(args: Args) -> nod::Result<()> {
     } else {
         output_dir = args.file.with_extension("");
     }
-    let disc = Disc::new_with_options(&args.file, &OpenOptions::default())?;
+    let disc =
+        DiscReader::new(&args.file, &DiscOptions { preloader_threads: 4, ..Default::default() })?;
     let header = disc.header();
     let is_wii = header.is_wii();
-    let partition_options = PartitionOptions { validate_hashes: args.validate };
+    let options = PartitionOptions { validate_hashes: args.validate };
     if let Some(partition) = args.partition {
         if partition.eq_ignore_ascii_case("all") {
             for info in disc.partitions() {
                 let mut out_dir = output_dir.clone();
                 out_dir.push(info.kind.dir_name().as_ref());
-                let mut partition =
-                    disc.open_partition_with_options(info.index, &partition_options)?;
+                let mut partition = disc.open_partition(info.index, &options)?;
                 extract_partition(&disc, partition.as_mut(), &out_dir, is_wii, args.quiet)?;
             }
         } else if partition.eq_ignore_ascii_case("data") {
-            let mut partition =
-                disc.open_partition_kind_with_options(PartitionKind::Data, &partition_options)?;
+            let mut partition = disc.open_partition_kind(PartitionKind::Data, &options)?;
             extract_partition(&disc, partition.as_mut(), &output_dir, is_wii, args.quiet)?;
         } else if partition.eq_ignore_ascii_case("update") {
-            let mut partition =
-                disc.open_partition_kind_with_options(PartitionKind::Update, &partition_options)?;
+            let mut partition = disc.open_partition_kind(PartitionKind::Update, &options)?;
             extract_partition(&disc, partition.as_mut(), &output_dir, is_wii, args.quiet)?;
         } else if partition.eq_ignore_ascii_case("channel") {
-            let mut partition =
-                disc.open_partition_kind_with_options(PartitionKind::Channel, &partition_options)?;
+            let mut partition = disc.open_partition_kind(PartitionKind::Channel, &options)?;
             extract_partition(&disc, partition.as_mut(), &output_dir, is_wii, args.quiet)?;
         } else {
             let idx = partition.parse::<usize>().map_err(|_| "Invalid partition index")?;
-            let mut partition = disc.open_partition_with_options(idx, &partition_options)?;
+            let mut partition = disc.open_partition(idx, &options)?;
             extract_partition(&disc, partition.as_mut(), &output_dir, is_wii, args.quiet)?;
         }
     } else {
-        let mut partition =
-            disc.open_partition_kind_with_options(PartitionKind::Data, &partition_options)?;
+        let mut partition = disc.open_partition_kind(PartitionKind::Data, &options)?;
         extract_partition(&disc, partition.as_mut(), &output_dir, is_wii, args.quiet)?;
     }
     Ok(())
 }
 
 fn extract_partition(
-    disc: &Disc,
-    partition: &mut dyn PartitionBase,
+    disc: &DiscReader,
+    partition: &mut dyn PartitionReader,
     out_dir: &Path,
     is_wii: bool,
     quiet: bool,
 ) -> nod::Result<()> {
     let meta = partition.meta()?;
-    extract_sys_files(disc, meta.as_ref(), out_dir, quiet)?;
+    extract_sys_files(disc, &meta, out_dir, quiet)?;
 
     // Extract FST
     let files_dir = out_dir.join("files");
     fs::create_dir_all(&files_dir)
-        .with_context(|| format!("Creating directory {}", display(&files_dir)))?;
+        .with_context(|| format!("Creating directory {}", path_display(&files_dir)))?;
 
     let fst = Fst::new(&meta.raw_fst)?;
-    let mut path_segments = Vec::<(Cow<str>, usize)>::new();
-    for (idx, node, name) in fst.iter() {
-        // Remove ended path segments
-        let mut new_size = 0;
-        for (_, end) in path_segments.iter() {
-            if *end == idx {
-                break;
-            }
-            new_size += 1;
-        }
-        path_segments.truncate(new_size);
-
-        // Add the new path segment
-        let end = if node.is_dir() { node.length() as usize } else { idx + 1 };
-        path_segments.push((name?, end));
-
-        let path = path_segments.iter().map(|(name, _)| name.as_ref()).join("/");
+    for (_, node, path) in fst.iter() {
         if node.is_dir() {
             fs::create_dir_all(files_dir.join(&path))
                 .with_context(|| format!("Creating directory {}", path))?;
@@ -135,14 +115,14 @@ fn extract_partition(
 }
 
 fn extract_sys_files(
-    disc: &Disc,
+    disc: &DiscReader,
     data: &PartitionMeta,
     out_dir: &Path,
     quiet: bool,
 ) -> nod::Result<()> {
     let sys_dir = out_dir.join("sys");
     fs::create_dir_all(&sys_dir)
-        .with_context(|| format!("Creating directory {}", display(&sys_dir)))?;
+        .with_context(|| format!("Creating directory {}", path_display(&sys_dir)))?;
     extract_file(data.raw_boot.as_ref(), &sys_dir.join("boot.bin"), quiet)?;
     extract_file(data.raw_bi2.as_ref(), &sys_dir.join("bi2.bin"), quiet)?;
     extract_file(data.raw_apploader.as_ref(), &sys_dir.join("apploader.img"), quiet)?;
@@ -154,7 +134,7 @@ fn extract_sys_files(
     if disc_header.is_wii() {
         let disc_dir = out_dir.join("disc");
         fs::create_dir_all(&disc_dir)
-            .with_context(|| format!("Creating directory {}", display(&disc_dir)))?;
+            .with_context(|| format!("Creating directory {}", path_display(&disc_dir)))?;
         extract_file(&disc_header.as_bytes()[..0x100], &disc_dir.join("header.bin"), quiet)?;
         if let Some(region) = disc.region() {
             extract_file(region, &disc_dir.join("region.bin"), quiet)?;
@@ -179,17 +159,18 @@ fn extract_file(bytes: &[u8], out_path: &Path, quiet: bool) -> nod::Result<()> {
     if !quiet {
         println!(
             "Extracting {} (size: {})",
-            display(out_path),
+            path_display(out_path),
             Size::from_bytes(bytes.len()).format().with_base(Base::Base10)
         );
     }
-    fs::write(out_path, bytes).with_context(|| format!("Writing file {}", display(out_path)))?;
+    fs::write(out_path, bytes)
+        .with_context(|| format!("Writing file {}", path_display(out_path)))?;
     Ok(())
 }
 
 fn extract_node(
     node: Node,
-    partition: &mut dyn PartitionBase,
+    partition: &mut dyn PartitionReader,
     base_path: &Path,
     name: &str,
     is_wii: bool,
@@ -199,12 +180,12 @@ fn extract_node(
     if !quiet {
         println!(
             "Extracting {} (size: {})",
-            display(&file_path),
+            path_display(&file_path),
             Size::from_bytes(node.length()).format().with_base(Base::Base10)
         );
     }
     let mut file = File::create(&file_path)
-        .with_context(|| format!("Creating file {}", display(&file_path)))?;
+        .with_context(|| format!("Creating file {}", path_display(&file_path)))?;
     let mut r = partition.open_file(node).with_context(|| {
         format!(
             "Opening file {} on disc for reading (offset {}, size {})",
@@ -214,15 +195,17 @@ fn extract_node(
         )
     })?;
     loop {
-        let buf =
-            r.fill_buf().with_context(|| format!("Extracting file {}", display(&file_path)))?;
+        let buf = r
+            .fill_buf()
+            .with_context(|| format!("Extracting file {}", path_display(&file_path)))?;
         let len = buf.len();
         if len == 0 {
             break;
         }
-        file.write_all(buf).with_context(|| format!("Writing file {}", display(&file_path)))?;
+        file.write_all(buf)
+            .with_context(|| format!("Writing file {}", path_display(&file_path)))?;
         r.consume(len);
     }
-    file.flush().with_context(|| format!("Flushing file {}", display(&file_path)))?;
+    file.flush().with_context(|| format!("Flushing file {}", path_display(&file_path)))?;
     Ok(())
 }

nodtool/src/cmd/gen.rs

@@ -0,0 +1,771 @@
+use std::{
+    fs,
+    fs::File,
+    io,
+    io::{BufRead, Read, Seek, SeekFrom, Write},
+    path::{Path, PathBuf},
+    str::from_utf8,
+    time::Instant,
+};
+
+use argp::FromArgs;
+use nod::{
+    build::gc::{FileCallback, FileInfo, GCPartitionBuilder, PartitionOverrides},
+    common::PartitionKind,
+    disc::{
+        fst::Fst, DiscHeader, PartitionHeader, BI2_SIZE, BOOT_SIZE, MINI_DVD_SIZE, SECTOR_SIZE,
+    },
+    read::{
+        DiscOptions, DiscReader, PartitionEncryption, PartitionMeta, PartitionOptions,
+        PartitionReader,
+    },
+    util::lfg::LaggedFibonacci,
+    write::{DiscWriter, FormatOptions, ProcessOptions},
+    ResultContext,
+};
+use tracing::{debug, error, info, warn};
+use zerocopy::{FromBytes, FromZeros};
+
+use crate::util::{array_ref, redump, shared::convert_and_verify};
+
+#[derive(FromArgs, Debug)]
+/// Generates a disc image.
+#[argp(subcommand, name = "gen")]
+pub struct Args {
+    #[argp(positional)]
+    /// Path to extracted disc image
+    dir: PathBuf,
+    #[argp(positional)]
+    /// Output ISO file
+    out: PathBuf,
+}
+
+#[derive(FromArgs, Debug)]
+/// Test disc image generation.
+#[argp(subcommand, name = "gentest")]
+pub struct TestArgs {
+    #[argp(positional)]
+    /// Path to original disc images
+    inputs: Vec<PathBuf>,
+    #[argp(option, short = 'o')]
+    /// Output ISO file
+    output: Option<PathBuf>,
+    #[argp(option, short = 't')]
+    /// Output original ISO for comparison
+    test_output: Option<PathBuf>,
+}
+
+fn read_fixed<const N: usize>(path: &Path) -> nod::Result<Box<[u8; N]>> {
+    let mut buf = <[u8; N]>::new_box_zeroed()?;
+    File::open(path)
+        .with_context(|| format!("Failed to open {}", path.display()))?
+        .read_exact(buf.as_mut())
+        .with_context(|| format!("Failed to read {}", path.display()))?;
+    Ok(buf)
+}
+
+fn read_all(path: &Path) -> nod::Result<Box<[u8]>> {
+    let mut buf = Vec::new();
+    File::open(path)
+        .with_context(|| format!("Failed to open {}", path.display()))?
+        .read_to_end(&mut buf)
+        .with_context(|| format!("Failed to read {}", path.display()))?;
+    Ok(buf.into_boxed_slice())
+}
+
+struct FileWriteInfo {
+    name: String,
+    offset: u64,
+    length: u64,
+}
+
+fn file_size(path: &Path) -> nod::Result<u64> {
+    Ok(fs::metadata(path)
+        .with_context(|| format!("Failed to get metadata for {}", path.display()))?
+        .len())
+}
+
+fn check_file_size(path: &Path, expected: u64) -> nod::Result<()> {
+    let actual = file_size(path)?;
+    if actual != expected {
+        return Err(nod::Error::DiscFormat(format!(
+            "File {} has size {}, expected {}",
+            path.display(),
+            actual,
+            expected
+        )));
+    }
+    Ok(())
+}
+
+pub fn run(args: Args) -> nod::Result<()> {
+    let start = Instant::now();
+
+    // Validate file sizes
+    let boot_path = args.dir.join("sys/boot.bin");
+    check_file_size(&boot_path, BOOT_SIZE as u64)?;
+    let bi2_path = args.dir.join("sys/bi2.bin");
+    check_file_size(&bi2_path, BI2_SIZE as u64)?;
+    let apploader_path = args.dir.join("sys/apploader.img");
+    let apploader_size = file_size(&apploader_path)?;
+    let dol_path = args.dir.join("sys/main.dol");
+    let dol_size = file_size(&dol_path)?;
+
+    // Build metadata
+    let mut file_infos = Vec::new();
+    let boot_data: Box<[u8; BOOT_SIZE]> = read_fixed(&boot_path)?;
+    let header = DiscHeader::ref_from_bytes(&boot_data[..size_of::<DiscHeader>()])
+        .expect("Failed to read disc header");
+    let junk_id = get_junk_id(header);
+    let partition_header = PartitionHeader::ref_from_bytes(&boot_data[size_of::<DiscHeader>()..])
+        .expect("Failed to read partition header");
+    let fst_path = args.dir.join("sys/fst.bin");
+    let fst_data = read_all(&fst_path)?;
+    let fst = Fst::new(&fst_data).expect("Failed to parse FST");
+
+    file_infos.push(FileWriteInfo {
+        name: "sys/boot.bin".to_string(),
+        offset: 0,
+        length: BOOT_SIZE as u64,
+    });
+    file_infos.push(FileWriteInfo {
+        name: "sys/bi2.bin".to_string(),
+        offset: BOOT_SIZE as u64,
+        length: BI2_SIZE as u64,
+    });
+    file_infos.push(FileWriteInfo {
+        name: "sys/apploader.img".to_string(),
+        offset: BOOT_SIZE as u64 + BI2_SIZE as u64,
+        length: apploader_size,
+    });
+    let fst_offset = partition_header.fst_offset(false);
+    let dol_offset = partition_header.dol_offset(false);
+    if dol_offset < fst_offset {
+        file_infos.push(FileWriteInfo {
+            name: "sys/main.dol".to_string(),
+            offset: dol_offset,
+            length: dol_size,
+        });
+    } else {
+        let mut found = false;
+        for (_, node, path) in fst.iter() {
+            if !node.is_file() {
+                continue;
+            }
+            let offset = node.offset(false);
+            if offset == dol_offset {
+                info!("Using DOL from FST: {}", path);
+                found = true;
+            }
+        }
+        if !found {
+            return Err(nod::Error::DiscFormat("DOL not found in FST".to_string()));
+        }
+    }
+    let fst_size = partition_header.fst_size(false);
+    file_infos.push(FileWriteInfo {
+        name: "sys/fst.bin".to_string(),
+        offset: fst_offset,
+        length: fst_size,
+    });
+
+    // Collect files
+    for (_, node, path) in fst.iter() {
+        let length = node.length() as u64;
+        if node.is_dir() {
+            continue;
+        }
+
+        let mut file_path = args.dir.join("files");
+        file_path.extend(path.split('/'));
+        let metadata = match fs::metadata(&file_path) {
+            Ok(meta) => meta,
+            Err(e) if e.kind() == io::ErrorKind::NotFound => {
+                warn!("File not found: {}", file_path.display());
+                continue;
+            }
+            Err(e) => {
+                return Err(e)
+                    .context(format!("Failed to get metadata for {}", file_path.display()))
+            }
+        };
+        if metadata.is_dir() {
+            return Err(nod::Error::Other(format!("Path {} is a directory", file_path.display())));
+        }
+        if metadata.len() != length {
+            return Err(nod::Error::Other(format!(
+                "File {} has size {}, expected {}",
+                file_path.display(),
+                metadata.len(),
+                length
+            )));
+        }
+        let offset = node.offset(false);
+        file_infos.push(FileWriteInfo {
+            name: file_path.into_os_string().into_string().unwrap(),
+            offset,
+            length,
+        });
+    }
+    sort_files(&mut file_infos)?;
+
+    // Write files
+    let mut out = File::create(&args.out)
+        .with_context(|| format!("Failed to create {}", args.out.display()))?;
+    info!("Writing disc image to {} ({} files)", args.out.display(), file_infos.len());
+    let crc = write_files(
+        &mut out,
+        &file_infos,
+        header,
+        partition_header,
+        junk_id,
+        |out, name| match name {
+            "sys/boot.bin" => out.write_all(boot_data.as_ref()),
+            "sys/fst.bin" => out.write_all(fst_data.as_ref()),
+            path => {
+                let mut in_file = File::open(args.dir.join(path))?;
+                io::copy(&mut in_file, out).map(|_| ())
+            }
+        },
+    )?;
+    out.flush().context("Failed to flush output file")?;
+    info!("Generated disc image in {:?} (CRC32: {:08X})", start.elapsed(), crc);
+    let redump_entry = redump::find_by_crc32(crc);
+    if let Some(entry) = &redump_entry {
+        println!("Redump: {} ✅", entry.name);
+    } else {
+        println!("Redump: Not found ❌");
+    }
+    Ok(())
+}
+
+#[inline]
+fn align_up<const N: u64>(n: u64) -> u64 { (n + N - 1) & !(N - 1) }
+
+#[inline]
+fn gcm_align(n: u64) -> u64 { (n + 31) & !3 }
+
+/// Files can be located on the inner rim of the disc (closer to the center) or the outer rim
+/// (closer to the edge). The inner rim is slower to read, so developers often configured certain
+/// files to be located on the outer rim. This function attempts to find a gap in the file offsets
+/// between the inner and outer rim, which we need to recreate junk data properly.
+fn find_file_gap(file_infos: &[FileWriteInfo], fst_end: u64) -> Option<u64> {
+    let mut last_offset = 0;
+    for info in file_infos {
+        if last_offset > fst_end && info.offset > last_offset + SECTOR_SIZE as u64 {
+            debug!("Found file gap at {:X} -> {:X}", last_offset, info.offset);
+            return Some(last_offset);
+        }
+        last_offset = info.offset + info.length;
+    }
+    None
+}
+
+fn write_files<W>(
+    w: &mut W,
+    file_infos: &[FileWriteInfo],
+    header: &DiscHeader,
+    partition_header: &PartitionHeader,
+    junk_id: Option<[u8; 4]>,
+    mut callback: impl FnMut(&mut HashStream<&mut W>, &str) -> io::Result<()>,
+) -> nod::Result<u32>
+where
+    W: Write + ?Sized,
+{
+    let fst_end = partition_header.fst_offset(false) + partition_header.fst_size(false);
+    let file_gap = find_file_gap(file_infos, fst_end);
+    let mut lfg = LaggedFibonacci::default();
+    let mut out = HashStream::new(w);
+    let mut last_end = 0;
+    for info in file_infos {
+        if let Some(junk_id) = junk_id {
+            let aligned_end = gcm_align(last_end);
+            if info.offset > aligned_end && last_end >= fst_end {
+                // Junk data is aligned to 4 bytes with a 28 byte padding (aka `(n + 31) & !3`)
+                // but a few cases don't have the 28 byte padding. Namely, the junk data after the
+                // FST, and the junk data in between the inner and outer rim files. This attempts to
+                // determine the correct alignment, but is not 100% accurate.
+                let junk_start =
+                    if file_gap == Some(last_end) { align_up::<4>(last_end) } else { aligned_end };
+                debug!("Writing junk data at {:X} -> {:X}", junk_start, info.offset);
+                write_junk_data(
+                    &mut lfg,
+                    &mut out,
+                    junk_id,
+                    header.disc_num,
+                    junk_start,
+                    info.offset,
+                )?;
+            }
+        }
+        debug!(
+            "Writing file {} at {:X} -> {:X}",
+            info.name,
+            info.offset,
+            info.offset + info.length
+        );
+        out.seek(SeekFrom::Start(info.offset))
+            .with_context(|| format!("Seeking to offset {}", info.offset))?;
+        if info.length > 0 {
+            callback(&mut out, &info.name)
+                .with_context(|| format!("Failed to write file {}", info.name))?;
+            let cur = out.stream_position().context("Getting current position")?;
+            if cur != info.offset + info.length {
+                return Err(nod::Error::Other(format!(
+                    "Wrote {} bytes, expected {}",
+                    cur - info.offset,
+                    info.length
+                )));
+            }
+        }
+        last_end = info.offset + info.length;
+    }
+    if let Some(junk_id) = junk_id {
+        let aligned_end = gcm_align(last_end);
+        if aligned_end < MINI_DVD_SIZE && aligned_end >= fst_end {
+            debug!("Writing junk data at {:X} -> {:X}", aligned_end, MINI_DVD_SIZE);
+            write_junk_data(
+                &mut lfg,
+                &mut out,
+                junk_id,
+                header.disc_num,
+                aligned_end,
+                MINI_DVD_SIZE,
+            )?;
+            last_end = MINI_DVD_SIZE;
+        }
+    }
+    out.write_zeroes(MINI_DVD_SIZE - last_end).context("Writing end of file")?;
+    out.flush().context("Flushing output")?;
+    Ok(out.finish())
+}
+
+fn write_junk_data<W>(
+    lfg: &mut LaggedFibonacci,
+    out: &mut W,
+    junk_id: [u8; 4],
+    disc_num: u8,
+    pos: u64,
+    end: u64,
+) -> nod::Result<()>
+where
+    W: Write + Seek + ?Sized,
+{
+    out.seek(SeekFrom::Start(pos)).with_context(|| format!("Seeking to offset {}", pos))?;
+    lfg.write_sector_chunked(out, end - pos, junk_id, disc_num, pos)
+        .with_context(|| format!("Failed to write junk data at offset {}", pos))?;
+    Ok(())
+}
+
+pub fn run_test(args: TestArgs) -> nod::Result<()> {
+    let mut failed = vec![];
+    for input in args.inputs {
+        match in_memory_test(&input, args.output.as_deref(), args.test_output.as_deref()) {
+            Ok(()) => {}
+            Err(e) => {
+                error!("Failed to generate disc image: {:?}", e);
+                failed.push((input, e));
+            }
+        }
+    }
+    if !failed.is_empty() {
+        error!("Failed to generate disc images:");
+        for (input, e) in failed {
+            error!("  {}: {:?}", input.display(), e);
+        }
+        std::process::exit(1);
+    }
+    Ok(())
+}
+
+/// Some games (mainly beta and sample discs) have junk data that doesn't match the game ID. This
+/// function returns the correct game ID to use, if an override is needed.
+fn get_override_junk_id(header: &DiscHeader) -> Option<[u8; 4]> {
+    match &header.game_id {
+        // Dairantou Smash Brothers DX (Japan) (Taikenban)
+        b"DALJ01" if header.disc_num == 0 && header.disc_version == 0 => Some(*b"DPIJ"),
+        // 2002 FIFA World Cup (Japan) (Jitsuen-you Sample)
+        b"DFIJ13" if header.disc_num == 0 && header.disc_version == 0 => Some(*b"GFIJ"),
+        // Disney's Magical Park (Japan) (Jitsuen-you Sample)
+        b"DMTJ18" if header.disc_num == 0 && header.disc_version == 0 => Some(*b"GMTJ"),
+        // Star Wars - Rogue Squadron II (Japan) (Jitsuen-you Sample)
+        b"DSWJ13" if header.disc_num == 0 && header.disc_version == 0 => Some(*b"GSWJ"),
+        // Homeland (Japan) (Rev 1) [T-En by DOL-Translations v20230606] [i]
+        b"GHEE91" if header.disc_num == 0 && header.disc_version == 1 => Some(*b"GHEJ"),
+        // Kururin Squash! (Japan) [T-En by DOL-Translations v2.0.0]
+        b"GKQE01" if header.disc_num == 0 && header.disc_version == 0 => Some(*b"GKQJ"),
+        // Lupin III - Lost Treasure Under the Sea (Japan) (Disc 1) [T-En by DOL-Translations v0.5.0] [i] [n]
+        b"GL3EE8" if header.disc_num == 0 && header.disc_version == 0 => Some(*b"GL3J"),
+        // Lupin III - Lost Treasure Under the Sea (Japan) (Disc 2) [T-En by DOL-Translations v0.5.0] [i] [n]
+        b"GL3EE8" if header.disc_num == 1 && header.disc_version == 0 => Some(*b"GL3J"),
+        // Taxi 3 - The Game (France) [T-En by DOL-Translations v20230801] [n]
+        b"GXQP41" if header.disc_num == 0 && header.disc_version == 0 => Some(*b"GXQF"),
+        // Donkey Konga 3 - Tabehoudai! Haru Mogitate 50-kyoku (Japan) [T-En by DOL-Translations v0.1.1] [i]
+        b"GY3E01" if header.disc_num == 0 && header.disc_version == 0 => Some(*b"GY3J"),
+        // Need for Speed - Underground (Europe) (Alt)
+        b"PZHP69" if header.disc_num == 0 && header.disc_version == 0 => Some(*b"GNDP"),
+        _ => None,
+    }
+}
+
+fn get_junk_id(header: &DiscHeader) -> Option<[u8; 4]> {
+    Some(match get_override_junk_id(header) {
+        Some(id) => {
+            info!("Using override junk ID: {:X?}", from_utf8(&id).unwrap());
+            id
+        }
+        None => *array_ref!(header.game_id, 0, 4),
+    })
+}
+
+fn sort_files(files: &mut [FileWriteInfo]) -> nod::Result<()> {
+    files.sort_unstable_by_key(|info| (info.offset, info.length));
+    for i in 1..files.len() {
+        let prev = &files[i - 1];
+        let cur = &files[i];
+        if cur.offset < prev.offset + prev.length {
+            return Err(nod::Error::Other(format!(
+                "File {} ({:#X}-{:#X}) overlaps with {} ({:#X}-{:#X})",
+                cur.name,
+                cur.offset,
+                cur.offset + cur.length,
+                prev.name,
+                prev.offset,
+                prev.offset + prev.length
+            )));
+        }
+    }
+    Ok(())
+}
+
+fn in_memory_test(
+    path: &Path,
+    output: Option<&Path>,
+    test_output: Option<&Path>,
+) -> nod::Result<()> {
+    let start = Instant::now();
+    info!("Opening disc image '{}'", path.display());
+    let disc = DiscReader::new(path, &DiscOptions::default())?;
+    info!(
+        "Opened disc image '{}' (Disc {}, Revision {})",
+        disc.header().game_title_str(),
+        disc.header().disc_num + 1,
+        disc.header().disc_version
+    );
+    let Some(orig_crc32) = disc.meta().crc32 else {
+        return Err(nod::Error::Other("CRC32 not found in disc metadata".to_string()));
+    };
+    let mut partition =
+        disc.open_partition_kind(PartitionKind::Data, &PartitionOptions::default())?;
+    let meta = partition.meta()?;
+
+    // Build metadata
+    let mut file_infos = Vec::new();
+    let header = meta.header();
+    let junk_id = get_junk_id(header);
+    let partition_header = meta.partition_header();
+    let fst = meta.fst()?;
+
+    file_infos.push(FileWriteInfo {
+        name: "sys/boot.bin".to_string(),
+        offset: 0,
+        length: BOOT_SIZE as u64,
+    });
+    file_infos.push(FileWriteInfo {
+        name: "sys/bi2.bin".to_string(),
+        offset: BOOT_SIZE as u64,
+        length: BI2_SIZE as u64,
+    });
+    file_infos.push(FileWriteInfo {
+        name: "sys/apploader.img".to_string(),
+        offset: BOOT_SIZE as u64 + BI2_SIZE as u64,
+        length: meta.raw_apploader.len() as u64,
+    });
+    let fst_offset = partition_header.fst_offset(false);
+    let dol_offset = partition_header.dol_offset(false);
+    if dol_offset < fst_offset {
+        file_infos.push(FileWriteInfo {
+            name: "sys/main.dol".to_string(),
+            offset: dol_offset,
+            length: meta.raw_dol.len() as u64,
+        });
+    } else {
+        let mut found = false;
+        for (_, node, name) in fst.iter() {
+            if !node.is_file() {
+                continue;
+            }
+            let offset = node.offset(false);
+            if offset == dol_offset {
+                info!("Using DOL from FST: {}", name);
+                found = true;
+            }
+        }
+        if !found {
+            return Err(nod::Error::Other("DOL not found in FST".to_string()));
+        }
+    }
+    let fst_size = partition_header.fst_size(false);
+    file_infos.push(FileWriteInfo {
+        name: "sys/fst.bin".to_string(),
+        offset: fst_offset,
+        length: fst_size,
+    });
+
+    // Collect files
+    let mut builder = GCPartitionBuilder::new(false, PartitionOverrides::default());
+    for (idx, node, path) in fst.iter() {
+        let offset = node.offset(false);
+        let length = node.length() as u64;
+        if node.is_dir() {
+            if length as usize == idx + 1 {
+                println!("Empty directory: {}", path);
+            }
+            continue;
+        }
+
+        if let Some(junk_id) = junk_id {
+            // Some games have junk data in place of files that were removed from the disc layout.
+            // This is a naive check to skip these files in our disc layout so that the junk data
+            // alignment is correct. This misses some cases where the junk data starts in the middle
+            // of a file, but handling those cases would require a more complex solution.
+            if length > 4
+                && check_junk_data(partition.as_mut(), offset, length, junk_id, header.disc_num)?
+            {
+                warn!("Skipping junk data file: {} (size {})", path, length);
+                builder.add_junk_file(path);
+                continue;
+            }
+        }
+
+        builder.add_file(FileInfo {
+            name: path,
+            size: length,
+            offset: Some(offset),
+            alignment: None,
+        })?;
+    }
+
+    // Write files
+    info!("Writing disc image with {} files", file_infos.len());
+    for file in &file_infos {
+        builder.add_file(FileInfo {
+            name: file.name.clone(),
+            size: file.length,
+            offset: Some(file.offset),
+            alignment: None,
+        })?;
+    }
+    let writer = builder.build(|out: &mut dyn Write, name: &str| match name {
+        "sys/boot.bin" => out.write_all(meta.raw_boot.as_ref()),
+        "sys/bi2.bin" => out.write_all(meta.raw_bi2.as_ref()),
+        "sys/fst.bin" => out.write_all(meta.raw_fst.as_ref()),
+        "sys/apploader.img" => out.write_all(meta.raw_apploader.as_ref()),
+        "sys/main.dol" => out.write_all(meta.raw_dol.as_ref()),
+        path => {
+            let Some((_, node)) = fst.find(path) else {
+                return Err(io::Error::new(
+                    io::ErrorKind::NotFound,
+                    format!("File not found: {}", path),
+                ));
+            };
+            let mut file = partition.open_file(node)?;
+            buf_copy(&mut file, out)?;
+            Ok(())
+        }
+    })?;
+    let disc_stream = writer.into_stream(PartitionFileReader { partition, meta })?;
+    let disc_reader = DiscReader::new_stream(disc_stream, &DiscOptions::default())?;
+    let disc_writer = DiscWriter::new(disc_reader, &FormatOptions::default())?;
+    let process_options = ProcessOptions { digest_crc32: true, ..Default::default() };
+    let finalization = if let Some(output) = output {
+        let mut out = File::create(output)
+            .with_context(|| format!("Failed to create {}", output.display()))?;
+        let finalization =
+            disc_writer.process(|data, _, _| out.write_all(data.as_ref()), &process_options)?;
+        out.flush().context("Failed to flush output file")?;
+        finalization
+    } else {
+        disc_writer.process(|_, _, _| Ok(()), &process_options)?
+    };
+    let crc = finalization.crc32.unwrap();
+    info!("Generated disc image in {:?} (CRC32: {:08X})", start.elapsed(), crc);
+    if crc != orig_crc32 {
+        if let Some(test_output) = test_output {
+            let open_options = DiscOptions {
+                partition_encryption: PartitionEncryption::Original,
+                preloader_threads: 4,
+            };
+            convert_and_verify(
+                path,
+                Some(test_output),
+                false,
+                &open_options,
+                &FormatOptions::default(),
+            )?;
+        }
+        return Err(nod::Error::Other(format!(
+            "CRC32 mismatch: {:08X} != {:08X}",
+            crc, orig_crc32
+        )));
+    }
+    Ok(())
+}
+
+#[derive(Clone)]
+struct PartitionFileReader {
+    partition: Box<dyn PartitionReader>,
+    meta: PartitionMeta,
+}
+
+impl FileCallback for PartitionFileReader {
+    fn read_file(&mut self, out: &mut [u8], name: &str, offset: u64) -> io::Result<()> {
+        let data: &[u8] = match name {
+            "sys/boot.bin" => self.meta.raw_boot.as_ref(),
+            "sys/bi2.bin" => self.meta.raw_bi2.as_ref(),
+            "sys/fst.bin" => self.meta.raw_fst.as_ref(),
+            "sys/apploader.img" => self.meta.raw_apploader.as_ref(),
+            "sys/main.dol" => self.meta.raw_dol.as_ref(),
+            path => {
+                let fst = self.meta.fst().map_err(|e| io::Error::new(io::ErrorKind::Other, e))?;
+                let Some((_, node)) = fst.find(path) else {
+                    return Err(io::Error::new(
+                        io::ErrorKind::NotFound,
+                        format!("File not found: {}", path),
+                    ));
+                };
+                let mut file = self.partition.open_file(node)?;
+                file.seek(SeekFrom::Start(offset))?;
+                file.read_exact(out)?;
+                return Ok(());
+            }
+        };
+        let offset = offset as usize;
+        let len = out.len().min(data.len() - offset);
+        out[..len].copy_from_slice(&data[offset..offset + len]);
+        Ok(())
+    }
+}
+
+/// Some disc files still exist in the FST, but were removed from the disc layout. These files had
+/// junk data written in their place, since the disc creator did not know about them. To match the
+/// original disc, we need to check for these files and remove them from our disc layout as well.
+/// This ensures that the junk data alignment is correct.
+fn check_junk_data(
+    partition: &mut dyn PartitionReader,
+    offset: u64,
+    len: u64,
+    junk_id: [u8; 4],
+    disc_num: u8,
+) -> nod::Result<bool> {
+    if len == 0 {
+        return Ok(false);
+    }
+
+    partition
+        .seek(SeekFrom::Start(offset))
+        .with_context(|| format!("Seeking to offset {}", offset))?;
+    let mut lfg = LaggedFibonacci::default();
+    let mut pos = offset;
+    let mut remaining = len;
+    while remaining > 0 {
+        let file_buf = partition
+            .fill_buf()
+            .with_context(|| format!("Failed to read disc file at offset {}", offset))?;
+        let read_len = (file_buf.len() as u64).min(remaining) as usize;
+        if !lfg.check_sector_chunked(&file_buf[..read_len], junk_id, disc_num, pos) {
+            return Ok(false);
+        }
+
+        pos += read_len as u64;
+        remaining -= read_len as u64;
+        partition.consume(read_len);
+    }
+    Ok(true)
+}
+
+pub struct HashStream<W> {
+    inner: W,
+    hasher: crc32fast::Hasher,
+    position: u64,
+}
+
+impl<W> HashStream<W> {
+    pub fn new(inner: W) -> Self { Self { inner, hasher: Default::default(), position: 0 } }
+
+    pub fn finish(self) -> u32 { self.hasher.finalize() }
+}
+
+impl<W> HashStream<W>
+where W: Write
+{
+    pub fn write_zeroes(&mut self, mut len: u64) -> io::Result<()> {
+        while len > 0 {
+            let write_len = len.min(SECTOR_SIZE as u64) as usize;
+            self.write_all(&ZERO_SECTOR[..write_len])?;
+            len -= write_len as u64;
+        }
+        Ok(())
+    }
+}
+
+impl<W> Write for HashStream<W>
+where W: Write
+{
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        self.hasher.update(buf);
+        self.position += buf.len() as u64;
+        self.inner.write(buf)
+    }
+
+    fn flush(&mut self) -> io::Result<()> { self.inner.flush() }
+}
+
+const ZERO_SECTOR: [u8; SECTOR_SIZE] = [0; SECTOR_SIZE];
+
+impl<W> Seek for HashStream<W>
+where W: Write
+{
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+        let new_position = match pos {
+            SeekFrom::Start(v) => v,
+            SeekFrom::Current(v) => self.position.saturating_add_signed(v),
+            SeekFrom::End(_) => {
+                return Err(io::Error::new(
+                    io::ErrorKind::Unsupported,
+                    "HashStream: SeekFrom::End is not supported".to_string(),
+                ));
+            }
+        };
+        if new_position < self.position {
+            return Err(io::Error::new(
+                io::ErrorKind::InvalidInput,
+                "HashStream: Cannot seek backwards".to_string(),
+            ));
+        }
+        self.write_zeroes(new_position - self.position)?;
+        Ok(new_position)
+    }
+
+    fn stream_position(&mut self) -> io::Result<u64> { Ok(self.position) }
+}
+
+/// Copies from a buffered reader to a writer without extra allocations.
+fn buf_copy<R, W>(reader: &mut R, writer: &mut W) -> io::Result<u64>
+where
+    R: BufRead + ?Sized,
+    W: Write + ?Sized,
+{
+    let mut copied = 0;
+    loop {
+        let buf = reader.fill_buf()?;
+        let len = buf.len();
+        if len == 0 {
+            break;
+        }
+        writer.write_all(buf)?;
+        reader.consume(len);
+        copied += len as u64;
+    }
+    Ok(copied)
+}

nodtool/src/cmd/info.rs

@@ -1,10 +1,14 @@
 use std::path::{Path, PathBuf};
 
 use argp::FromArgs;
-use nod::{Disc, SECTOR_SIZE};
+use nod::{
+    disc::SECTOR_SIZE,
+    read::{DiscOptions, DiscReader, PartitionOptions},
+};
 use size::Size;
+use tracing::info;
 
-use crate::util::{display, shared::print_header};
+use crate::util::{path_display, shared::print_header};
 
 #[derive(FromArgs, Debug)]
 /// Displays information about disc images.
@@ -23,15 +27,15 @@ pub fn run(args: Args) -> nod::Result<()> {
 }
 
 fn info_file(path: &Path) -> nod::Result<()> {
-    log::info!("Loading {}", display(path));
-    let disc = Disc::new(path)?;
+    info!("Loading {}", path_display(path));
+    let disc = DiscReader::new(path, &DiscOptions::default())?;
     let header = disc.header();
     let meta = disc.meta();
     print_header(header, &meta);
 
     if header.is_wii() {
         for (idx, info) in disc.partitions().iter().enumerate() {
-            let mut partition = disc.open_partition(idx)?;
+            let mut partition = disc.open_partition(idx, &PartitionOptions::default())?;
             let meta = partition.meta()?;
 
             println!();

nodtool/src/cmd/mod.rs

@@ -1,5 +1,6 @@
 pub mod convert;
 pub mod dat;
 pub mod extract;
+pub mod gen;
 pub mod info;
 pub mod verify;

nodtool/src/cmd/verify.rs

@@ -1,7 +1,10 @@
 use std::path::PathBuf;
 
 use argp::FromArgs;
-use nod::{OpenOptions, PartitionEncryptionMode};
+use nod::{
+    read::{DiscOptions, PartitionEncryption},
+    write::FormatOptions,
+};
 
 use crate::util::{redump, shared::convert_and_verify};
 
@@ -18,6 +21,12 @@ pub struct Args {
     #[argp(option, short = 'd')]
     /// path to DAT file(s) for verification (optional)
     dat: Vec<PathBuf>,
+    #[argp(switch)]
+    /// decrypt Wii partition data
+    decrypt: bool,
+    #[argp(switch)]
+    /// encrypt Wii partition data
+    encrypt: bool,
 }
 
 pub fn run(args: Args) -> nod::Result<()> {
@@ -25,9 +34,21 @@ pub fn run(args: Args) -> nod::Result<()> {
         println!("Loading dat files...");
         redump::load_dats(args.dat.iter().map(PathBuf::as_ref))?;
     }
-    let options = OpenOptions { partition_encryption: PartitionEncryptionMode::Original };
+    let cpus = num_cpus::get();
+    let options = DiscOptions {
+        partition_encryption: match (args.decrypt, args.encrypt) {
+            (true, false) => PartitionEncryption::ForceDecrypted,
+            (false, true) => PartitionEncryption::ForceEncrypted,
+            (false, false) => PartitionEncryption::Original,
+            (true, true) => {
+                return Err(nod::Error::Other("Both --decrypt and --encrypt specified".to_string()))
+            }
+        },
+        preloader_threads: 4.min(cpus),
+    };
+    let format_options = FormatOptions::default();
     for file in &args.file {
-        convert_and_verify(file, None, args.md5, &options)?;
+        convert_and_verify(file, None, args.md5, &options, &format_options)?;
         println!();
     }
     Ok(())

nodtool/src/lib.rs

@@ -9,19 +9,23 @@ pub use nod;
 #[derive(FromArgs, Debug)]
 #[argp(subcommand)]
 pub enum SubCommand {
-    Dat(cmd::dat::Args),
-    Info(cmd::info::Args),
-    Extract(cmd::extract::Args),
     Convert(cmd::convert::Args),
+    Dat(cmd::dat::Args),
+    Extract(cmd::extract::Args),
+    // Gen(cmd::gen::Args),
+    GenTest(cmd::gen::TestArgs),
+    Info(cmd::info::Args),
     Verify(cmd::verify::Args),
 }
 
 pub fn run(command: SubCommand) -> nod::Result<()> {
     match command {
-        SubCommand::Dat(c_args) => cmd::dat::run(c_args),
-        SubCommand::Info(c_args) => cmd::info::run(c_args),
         SubCommand::Convert(c_args) => cmd::convert::run(c_args),
+        SubCommand::Dat(c_args) => cmd::dat::run(c_args),
         SubCommand::Extract(c_args) => cmd::extract::run(c_args),
+        // SubCommand::Gen(c_args) => cmd::gen::run(c_args),
+        SubCommand::GenTest(c_args) => cmd::gen::run_test(c_args),
+        SubCommand::Info(c_args) => cmd::info::run(c_args),
         SubCommand::Verify(c_args) => cmd::verify::run(c_args),
     }
 }

nodtool/src/main.rs

@@ -12,8 +12,6 @@ use argp::{FromArgValue, FromArgs};
 use enable_ansi_support::enable_ansi_support;
 use nodtool::{run, SubCommand};
 use supports_color::Stream;
-use tracing::level_filters::LevelFilter;
-use tracing_subscriber::EnvFilter;
 
 #[derive(FromArgs, Debug)]
 /// Tool for reading GameCube and Wii disc images.
@@ -99,8 +97,23 @@ fn main() {
         supports_color::on(Stream::Stdout).is_some_and(|c| c.has_basic)
     };
 
-    let format =
-        tracing_subscriber::fmt::format().with_ansi(use_colors).with_target(false).without_time();
+    #[cfg(feature = "tracy")]
+    {
+        use tracing_subscriber::layer::SubscriberExt;
+        tracing::subscriber::set_global_default(
+            tracing_subscriber::registry().with(tracing_tracy::TracyLayer::default()),
+        )
+        .expect("setup tracy layer");
+    }
+
+    #[cfg(not(feature = "tracy"))]
+    {
+        use tracing::level_filters::LevelFilter;
+        use tracing_subscriber::EnvFilter;
+        let format = tracing_subscriber::fmt::format()
+            .with_ansi(use_colors)
+            .with_target(false)
+            .without_time();
         let builder = tracing_subscriber::fmt().event_format(format);
         if let Some(level) = args.log_level {
             builder
@@ -121,6 +134,7 @@ fn main() {
                 )
                 .init();
         }
+    }
 
     let mut result = Ok(());
     if let Some(dir) = &args.chdir {

nodtool/src/util/digest.rs

@@ -1,29 +1,4 @@
-use std::{
-    fmt,
-    sync::{
-        mpsc::{sync_channel, SyncSender},
-        Arc,
-    },
-    thread,
-    thread::JoinHandle,
-};
-
-use digest::{Digest, Output};
-
-pub type DigestThread = (SyncSender<Arc<[u8]>>, JoinHandle<DigestResult>);
-
-pub fn digest_thread<H>() -> DigestThread
-where H: Hasher + Send + 'static {
-    let (tx, rx) = sync_channel::<Arc<[u8]>>(1);
-    let handle = thread::spawn(move || {
-        let mut hasher = H::new();
-        while let Ok(data) = rx.recv() {
-            hasher.update(data.as_ref());
-        }
-        hasher.finalize()
-    });
-    (tx, handle)
-}
+use std::fmt;
 
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum DigestResult {
@@ -48,49 +23,9 @@ impl fmt::Display for DigestResult {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
             DigestResult::Crc32(crc) => write!(f, "{:08x}", crc),
-            DigestResult::Md5(md5) => write!(f, "{:032x}", <Output<md5::Md5>>::from(*md5)),
-            DigestResult::Sha1(sha1) => write!(f, "{:040x}", <Output<sha1::Sha1>>::from(*sha1)),
+            DigestResult::Md5(md5) => write!(f, "{}", hex::encode(md5)),
+            DigestResult::Sha1(sha1) => write!(f, "{}", hex::encode(sha1)),
             DigestResult::Xxh64(xxh64) => write!(f, "{:016x}", xxh64),
         }
     }
 }
-
-pub trait Hasher {
-    fn new() -> Self;
-    fn finalize(self) -> DigestResult;
-    fn update(&mut self, data: &[u8]);
-}
-
-impl Hasher for md5::Md5 {
-    fn new() -> Self { Digest::new() }
-
-    fn finalize(self) -> DigestResult { DigestResult::Md5(Digest::finalize(self).into()) }
-
-    fn update(&mut self, data: &[u8]) { Digest::update(self, data) }
-}
-
-impl Hasher for sha1::Sha1 {
-    fn new() -> Self { Digest::new() }
-
-    fn finalize(self) -> DigestResult { DigestResult::Sha1(Digest::finalize(self).into()) }
-
-    fn update(&mut self, data: &[u8]) { Digest::update(self, data) }
-}
-
-impl Hasher for crc32fast::Hasher {
-    fn new() -> Self { crc32fast::Hasher::new() }
-
-    fn finalize(self) -> DigestResult { DigestResult::Crc32(crc32fast::Hasher::finalize(self)) }
-
-    fn update(&mut self, data: &[u8]) { crc32fast::Hasher::update(self, data) }
-}
-
-impl Hasher for xxhash_rust::xxh64::Xxh64 {
-    fn new() -> Self { xxhash_rust::xxh64::Xxh64::new(0) }
-
-    fn finalize(self) -> DigestResult {
-        DigestResult::Xxh64(xxhash_rust::xxh64::Xxh64::digest(&self))
-    }
-
-    fn update(&mut self, data: &[u8]) { xxhash_rust::xxh64::Xxh64::update(self, data) }
-}

nodtool/src/util/mod.rs

@@ -8,7 +8,7 @@ use std::{
     path::{Path, MAIN_SEPARATOR},
 };
 
-pub fn display(path: &Path) -> PathDisplay { PathDisplay { path } }
+pub fn path_display(path: &Path) -> PathDisplay { PathDisplay { path } }
 
 pub struct PathDisplay<'a> {
     path: &'a Path,
@@ -19,7 +19,7 @@ impl fmt::Display for PathDisplay<'_> {
         let mut first = true;
         for segment in self.path.iter() {
             let segment_str = segment.to_string_lossy();
-            if segment_str == "." {
+            if segment_str == "/" || segment_str == "." {
                 continue;
             }
             if first {
@@ -39,3 +39,15 @@ pub fn has_extension(filename: &Path, extension: &str) -> bool {
         None => false,
     }
 }
+
+/// Creates a fixed-size array reference from a slice.
+macro_rules! array_ref {
+    ($slice:expr, $offset:expr, $size:expr) => {{
+        #[inline(always)]
+        fn to_array<T>(slice: &[T]) -> &[T; $size] {
+            unsafe { &*(slice.as_ptr() as *const [_; $size]) }
+        }
+        to_array(&$slice[$offset..$offset + $size])
+    }};
+}
+pub(crate) use array_ref;

nodtool/src/util/redump.rs

@@ -8,10 +8,12 @@ use std::{
 };
 
 use hex::deserialize as deserialize_hex;
-use nod::{array_ref, Result};
+use nod::Result;
 use serde::Deserialize;
 use zerocopy::{FromBytes, FromZeros, Immutable, IntoBytes, KnownLayout};
 
+use crate::util::array_ref;
+
 #[derive(Clone, Debug)]
 pub struct GameResult<'a> {
     pub name: &'a str,

nodtool/src/util/shared.rs

@@ -1,22 +1,21 @@
 use std::{
-    cmp::min,
     fmt,
     fs::File,
-    io::{Read, Write},
+    io::{Seek, SeekFrom, Write},
     path::Path,
-    sync::{mpsc::sync_channel, Arc},
-    thread,
 };
 
 use indicatif::{ProgressBar, ProgressState, ProgressStyle};
-use nod::{Compression, Disc, DiscHeader, DiscMeta, OpenOptions, Result, ResultContext};
-use size::Size;
-use zerocopy::FromZeros;
-
-use crate::util::{
-    digest::{digest_thread, DigestResult},
-    display, redump,
+use nod::{
+    common::Compression,
+    disc::DiscHeader,
+    read::{DiscMeta, DiscOptions, DiscReader, PartitionEncryption},
+    write::{DiscWriter, DiscWriterWeight, FormatOptions, ProcessOptions},
+    Result, ResultContext,
 };
+use size::Size;
+
+use crate::util::{digest::DigestResult, path_display, redump};
 
 pub fn print_header(header: &DiscHeader, meta: &DiscMeta) {
     println!("Format: {}", meta.format);
@@ -29,52 +28,71 @@ pub fn print_header(header: &DiscHeader, meta: &DiscMeta) {
     println!("Lossless: {}", meta.lossless);
     println!(
         "Verification data: {}",
-        meta.crc32.is_some()
-            || meta.md5.is_some()
-            || meta.sha1.is_some()
-            || meta.xxhash64.is_some()
+        meta.crc32.is_some() || meta.md5.is_some() || meta.sha1.is_some() || meta.xxh64.is_some()
     );
     println!();
     println!("Title: {}", header.game_title_str());
     println!("Game ID: {}", header.game_id_str());
     println!("Disc {}, Revision {}", header.disc_num + 1, header.disc_version);
-    if !header.has_partition_hashes() {
-        println!("[!] Disc has no hashes");
-    }
     if !header.has_partition_encryption() {
         println!("[!] Disc is not encrypted");
     }
+    if !header.has_partition_hashes() {
+        println!("[!] Disc has no hashes");
+    }
 }
 
 pub fn convert_and_verify(
     in_file: &Path,
     out_file: Option<&Path>,
     md5: bool,
-    options: &OpenOptions,
+    options: &DiscOptions,
+    format_options: &FormatOptions,
 ) -> Result<()> {
-    println!("Loading {}", display(in_file));
-    let mut disc = Disc::new_with_options(in_file, options)?;
+    println!("Loading {}", path_display(in_file));
+    let disc = DiscReader::new(in_file, options)?;
     let header = disc.header();
     let meta = disc.meta();
     print_header(header, &meta);
 
-    let disc_size = disc.disc_size();
-
     let mut file = if let Some(out_file) = out_file {
         Some(
             File::create(out_file)
-                .with_context(|| format!("Creating file {}", display(out_file)))?,
+                .with_context(|| format!("Creating file {}", path_display(out_file)))?,
         )
     } else {
         None
     };
 
     if out_file.is_some() {
-        println!("\nConverting...");
-    } else {
-        println!("\nVerifying...");
+        match options.partition_encryption {
+            PartitionEncryption::ForceEncrypted => {
+                println!("\nConverting to {} (encrypted)...", format_options.format)
             }
-    let pb = ProgressBar::new(disc_size);
+            PartitionEncryption::ForceDecrypted => {
+                println!("\nConverting to {} (decrypted)...", format_options.format)
+            }
+            _ => println!("\nConverting to {}...", format_options.format),
+        }
+        if format_options.compression != Compression::None {
+            println!("Compression: {}", format_options.compression);
+        }
+        if format_options.block_size > 0 {
+            println!("Block size: {}", Size::from_bytes(format_options.block_size));
+        }
+    } else {
+        match options.partition_encryption {
+            PartitionEncryption::ForceEncrypted => {
+                println!("\nVerifying (encrypted)...")
+            }
+            PartitionEncryption::ForceDecrypted => {
+                println!("\nVerifying (decrypted)...")
+            }
+            _ => println!("\nVerifying..."),
+        }
+    }
+    let disc_writer = DiscWriter::new(disc, format_options)?;
+    let pb = ProgressBar::new(disc_writer.progress_bound());
     pb.set_style(ProgressStyle::with_template("{spinner:.green} [{elapsed_precise}] [{wide_bar:.cyan/blue}] {bytes}/{total_bytes} ({bytes_per_sec}, {eta})")
         .unwrap()
         .with_key("eta", |state: &ProgressState, w: &mut dyn fmt::Write| {
@@ -82,85 +100,71 @@ pub fn convert_and_verify(
         })
         .progress_chars("#>-"));
 
-    const BUFFER_SIZE: usize = 1015808; // LCM(0x8000, 0x7C00)
-    let digest_threads = if md5 {
-        vec![
-            digest_thread::<crc32fast::Hasher>(),
-            digest_thread::<md5::Md5>(),
-            digest_thread::<sha1::Sha1>(),
-            digest_thread::<xxhash_rust::xxh64::Xxh64>(),
-        ]
-    } else {
-        vec![
-            digest_thread::<crc32fast::Hasher>(),
-            digest_thread::<sha1::Sha1>(),
-            digest_thread::<xxhash_rust::xxh64::Xxh64>(),
-        ]
+    let cpus = num_cpus::get();
+    let processor_threads = match disc_writer.weight() {
+        DiscWriterWeight::Light => 0,
+        DiscWriterWeight::Medium => cpus / 2,
+        DiscWriterWeight::Heavy => cpus,
     };
 
-    let (w_tx, w_rx) = sync_channel::<Arc<[u8]>>(1);
-    let w_thread = thread::spawn(move || {
     let mut total_written = 0u64;
-        while let Ok(data) = w_rx.recv() {
+    let finalization = disc_writer.process(
+        |data, pos, _| {
             if let Some(file) = &mut file {
-                file.write_all(data.as_ref())
-                    .with_context(|| {
-                        format!("Writing {} bytes at offset {}", data.len(), total_written)
-                    })
-                    .unwrap();
+                file.write_all(data.as_ref())?;
             }
             total_written += data.len() as u64;
-            pb.set_position(total_written);
+            pb.set_position(pos);
+            Ok(())
+        },
+        &ProcessOptions {
+            processor_threads,
+            digest_crc32: true,
+            digest_md5: md5,
+            digest_sha1: true,
+            digest_xxh64: true,
+        },
+    )?;
+    pb.finish();
+
+    // Finalize disc writer
+    if !finalization.header.is_empty() {
+        if let Some(file) = &mut file {
+            file.seek(SeekFrom::Start(0)).context("Seeking to start of output file")?;
+            file.write_all(finalization.header.as_ref()).context("Writing header")?;
+        } else {
+            return Err(nod::Error::Other("No output file, but requires finalization".to_string()));
+        }
     }
     if let Some(mut file) = file {
-            file.flush().context("Flushing output file").unwrap();
+        file.flush().context("Flushing output file")?;
     }
-        pb.finish();
-    });
-
-    let mut total_read = 0u64;
-    let mut buf = <[u8]>::new_box_zeroed_with_elems(BUFFER_SIZE)?;
-    while total_read < disc_size {
-        let read = min(BUFFER_SIZE as u64, disc_size - total_read) as usize;
-        disc.read_exact(&mut buf[..read]).with_context(|| {
-            format!("Reading {} bytes at disc offset {}", BUFFER_SIZE, total_read)
-        })?;
-
-        let arc = Arc::<[u8]>::from(&buf[..read]);
-        for (tx, _) in &digest_threads {
-            tx.send(arc.clone()).map_err(|_| "Sending data to hash thread")?;
-        }
-        w_tx.send(arc).map_err(|_| "Sending data to write thread")?;
-        total_read += read as u64;
-    }
-    drop(w_tx); // Close channel
-    w_thread.join().unwrap();
 
     println!();
     if let Some(path) = out_file {
-        println!("Wrote {} to {}", Size::from_bytes(total_read), display(path));
+        println!("Wrote {} to {}", Size::from_bytes(total_written), path_display(path));
     }
-
     println!();
-    let mut crc32 = None;
-    let mut md5 = None;
-    let mut sha1 = None;
-    let mut xxh64 = None;
-    for (tx, handle) in digest_threads {
-        drop(tx); // Close channel
-        match handle.join().unwrap() {
-            DigestResult::Crc32(v) => crc32 = Some(v),
-            DigestResult::Md5(v) => md5 = Some(v),
-            DigestResult::Sha1(v) => sha1 = Some(v),
-            DigestResult::Xxh64(v) => xxh64 = Some(v),
-        }
-    }
 
-    let redump_entry = crc32.and_then(redump::find_by_crc32);
-    let expected_crc32 = meta.crc32.or(redump_entry.as_ref().map(|e| e.crc32));
-    let expected_md5 = meta.md5.or(redump_entry.as_ref().map(|e| e.md5));
-    let expected_sha1 = meta.sha1.or(redump_entry.as_ref().map(|e| e.sha1));
-    let expected_xxh64 = meta.xxhash64;
+    let mut redump_entry = None;
+    let mut expected_crc32 = None;
+    let mut expected_md5 = None;
+    let mut expected_sha1 = None;
+    let mut expected_xxh64 = None;
+    if options.partition_encryption == PartitionEncryption::Original {
+        // Use verification data in disc and check redump
+        redump_entry = finalization.crc32.and_then(redump::find_by_crc32);
+        expected_crc32 = meta.crc32.or(redump_entry.as_ref().map(|e| e.crc32));
+        expected_md5 = meta.md5.or(redump_entry.as_ref().map(|e| e.md5));
+        expected_sha1 = meta.sha1.or(redump_entry.as_ref().map(|e| e.sha1));
+        expected_xxh64 = meta.xxh64;
+    } else if options.partition_encryption == PartitionEncryption::ForceEncrypted {
+        // Ignore verification data in disc, but still check redump
+        redump_entry = finalization.crc32.and_then(redump::find_by_crc32);
+        expected_crc32 = redump_entry.as_ref().map(|e| e.crc32);
+        expected_md5 = redump_entry.as_ref().map(|e| e.md5);
+        expected_sha1 = redump_entry.as_ref().map(|e| e.sha1);
+    }
 
     fn print_digest(value: DigestResult, expected: Option<DigestResult>) {
         print!("{:<6}: ", value.name());
@@ -176,14 +180,15 @@ pub fn convert_and_verify(
         println!();
     }
 
+    if let Some(crc32) = finalization.crc32 {
         if let Some(entry) = &redump_entry {
             let mut full_match = true;
-        if let Some(md5) = md5 {
+            if let Some(md5) = finalization.md5 {
                 if entry.md5 != md5 {
                     full_match = false;
                 }
             }
-        if let Some(sha1) = sha1 {
+            if let Some(sha1) = finalization.sha1 {
                 if entry.sha1 != sha1 {
                     full_match = false;
                 }
@@ -196,16 +201,15 @@ pub fn convert_and_verify(
         } else {
             println!("Redump: Not found ❌");
         }
-    if let Some(crc32) = crc32 {
         print_digest(DigestResult::Crc32(crc32), expected_crc32.map(DigestResult::Crc32));
     }
-    if let Some(md5) = md5 {
+    if let Some(md5) = finalization.md5 {
         print_digest(DigestResult::Md5(md5), expected_md5.map(DigestResult::Md5));
     }
-    if let Some(sha1) = sha1 {
+    if let Some(sha1) = finalization.sha1 {
         print_digest(DigestResult::Sha1(sha1), expected_sha1.map(DigestResult::Sha1));
     }
-    if let Some(xxh64) = xxh64 {
+    if let Some(xxh64) = finalization.xxh64 {
         print_digest(DigestResult::Xxh64(xxh64), expected_xxh64.map(DigestResult::Xxh64));
     }
     Ok(())

rustfmt.toml

@@ -6,3 +6,4 @@ reorder_impl_items = true
 use_field_init_shorthand = true
 use_small_heuristics = "Max"
 where_single_line = true
+format_code_in_doc_comments = true