Fix SplitFileReader at file boundaries

Cargo.lock

@@ -557,7 +557,7 @@ checksum = "cf5a574dadd7941adeaa71823ecba5e28331b8313fb2e1c6a5c7e5981ea53ad6"
 
 [[package]]
 name = "nod"
-version = "2.0.0-alpha.2"
+version = "2.0.0-alpha.3"
 dependencies = [
  "adler",
  "aes",
@@ -591,7 +591,7 @@ dependencies = [
 
 [[package]]
 name = "nodtool"
-version = "2.0.0-alpha.2"
+version = "2.0.0-alpha.3"
 dependencies = [
  "argp",
  "crc32fast",

Cargo.toml

@@ -12,7 +12,7 @@ strip = "debuginfo"
 codegen-units = 1
 
 [workspace.package]
-version = "2.0.0-alpha.2"
+version = "2.0.0-alpha.3"
 edition = "2024"
 rust-version = "1.85"
 authors = ["Luke Street <luke@street.dev>"]

nod/src/io/split.rs

@@ -105,7 +105,8 @@ impl Clone for SplitFileReader {
 }
 
 impl DiscStream for SplitFileReader {
-    fn read_exact_at(&mut self, buf: &mut [u8], offset: u64) -> io::Result<()> {
+    fn read_exact_at(&mut self, mut buf: &mut [u8], mut offset: u64) -> io::Result<()> {
+        while !buf.is_empty() {
             let split = if self.open_file.as_ref().is_none_or(|s| !s.contains(offset)) {
                 let split = if let Some(split) = self.files.iter().find(|f| f.contains(offset)) {
                     let file = File::open(&split.inner)?;
@@ -117,17 +118,24 @@ impl DiscStream for SplitFileReader {
             } else {
                 self.open_file.as_mut().unwrap()
             };
+            let file_offset = offset - split.begin;
+            let len = (split.size - file_offset).min(buf.len() as u64) as usize;
+            let (out, remain) = buf.split_at_mut(len);
             #[cfg(unix)]
             {
                 use std::os::unix::fs::FileExt;
-            split.inner.read_exact_at(buf, offset)
+                split.inner.read_exact_at(out, file_offset)?;
             }
             #[cfg(not(unix))]
             {
                 use std::io::{Read, Seek, SeekFrom};
-            split.inner.seek(SeekFrom::Start(offset - split.begin))?;
-            split.inner.read_exact(buf)
+                split.inner.seek(SeekFrom::Start(file_offset))?;
+                split.inner.read_exact(out)?
             }
+            buf = remain;
+            offset += len as u64;
+        }
+        Ok(())
     }
 
     fn stream_len(&mut self) -> io::Result<u64> { Ok(self.len()) }