mirror of https://github.com/AxioDL/lzokay.git
77 lines
2.3 KiB
C++
77 lines
2.3 KiB
C++
|
#pragma once
|
||
|
|
#include <cstddef>
|
||
|
|
#include <cstdint>
|
||
|
|
#include <memory>
|
||
|
|
|
||
|
|
namespace lzokay {
|
||
|
|
|
||
|
|
enum class EResult {
|
||
|
|
LookbehindOverrun = -4,
|
||
|
|
OutputOverrun = -3,
|
||
|
|
InputOverrun = -2,
|
||
|
|
Error = -1,
|
||
|
|
Success = 0,
|
||
|
|
InputNotConsumed = 1,
|
||
|
|
};
|
||
|
|
|
||
|
|
class DictBase {
|
||
|
|
protected:
|
||
|
|
static constexpr uint32_t HashSize = 0x4000;
|
||
|
|
static constexpr uint32_t MaxDist = 0xbfff;
|
||
|
|
static constexpr uint32_t MaxMatchLen = 0x800;
|
||
|
|
static constexpr uint32_t BufSize = MaxDist + MaxMatchLen;
|
||
|
|
|
||
|
|
/* List encoding of previous 3-byte data matches */
|
||
|
|
struct Match3 {
|
||
|
|
uint16_t head[HashSize]; /* key -> chain-head-pos */
|
||
|
|
uint16_t chain_sz[HashSize]; /* key -> chain-size */
|
||
|
|
uint16_t chain[BufSize]; /* chain-pos -> next-chain-pos */
|
||
|
|
uint16_t best_len[BufSize]; /* chain-pos -> best-match-length */
|
||
|
|
};
|
||
|
|
/* Encoding of 2-byte data matches */
|
||
|
|
struct Match2 {
|
||
|
|
uint16_t head[1 << 16]; /* 2-byte-data -> head-pos */
|
||
|
|
};
|
||
|
|
|
||
|
|
struct Data {
|
||
|
|
Match3 match3;
|
||
|
|
Match2 match2;
|
||
|
|
|
||
|
|
/* Circular buffer caching enough data to access the maximum lookback
|
||
|
|
* distance of 48K + maximum match length of 2K. An additional 2K is
|
||
|
|
* allocated so the start of the buffer may be replicated at the end,
|
||
|
|
* therefore providing efficient circular access.
|
||
|
|
*/
|
||
|
|
uint8_t buffer[BufSize + MaxMatchLen];
|
||
|
|
};
|
||
|
|
using storage_type = Data;
|
||
|
|
storage_type* _storage;
|
||
|
|
DictBase() = default;
|
||
|
|
friend struct State;
|
||
|
|
friend EResult compress(const uint8_t* src, std::size_t src_size,
|
||
|
|
uint8_t* dst, std::size_t& dst_size, DictBase& dict);
|
||
|
|
};
|
||
|
|
template <template<typename> class _Alloc = std::allocator>
|
||
|
|
class Dict : public DictBase {
|
||
|
|
_Alloc<DictBase::storage_type> _allocator;
|
||
|
|
public:
|
||
|
|
Dict() { _storage = _allocator.allocate(1); }
|
||
|
|
~Dict() { _allocator.deallocate(_storage, 1); }
|
||
|
|
};
|
||
|
|
|
||
|
|
EResult decompress(const uint8_t* src, std::size_t src_size,
|
||
|
|
uint8_t* dst, std::size_t& dst_size);
|
||
|
|
EResult compress(const uint8_t* src, std::size_t src_size,
|
||
|
|
uint8_t* dst, std::size_t& dst_size, DictBase& dict);
|
||
|
|
inline EResult compress(const uint8_t* src, std::size_t src_size,
|
||
|
|
uint8_t* dst, std::size_t& dst_size) {
|
||
|
|
Dict<> dict;
|
||
|
|
return compress(src, src_size, dst, dst_size, dict);
|
||
|
|
}
|
||
|
|
|
||
|
|
constexpr std::size_t compress_worst_size(std::size_t s) {
|
||
|
|
return s + s / 16 + 64 + 3;
|
||
|
|
}
|
||
|
|
|
||
|
|
}
|