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#pragma once
#include "decompress.h"
#include "stdafx.h"
// Mermaid/Selkie decompression also happens in two phases, just like in
// Kraken, but the match copier works differently. Both Mermaid and Selkie use
// the same on-disk format, only the compressor differs.
struct MermaidLzTable
{
// Flag stream. Format of flags:
// Read flagbyte from |cmd_stream|
// If flagbyte >= 24:
// flagbyte & 0x80 == 0 : Read from |off16_stream| into |recent_offs|.
// != 0 : Don't read offset.
// flagbyte & 7 = Number of literals to copy first from |lit_stream|.
// (flagbyte >> 3) & 0xF = Number of bytes to copy from |recent_offs|.
//
// If flagbyte == 0 :
// Read uint8_t L from |length_stream|
// If L > 251: L += 4 * Read word from |length_stream|
// L += 64
// Copy L bytes from |lit_stream|.
//
// If flagbyte == 1 :
// Read uint8_t L from |length_stream|
// If L > 251: L += 4 * Read word from |length_stream|
// L += 91
// Copy L bytes from match pointed by next offset from |off16_stream|
//
// If flagbyte == 2 :
// Read uint8_t L from |length_stream|
// If L > 251: L += 4 * Read word from |length_stream|
// L += 29
// Copy L bytes from match pointed by next offset from |off32_stream|,
// relative to start of block.
// Then prefetch |off32_stream[3]|
//
// If flagbyte > 2:
// L = flagbyte + 5
// Copy L bytes from match pointed by next offset from |off32_stream|,
// relative to start of block.
// Then prefetch |off32_stream[3]|
const uint8_t *cmd_stream, *cmd_stream_end;
// Length stream
const uint8_t *length_stream;
// Literal stream
const uint8_t *lit_stream, *lit_stream_end;
// Near offsets
const uint16_t *off16_stream, *off16_stream_end;
// Far offsets for current chunk
uint32_t *off32_stream, *off32_stream_end;
// Holds the offsets for the two chunks
uint32_t *off32_stream_1, *off32_stream_2;
uint32_t off32_size_1, off32_size_2;
// Flag offsets for next 64k chunk.
uint32_t cmd_stream_2_offs, cmd_stream_2_offs_end;
};
int32_t Mermaid_DecodeFarOffsets (const uint8_t *src, const uint8_t *src_end,
uint32_t *output, size_t output_size,
int64_t offset);
void Mermaid_CombineOffs16 (uint16_t *dst, size_t size, const uint8_t *lo,
const uint8_t *hi);
bool Mermaid_ReadLzTable (int32_t mode, const uint8_t *src,
const uint8_t *src_end, uint8_t *dst,
int32_t dst_size, int64_t offset, uint8_t *scratch,
uint8_t *scratch_end, MermaidLzTable *lz);
const uint8_t *Mermaid_Mode0 (uint8_t *dst, size_t dst_size,
uint8_t *dst_ptr_end, uint8_t *dst_start,
const uint8_t *src_end, MermaidLzTable *lz,
int32_t *saved_dist, size_t startoff);
const uint8_t *Mermaid_Mode1 (uint8_t *dst, size_t dst_size,
uint8_t *dst_ptr_end, uint8_t *dst_start,
const uint8_t *src_end, MermaidLzTable *lz,
int32_t *saved_dist, size_t startoff);
bool Mermaid_ProcessLzRuns (int32_t mode, const uint8_t *src,
const uint8_t *src_end, uint8_t *dst,
size_t dst_size, uint64_t offset,
uint8_t *dst_end, MermaidLzTable *lz);
int32_t Mermaid_DecodeQuantum (uint8_t *dst, uint8_t *dst_end,
uint8_t *dst_start, const uint8_t *src,
const uint8_t *src_end, uint8_t *temp,
uint8_t *temp_end);