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Remove file after restructuring
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Emmanuel Marty
GitHub
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commit
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730
src/shrink_v2.c
730
src/shrink_v2.c
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/*
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* shrink_v2.c - LZSA2 block compressor implementation
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*
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* Copyright (C) 2019 Emmanuel Marty
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*
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* This software is provided 'as-is', without any express or implied
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* warranty. In no event will the authors be held liable for any damages
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* arising from the use of this software.
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*
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* Permission is granted to anyone to use this software for any purpose,
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* including commercial applications, and to alter it and redistribute it
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* freely, subject to the following restrictions:
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*
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* 1. The origin of this software must not be misrepresented; you must not
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* claim that you wrote the original software. If you use this software
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* in a product, an acknowledgment in the product documentation would be
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* appreciated but is not required.
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* 2. Altered source versions must be plainly marked as such, and must not be
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* misrepresented as being the original software.
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* 3. This notice may not be removed or altered from any source distribution.
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*/
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/*
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* Uses the libdivsufsort library Copyright (c) 2003-2008 Yuta Mori
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*
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* Inspired by LZ4 by Yann Collet. https://github.com/lz4/lz4
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* With help, ideas, optimizations and speed measurements by spke <zxintrospec@gmail.com>
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* With ideas from Lizard by Przemyslaw Skibinski and Yann Collet. https://github.com/inikep/lizard
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* Also with ideas from smallz4 by Stephan Brumme. https://create.stephan-brumme.com/smallz4/
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*
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "lib.h"
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#include "shrink_v2.h"
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#include "format.h"
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/**
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* Write 4-bit nibble to output (compressed) buffer
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*
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* @param pOutData pointer to output buffer
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* @param nOutOffset current write index into output buffer
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* @param nMaxOutDataSize maximum size of output buffer, in bytes
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* @param nCurNibbleOffset write index into output buffer, of current byte being filled with nibbles
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* @param nCurFreeNibbles current number of free nibbles in byte
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* @param nNibbleValue value to write (0..15)
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*/
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static int lzsa_write_nibble_v2(unsigned char *pOutData, int nOutOffset, const int nMaxOutDataSize, int *nCurNibbleOffset, int *nCurFreeNibbles, int nNibbleValue) {
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if (nOutOffset < 0) return -1;
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if ((*nCurNibbleOffset) == -1) {
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if (nOutOffset >= nMaxOutDataSize) return -1;
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(*nCurNibbleOffset) = nOutOffset;
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(*nCurFreeNibbles) = 2;
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pOutData[nOutOffset++] = 0;
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}
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pOutData[*nCurNibbleOffset] = (pOutData[*nCurNibbleOffset] << 4) | (nNibbleValue & 0x0f);
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(*nCurFreeNibbles)--;
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if ((*nCurFreeNibbles) == 0) {
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(*nCurNibbleOffset) = -1;
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}
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return nOutOffset;
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}
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/**
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* Get the number of extra bits required to represent a literals length
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*
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* @param nLength literals length
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*
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* @return number of extra bits required
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*/
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static inline int lzsa_get_literals_varlen_size_v2(const int nLength) {
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if (nLength < LITERALS_RUN_LEN_V2) {
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return 0;
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}
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else {
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if (nLength < (LITERALS_RUN_LEN_V2 + 15)) {
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return 4;
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}
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else {
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if (nLength < 256)
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return 4+8;
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else {
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return 4+24;
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}
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}
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}
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}
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/**
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* Write extra literals length bytes to output (compressed) buffer. The caller must first check that there is enough
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* room to write the bytes.
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*
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* @param pOutData pointer to output buffer
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* @param nOutOffset current write index into output buffer
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* @param nLength literals length
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*/
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static inline int lzsa_write_literals_varlen_v2(unsigned char *pOutData, int nOutOffset, const int nMaxOutDataSize, int *nCurNibbleOffset, int *nCurFreeNibbles, int nLength) {
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if (nLength >= LITERALS_RUN_LEN_V2) {
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if (nLength < (LITERALS_RUN_LEN_V2 + 15)) {
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nOutOffset = lzsa_write_nibble_v2(pOutData, nOutOffset, nMaxOutDataSize, nCurNibbleOffset, nCurFreeNibbles, nLength - LITERALS_RUN_LEN_V2);
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}
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else {
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nOutOffset = lzsa_write_nibble_v2(pOutData, nOutOffset, nMaxOutDataSize, nCurNibbleOffset, nCurFreeNibbles, 15);
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if (nOutOffset < 0) return -1;
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if (nLength < 256)
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pOutData[nOutOffset++] = nLength;
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else {
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pOutData[nOutOffset++] = 0;
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pOutData[nOutOffset++] = nLength & 0xff;
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pOutData[nOutOffset++] = (nLength >> 8) & 0xff;
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}
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}
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}
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return nOutOffset;
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}
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/**
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* Get the number of extra bits required to represent an encoded match length
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*
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* @param nLength encoded match length (actual match length - MIN_MATCH_SIZE_V2)
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*
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* @return number of extra bits required
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*/
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static inline int lzsa_get_match_varlen_size_v2(const int nLength) {
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if (nLength < MATCH_RUN_LEN_V2) {
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return 0;
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}
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else {
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if (nLength < (MATCH_RUN_LEN_V2 + 15))
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return 4;
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else {
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if ((nLength + MIN_MATCH_SIZE_V2) < 256)
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return 4+8;
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else {
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return 4 + 24;
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}
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}
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}
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}
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/**
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* Write extra encoded match length bytes to output (compressed) buffer. The caller must first check that there is enough
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* room to write the bytes.
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*
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* @param pOutData pointer to output buffer
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* @param nOutOffset current write index into output buffer
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* @param nLength encoded match length (actual match length - MIN_MATCH_SIZE_V2)
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*/
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static inline int lzsa_write_match_varlen_v2(unsigned char *pOutData, int nOutOffset, const int nMaxOutDataSize, int *nCurNibbleOffset, int *nCurFreeNibbles, int nLength) {
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if (nLength >= MATCH_RUN_LEN_V2) {
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if (nLength < (MATCH_RUN_LEN_V2 + 15)) {
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nOutOffset = lzsa_write_nibble_v2(pOutData, nOutOffset, nMaxOutDataSize, nCurNibbleOffset, nCurFreeNibbles, nLength - MATCH_RUN_LEN_V2);
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}
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else {
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nOutOffset = lzsa_write_nibble_v2(pOutData, nOutOffset, nMaxOutDataSize, nCurNibbleOffset, nCurFreeNibbles, 15);
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if (nOutOffset < 0) return -1;
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if ((nLength + MIN_MATCH_SIZE_V2) < 256)
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pOutData[nOutOffset++] = nLength + MIN_MATCH_SIZE_V2;
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else {
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pOutData[nOutOffset++] = 0;
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pOutData[nOutOffset++] = (nLength + MIN_MATCH_SIZE_V2) & 0xff;
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pOutData[nOutOffset++] = ((nLength + MIN_MATCH_SIZE_V2) >> 8) & 0xff;
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}
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}
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}
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return nOutOffset;
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}
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/**
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* Attempt to pick optimal matches, so as to produce the smallest possible output that decompresses to the same input
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*
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* @param pCompressor compression context
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* @param nStartOffset current offset in input window (typically the number of previously compressed bytes)
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* @param nEndOffset offset to end finding matches at (typically the size of the total input window in bytes
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*/
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static void lzsa_optimize_matches_v2(lsza_compressor *pCompressor, const int nStartOffset, const int nEndOffset) {
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int *cost = (int*)pCompressor->pos_data; /* Reuse */
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int *prev_match = (int*)pCompressor->intervals; /* Reuse */
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lzsa_repmatch_opt *repmatch_opt = pCompressor->repmatch_opt;
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lzsa_match *pBestMatch = pCompressor->best_match;
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int nLastLiteralsOffset;
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int nMinMatchSize = pCompressor->min_match_size;
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const int nFavorRatio = (pCompressor->flags & LZSA_FLAG_FAVOR_RATIO) ? 1 : 0;
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int i;
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cost[nEndOffset - 1] = 8;
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prev_match[nEndOffset - 1] = nEndOffset;
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nLastLiteralsOffset = nEndOffset;
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pCompressor->best_match[nEndOffset - 1].length = 0;
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pCompressor->best_match[nEndOffset - 1].offset = 0;
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repmatch_opt[nEndOffset - 1].best_slot_for_incoming = -1;
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repmatch_opt[nEndOffset - 1].incoming_offset = -1;
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repmatch_opt[nEndOffset - 1].expected_repmatch = 0;
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for (i = nEndOffset - 2; i != (nStartOffset - 1); i--) {
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int nLiteralsCost;
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int nLiteralsLen = nLastLiteralsOffset - i;
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nLiteralsCost = 8 + cost[i + 1];
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/* Add to the cost of encoding literals as their number crosses a variable length encoding boundary.
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* The cost automatically accumulates down the chain. */
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if (nLiteralsLen == LITERALS_RUN_LEN_V2) {
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nLiteralsCost += 4;
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}
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else if (nLiteralsLen == (LITERALS_RUN_LEN_V2 + 15)) {
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nLiteralsCost += 8;
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}
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else if (nLiteralsLen == 256) {
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nLiteralsCost += 16;
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}
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if (pCompressor->best_match[i + 1].length >= MIN_MATCH_SIZE_V2)
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nLiteralsCost += MODESWITCH_PENALTY;
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lzsa_match *pMatch = pCompressor->match + (i << MATCHES_PER_OFFSET_SHIFT);
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int *pSlotCost = pCompressor->slot_cost + (i << MATCHES_PER_OFFSET_SHIFT);
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int m;
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cost[i] = nLiteralsCost;
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pCompressor->best_match[i].length = 0;
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pCompressor->best_match[i].offset = 0;
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repmatch_opt[i].best_slot_for_incoming = -1;
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repmatch_opt[i].incoming_offset = -1;
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repmatch_opt[i].expected_repmatch = 0;
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for (m = 0; m < NMATCHES_PER_OFFSET && pMatch[m].length >= nMinMatchSize; m++) {
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int nBestCost, nBestMatchLen, nBestMatchOffset, nBestUpdatedSlot, nBestUpdatedIndex, nBestExpectedRepMatch;
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nBestCost = nLiteralsCost;
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nBestMatchLen = 0;
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nBestMatchOffset = 0;
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nBestUpdatedSlot = -1;
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nBestUpdatedIndex = -1;
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nBestExpectedRepMatch = 0;
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if (pMatch[m].length >= LEAVE_ALONE_MATCH_SIZE) {
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int nCurCost;
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int nMatchLen = pMatch[m].length;
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if ((i + nMatchLen) > (nEndOffset - LAST_LITERALS))
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nMatchLen = nEndOffset - LAST_LITERALS - i;
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int nCurIndex = prev_match[i + nMatchLen];
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int nMatchOffsetSize = 0;
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int nCurExpectedRepMatch = 1;
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if (nCurIndex >= nEndOffset || pCompressor->best_match[nCurIndex].length < MIN_MATCH_SIZE_V2 ||
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pCompressor->best_match[nCurIndex].offset != pMatch[m].offset) {
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nMatchOffsetSize = (pMatch[m].offset <= 32) ? 4 : ((pMatch[m].offset <= 512) ? 8 : ((pMatch[m].offset <= (8192 + 512)) ? 12 : 16));
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nCurExpectedRepMatch = 0;
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}
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nCurCost = 8 + nMatchOffsetSize + lzsa_get_match_varlen_size_v2(nMatchLen - MIN_MATCH_SIZE_V2);
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nCurCost += cost[i + nMatchLen];
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if (pCompressor->best_match[i + nMatchLen].length >= MIN_MATCH_SIZE_V2)
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nCurCost += MODESWITCH_PENALTY;
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if (nBestCost > (nCurCost - nFavorRatio)) {
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nBestCost = nCurCost;
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nBestMatchLen = nMatchLen;
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nBestMatchOffset = pMatch[m].offset;
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nBestUpdatedSlot = -1;
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nBestUpdatedIndex = -1;
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nBestExpectedRepMatch = nCurExpectedRepMatch;
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}
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}
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else {
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int nMatchLen = pMatch[m].length;
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int k, nMatchRunLen;
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if ((i + nMatchLen) > (nEndOffset - LAST_LITERALS))
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nMatchLen = nEndOffset - LAST_LITERALS - i;
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nMatchRunLen = nMatchLen;
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if (nMatchRunLen > MATCH_RUN_LEN_V2)
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nMatchRunLen = MATCH_RUN_LEN_V2;
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for (k = nMinMatchSize; k < nMatchRunLen; k++) {
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int nCurCost;
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int nCurIndex = prev_match[i + k];
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int nMatchOffsetSize = 0;
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int nCurExpectedRepMatch = 1;
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if (nCurIndex >= nEndOffset || pCompressor->best_match[nCurIndex].length < MIN_MATCH_SIZE_V2 ||
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pCompressor->best_match[nCurIndex].offset != pMatch[m].offset) {
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nMatchOffsetSize = (pMatch[m].offset <= 32) ? 4 : ((pMatch[m].offset <= 512) ? 8 : ((pMatch[m].offset <= (8192 + 512)) ? 12 : 16));
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nCurExpectedRepMatch = 0;
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}
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nCurCost = 8 + nMatchOffsetSize /* no extra match len bytes */;
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nCurCost += cost[i + k];
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if (pCompressor->best_match[i + k].length >= MIN_MATCH_SIZE_V2)
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nCurCost += MODESWITCH_PENALTY;
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int nCurUpdatedSlot = -1;
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int nCurUpdatedIndex = -1;
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if (nMatchOffsetSize && nCurIndex < nEndOffset && pCompressor->best_match[nCurIndex].length >= MIN_MATCH_SIZE_V2 && !repmatch_opt[nCurIndex].expected_repmatch) {
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int r;
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for (r = 0; r < NMATCHES_PER_OFFSET && pCompressor->match[(nCurIndex << MATCHES_PER_OFFSET_SHIFT) + r].length >= MIN_MATCH_SIZE_V2; r++) {
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if (pCompressor->match[(nCurIndex << MATCHES_PER_OFFSET_SHIFT) + r].offset == pMatch[m].offset) {
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int nAltCost = nCurCost - nMatchOffsetSize + pCompressor->slot_cost[(nCurIndex << MATCHES_PER_OFFSET_SHIFT) + r] - cost[nCurIndex];
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if (nAltCost <= nCurCost) {
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nCurUpdatedSlot = r;
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nCurUpdatedIndex = nCurIndex;
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nCurCost = nAltCost;
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nCurExpectedRepMatch = 2;
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}
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}
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}
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}
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if (nBestCost > (nCurCost - nFavorRatio)) {
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nBestCost = nCurCost;
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nBestMatchLen = k;
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nBestMatchOffset = pMatch[m].offset;
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nBestUpdatedSlot = nCurUpdatedSlot;
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nBestUpdatedIndex = nCurUpdatedIndex;
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nBestExpectedRepMatch = nCurExpectedRepMatch;
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}
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}
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for (; k <= nMatchLen; k++) {
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int nCurCost;
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int nCurIndex = prev_match[i + k];
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int nMatchOffsetSize = 0;
|
|
||||||
int nCurExpectedRepMatch = 1;
|
|
||||||
if (nCurIndex >= nEndOffset || pCompressor->best_match[nCurIndex].length < MIN_MATCH_SIZE_V2 ||
|
|
||||||
pCompressor->best_match[nCurIndex].offset != pMatch[m].offset) {
|
|
||||||
nMatchOffsetSize = (pMatch[m].offset <= 32) ? 4 : ((pMatch[m].offset <= 512) ? 8 : ((pMatch[m].offset <= (8192 + 512)) ? 12 : 16));
|
|
||||||
nCurExpectedRepMatch = 0;
|
|
||||||
}
|
|
||||||
|
|
||||||
nCurCost = 8 + nMatchOffsetSize + lzsa_get_match_varlen_size_v2(k - MIN_MATCH_SIZE_V2);
|
|
||||||
nCurCost += cost[i + k];
|
|
||||||
if (pCompressor->best_match[i + k].length >= MIN_MATCH_SIZE_V2)
|
|
||||||
nCurCost += MODESWITCH_PENALTY;
|
|
||||||
|
|
||||||
int nCurUpdatedSlot = -1;
|
|
||||||
int nCurUpdatedIndex = -1;
|
|
||||||
|
|
||||||
if (nMatchOffsetSize && nCurIndex < nEndOffset && pCompressor->best_match[nCurIndex].length >= MIN_MATCH_SIZE_V2 && !repmatch_opt[nCurIndex].expected_repmatch) {
|
|
||||||
int r;
|
|
||||||
|
|
||||||
for (r = 0; r < NMATCHES_PER_OFFSET && pCompressor->match[(nCurIndex << MATCHES_PER_OFFSET_SHIFT) + r].length >= MIN_MATCH_SIZE_V2; r++) {
|
|
||||||
if (pCompressor->match[(nCurIndex << MATCHES_PER_OFFSET_SHIFT) + r].offset == pMatch[m].offset) {
|
|
||||||
int nAltCost = nCurCost - nMatchOffsetSize + pCompressor->slot_cost[(nCurIndex << MATCHES_PER_OFFSET_SHIFT) + r] - cost[nCurIndex];
|
|
||||||
|
|
||||||
if (nAltCost <= nCurCost) {
|
|
||||||
nCurUpdatedSlot = r;
|
|
||||||
nCurUpdatedIndex = nCurIndex;
|
|
||||||
nCurCost = nAltCost;
|
|
||||||
nCurExpectedRepMatch = 2;
|
|
||||||
}
|
|
||||||
}
|
|
||||||
}
|
|
||||||
}
|
|
||||||
|
|
||||||
if (nBestCost > (nCurCost - nFavorRatio)) {
|
|
||||||
nBestCost = nCurCost;
|
|
||||||
nBestMatchLen = k;
|
|
||||||
nBestMatchOffset = pMatch[m].offset;
|
|
||||||
nBestUpdatedSlot = nCurUpdatedSlot;
|
|
||||||
nBestUpdatedIndex = nCurUpdatedIndex;
|
|
||||||
nBestExpectedRepMatch = nCurExpectedRepMatch;
|
|
||||||
}
|
|
||||||
}
|
|
||||||
}
|
|
||||||
|
|
||||||
pSlotCost[m] = nBestCost;
|
|
||||||
pMatch[m].length = nBestMatchLen;
|
|
||||||
pMatch[m].offset = nBestMatchOffset; /* not necessary */
|
|
||||||
|
|
||||||
if (m == 0 || (nBestMatchLen && cost[i] >= nBestCost)) {
|
|
||||||
cost[i] = nBestCost;
|
|
||||||
pCompressor->best_match[i].length = nBestMatchLen;
|
|
||||||
pCompressor->best_match[i].offset = nBestMatchOffset;
|
|
||||||
|
|
||||||
repmatch_opt[i].expected_repmatch = nBestExpectedRepMatch;
|
|
||||||
|
|
||||||
if (nBestUpdatedSlot >= 0 && nBestUpdatedIndex >= 0) {
|
|
||||||
repmatch_opt[nBestUpdatedIndex].best_slot_for_incoming = nBestUpdatedSlot;
|
|
||||||
repmatch_opt[nBestUpdatedIndex].incoming_offset = i;
|
|
||||||
}
|
|
||||||
}
|
|
||||||
}
|
|
||||||
for (; m < NMATCHES_PER_OFFSET; m++) {
|
|
||||||
pSlotCost[m] = 0;
|
|
||||||
}
|
|
||||||
|
|
||||||
if (pCompressor->best_match[i].length >= MIN_MATCH_SIZE_V2)
|
|
||||||
nLastLiteralsOffset = i;
|
|
||||||
|
|
||||||
prev_match[i] = nLastLiteralsOffset;
|
|
||||||
}
|
|
||||||
|
|
||||||
int nIncomingOffset = -1;
|
|
||||||
for (i = nStartOffset; i < nEndOffset; ) {
|
|
||||||
if (pCompressor->best_match[i].length >= MIN_MATCH_SIZE_V2) {
|
|
||||||
if (nIncomingOffset >= 0 && repmatch_opt[i].incoming_offset == nIncomingOffset && repmatch_opt[i].best_slot_for_incoming >= 0) {
|
|
||||||
lzsa_match *pMatch = pCompressor->match + (i << MATCHES_PER_OFFSET_SHIFT) + repmatch_opt[i].best_slot_for_incoming;
|
|
||||||
int *pSlotCost = pCompressor->slot_cost + (i << MATCHES_PER_OFFSET_SHIFT) + repmatch_opt[i].best_slot_for_incoming;
|
|
||||||
|
|
||||||
pCompressor->best_match[i].length = pMatch->length;
|
|
||||||
pCompressor->best_match[i].offset = pMatch->offset;
|
|
||||||
cost[i] = *pSlotCost;
|
|
||||||
|
|
||||||
if (repmatch_opt[i].expected_repmatch == 2)
|
|
||||||
repmatch_opt[i].expected_repmatch = 1;
|
|
||||||
}
|
|
||||||
else {
|
|
||||||
if (repmatch_opt[i].expected_repmatch == 2)
|
|
||||||
repmatch_opt[i].expected_repmatch = 0;
|
|
||||||
}
|
|
||||||
|
|
||||||
nIncomingOffset = i;
|
|
||||||
i += pCompressor->best_match[i].length;
|
|
||||||
}
|
|
||||||
else {
|
|
||||||
i++;
|
|
||||||
}
|
|
||||||
}
|
|
||||||
}
|
|
||||||
|
|
||||||
/**
|
|
||||||
* Attempt to minimize the number of commands issued in the compressed data block, in order to speed up decompression without
|
|
||||||
* impacting the compression ratio
|
|
||||||
*
|
|
||||||
* @param pCompressor compression context
|
|
||||||
* @param nStartOffset current offset in input window (typically the number of previously compressed bytes)
|
|
||||||
* @param nEndOffset offset to end finding matches at (typically the size of the total input window in bytes
|
|
||||||
*
|
|
||||||
* @return non-zero if the number of tokens was reduced, 0 if it wasn't
|
|
||||||
*/
|
|
||||||
static int lzsa_optimize_command_count_v2(lsza_compressor *pCompressor, const int nStartOffset, const int nEndOffset) {
|
|
||||||
int i;
|
|
||||||
int nNumLiterals = 0;
|
|
||||||
int nDidReduce = 0;
|
|
||||||
int nPreviousMatchOffset = -1;
|
|
||||||
lzsa_repmatch_opt *repmatch_opt = pCompressor->repmatch_opt;
|
|
||||||
|
|
||||||
for (i = nStartOffset; i < nEndOffset; ) {
|
|
||||||
lzsa_match *pMatch = pCompressor->best_match + i;
|
|
||||||
|
|
||||||
if (pMatch->length >= MIN_MATCH_SIZE_V2) {
|
|
||||||
int nMatchLen = pMatch->length;
|
|
||||||
int nReduce = 0;
|
|
||||||
int nCurrentMatchOffset = i;
|
|
||||||
|
|
||||||
if (nMatchLen <= 9 && (i + nMatchLen) < nEndOffset) /* max reducable command size: <token> <EE> <ll> <ll> <offset> <offset> <EE> <mm> <mm> */ {
|
|
||||||
int nMatchOffset = pMatch->offset;
|
|
||||||
int nEncodedMatchLen = nMatchLen - MIN_MATCH_SIZE_V2;
|
|
||||||
int nUndoRepMatchCost = (nPreviousMatchOffset < 0 || !repmatch_opt[nPreviousMatchOffset].expected_repmatch) ? 0 : 16;
|
|
||||||
|
|
||||||
if (pCompressor->best_match[i + nMatchLen].length >= MIN_MATCH_SIZE_V2) {
|
|
||||||
int nCommandSize = 8 /* token */ + lzsa_get_literals_varlen_size_v2(nNumLiterals) + lzsa_get_match_varlen_size_v2(nEncodedMatchLen) - nUndoRepMatchCost;
|
|
||||||
|
|
||||||
if (pCompressor->best_match[i + nMatchLen].offset != nMatchOffset) {
|
|
||||||
nCommandSize += (nMatchOffset <= 32) ? 4 : ((nMatchOffset <= 512) ? 8 : ((nMatchOffset <= (8192 + 512)) ? 12 : 16)) /* match offset */;
|
|
||||||
}
|
|
||||||
|
|
||||||
if (nCommandSize >= ((nMatchLen << 3) + lzsa_get_literals_varlen_size_v2(nNumLiterals + nMatchLen))) {
|
|
||||||
/* This command is a match; the next command is also a match. The next command currently has no literals; replacing this command by literals will
|
|
||||||
* make the next command eat the cost of encoding the current number of literals, + nMatchLen extra literals. The size of the current match command is
|
|
||||||
* at least as much as the number of literal bytes + the extra cost of encoding them in the next match command, so we can safely replace the current
|
|
||||||
* match command by literals, the output size will not increase and it will remove one command. */
|
|
||||||
nReduce = 1;
|
|
||||||
}
|
|
||||||
}
|
|
||||||
else {
|
|
||||||
int nCurIndex = i + nMatchLen;
|
|
||||||
int nNextNumLiterals = 0;
|
|
||||||
int nCommandSize = 8 /* token */ + lzsa_get_literals_varlen_size_v2(nNumLiterals) + lzsa_get_match_varlen_size_v2(nEncodedMatchLen) - nUndoRepMatchCost;;
|
|
||||||
|
|
||||||
do {
|
|
||||||
nCurIndex++;
|
|
||||||
nNextNumLiterals++;
|
|
||||||
} while (nCurIndex < nEndOffset && pCompressor->best_match[nCurIndex].length < MIN_MATCH_SIZE_V2);
|
|
||||||
|
|
||||||
if (nCurIndex >= nEndOffset || pCompressor->best_match[nCurIndex].length < MIN_MATCH_SIZE_V2 ||
|
|
||||||
pCompressor->best_match[nCurIndex].offset != nMatchOffset) {
|
|
||||||
nCommandSize += (nMatchOffset <= 32) ? 4 : ((nMatchOffset <= 512) ? 8 : ((nMatchOffset <= (8192 + 512)) ? 12 : 16)) /* match offset */;
|
|
||||||
}
|
|
||||||
|
|
||||||
if (nCommandSize >= ((nMatchLen << 3) + lzsa_get_literals_varlen_size_v2(nNumLiterals + nNextNumLiterals + nMatchLen) - lzsa_get_literals_varlen_size_v2(nNextNumLiterals))) {
|
|
||||||
/* This command is a match, and is followed by literals, and then another match or the end of the input data. If encoding this match as literals doesn't take
|
|
||||||
* more room than the match, and doesn't grow the next match command's literals encoding, go ahead and remove the command. */
|
|
||||||
nReduce = 1;
|
|
||||||
}
|
|
||||||
}
|
|
||||||
}
|
|
||||||
|
|
||||||
if (nReduce) {
|
|
||||||
int j;
|
|
||||||
|
|
||||||
for (j = 0; j < nMatchLen; j++) {
|
|
||||||
pCompressor->best_match[i + j].length = 0;
|
|
||||||
}
|
|
||||||
nNumLiterals += nMatchLen;
|
|
||||||
i += nMatchLen;
|
|
||||||
|
|
||||||
nDidReduce = 1;
|
|
||||||
|
|
||||||
if (nPreviousMatchOffset >= 0) {
|
|
||||||
repmatch_opt[nPreviousMatchOffset].expected_repmatch = 0;
|
|
||||||
nPreviousMatchOffset = -1;
|
|
||||||
}
|
|
||||||
}
|
|
||||||
else {
|
|
||||||
if ((i + nMatchLen) < nEndOffset && nMatchLen >= LCP_MAX &&
|
|
||||||
pMatch->offset && pMatch->offset <= 32 && pCompressor->best_match[i + nMatchLen].offset == pMatch->offset && (nMatchLen % pMatch->offset) == 0 &&
|
|
||||||
(nMatchLen + pCompressor->best_match[i + nMatchLen].length) <= MAX_VARLEN) {
|
|
||||||
/* Join */
|
|
||||||
|
|
||||||
pMatch->length += pCompressor->best_match[i + nMatchLen].length;
|
|
||||||
pCompressor->best_match[i + nMatchLen].offset = 0;
|
|
||||||
pCompressor->best_match[i + nMatchLen].length = -1;
|
|
||||||
continue;
|
|
||||||
}
|
|
||||||
|
|
||||||
nNumLiterals = 0;
|
|
||||||
i += nMatchLen;
|
|
||||||
}
|
|
||||||
|
|
||||||
nPreviousMatchOffset = nCurrentMatchOffset;
|
|
||||||
}
|
|
||||||
else {
|
|
||||||
nNumLiterals++;
|
|
||||||
i++;
|
|
||||||
}
|
|
||||||
}
|
|
||||||
|
|
||||||
return nDidReduce;
|
|
||||||
}
|
|
||||||
|
|
||||||
/**
|
|
||||||
* Emit block of compressed data
|
|
||||||
*
|
|
||||||
* @param pCompressor compression context
|
|
||||||
* @param pInWindow pointer to input data window (previously compressed bytes + bytes to compress)
|
|
||||||
* @param nStartOffset current offset in input window (typically the number of previously compressed bytes)
|
|
||||||
* @param nEndOffset offset to end finding matches at (typically the size of the total input window in bytes
|
|
||||||
* @param pOutData pointer to output buffer
|
|
||||||
* @param nMaxOutDataSize maximum size of output buffer, in bytes
|
|
||||||
*
|
|
||||||
* @return size of compressed data in output buffer, or -1 if the data is uncompressible
|
|
||||||
*/
|
|
||||||
static int lzsa_write_block_v2(lsza_compressor *pCompressor, const unsigned char *pInWindow, const int nStartOffset, const int nEndOffset, unsigned char *pOutData, const int nMaxOutDataSize) {
|
|
||||||
int i;
|
|
||||||
int nNumLiterals = 0;
|
|
||||||
int nInFirstLiteralOffset = 0;
|
|
||||||
int nOutOffset = 0;
|
|
||||||
int nCurNibbleOffset = -1, nCurFreeNibbles = 0;
|
|
||||||
int nRepMatchOffset = 0;
|
|
||||||
lzsa_repmatch_opt *repmatch_opt = pCompressor->repmatch_opt;
|
|
||||||
|
|
||||||
for (i = nStartOffset; i < nEndOffset; ) {
|
|
||||||
lzsa_match *pMatch = pCompressor->best_match + i;
|
|
||||||
|
|
||||||
if (pMatch->length >= MIN_MATCH_SIZE_V2) {
|
|
||||||
int nMatchOffset = pMatch->offset;
|
|
||||||
int nMatchLen = pMatch->length;
|
|
||||||
int nEncodedMatchLen = nMatchLen - MIN_MATCH_SIZE_V2;
|
|
||||||
int nTokenLiteralsLen = (nNumLiterals >= LITERALS_RUN_LEN_V2) ? LITERALS_RUN_LEN_V2 : nNumLiterals;
|
|
||||||
int nTokenMatchLen = (nEncodedMatchLen >= MATCH_RUN_LEN_V2) ? MATCH_RUN_LEN_V2 : nEncodedMatchLen;
|
|
||||||
int nTokenOffsetMode;
|
|
||||||
int nOffsetSize;
|
|
||||||
|
|
||||||
if (nMatchOffset == nRepMatchOffset) {
|
|
||||||
nTokenOffsetMode = 0xe0;
|
|
||||||
nOffsetSize = 0;
|
|
||||||
}
|
|
||||||
else {
|
|
||||||
if (nMatchOffset <= 32) {
|
|
||||||
nTokenOffsetMode = 0x00 | (((-nMatchOffset) & 0x10) << 1);
|
|
||||||
nOffsetSize = 4;
|
|
||||||
}
|
|
||||||
else if (nMatchOffset <= 512) {
|
|
||||||
nTokenOffsetMode = 0x40 | (((-nMatchOffset) & 0x100) >> 3);
|
|
||||||
nOffsetSize = 8;
|
|
||||||
}
|
|
||||||
else if (nMatchOffset <= (8192 + 512)) {
|
|
||||||
nTokenOffsetMode = 0x80 | (((-(nMatchOffset - 512)) & 0x1000) >> 7);
|
|
||||||
nOffsetSize = 12;
|
|
||||||
}
|
|
||||||
else {
|
|
||||||
nTokenOffsetMode = 0xc0;
|
|
||||||
nOffsetSize = 16;
|
|
||||||
}
|
|
||||||
}
|
|
||||||
|
|
||||||
int nCommandSize = 8 /* token */ + lzsa_get_literals_varlen_size_v2(nNumLiterals) + (nNumLiterals << 3) + nOffsetSize /* match offset */ + lzsa_get_match_varlen_size_v2(nEncodedMatchLen);
|
|
||||||
|
|
||||||
if ((nOutOffset + ((nCommandSize + 7) >> 3)) > nMaxOutDataSize)
|
|
||||||
return -1;
|
|
||||||
if (nMatchOffset < MIN_OFFSET || nMatchOffset > MAX_OFFSET)
|
|
||||||
return -1;
|
|
||||||
|
|
||||||
pOutData[nOutOffset++] = nTokenOffsetMode | (nTokenLiteralsLen << 3) | nTokenMatchLen;
|
|
||||||
nOutOffset = lzsa_write_literals_varlen_v2(pOutData, nOutOffset, nMaxOutDataSize, &nCurNibbleOffset, &nCurFreeNibbles, nNumLiterals);
|
|
||||||
if (nOutOffset < 0) return -1;
|
|
||||||
|
|
||||||
if (nNumLiterals != 0) {
|
|
||||||
memcpy(pOutData + nOutOffset, pInWindow + nInFirstLiteralOffset, nNumLiterals);
|
|
||||||
nOutOffset += nNumLiterals;
|
|
||||||
nNumLiterals = 0;
|
|
||||||
}
|
|
||||||
|
|
||||||
if (nTokenOffsetMode == 0x00 || nTokenOffsetMode == 0x20) {
|
|
||||||
nOutOffset = lzsa_write_nibble_v2(pOutData, nOutOffset, nMaxOutDataSize, &nCurNibbleOffset, &nCurFreeNibbles, (-nMatchOffset) & 0x0f);
|
|
||||||
if (nOutOffset < 0) return -1;
|
|
||||||
}
|
|
||||||
else if (nTokenOffsetMode == 0x40 || nTokenOffsetMode == 0x60) {
|
|
||||||
pOutData[nOutOffset++] = (-nMatchOffset) & 0xff;
|
|
||||||
}
|
|
||||||
else if (nTokenOffsetMode == 0x80 || nTokenOffsetMode == 0xa0) {
|
|
||||||
pOutData[nOutOffset++] = (-(nMatchOffset - 512)) & 0xff;
|
|
||||||
nOutOffset = lzsa_write_nibble_v2(pOutData, nOutOffset, nMaxOutDataSize, &nCurNibbleOffset, &nCurFreeNibbles, ((-(nMatchOffset - 512)) >> 8) & 0x0f);
|
|
||||||
if (nOutOffset < 0) return -1;
|
|
||||||
}
|
|
||||||
else if (nTokenOffsetMode == 0xc0) {
|
|
||||||
pOutData[nOutOffset++] = (-nMatchOffset) & 0xff;
|
|
||||||
pOutData[nOutOffset++] = (-nMatchOffset) >> 8;
|
|
||||||
}
|
|
||||||
nRepMatchOffset = nMatchOffset;
|
|
||||||
|
|
||||||
nOutOffset = lzsa_write_match_varlen_v2(pOutData, nOutOffset, nMaxOutDataSize, &nCurNibbleOffset, &nCurFreeNibbles, nEncodedMatchLen);
|
|
||||||
if (nOutOffset < 0) return -1;
|
|
||||||
|
|
||||||
i += nMatchLen;
|
|
||||||
|
|
||||||
pCompressor->num_commands++;
|
|
||||||
}
|
|
||||||
else {
|
|
||||||
if (nNumLiterals == 0)
|
|
||||||
nInFirstLiteralOffset = i;
|
|
||||||
nNumLiterals++;
|
|
||||||
i++;
|
|
||||||
}
|
|
||||||
}
|
|
||||||
|
|
||||||
{
|
|
||||||
int nTokenLiteralsLen = (nNumLiterals >= LITERALS_RUN_LEN_V2) ? LITERALS_RUN_LEN_V2 : nNumLiterals;
|
|
||||||
int nCommandSize = 8 /* token */ + lzsa_get_literals_varlen_size_v2(nNumLiterals) + (nNumLiterals << 3);
|
|
||||||
|
|
||||||
if ((nOutOffset + ((nCommandSize + 7) >> 3)) > nMaxOutDataSize)
|
|
||||||
return -1;
|
|
||||||
|
|
||||||
if (pCompressor->flags & LZSA_FLAG_RAW_BLOCK)
|
|
||||||
pOutData[nOutOffset++] = (nTokenLiteralsLen << 3) | 0x47;
|
|
||||||
else
|
|
||||||
pOutData[nOutOffset++] = (nTokenLiteralsLen << 3) | 0x00;
|
|
||||||
nOutOffset = lzsa_write_literals_varlen_v2(pOutData, nOutOffset, nMaxOutDataSize, &nCurNibbleOffset, &nCurFreeNibbles, nNumLiterals);
|
|
||||||
if (nOutOffset < 0) return -1;
|
|
||||||
|
|
||||||
if (nNumLiterals != 0) {
|
|
||||||
memcpy(pOutData + nOutOffset, pInWindow + nInFirstLiteralOffset, nNumLiterals);
|
|
||||||
nOutOffset += nNumLiterals;
|
|
||||||
nNumLiterals = 0;
|
|
||||||
}
|
|
||||||
|
|
||||||
pCompressor->num_commands++;
|
|
||||||
}
|
|
||||||
|
|
||||||
if (pCompressor->flags & LZSA_FLAG_RAW_BLOCK) {
|
|
||||||
/* Emit EOD marker for raw block */
|
|
||||||
|
|
||||||
if (nOutOffset >= nMaxOutDataSize)
|
|
||||||
return -1;
|
|
||||||
pOutData[nOutOffset++] = 0; /* Match offset */
|
|
||||||
|
|
||||||
nOutOffset = lzsa_write_nibble_v2(pOutData, nOutOffset, nMaxOutDataSize, &nCurNibbleOffset, &nCurFreeNibbles, 15); /* Extended match length nibble */
|
|
||||||
if (nOutOffset < 0) return -1;
|
|
||||||
|
|
||||||
if ((nOutOffset + 3) > nMaxOutDataSize)
|
|
||||||
return -1;
|
|
||||||
|
|
||||||
pOutData[nOutOffset++] = 0; /* Extended match length byte */
|
|
||||||
pOutData[nOutOffset++] = 0; /* 16-bit match length */
|
|
||||||
pOutData[nOutOffset++] = 0;
|
|
||||||
}
|
|
||||||
|
|
||||||
if (nCurNibbleOffset != -1) {
|
|
||||||
nOutOffset = lzsa_write_nibble_v2(pOutData, nOutOffset, nMaxOutDataSize, &nCurNibbleOffset, &nCurFreeNibbles, 0);
|
|
||||||
if (nOutOffset < 0 || nCurNibbleOffset != -1)
|
|
||||||
return -1;
|
|
||||||
}
|
|
||||||
|
|
||||||
return nOutOffset;
|
|
||||||
}
|
|
||||||
|
|
||||||
/**
|
|
||||||
* Select the most optimal matches, reduce the token count if possible, and then emit a block of compressed LZSA2 data
|
|
||||||
*
|
|
||||||
* @param pCompressor compression context
|
|
||||||
* @param pInWindow pointer to input data window (previously compressed bytes + bytes to compress)
|
|
||||||
* @param nStartOffset current offset in input window (typically the number of previously compressed bytes)
|
|
||||||
* @param nEndOffset offset to end finding matches at (typically the size of the total input window in bytes
|
|
||||||
* @param pOutData pointer to output buffer
|
|
||||||
* @param nMaxOutDataSize maximum size of output buffer, in bytes
|
|
||||||
*
|
|
||||||
* @return size of compressed data in output buffer, or -1 if the data is uncompressible
|
|
||||||
*/
|
|
||||||
int lzsa_optimize_and_write_block_v2(lsza_compressor *pCompressor, const unsigned char *pInWindow, const int nPreviousBlockSize, const int nInDataSize, unsigned char *pOutData, const int nMaxOutDataSize) {
|
|
||||||
lzsa_optimize_matches_v2(pCompressor, nPreviousBlockSize, nPreviousBlockSize + nInDataSize);
|
|
||||||
|
|
||||||
int nDidReduce;
|
|
||||||
int nPasses = 0;
|
|
||||||
do {
|
|
||||||
nDidReduce = lzsa_optimize_command_count_v2(pCompressor, nPreviousBlockSize, nPreviousBlockSize + nInDataSize);
|
|
||||||
nPasses++;
|
|
||||||
} while (nDidReduce && nPasses < 20);
|
|
||||||
|
|
||||||
return lzsa_write_block_v2(pCompressor, pInWindow, nPreviousBlockSize, nPreviousBlockSize + nInDataSize, pOutData, nMaxOutDataSize);
|
|
||||||
}
|
|
||||||
Loading…
Reference in New Issue
Block a user