mirror of
https://github.com/emmanuel-marty/lzsa.git
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1106 lines
52 KiB
C
1106 lines
52 KiB
C
/*
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* shrink_block_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 <stdlib.h>
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#include <string.h>
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#include "lib.h"
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#include "shrink_block_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 - 18;
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else {
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pOutData[nOutOffset++] = 239;
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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 - 24;
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else {
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pOutData[nOutOffset++] = 233;
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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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* Insert forward rep candidate
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*
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* @param pCompressor compression context
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* @param pInWindow pointer to input data window (previously compressed bytes + bytes to compress)
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* @param i input data window position whose matches are being considered
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* @param nMatchOffset match offset to use as rep candidate
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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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* @param nDepth current insertion depth
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*/
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static void lzsa_insert_forward_match_v2(lzsa_compressor *pCompressor, const unsigned char *pInWindow, const int i, const int nMatchOffset, const int nStartOffset, const int nEndOffset, const int nMatchesPerArrival, int nDepth) {
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lzsa_arrival *arrival = pCompressor->arrival - (nStartOffset << MATCHES_PER_ARRIVAL_SHIFT);
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int j;
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if (nDepth >= 10) return;
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for (j = 0; j < nMatchesPerArrival && arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].from_slot; j++) {
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int nRepOffset = arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].rep_offset;
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if (nMatchOffset != nRepOffset && nRepOffset && arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].rep_len >= MIN_MATCH_SIZE_V2) {
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int nRepPos = arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].rep_pos;
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int nRepLen = arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].rep_len;
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if (nRepPos > nMatchOffset &&
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(nRepPos - nMatchOffset + nRepLen) <= (nEndOffset - LAST_LITERALS) &&
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!memcmp(pInWindow + nRepPos - nRepOffset, pInWindow + nRepPos - nMatchOffset, nRepLen)) {
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lzsa_match *fwd_match = pCompressor->match + ((nRepPos - nStartOffset) << MATCHES_PER_INDEX_SHIFT_V2);
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int exists = 0;
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int r;
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for (r = 0; r < NMATCHES_PER_INDEX_V2 && fwd_match[r].length >= MIN_MATCH_SIZE_V2; r++) {
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if (fwd_match[r].offset == nMatchOffset) {
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exists = 1;
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if (fwd_match[r].length < nRepLen) {
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fwd_match[r].length = nRepLen;
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lzsa_insert_forward_match_v2(pCompressor, pInWindow, nRepPos, nMatchOffset, nStartOffset, nEndOffset, nMatchesPerArrival, nDepth + 1);
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}
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break;
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}
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}
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if (!exists && r < NMATCHES_PER_INDEX_V2) {
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fwd_match[r].offset = nMatchOffset;
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fwd_match[r].length = nRepLen;
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lzsa_insert_forward_match_v2(pCompressor, pInWindow, nRepPos, nMatchOffset, nStartOffset, nEndOffset, nMatchesPerArrival, nDepth + 1);
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}
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}
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}
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}
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}
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/**
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* Attempt to pick optimal matches using a forward arrivals parser, 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 pInWindow pointer to input data window (previously compressed bytes + bytes to compress)
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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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* @param nInsertForwardReps non-zero to insert forward repmatch candidates, zero to use the previously inserted candidates
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*/
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static void lzsa_optimize_forward_v2(lzsa_compressor *pCompressor, const unsigned char *pInWindow, lzsa_match *pBestMatch, const int nStartOffset, const int nEndOffset, const int nReduce, const int nInsertForwardReps, const int nMatchesPerArrival) {
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lzsa_arrival *arrival = pCompressor->arrival - (nStartOffset << MATCHES_PER_ARRIVAL_SHIFT);
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const int nFavorRatio = (pCompressor->flags & LZSA_FLAG_FAVOR_RATIO) ? 1 : 0;
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const int nMinMatchSize = pCompressor->min_match_size;
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const int nDisableScore = nReduce ? 0 : (2 * BLOCK_SIZE);
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int i, j, n;
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if ((nEndOffset - nStartOffset) > BLOCK_SIZE) return;
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memset(arrival + (nStartOffset << MATCHES_PER_ARRIVAL_SHIFT), 0, sizeof(lzsa_arrival) * ((nEndOffset - nStartOffset) << MATCHES_PER_ARRIVAL_SHIFT));
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for (i = (nStartOffset << MATCHES_PER_ARRIVAL_SHIFT); i != (nEndOffset << MATCHES_PER_ARRIVAL_SHIFT); i++) {
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arrival[i].cost = 0x40000000;
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}
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arrival[nStartOffset << MATCHES_PER_ARRIVAL_SHIFT].from_slot = -1;
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for (i = nStartOffset; i != (nEndOffset - 1); i++) {
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int m;
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for (j = 0; j < nMatchesPerArrival && arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].from_slot; j++) {
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const int nPrevCost = arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].cost & 0x3fffffff;
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int nCodingChoiceCost = nPrevCost + 8 /* literal */;
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int nNumLiterals = arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].num_literals + 1;
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if (nNumLiterals == LITERALS_RUN_LEN_V2) {
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nCodingChoiceCost += 4;
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}
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else if (nNumLiterals == (LITERALS_RUN_LEN_V2 + 15)) {
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nCodingChoiceCost += 8;
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}
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else if (nNumLiterals == 256) {
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nCodingChoiceCost += 16;
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}
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if (!nFavorRatio && nNumLiterals == 1)
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nCodingChoiceCost += MODESWITCH_PENALTY;
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lzsa_arrival *pDestSlots = &arrival[(i + 1) << MATCHES_PER_ARRIVAL_SHIFT];
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if (nCodingChoiceCost <= pDestSlots[nMatchesPerArrival - 1].cost) {
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int exists = 0;
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for (n = 0;
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n < nMatchesPerArrival && pDestSlots[n].cost <= nCodingChoiceCost;
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n++) {
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if (pDestSlots[n].rep_offset == arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].rep_offset) {
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exists = 1;
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break;
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}
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}
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if (!exists) {
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int nScore = arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].score + 1;
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for (n = 0; n < nMatchesPerArrival; n++) {
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lzsa_arrival *pDestArrival = &pDestSlots[n];
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if (nCodingChoiceCost < pDestArrival->cost ||
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(nCodingChoiceCost == pDestArrival->cost && nScore < (pDestArrival->score + nDisableScore))) {
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if (pDestArrival->from_slot) {
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memmove(&pDestSlots[n + 1],
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&pDestSlots[n],
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sizeof(lzsa_arrival) * (nMatchesPerArrival - n - 1));
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}
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pDestArrival->cost = nCodingChoiceCost;
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pDestArrival->from_pos = i;
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pDestArrival->from_slot = j + 1;
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pDestArrival->match_offset = 0;
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pDestArrival->match_len = 0;
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pDestArrival->num_literals = nNumLiterals;
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pDestArrival->score = nScore;
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pDestArrival->rep_offset = arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].rep_offset;
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pDestArrival->rep_pos = arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].rep_pos;
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pDestArrival->rep_len = arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].rep_len;
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break;
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}
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}
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}
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}
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}
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lzsa_match *match = pCompressor->match + ((i - nStartOffset) << MATCHES_PER_INDEX_SHIFT_V2);
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for (m = 0; m < NMATCHES_PER_INDEX_V2 && match[m].length; m++) {
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int nMatchLen = match[m].length;
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int nMatchOffset = match[m].offset;
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int nNoRepmatchOffsetCost = (nMatchOffset <= 32) ? 4 : ((nMatchOffset <= 512) ? 8 : ((nMatchOffset <= (8192 + 512)) ? 12 : 16));
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int nStartingMatchLen, k;
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int nMaxRepLen[NMATCHES_PER_ARRIVAL_BIG];
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if ((i + nMatchLen) > (nEndOffset - LAST_LITERALS))
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nMatchLen = nEndOffset - LAST_LITERALS - i;
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for (j = 0; j < nMatchesPerArrival && arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].from_slot; j++) {
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int nRepOffset = arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].rep_offset;
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int nCurMaxRepLen = 0;
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if (nMatchOffset != nRepOffset &&
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nRepOffset &&
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i > nRepOffset &&
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(i - nRepOffset + nMatchLen) <= (nEndOffset - LAST_LITERALS)) {
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while (nCurMaxRepLen < nMatchLen && pInWindow[i - nRepOffset + nCurMaxRepLen] == pInWindow[i - nMatchOffset + nCurMaxRepLen])
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nCurMaxRepLen++;
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}
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nMaxRepLen[j] = nCurMaxRepLen;
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}
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while (j < nMatchesPerArrival)
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nMaxRepLen[j++] = 0;
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if (nInsertForwardReps)
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lzsa_insert_forward_match_v2(pCompressor, pInWindow, i, nMatchOffset, nStartOffset, nEndOffset, nMatchesPerArrival, 0);
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if (nMatchLen >= LEAVE_ALONE_MATCH_SIZE)
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nStartingMatchLen = nMatchLen;
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else
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nStartingMatchLen = nMinMatchSize;
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for (k = nStartingMatchLen; k <= nMatchLen; k++) {
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int nMatchLenCost = lzsa_get_match_varlen_size_v2(k - MIN_MATCH_SIZE_V2);
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lzsa_arrival *pDestSlots = &arrival[(i + k) << MATCHES_PER_ARRIVAL_SHIFT];
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for (j = 0; j < nMatchesPerArrival && arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].from_slot; j++) {
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const int nPrevCost = arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].cost & 0x3fffffff;
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int nRepOffset = arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].rep_offset;
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int nMatchOffsetCost = (nMatchOffset == nRepOffset) ? 0 : nNoRepmatchOffsetCost;
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int nRepCodingChoiceCost = nPrevCost + 8 /* token */ /* the actual cost of the literals themselves accumulates up the chain */ + nMatchLenCost;
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int nCodingChoiceCost = nRepCodingChoiceCost + nMatchOffsetCost;
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if (!nFavorRatio && !arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].num_literals)
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nCodingChoiceCost += MODESWITCH_PENALTY;
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if (nRepCodingChoiceCost <= pDestSlots[nMatchesPerArrival - 1].cost) {
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if (nCodingChoiceCost <= pDestSlots[nMatchesPerArrival - 1].cost) {
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int exists = 0;
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int nScore = arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].score + ((nMatchOffset == nRepOffset) ? 2 : 3);
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for (n = 0;
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n < nMatchesPerArrival && pDestSlots[n].cost <= nCodingChoiceCost;
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n++) {
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if (pDestSlots[n].rep_offset == nMatchOffset &&
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(!nInsertForwardReps || pDestSlots[n].cost != nCodingChoiceCost || pDestSlots[n].rep_pos >= i || nScore >= (pDestSlots[n].score + nDisableScore) ||
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pDestSlots[nMatchesPerArrival - 1].from_slot)) {
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exists = 1;
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break;
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}
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}
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if (!exists) {
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for (n = 0; n < nMatchesPerArrival; n++) {
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lzsa_arrival *pDestArrival = &pDestSlots[n];
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if (nCodingChoiceCost < pDestArrival->cost ||
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(nCodingChoiceCost == pDestArrival->cost && nScore < (pDestArrival->score + nDisableScore))) {
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if (pDestArrival->from_slot) {
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memmove(&pDestSlots[n + 1],
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&pDestSlots[n],
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sizeof(lzsa_arrival) * (nMatchesPerArrival - n - 1));
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}
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pDestArrival->cost = nCodingChoiceCost;
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pDestArrival->from_pos = i;
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pDestArrival->from_slot = j + 1;
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pDestArrival->match_offset = nMatchOffset;
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pDestArrival->match_len = k;
|
|
pDestArrival->num_literals = 0;
|
|
pDestArrival->score = nScore;
|
|
pDestArrival->rep_offset = nMatchOffset;
|
|
pDestArrival->rep_pos = i;
|
|
pDestArrival->rep_len = k;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/* If this coding choice doesn't rep-match, see if we still get a match by using the current repmatch offset for this arrival. This can occur (and not have the
|
|
* matchfinder offer the offset in the first place, or have too many choices with the same cost to retain the repmatchable offset) when compressing regions
|
|
* of identical bytes, for instance. Checking for this provides a big compression win on some files. */
|
|
|
|
if (nMaxRepLen[j] >= k) {
|
|
int exists = 0;
|
|
|
|
/* A match is possible at the rep offset; insert the extra coding choice. */
|
|
|
|
for (n = 0;
|
|
n < nMatchesPerArrival && pDestSlots[n].cost <= nRepCodingChoiceCost;
|
|
n++) {
|
|
if (pDestSlots[n].rep_offset == nRepOffset) {
|
|
exists = 1;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (!exists) {
|
|
int nScore = arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].score + 2;
|
|
|
|
for (n = 0; n < nMatchesPerArrival; n++) {
|
|
lzsa_arrival *pDestArrival = &pDestSlots[n];
|
|
|
|
if (nRepCodingChoiceCost < pDestArrival->cost ||
|
|
(nRepCodingChoiceCost == pDestArrival->cost && nScore < (pDestArrival->score + nDisableScore))) {
|
|
if (pDestArrival->from_slot) {
|
|
memmove(&pDestSlots[n + 1],
|
|
&pDestSlots[n],
|
|
sizeof(lzsa_arrival) * (nMatchesPerArrival - n - 1));
|
|
}
|
|
|
|
pDestArrival->cost = nRepCodingChoiceCost;
|
|
pDestArrival->from_pos = i;
|
|
pDestArrival->from_slot = j + 1;
|
|
pDestArrival->match_offset = nRepOffset;
|
|
pDestArrival->match_len = k;
|
|
pDestArrival->num_literals = 0;
|
|
pDestArrival->score = nScore;
|
|
pDestArrival->rep_offset = nRepOffset;
|
|
pDestArrival->rep_pos = i;
|
|
pDestArrival->rep_len = k;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
lzsa_arrival *end_arrival = &arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + 0];
|
|
pBestMatch[i].length = 0;
|
|
pBestMatch[i].offset = 0;
|
|
|
|
while (end_arrival->from_slot > 0 && end_arrival->from_pos >= 0) {
|
|
pBestMatch[end_arrival->from_pos].length = end_arrival->match_len;
|
|
pBestMatch[end_arrival->from_pos].offset = end_arrival->match_offset;
|
|
end_arrival = &arrival[(end_arrival->from_pos << MATCHES_PER_ARRIVAL_SHIFT) + (end_arrival->from_slot - 1)];
|
|
}
|
|
}
|
|
|
|
/**
|
|
* 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 pInWindow pointer to input data window (previously compressed bytes + bytes to compress)
|
|
* @param pBestMatch optimal matches to evaluate and update
|
|
* @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(lzsa_compressor *pCompressor, const unsigned char *pInWindow, lzsa_match *pBestMatch, const int nStartOffset, const int nEndOffset) {
|
|
int i;
|
|
int nNumLiterals = 0;
|
|
int nPrevRepMatchOffset = 0;
|
|
int nRepMatchOffset = 0;
|
|
int nRepMatchLen = 0;
|
|
int nRepIndex = 0;
|
|
int nDidReduce = 0;
|
|
|
|
for (i = nStartOffset; i < nEndOffset; ) {
|
|
lzsa_match *pMatch = pBestMatch + i;
|
|
|
|
if (pMatch->length == 0 &&
|
|
(i + 1) < (nEndOffset - LAST_LITERALS) &&
|
|
pBestMatch[i + 1].length >= MIN_MATCH_SIZE_V2 &&
|
|
pBestMatch[i + 1].offset &&
|
|
i >= pBestMatch[i + 1].offset &&
|
|
(i + pBestMatch[i + 1].length + 1) <= (nEndOffset - LAST_LITERALS) &&
|
|
!memcmp(pInWindow + i - (pBestMatch[i + 1].offset), pInWindow + i, pBestMatch[i + 1].length + 1)) {
|
|
int nCurLenSize = lzsa_get_match_varlen_size_v2(pBestMatch[i + 1].length);
|
|
int nReducedLenSize = lzsa_get_match_varlen_size_v2(pBestMatch[i + 1].length + 1);
|
|
|
|
if ((nReducedLenSize - nCurLenSize) <= 8) {
|
|
/* Merge */
|
|
pBestMatch[i].length = pBestMatch[i + 1].length + 1;
|
|
pBestMatch[i].offset = pBestMatch[i + 1].offset;
|
|
pBestMatch[i + 1].length = 0;
|
|
pBestMatch[i + 1].offset = 0;
|
|
nDidReduce = 1;
|
|
continue;
|
|
}
|
|
}
|
|
|
|
if (pMatch->length >= MIN_MATCH_SIZE_V2) {
|
|
if ((i + pMatch->length) < nEndOffset /* Don't consider the last match in the block, we can only reduce a match inbetween other tokens */) {
|
|
int nNextIndex = i + pMatch->length;
|
|
int nNextLiterals = 0;
|
|
|
|
while (nNextIndex < nEndOffset && pBestMatch[nNextIndex].length < MIN_MATCH_SIZE_V2) {
|
|
nNextLiterals++;
|
|
nNextIndex++;
|
|
}
|
|
|
|
if (nNextIndex < nEndOffset && pBestMatch[nNextIndex].length >= MIN_MATCH_SIZE_V2) {
|
|
/* This command is a match, is followed by 'nNextLiterals' literals and then by another match */
|
|
|
|
if (nRepMatchOffset && pMatch->offset != nRepMatchOffset && (pBestMatch[nNextIndex].offset != pMatch->offset || pBestMatch[nNextIndex].offset == nRepMatchOffset ||
|
|
((pMatch->offset <= 32) ? 4 : ((pMatch->offset <= 512) ? 8 : ((pMatch->offset <= (8192 + 512)) ? 12 : 16))) >
|
|
((pBestMatch[nNextIndex].offset <= 32) ? 4 : ((pBestMatch[nNextIndex].offset <= 512) ? 8 : ((pBestMatch[nNextIndex].offset <= (8192 + 512)) ? 12 : 16))))) {
|
|
/* Check if we can change the current match's offset to be the same as the previous match's offset, and get an extra repmatch. This will occur when
|
|
* matching large regions of identical bytes for instance, where there are too many offsets to be considered by the parser, and when not compressing to favor the
|
|
* ratio (the forward arrivals parser already has this covered). */
|
|
if (i > nRepMatchOffset &&
|
|
(i - nRepMatchOffset + pMatch->length) <= (nEndOffset - LAST_LITERALS) &&
|
|
!memcmp(pInWindow + i - nRepMatchOffset, pInWindow + i - pMatch->offset, pMatch->length)) {
|
|
pMatch->offset = nRepMatchOffset;
|
|
nDidReduce = 1;
|
|
}
|
|
}
|
|
|
|
if (pBestMatch[nNextIndex].offset && pMatch->offset != pBestMatch[nNextIndex].offset && nRepMatchOffset != pBestMatch[nNextIndex].offset) {
|
|
/* Otherwise, try to gain a match forward as well */
|
|
if (i > pBestMatch[nNextIndex].offset && (i - pBestMatch[nNextIndex].offset + pMatch->length) <= (nEndOffset - LAST_LITERALS)) {
|
|
int nMaxLen = 0;
|
|
while (nMaxLen < pMatch->length && pInWindow[i - pBestMatch[nNextIndex].offset + nMaxLen] == pInWindow[i - pMatch->offset + nMaxLen])
|
|
nMaxLen++;
|
|
if (nMaxLen >= pMatch->length) {
|
|
/* Replace */
|
|
pMatch->offset = pBestMatch[nNextIndex].offset;
|
|
nDidReduce = 1;
|
|
}
|
|
else if (nMaxLen >= 2 && pMatch->offset != nRepMatchOffset) {
|
|
int nPartialSizeBefore, nPartialSizeAfter;
|
|
|
|
nPartialSizeBefore = lzsa_get_match_varlen_size_v2(pMatch->length - MIN_MATCH_SIZE_V2);
|
|
nPartialSizeBefore += (pMatch->offset <= 32) ? 4 : ((pMatch->offset <= 512) ? 8 : ((pMatch->offset <= (8192 + 512)) ? 12 : 16));
|
|
nPartialSizeBefore += lzsa_get_literals_varlen_size_v2(nNextLiterals);
|
|
|
|
nPartialSizeAfter = lzsa_get_match_varlen_size_v2(nMaxLen - MIN_MATCH_SIZE_V2);
|
|
nPartialSizeAfter += lzsa_get_literals_varlen_size_v2(nNextLiterals + (pMatch->length - nMaxLen)) + ((pMatch->length - nMaxLen) << 3);
|
|
|
|
if (nPartialSizeAfter < nPartialSizeBefore) {
|
|
int j;
|
|
|
|
/* We gain a repmatch that is shorter than the original match as this is the best we can do, so it is followed by extra literals, but
|
|
* we have calculated that this is shorter */
|
|
pMatch->offset = pBestMatch[nNextIndex].offset;
|
|
for (j = nMaxLen; j < pMatch->length; j++) {
|
|
pBestMatch[i + j].length = 0;
|
|
}
|
|
pMatch->length = nMaxLen;
|
|
nDidReduce = 1;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
if (pMatch->length < 9 /* Don't waste time considering large matches, they will always win over literals */) {
|
|
/* Calculate this command's current cost (excluding 'nNumLiterals' bytes) */
|
|
|
|
int nCurCommandSize = 8 /* token */ + lzsa_get_literals_varlen_size_v2(nNumLiterals) + lzsa_get_match_varlen_size_v2(pMatch->length - MIN_MATCH_SIZE_V2);
|
|
if (pMatch->offset != nRepMatchOffset)
|
|
nCurCommandSize += (pMatch->offset <= 32) ? 4 : ((pMatch->offset <= 512) ? 8 : ((pMatch->offset <= (8192 + 512)) ? 12 : 16));
|
|
|
|
/* Calculate the next command's current cost */
|
|
int nNextCommandSize = 8 /* token */ + lzsa_get_literals_varlen_size_v2(nNextLiterals) + (nNextLiterals << 3) + lzsa_get_match_varlen_size_v2(pBestMatch[nNextIndex].length - MIN_MATCH_SIZE_V2);
|
|
if (pBestMatch[nNextIndex].offset != pMatch->offset)
|
|
nNextCommandSize += (pBestMatch[nNextIndex].offset <= 32) ? 4 : ((pBestMatch[nNextIndex].offset <= 512) ? 8 : ((pBestMatch[nNextIndex].offset <= (8192 + 512)) ? 12 : 16));
|
|
|
|
int nOriginalCombinedCommandSize = nCurCommandSize + nNextCommandSize;
|
|
|
|
/* Calculate the cost of replacing this match command by literals + the next command with the cost of encoding these literals (excluding 'nNumLiterals' bytes) */
|
|
int nReducedCommandSize = (pMatch->length << 3) + 8 /* token */ + lzsa_get_literals_varlen_size_v2(nNumLiterals + pMatch->length + nNextLiterals) + (nNextLiterals << 3) + lzsa_get_match_varlen_size_v2(pBestMatch[nNextIndex].length - MIN_MATCH_SIZE_V2);
|
|
if (pBestMatch[nNextIndex].offset != nRepMatchOffset)
|
|
nReducedCommandSize += (pBestMatch[nNextIndex].offset <= 32) ? 4 : ((pBestMatch[nNextIndex].offset <= 512) ? 8 : ((pBestMatch[nNextIndex].offset <= (8192 + 512)) ? 12 : 16));
|
|
|
|
int nReplaceRepOffset = 0;
|
|
if (nRepMatchOffset && nRepMatchOffset != nPrevRepMatchOffset && nRepMatchLen >= MIN_MATCH_SIZE_V2 && nRepMatchOffset != pBestMatch[nNextIndex].offset && nRepIndex > pBestMatch[nNextIndex].offset &&
|
|
(nRepIndex - pBestMatch[nNextIndex].offset + nRepMatchLen) <= (nEndOffset - LAST_LITERALS) &&
|
|
!memcmp(pInWindow + nRepIndex - nRepMatchOffset, pInWindow + nRepIndex - pBestMatch[nNextIndex].offset, nRepMatchLen)) {
|
|
/* Replacing this match command by literals would let us create a repmatch */
|
|
nReplaceRepOffset = 1;
|
|
nReducedCommandSize -= (nRepMatchOffset <= 32) ? 4 : ((nRepMatchOffset <= 512) ? 8 : ((nRepMatchOffset <= (8192 + 512)) ? 12 : 16));
|
|
}
|
|
|
|
if (nOriginalCombinedCommandSize >= nReducedCommandSize) {
|
|
/* Reduce */
|
|
int nMatchLen = pMatch->length;
|
|
int j;
|
|
|
|
for (j = 0; j < nMatchLen; j++) {
|
|
pBestMatch[i + j].length = 0;
|
|
}
|
|
|
|
nDidReduce = 1;
|
|
|
|
if (nReplaceRepOffset) {
|
|
pBestMatch[nRepIndex].offset = pBestMatch[nNextIndex].offset;
|
|
nRepMatchOffset = pBestMatch[nNextIndex].offset;
|
|
}
|
|
continue;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
if ((i + pMatch->length) < nEndOffset && pMatch->offset > 0 && pMatch->length >= MIN_MATCH_SIZE_V2 &&
|
|
pBestMatch[i + pMatch->length].offset > 0 &&
|
|
pBestMatch[i + pMatch->length].length >= MIN_MATCH_SIZE_V2 &&
|
|
(pMatch->length + pBestMatch[i + pMatch->length].length) >= LEAVE_ALONE_MATCH_SIZE &&
|
|
(pMatch->length + pBestMatch[i + pMatch->length].length) <= MAX_VARLEN &&
|
|
(i + pMatch->length) > pMatch->offset &&
|
|
(i + pMatch->length) > pBestMatch[i + pMatch->length].offset &&
|
|
(i + pMatch->length + pBestMatch[i + pMatch->length].length) < nEndOffset &&
|
|
!memcmp(pInWindow + i - pMatch->offset + pMatch->length,
|
|
pInWindow + i + pMatch->length - pBestMatch[i + pMatch->length].offset,
|
|
pBestMatch[i + pMatch->length].length)) {
|
|
|
|
int nNextIndex = i + pMatch->length;
|
|
int nNextLiterals = 0;
|
|
|
|
while (nNextIndex < nEndOffset && pBestMatch[nNextIndex].length < MIN_MATCH_SIZE_V2) {
|
|
nNextLiterals++;
|
|
nNextIndex++;
|
|
}
|
|
|
|
int nCurPartialSize = lzsa_get_match_varlen_size_v2(pMatch->length - MIN_MATCH_SIZE_V2);
|
|
|
|
nCurPartialSize += 8 /* token */ + lzsa_get_literals_varlen_size_v2(0) + lzsa_get_match_varlen_size_v2(pBestMatch[i + pMatch->length].length - MIN_MATCH_SIZE_V2);
|
|
if (pBestMatch[i + pMatch->length].offset != pMatch->offset)
|
|
nCurPartialSize += (pBestMatch[i + pMatch->length].offset <= 32) ? 4 : ((pBestMatch[i + pMatch->length].offset <= 512) ? 8 : ((pBestMatch[i + pMatch->length].offset <= (8192 + 512)) ? 12 : 16));
|
|
|
|
if (pBestMatch[nNextIndex].offset != pBestMatch[i + pMatch->length].offset)
|
|
nCurPartialSize += (pBestMatch[nNextIndex].offset <= 32) ? 4 : ((pBestMatch[nNextIndex].offset <= 512) ? 8 : ((pBestMatch[nNextIndex].offset <= (8192 + 512)) ? 12 : 16));
|
|
|
|
int nReducedPartialSize = lzsa_get_match_varlen_size_v2(pMatch->length + pBestMatch[i + pMatch->length].length - MIN_MATCH_SIZE_V2);
|
|
|
|
if (pBestMatch[nNextIndex].offset != pMatch->offset)
|
|
nReducedPartialSize += (pBestMatch[nNextIndex].offset <= 32) ? 4 : ((pBestMatch[nNextIndex].offset <= 512) ? 8 : ((pBestMatch[nNextIndex].offset <= (8192 + 512)) ? 12 : 16));
|
|
|
|
if (nCurPartialSize >= nReducedPartialSize) {
|
|
int nMatchLen = pMatch->length;
|
|
|
|
/* Join */
|
|
|
|
pMatch->length += pBestMatch[i + nMatchLen].length;
|
|
pBestMatch[i + nMatchLen].offset = 0;
|
|
pBestMatch[i + nMatchLen].length = -1;
|
|
nDidReduce = 1;
|
|
continue;
|
|
}
|
|
}
|
|
|
|
nPrevRepMatchOffset = nRepMatchOffset;
|
|
nRepMatchOffset = pMatch->offset;
|
|
nRepMatchLen = pMatch->length;
|
|
nRepIndex = i;
|
|
|
|
i += pMatch->length;
|
|
nNumLiterals = 0;
|
|
}
|
|
else {
|
|
nNumLiterals++;
|
|
i++;
|
|
}
|
|
}
|
|
|
|
return nDidReduce;
|
|
}
|
|
|
|
/**
|
|
* Get compressed data block size
|
|
*
|
|
* @param pCompressor compression context
|
|
* @param pBestMatch optimal matches to emit
|
|
* @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 size of compressed data that will be written to output buffer
|
|
*/
|
|
static int lzsa_get_compressed_size_v2(lzsa_compressor *pCompressor, lzsa_match *pBestMatch, const int nStartOffset, const int nEndOffset) {
|
|
int i;
|
|
int nNumLiterals = 0;
|
|
int nOutOffset = 0;
|
|
int nRepMatchOffset = 0;
|
|
int nCompressedSize = 0;
|
|
|
|
for (i = nStartOffset; i < nEndOffset; ) {
|
|
const lzsa_match *pMatch = pBestMatch + i;
|
|
|
|
if (pMatch->length >= MIN_MATCH_SIZE_V2) {
|
|
int nMatchOffset = pMatch->offset;
|
|
int nMatchLen = pMatch->length;
|
|
int nEncodedMatchLen = nMatchLen - MIN_MATCH_SIZE_V2;
|
|
int nOffsetSize;
|
|
|
|
if (nMatchOffset == nRepMatchOffset) {
|
|
nOffsetSize = 0;
|
|
}
|
|
else {
|
|
if (nMatchOffset <= 32) {
|
|
nOffsetSize = 4;
|
|
}
|
|
else if (nMatchOffset <= 512) {
|
|
nOffsetSize = 8;
|
|
}
|
|
else if (nMatchOffset <= (8192 + 512)) {
|
|
nOffsetSize = 12;
|
|
}
|
|
else {
|
|
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);
|
|
nCompressedSize += nCommandSize;
|
|
|
|
nNumLiterals = 0;
|
|
nRepMatchOffset = nMatchOffset;
|
|
i += nMatchLen;
|
|
}
|
|
else {
|
|
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);
|
|
|
|
nCompressedSize += nCommandSize;
|
|
nNumLiterals = 0;
|
|
}
|
|
|
|
if (pCompressor->flags & LZSA_FLAG_RAW_BLOCK) {
|
|
nCompressedSize += (8 + 4 + 8);
|
|
}
|
|
|
|
return nCompressedSize;
|
|
}
|
|
|
|
/**
|
|
* Emit block of compressed data
|
|
*
|
|
* @param pCompressor compression context
|
|
* @param pBestMatch optimal matches to emit
|
|
* @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(lzsa_compressor *pCompressor, lzsa_match *pBestMatch, 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;
|
|
|
|
for (i = nStartOffset; i < nEndOffset; ) {
|
|
const lzsa_match *pMatch = pBestMatch + 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) & 0x01) << 5) ^ 0x20);
|
|
nOffsetSize = 4;
|
|
}
|
|
else if (nMatchOffset <= 512) {
|
|
nTokenOffsetMode = 0x40 | ((((-nMatchOffset) & 0x100) >> 3) ^ 0x20);
|
|
nOffsetSize = 8;
|
|
}
|
|
else if (nMatchOffset <= (8192 + 512)) {
|
|
nTokenOffsetMode = 0x80 | ((((-(nMatchOffset - 512)) & 0x0100) >> 3) ^ 0x20);
|
|
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 < pCompressor->stats.min_literals || pCompressor->stats.min_literals == -1)
|
|
pCompressor->stats.min_literals = nNumLiterals;
|
|
if (nNumLiterals > pCompressor->stats.max_literals)
|
|
pCompressor->stats.max_literals = nNumLiterals;
|
|
pCompressor->stats.total_literals += nNumLiterals;
|
|
pCompressor->stats.literals_divisor++;
|
|
|
|
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) & 0x1e) >> 1);
|
|
if (nOutOffset < 0) return -1;
|
|
}
|
|
else if (nTokenOffsetMode == 0x40 || nTokenOffsetMode == 0x60) {
|
|
pOutData[nOutOffset++] = (-nMatchOffset) & 0xff;
|
|
}
|
|
else if (nTokenOffsetMode == 0x80 || nTokenOffsetMode == 0xa0) {
|
|
nOutOffset = lzsa_write_nibble_v2(pOutData, nOutOffset, nMaxOutDataSize, &nCurNibbleOffset, &nCurFreeNibbles, ((-(nMatchOffset - 512)) >> 9) & 0x0f);
|
|
if (nOutOffset < 0) return -1;
|
|
pOutData[nOutOffset++] = (-(nMatchOffset - 512)) & 0xff;
|
|
}
|
|
else if (nTokenOffsetMode == 0xc0) {
|
|
pOutData[nOutOffset++] = (-nMatchOffset) >> 8;
|
|
pOutData[nOutOffset++] = (-nMatchOffset) & 0xff;
|
|
}
|
|
|
|
if (nMatchOffset == nRepMatchOffset)
|
|
pCompressor->stats.num_rep_offsets++;
|
|
|
|
nRepMatchOffset = nMatchOffset;
|
|
|
|
nOutOffset = lzsa_write_match_varlen_v2(pOutData, nOutOffset, nMaxOutDataSize, &nCurNibbleOffset, &nCurFreeNibbles, nEncodedMatchLen);
|
|
if (nOutOffset < 0) return -1;
|
|
|
|
if (nMatchOffset < pCompressor->stats.min_offset || pCompressor->stats.min_offset == -1)
|
|
pCompressor->stats.min_offset = nMatchOffset;
|
|
if (nMatchOffset > pCompressor->stats.max_offset)
|
|
pCompressor->stats.max_offset = nMatchOffset;
|
|
pCompressor->stats.total_offsets += nMatchOffset;
|
|
|
|
if (nMatchLen < pCompressor->stats.min_match_len || pCompressor->stats.min_match_len == -1)
|
|
pCompressor->stats.min_match_len = nMatchLen;
|
|
if (nMatchLen > pCompressor->stats.max_match_len)
|
|
pCompressor->stats.max_match_len = nMatchLen;
|
|
pCompressor->stats.total_match_lens += nMatchLen;
|
|
pCompressor->stats.match_divisor++;
|
|
|
|
if (nMatchOffset == 1) {
|
|
if (nMatchLen < pCompressor->stats.min_rle1_len || pCompressor->stats.min_rle1_len == -1)
|
|
pCompressor->stats.min_rle1_len = nMatchLen;
|
|
if (nMatchLen > pCompressor->stats.max_rle1_len)
|
|
pCompressor->stats.max_rle1_len = nMatchLen;
|
|
pCompressor->stats.total_rle1_lens += nMatchLen;
|
|
pCompressor->stats.rle1_divisor++;
|
|
}
|
|
else if (nMatchOffset == 2) {
|
|
if (nMatchLen < pCompressor->stats.min_rle2_len || pCompressor->stats.min_rle2_len == -1)
|
|
pCompressor->stats.min_rle2_len = nMatchLen;
|
|
if (nMatchLen > pCompressor->stats.max_rle2_len)
|
|
pCompressor->stats.max_rle2_len = nMatchLen;
|
|
pCompressor->stats.total_rle2_lens += nMatchLen;
|
|
pCompressor->stats.rle2_divisor++;
|
|
}
|
|
|
|
i += nMatchLen;
|
|
|
|
if (pCompressor->flags & LZSA_FLAG_RAW_BLOCK) {
|
|
int nCurSafeDist = (i - nStartOffset) - nOutOffset;
|
|
if (nCurSafeDist >= 0 && pCompressor->safe_dist < nCurSafeDist)
|
|
pCompressor->safe_dist = nCurSafeDist;
|
|
}
|
|
|
|
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 < pCompressor->stats.min_literals || pCompressor->stats.min_literals == -1)
|
|
pCompressor->stats.min_literals = nNumLiterals;
|
|
if (nNumLiterals > pCompressor->stats.max_literals)
|
|
pCompressor->stats.max_literals = nNumLiterals;
|
|
pCompressor->stats.total_literals += nNumLiterals;
|
|
pCompressor->stats.literals_divisor++;
|
|
|
|
if (nNumLiterals != 0) {
|
|
memcpy(pOutData + nOutOffset, pInWindow + nInFirstLiteralOffset, nNumLiterals);
|
|
nOutOffset += nNumLiterals;
|
|
nNumLiterals = 0;
|
|
}
|
|
|
|
if (pCompressor->flags & LZSA_FLAG_RAW_BLOCK) {
|
|
int nCurSafeDist = (i - nStartOffset) - nOutOffset;
|
|
if (nCurSafeDist >= 0 && pCompressor->safe_dist < nCurSafeDist)
|
|
pCompressor->safe_dist = nCurSafeDist;
|
|
}
|
|
|
|
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 + 1) > nMaxOutDataSize)
|
|
return -1;
|
|
|
|
pOutData[nOutOffset++] = 232; /* EOD match length byte */
|
|
}
|
|
|
|
if (nCurNibbleOffset != -1) {
|
|
nOutOffset = lzsa_write_nibble_v2(pOutData, nOutOffset, nMaxOutDataSize, &nCurNibbleOffset, &nCurFreeNibbles, 0);
|
|
if (nOutOffset < 0 || nCurNibbleOffset != -1)
|
|
return -1;
|
|
}
|
|
|
|
return nOutOffset;
|
|
}
|
|
|
|
/**
|
|
* Emit raw block of uncompressible 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_raw_uncompressed_block_v2(lzsa_compressor *pCompressor, const unsigned char *pInWindow, const int nStartOffset, const int nEndOffset, unsigned char *pOutData, const int nMaxOutDataSize) {
|
|
int nCurNibbleOffset = -1, nCurFreeNibbles = 0;
|
|
int nNumLiterals = nEndOffset - nStartOffset;
|
|
int nTokenLiteralsLen = (nNumLiterals >= LITERALS_RUN_LEN_V2) ? LITERALS_RUN_LEN_V2 : nNumLiterals;
|
|
int nOutOffset = 0;
|
|
|
|
int nCommandSize = 8 /* token */ + lzsa_get_literals_varlen_size_v2(nNumLiterals) + (nNumLiterals << 3) + 8 + 4 + 8;
|
|
if ((nOutOffset + ((nCommandSize + 7) >> 3)) > nMaxOutDataSize)
|
|
return -1;
|
|
|
|
pCompressor->num_commands = 0;
|
|
pOutData[nOutOffset++] = (nTokenLiteralsLen << 3) | 0x47;
|
|
|
|
nOutOffset = lzsa_write_literals_varlen_v2(pOutData, nOutOffset, nMaxOutDataSize, &nCurNibbleOffset, &nCurFreeNibbles, nNumLiterals);
|
|
if (nOutOffset < 0) return -1;
|
|
|
|
if (nNumLiterals != 0) {
|
|
memcpy(pOutData + nOutOffset, pInWindow + nStartOffset, nNumLiterals);
|
|
nOutOffset += nNumLiterals;
|
|
nNumLiterals = 0;
|
|
}
|
|
|
|
/* Emit EOD marker for raw block */
|
|
|
|
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 + 1) > nMaxOutDataSize)
|
|
return -1;
|
|
|
|
pOutData[nOutOffset++] = 232; /* EOD match length byte */
|
|
|
|
pCompressor->num_commands++;
|
|
|
|
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 nPreviousBlockSize number of previously compressed bytes (or 0 for none)
|
|
* @param nInDataSize number of input bytes to compress
|
|
* @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(lzsa_compressor *pCompressor, const unsigned char *pInWindow, const int nPreviousBlockSize, const int nInDataSize, unsigned char *pOutData, const int nMaxOutDataSize) {
|
|
int nResult, nBaseCompressedSize;
|
|
int nMatchesPerArrival = (nInDataSize < 65536) ? NMATCHES_PER_ARRIVAL_BIG : NMATCHES_PER_ARRIVAL_SMALL;
|
|
|
|
/* Compress optimally without breaking ties in favor of less tokens */
|
|
|
|
memset(pCompressor->best_match, 0, BLOCK_SIZE * sizeof(lzsa_match));
|
|
lzsa_optimize_forward_v2(pCompressor, pInWindow, pCompressor->best_match - nPreviousBlockSize, nPreviousBlockSize, nPreviousBlockSize + nInDataSize, 0 /* reduce */, (nInDataSize < 65536) ? 1 : 0 /* insert forward reps */, nMatchesPerArrival);
|
|
if (nInDataSize < 65536)
|
|
lzsa_optimize_forward_v2(pCompressor, pInWindow, pCompressor->best_match - nPreviousBlockSize, nPreviousBlockSize, nPreviousBlockSize + nInDataSize, 0 /* reduce */, 1 /* insert forward reps */, nMatchesPerArrival);
|
|
|
|
int nDidReduce;
|
|
int nPasses = 0;
|
|
do {
|
|
nDidReduce = lzsa_optimize_command_count_v2(pCompressor, pInWindow, pCompressor->best_match - nPreviousBlockSize, nPreviousBlockSize, nPreviousBlockSize + nInDataSize);
|
|
nPasses++;
|
|
} while (nDidReduce && nPasses < 20);
|
|
|
|
nBaseCompressedSize = lzsa_get_compressed_size_v2(pCompressor, pCompressor->best_match - nPreviousBlockSize, nPreviousBlockSize, nPreviousBlockSize + nInDataSize);
|
|
lzsa_match *pBestMatch = pCompressor->best_match - nPreviousBlockSize;
|
|
|
|
if (nBaseCompressedSize > 0 && nInDataSize < 65536) {
|
|
int nReducedCompressedSize;
|
|
|
|
/* Compress optimally and do break ties in favor of less tokens */
|
|
memset(pCompressor->improved_match, 0, BLOCK_SIZE * sizeof(lzsa_match));
|
|
lzsa_optimize_forward_v2(pCompressor, pInWindow, pCompressor->improved_match - nPreviousBlockSize, nPreviousBlockSize, nPreviousBlockSize + nInDataSize, 1 /* reduce */, 0 /* use forward reps */, nMatchesPerArrival);
|
|
|
|
nPasses = 0;
|
|
do {
|
|
nDidReduce = lzsa_optimize_command_count_v2(pCompressor, pInWindow, pCompressor->improved_match - nPreviousBlockSize, nPreviousBlockSize, nPreviousBlockSize + nInDataSize);
|
|
nPasses++;
|
|
} while (nDidReduce && nPasses < 20);
|
|
|
|
nReducedCompressedSize = lzsa_get_compressed_size_v2(pCompressor, pCompressor->improved_match - nPreviousBlockSize, nPreviousBlockSize, nPreviousBlockSize + nInDataSize);
|
|
if (nReducedCompressedSize > 0 && nReducedCompressedSize <= nBaseCompressedSize) {
|
|
/* Pick the parse with the reduced number of tokens as it didn't negatively affect the size */
|
|
pBestMatch = pCompressor->improved_match - nPreviousBlockSize;
|
|
}
|
|
}
|
|
|
|
nResult = lzsa_write_block_v2(pCompressor, pBestMatch, pInWindow, nPreviousBlockSize, nPreviousBlockSize + nInDataSize, pOutData, nMaxOutDataSize);
|
|
if (nResult < 0 && pCompressor->flags & LZSA_FLAG_RAW_BLOCK) {
|
|
nResult = lzsa_write_raw_uncompressed_block_v2(pCompressor, pInWindow, nPreviousBlockSize, nPreviousBlockSize + nInDataSize, pOutData, nMaxOutDataSize);
|
|
}
|
|
|
|
return nResult;
|
|
}
|