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lzsa/src/shrink_block_v2.c

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/*
* shrink_block_v2.c - LZSA2 block compressor implementation
*
* Copyright (C) 2019 Emmanuel Marty
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
*
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
*
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
/*
* Uses the libdivsufsort library Copyright (c) 2003-2008 Yuta Mori
*
* Inspired by LZ4 by Yann Collet. https://github.com/lz4/lz4
* With help, ideas, optimizations and speed measurements by spke <zxintrospec@gmail.com>
* With ideas from Lizard by Przemyslaw Skibinski and Yann Collet. https://github.com/inikep/lizard
* Also with ideas from smallz4 by Stephan Brumme. https://create.stephan-brumme.com/smallz4/
*
*/
#include <stdlib.h>
#include <string.h>
#include "lib.h"
#include "shrink_block_v2.h"
#include "format.h"
/**
* Write 4-bit nibble to output (compressed) buffer
*
* @param pOutData pointer to output buffer
* @param nOutOffset current write index into output buffer
* @param nMaxOutDataSize maximum size of output buffer, in bytes
* @param nCurNibbleOffset write index into output buffer, of current byte being filled with nibbles
* @param nNibbleValue value to write (0..15)
*
* @return updated write index into output buffer
*/
static int lzsa_write_nibble_v2(unsigned char *pOutData, int nOutOffset, const int nMaxOutDataSize, int *nCurNibbleOffset, const int nNibbleValue) {
if (nOutOffset >= 0) {
if ((*nCurNibbleOffset) == -1) {
if (nOutOffset >= nMaxOutDataSize) return -1;
(*nCurNibbleOffset) = nOutOffset;
pOutData[nOutOffset++] = nNibbleValue << 4;
}
else {
pOutData[*nCurNibbleOffset] |= (nNibbleValue & 0x0f);
(*nCurNibbleOffset) = -1;
}
}
return nOutOffset;
}
/**
* Get the number of extra bits required to represent a literals length
*
* @param nLength literals length
*
* @return number of extra bits required
*/
static inline int lzsa_get_literals_varlen_size_v2(const int nLength) {
if (nLength < LITERALS_RUN_LEN_V2) {
return 0;
}
else {
if (nLength < (LITERALS_RUN_LEN_V2 + 15)) {
return 4;
}
else {
if (nLength < 256)
return 4 + 8;
else {
return 4 + 24;
}
}
}
}
/**
* Write extra literals length bytes to output (compressed) buffer. The caller must first check that there is enough
* room to write the bytes.
*
* @param pOutData pointer to output buffer
* @param nOutOffset current write index into output buffer
* @param nMaxOutDataSize maximum size of output buffer, in bytes
* @param nCurNibbleOffset write index into output buffer, of current byte being filled with nibbles
* @param nLength literals length
*
* @return updated write index into output buffer
*/
static inline int lzsa_write_literals_varlen_v2(unsigned char *pOutData, int nOutOffset, const int nMaxOutDataSize, int *nCurNibbleOffset, const int nLength) {
if (nLength >= LITERALS_RUN_LEN_V2) {
if (nLength < (LITERALS_RUN_LEN_V2 + 15)) {
nOutOffset = lzsa_write_nibble_v2(pOutData, nOutOffset, nMaxOutDataSize, nCurNibbleOffset, nLength - LITERALS_RUN_LEN_V2);
}
else {
nOutOffset = lzsa_write_nibble_v2(pOutData, nOutOffset, nMaxOutDataSize, nCurNibbleOffset, 15);
if (nOutOffset < 0) return -1;
if (nLength < 256)
pOutData[nOutOffset++] = nLength - 18;
else {
pOutData[nOutOffset++] = 239;
pOutData[nOutOffset++] = nLength & 0xff;
pOutData[nOutOffset++] = (nLength >> 8) & 0xff;
}
}
}
return nOutOffset;
}
/**
* Get the number of extra bits required to represent an encoded match length
*
* @param nLength encoded match length (actual match length - MIN_MATCH_SIZE_V2)
*
* @return number of extra bits required
*/
static inline int lzsa_get_match_varlen_size_v2(const int nLength) {
if (nLength < MATCH_RUN_LEN_V2) {
return 0;
}
else {
if (nLength < (MATCH_RUN_LEN_V2 + 15))
return 4;
else {
if ((nLength + MIN_MATCH_SIZE_V2) < 256)
return 4 + 8;
else {
return 4 + 24;
}
}
}
}
/**
* Write extra encoded match length bytes to output (compressed) buffer. The caller must first check that there is enough
* room to write the bytes.
*
* @param pOutData pointer to output buffer
* @param nOutOffset current write index into output buffer
* @param nMaxOutDataSize maximum size of output buffer, in bytes
* @param nCurNibbleOffset write index into output buffer, of current byte being filled with nibbles
* @param nLength encoded match length (actual match length - MIN_MATCH_SIZE_V2)
*
* @return updated write index into output buffer
*/
static inline int lzsa_write_match_varlen_v2(unsigned char *pOutData, int nOutOffset, const int nMaxOutDataSize, int *nCurNibbleOffset, const int nLength) {
if (nLength >= MATCH_RUN_LEN_V2) {
if (nLength < (MATCH_RUN_LEN_V2 + 15)) {
nOutOffset = lzsa_write_nibble_v2(pOutData, nOutOffset, nMaxOutDataSize, nCurNibbleOffset, nLength - MATCH_RUN_LEN_V2);
}
else {
nOutOffset = lzsa_write_nibble_v2(pOutData, nOutOffset, nMaxOutDataSize, nCurNibbleOffset, 15);
if (nOutOffset < 0) return -1;
if ((nLength + MIN_MATCH_SIZE_V2) < 256)
pOutData[nOutOffset++] = nLength + MIN_MATCH_SIZE_V2 - 24;
else {
pOutData[nOutOffset++] = 233;
pOutData[nOutOffset++] = (nLength + MIN_MATCH_SIZE_V2) & 0xff;
pOutData[nOutOffset++] = ((nLength + MIN_MATCH_SIZE_V2) >> 8) & 0xff;
}
}
}
return nOutOffset;
}
/**
* Insert forward rep candidate
*
* @param pCompressor compression context
* @param pInWindow pointer to input data window (previously compressed bytes + bytes to compress)
* @param i input data window position whose matches are being considered
* @param nMatchOffset match offset to use as rep candidate
* @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 nDepth current insertion depth
*/
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 nDepth) {
const lzsa_arrival *arrival = pCompressor->arrival + ((i - nStartOffset) << ARRIVALS_PER_POSITION_SHIFT_V2);
const int *rle_len = (const int*)pCompressor->intervals /* reuse */;
lzsa_match* visited = ((lzsa_match*)pCompressor->pos_data) - nStartOffset /* reuse */;
int j;
for (j = 0; j < NARRIVALS_PER_POSITION_V2_BIG && arrival[j].from_slot; j++) {
const int nRepOffset = arrival[j].rep_offset;
if (nMatchOffset != nRepOffset) {
const int nRepLen = arrival[j].rep_len;
const int nRepPos = arrival[j].rep_pos;
if (nRepPos >= nStartOffset &&
(nRepPos + nRepLen) <= nEndOffset) {
if (visited[nRepPos].offset != nMatchOffset || visited[nRepPos].length > nRepLen) {
visited[nRepPos].length = 0;
visited[nRepPos].offset = nMatchOffset;
lzsa_match* fwd_match = pCompressor->match + ((nRepPos - nStartOffset) << MATCHES_PER_INDEX_SHIFT_V2);
if (fwd_match[NMATCHES_PER_INDEX_V2 - 1].length == 0) {
if (nRepPos >= nMatchOffset) {
const unsigned char* pInWindowStart = pInWindow + nRepPos;
if (!memcmp(pInWindowStart, pInWindowStart - nMatchOffset, 2)) {
const int nLen0 = rle_len[nRepPos - nMatchOffset];
const int nLen1 = rle_len[nRepPos];
const int nMinLen = (nLen0 < nLen1) ? nLen0 : nLen1;
if (nMinLen >= nRepLen || !memcmp(pInWindowStart + nMinLen, pInWindowStart + nMinLen - nMatchOffset, nRepLen - nMinLen)) {
int r;
for (r = 0; fwd_match[r].length; r++) {
if (fwd_match[r].offset == nMatchOffset) {
break;
}
}
if (fwd_match[r].length == 0) {
if (nRepLen >= MIN_MATCH_SIZE_V2) {
if (nRepOffset) {
int nMaxRepLen = nEndOffset - nRepPos;
if (nMaxRepLen > LCP_MAX)
nMaxRepLen = LCP_MAX;
const int nCurRepLen = (nMinLen > nRepLen) ? nMinLen : nRepLen;
const unsigned char* pInWindowMax = pInWindowStart + nMaxRepLen;
const unsigned char* pInWindowAtRepPos = pInWindowStart + nCurRepLen;
if (pInWindowAtRepPos > pInWindowMax)
pInWindowAtRepPos = pInWindowMax;
while ((pInWindowAtRepPos + 8) < pInWindowMax && !memcmp(pInWindowAtRepPos, pInWindowAtRepPos - nMatchOffset, 8))
pInWindowAtRepPos += 8;
while ((pInWindowAtRepPos + 4) < pInWindowMax && !memcmp(pInWindowAtRepPos, pInWindowAtRepPos - nMatchOffset, 4))
pInWindowAtRepPos += 4;
while (pInWindowAtRepPos < pInWindowMax && pInWindowAtRepPos[0] == pInWindowAtRepPos[-nMatchOffset])
pInWindowAtRepPos++;
fwd_match[r].length = (const unsigned short)(pInWindowAtRepPos - pInWindowStart);
fwd_match[r].offset = nMatchOffset;
if (nDepth < 9)
lzsa_insert_forward_match_v2(pCompressor, pInWindow, nRepPos, nMatchOffset, nStartOffset, nEndOffset, nDepth + 1);
}
}
}
}
else {
visited[nRepPos].length = nRepLen;
}
}
}
}
}
}
}
}
}
/**
* Attempt to pick optimal matches using a forward arrivals parser, so as to produce the smallest possible output that decompresses to the same input
*
* @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 nReduce non-zero to reduce the number of tokens when the path costs are equal, zero not to
* @param nInsertForwardReps non-zero to insert forward repmatch candidates, zero to use the previously inserted candidates
* @param nArrivalsPerPosition number of arrivals to record per input buffer position
*/
static void lzsa_optimize_forward_v2(lzsa_compressor *pCompressor, const unsigned char *pInWindow, const int nStartOffset, const int nEndOffset, const int nReduce, const int nInsertForwardReps, const int nArrivalsPerPosition) {
lzsa_arrival *arrival = pCompressor->arrival - (nStartOffset << ARRIVALS_PER_POSITION_SHIFT_V2);
const int *rle_len = (const int*)pCompressor->intervals /* reuse */;
lzsa_match *visited = ((lzsa_match*)pCompressor->pos_data) - nStartOffset /* reuse */;
unsigned char *nRepSlotHandledMask = pCompressor->rep_slot_handled_mask;
unsigned char *nRepLenHandledMask = pCompressor->rep_len_handled_mask;
const int nModeSwitchPenalty = (pCompressor->flags & LZSA_FLAG_FAVOR_RATIO) ? 0 : MODESWITCH_PENALTY;
const int nMinMatchSize = pCompressor->min_match_size;
const int nDisableScore = nReduce ? 0 : (2 * BLOCK_SIZE);
const int nMaxRepInsertedLen = nReduce ? LEAVE_ALONE_MATCH_SIZE : 0;
const int nLeaveAloneMatchSize = (nArrivalsPerPosition == NARRIVALS_PER_POSITION_V2_SMALL) ? LEAVE_ALONE_MATCH_SIZE_SMALL : LEAVE_ALONE_MATCH_SIZE;
int i;
if ((nEndOffset - nStartOffset) > BLOCK_SIZE) return;
for (i = (nStartOffset << ARRIVALS_PER_POSITION_SHIFT_V2); i != ((nEndOffset + 1) << ARRIVALS_PER_POSITION_SHIFT_V2); i += NARRIVALS_PER_POSITION_V2_MAX) {
lzsa_arrival *cur_arrival = &arrival[i];
int j;
memset(cur_arrival, 0, sizeof(lzsa_arrival) * NARRIVALS_PER_POSITION_V2_MAX);
for (j = 0; j < NARRIVALS_PER_POSITION_V2_MAX; j++)
cur_arrival[j].cost = 0x40000000;
}
arrival[nStartOffset << ARRIVALS_PER_POSITION_SHIFT_V2].cost = 0;
arrival[nStartOffset << ARRIVALS_PER_POSITION_SHIFT_V2].from_slot = -1;
if (nInsertForwardReps) {
memset(visited + nStartOffset, 0, (nEndOffset - nStartOffset) * sizeof(lzsa_match));
}
for (i = nStartOffset; i != nEndOffset; i++) {
lzsa_arrival *cur_arrival = &arrival[i << ARRIVALS_PER_POSITION_SHIFT_V2];
lzsa_arrival *pDestLiteralSlots = &cur_arrival[NARRIVALS_PER_POSITION_V2_MAX];
int j, m;
for (j = 0; j < nArrivalsPerPosition && cur_arrival[j].from_slot; j++) {
const int nPrevCost = cur_arrival[j].cost;
int nCodingChoiceCost = nPrevCost + 8 /* literal */;
const int nScore = cur_arrival[j].score + 1 - nDisableScore;
const int nNumLiterals = cur_arrival[j].num_literals + 1;
const int nRepOffset = cur_arrival[j].rep_offset;
switch (nNumLiterals) {
case 1:
nCodingChoiceCost += nModeSwitchPenalty;
break;
case LITERALS_RUN_LEN_V2:
nCodingChoiceCost += 4;
break;
case LITERALS_RUN_LEN_V2 + 15:
nCodingChoiceCost += 8;
break;
case 256:
nCodingChoiceCost += 16;
break;
default:
break;
}
if (nCodingChoiceCost < pDestLiteralSlots[nArrivalsPerPosition - 1].cost ||
(nCodingChoiceCost == pDestLiteralSlots[nArrivalsPerPosition - 1].cost && nScore < pDestLiteralSlots[nArrivalsPerPosition - 1].score &&
nRepOffset != pDestLiteralSlots[nArrivalsPerPosition - 1].rep_offset)) {
int exists = 0, n;
for (n = 0;
pDestLiteralSlots[n].cost < nCodingChoiceCost;
n++) {
if (pDestLiteralSlots[n].rep_offset == nRepOffset) {
exists = 1;
break;
}
}
if (!exists) {
for (;
n < nArrivalsPerPosition && pDestLiteralSlots[n].cost == nCodingChoiceCost && nScore >= pDestLiteralSlots[n].score;
n++) {
if (pDestLiteralSlots[n].rep_offset == nRepOffset) {
exists = 1;
break;
}
}
if (!exists) {
if (n < nArrivalsPerPosition) {
int z;
for (z = n;
z < nArrivalsPerPosition - 1 && pDestLiteralSlots[z].cost == nCodingChoiceCost;
z++) {
if (pDestLiteralSlots[z].rep_offset == nRepOffset) {
exists = 1;
break;
}
}
if (!exists) {
for (; z < nArrivalsPerPosition - 1 && pDestLiteralSlots[z].from_slot; z++) {
if (pDestLiteralSlots[z].rep_offset == nRepOffset)
break;
}
memmove(&pDestLiteralSlots[n + 1],
&pDestLiteralSlots[n],
sizeof(lzsa_arrival) * (z - n));
lzsa_arrival* pDestArrival = &pDestLiteralSlots[n];
pDestArrival->cost = nCodingChoiceCost;
pDestArrival->rep_offset = nRepOffset;
pDestArrival->from_slot = j + 1;
pDestArrival->from_pos = i - nStartOffset;
pDestArrival->rep_len = cur_arrival[j].rep_len;
pDestArrival->match_len = 0;
pDestArrival->num_literals = nNumLiterals;
pDestArrival->rep_pos = cur_arrival[j].rep_pos;
pDestArrival->score = nScore + nDisableScore;
}
}
}
}
}
}
const lzsa_match *match = pCompressor->match + ((i - nStartOffset) << MATCHES_PER_INDEX_SHIFT_V2);
const int nNumArrivalsForThisPos = j;
int nMinOverallRepLen = 0, nMaxOverallRepLen = 0;
int nRepMatchArrivalIdxAndLen[(NARRIVALS_PER_POSITION_V2_MAX * 2) + 1];
int nNumRepMatchArrivals = 0;
if ((i + MIN_MATCH_SIZE_V2) <= nEndOffset) {
int nMaxRepLenForPos = nEndOffset - i;
if (nMaxRepLenForPos > LCP_MAX)
nMaxRepLenForPos = LCP_MAX;
const unsigned char* pInWindowStart = pInWindow + i;
const unsigned char* pInWindowMax = pInWindowStart + nMaxRepLenForPos;
for (j = 0; j < nNumArrivalsForThisPos; j++) {
const int nRepOffset = cur_arrival[j].rep_offset;
if (i >= nRepOffset) {
if (!memcmp(pInWindowStart, pInWindowStart - nRepOffset, MIN_MATCH_SIZE_V2)) {
if (nRepOffset) {
const unsigned char* pInWindowAtPos;
const int nLen0 = rle_len[i - nRepOffset];
const int nLen1 = rle_len[i];
int nMinLen = (nLen0 < nLen1) ? nLen0 : nLen1;
if (nMinLen > nMaxRepLenForPos)
nMinLen = nMaxRepLenForPos;
pInWindowAtPos = pInWindowStart + nMinLen;
while ((pInWindowAtPos + 8) < pInWindowMax && !memcmp(pInWindowAtPos, pInWindowAtPos - nRepOffset, 8))
pInWindowAtPos += 8;
while ((pInWindowAtPos + 4) < pInWindowMax && !memcmp(pInWindowAtPos, pInWindowAtPos - nRepOffset, 4))
pInWindowAtPos += 4;
while (pInWindowAtPos < pInWindowMax && pInWindowAtPos[0] == pInWindowAtPos[-nRepOffset])
pInWindowAtPos++;
const int nCurRepLen = (const int)(pInWindowAtPos - pInWindowStart);
if (nMaxOverallRepLen < nCurRepLen)
nMaxOverallRepLen = nCurRepLen;
nRepMatchArrivalIdxAndLen[nNumRepMatchArrivals++] = j;
nRepMatchArrivalIdxAndLen[nNumRepMatchArrivals++] = nCurRepLen;
}
}
}
}
}
nRepMatchArrivalIdxAndLen[nNumRepMatchArrivals] = -1;
if (!nReduce) {
memset(nRepSlotHandledMask, 0, nArrivalsPerPosition * ((LCP_MAX + 1) / 8) * sizeof(unsigned char));
}
memset(nRepLenHandledMask, 0, ((LCP_MAX + 1) / 8) * sizeof(unsigned char));
for (m = 0; m < NMATCHES_PER_INDEX_V2 && match[m].length; m++) {
int nMatchLen = match[m].length & 0x7fff;
const int nMatchOffset = match[m].offset;
int nNoRepmatchOffsetCost = 0, nNoRepmatchScore = 0;
int nStartingMatchLen, k;
if ((i + nMatchLen) > nEndOffset)
nMatchLen = nEndOffset - i;
if (nInsertForwardReps)
lzsa_insert_forward_match_v2(pCompressor, pInWindow, i, nMatchOffset, nStartOffset, nEndOffset, 0);
int nNonRepMatchArrivalIdx = -1;
for (j = 0; j < nNumArrivalsForThisPos; j++) {
if (nMatchOffset != cur_arrival[j].rep_offset) {
const int nPrevCost = cur_arrival[j].cost;
const int nScorePenalty = 3 + (match[m].length >> 15);
nNoRepmatchOffsetCost = nPrevCost /* the actual cost of the literals themselves accumulates up the chain */;
if (!cur_arrival[j].num_literals)
nNoRepmatchOffsetCost += nModeSwitchPenalty;
nNoRepmatchOffsetCost += (nMatchOffset <= 32) ? 4 : ((nMatchOffset <= 512) ? 8 : ((nMatchOffset <= (8192 + 512)) ? 12 : 16));
nNoRepmatchScore = cur_arrival[j].score + nScorePenalty - nDisableScore;
nNonRepMatchArrivalIdx = j;
break;
}
}
int nMatchLenCost;
if (nMatchLen >= nLeaveAloneMatchSize) {
nStartingMatchLen = nMatchLen;
nMatchLenCost = 4 + 24 + 8 /* token */;
}
else {
nStartingMatchLen = nMinMatchSize;
nMatchLenCost = /* 0 + */ 8 /* token */;
}
for (k = nStartingMatchLen; k <= nMatchLen; k++) {
if (k == (MATCH_RUN_LEN_V2 + MIN_MATCH_SIZE_V2)) {
nMatchLenCost = 4 + 8 /* token */;
}
else {
if (k == (MATCH_RUN_LEN_V2 + 15 + MIN_MATCH_SIZE_V2))
nMatchLenCost = 4 + 8 + 8 /* token */;
else {
if (k == 256)
nMatchLenCost = 4 + 24 + 8 /* token */;
}
}
lzsa_arrival *pDestSlots = &cur_arrival[k << ARRIVALS_PER_POSITION_SHIFT_V2];
/* Insert non-repmatch candidate */
if (nNonRepMatchArrivalIdx >= 0) {
const int nCodingChoiceCost = nMatchLenCost + nNoRepmatchOffsetCost;
if (nCodingChoiceCost < pDestSlots[nArrivalsPerPosition - 2].cost ||
(nCodingChoiceCost == pDestSlots[nArrivalsPerPosition - 2].cost && nNoRepmatchScore < pDestSlots[nArrivalsPerPosition - 2].score &&
(nCodingChoiceCost != pDestSlots[nArrivalsPerPosition - 1].cost || nMatchOffset != pDestSlots[nArrivalsPerPosition - 1].rep_offset))) {
int exists = 0, n;
for (n = 0;
pDestSlots[n].cost < nCodingChoiceCost;
n++) {
if (pDestSlots[n].rep_offset == nMatchOffset) {
exists = 1;
break;
}
}
if (!exists) {
for (;
n < nArrivalsPerPosition && pDestSlots[n].cost == nCodingChoiceCost && nNoRepmatchScore >= pDestSlots[n].score;
n++) {
if (pDestSlots[n].rep_offset == nMatchOffset) {
exists = 1;
break;
}
}
if (!exists) {
if (n < nArrivalsPerPosition - 1) {
int z;
for (z = n;
z < nArrivalsPerPosition - 1 && pDestSlots[z].cost == nCodingChoiceCost;
z++) {
if (pDestSlots[z].rep_offset == nMatchOffset) {
if (!nInsertForwardReps || pDestSlots[nArrivalsPerPosition - 1].from_slot || pDestSlots[z].rep_pos >= i) {
exists = 1;
}
break;
}
}
if (!exists) {
for (; z < nArrivalsPerPosition - 1 && pDestSlots[z].from_slot; z++) {
if (pDestSlots[z].rep_offset == nMatchOffset)
break;
}
memmove(&pDestSlots[n + 1],
&pDestSlots[n],
sizeof(lzsa_arrival) * (z - n));
lzsa_arrival* pDestArrival = &pDestSlots[n];
pDestArrival->cost = nCodingChoiceCost;
pDestArrival->rep_offset = nMatchOffset;
pDestArrival->from_slot = nNonRepMatchArrivalIdx + 1;
pDestArrival->from_pos = i - nStartOffset;
pDestArrival->rep_len = k;
pDestArrival->match_len = k;
pDestArrival->num_literals = 0;
pDestArrival->rep_pos = i;
pDestArrival->score = nNoRepmatchScore + nDisableScore;
nRepLenHandledMask[k >> 3] &= ~((1 ^ nReduce) << (k & 7));
}
}
}
}
}
}
/* Insert repmatch candidates */
if (k > nMinOverallRepLen && k <= nMaxOverallRepLen && (nRepLenHandledMask[k >> 3] & (1 << (k & 7))) == 0) {
int nCurRepMatchArrival;
nRepLenHandledMask[k >> 3] |= 1 << (k & 7);
for (nCurRepMatchArrival = 0; (j = nRepMatchArrivalIdxAndLen[nCurRepMatchArrival]) >= 0; nCurRepMatchArrival += 2) {
if (nRepMatchArrivalIdxAndLen[nCurRepMatchArrival + 1] >= k) {
const int nMaskOffset = (j << 7) + (k >> 3);
if (nReduce || !(nRepSlotHandledMask[nMaskOffset] & (1 << (k & 7)))) {
const int nScore = cur_arrival[j].score + 2 - nDisableScore;
const int nRepOffset = cur_arrival[j].rep_offset;
if (nRepOffset != pDestSlots[nArrivalsPerPosition - 1].rep_offset) {
const int nPrevCost = cur_arrival[j].cost;
const int nRepCodingChoiceCost = nPrevCost /* the actual cost of the literals themselves accumulates up the chain */ + nMatchLenCost;
if (nRepCodingChoiceCost < pDestSlots[nArrivalsPerPosition - 1].cost ||
(nRepCodingChoiceCost == pDestSlots[nArrivalsPerPosition - 1].cost && nScore < pDestSlots[nArrivalsPerPosition - 1].score)) {
int exists = 0, n;
for (n = 0;
pDestSlots[n].cost < nRepCodingChoiceCost;
n++) {
if (pDestSlots[n].rep_offset == nRepOffset) {
exists = 1;
if (!nReduce)
nRepSlotHandledMask[nMaskOffset] |= 1 << (k & 7);
break;
}
}
if (!exists) {
for (;
n < nArrivalsPerPosition && pDestSlots[n].cost == nRepCodingChoiceCost && nScore >= pDestSlots[n].score;
n++) {
if (pDestSlots[n].rep_offset == nRepOffset) {
exists = 1;
break;
}
}
if (!exists) {
if (n < nArrivalsPerPosition) {
int z;
for (z = n;
z < nArrivalsPerPosition - 1 && pDestSlots[z].cost == nRepCodingChoiceCost;
z++) {
if (pDestSlots[z].rep_offset == nRepOffset) {
exists = 1;
break;
}
}
if (!exists) {
for (; z < nArrivalsPerPosition - 1 && pDestSlots[z].from_slot; z++) {
if (pDestSlots[z].rep_offset == nRepOffset)
break;
}
memmove(&pDestSlots[n + 1],
&pDestSlots[n],
sizeof(lzsa_arrival) * (z - n));
lzsa_arrival* pDestArrival = &pDestSlots[n];
pDestArrival->cost = nRepCodingChoiceCost;
pDestArrival->rep_offset = nRepOffset;
pDestArrival->from_slot = j + 1;
pDestArrival->from_pos = i - nStartOffset;
pDestArrival->rep_len = k;
pDestArrival->match_len = k;
pDestArrival->num_literals = 0;
pDestArrival->rep_pos = i;
pDestArrival->score = nScore + nDisableScore;
nRepLenHandledMask[k >> 3] &= ~((1 ^ nReduce) << (k & 7));
}
}
}
}
}
else {
break;
}
}
}
}
}
if (k < nMaxRepInsertedLen)
nMinOverallRepLen = k;
}
}
if (nMatchLen >= LCP_MAX && ((m + 1) >= NMATCHES_PER_INDEX_V2 || (match[m + 1].length & 0x7fff) < LCP_MAX))
break;
}
}
if (!nInsertForwardReps) {
const lzsa_arrival* end_arrival = &arrival[i << ARRIVALS_PER_POSITION_SHIFT_V2];
lzsa_match* pBestMatch = pCompressor->best_match - nStartOffset;
while (end_arrival->from_slot > 0 && (end_arrival->from_pos + nStartOffset) < nEndOffset) {
pBestMatch[end_arrival->from_pos + nStartOffset].length = end_arrival->match_len;
pBestMatch[end_arrival->from_pos + nStartOffset].offset = (end_arrival->match_len) ? end_arrival->rep_offset : 0;
end_arrival = &arrival[((end_arrival->from_pos + nStartOffset) << ARRIVALS_PER_POSITION_SHIFT_V2) + (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 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, const int nStartOffset, const int nEndOffset) {
lzsa_match* pBestMatch = pCompressor->best_match - nStartOffset;
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 &&
pBestMatch[i + 1].length >= MIN_MATCH_SIZE_V2 &&
pBestMatch[i + 1].length < MAX_VARLEN &&
pBestMatch[i + 1].offset &&
i >= pBestMatch[i + 1].offset &&
(i + pBestMatch[i + 1].length + 1) <= nEndOffset &&
!memcmp(pInWindow + i - (pBestMatch[i + 1].offset), pInWindow + i, pBestMatch[i + 1].length + 1)) {
const int nCurLenSize = lzsa_get_match_varlen_size_v2(pBestMatch[i + 1].length - MIN_MATCH_SIZE_V2);
const int nReducedLenSize = lzsa_get_match_varlen_size_v2(pBestMatch[i + 1].length + 1 - MIN_MATCH_SIZE_V2);
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) {
/* 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 ||
((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 &&
!memcmp(pInWindow + i - nRepMatchOffset, pInWindow + i, pMatch->length)) {
pMatch->offset = nRepMatchOffset;
nDidReduce = 1;
}
}
if (pBestMatch[nNextIndex].offset && pMatch->offset != pBestMatch[nNextIndex].offset) {
/* Otherwise, try to gain a match forward as well */
if (i >= pBestMatch[nNextIndex].offset && (i + pMatch->length) <= nEndOffset) {
int nMaxLen = 0;
const unsigned char *pInWindowAtPos = pInWindow + i;
while ((nMaxLen + 8) < pMatch->length && !memcmp(pInWindowAtPos + nMaxLen - pBestMatch[nNextIndex].offset, pInWindowAtPos + nMaxLen, 8))
nMaxLen += 8;
while ((nMaxLen + 4) < pMatch->length && !memcmp(pInWindowAtPos + nMaxLen - pBestMatch[nNextIndex].offset, pInWindowAtPos + nMaxLen, 4))
nMaxLen += 4;
while (nMaxLen < pMatch->length && pInWindowAtPos[nMaxLen - pBestMatch[nNextIndex].offset] == pInWindowAtPos[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);
nPartialSizeBefore += (pBestMatch[nNextIndex].offset <= 32) ? 4 : ((pBestMatch[nNextIndex].offset <= 512) ? 8 : ((pBestMatch[nNextIndex].offset <= (8192 + 512)) ? 12 : 16));
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 (nRepMatchOffset != pBestMatch[nNextIndex].offset)
nPartialSizeAfter += (pBestMatch[nNextIndex].offset <= 32) ? 4 : ((pBestMatch[nNextIndex].offset <= 512) ? 8 : ((pBestMatch[nNextIndex].offset <= (8192 + 512)) ? 12 : 16));
if (nPartialSizeAfter < nPartialSizeBefore) {
const int nMatchLen = pMatch->length;
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->length = nMaxLen;
pMatch->offset = pBestMatch[nNextIndex].offset;
for (j = nMaxLen; j < nMatchLen; j++) {
pBestMatch[i + j].length = 0;
}
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));
const 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 &&
!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 */
const 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 && pMatch->length >= MIN_MATCH_SIZE_V2 &&
pBestMatch[i + pMatch->length].offset &&
pBestMatch[i + pMatch->length].length >= MIN_MATCH_SIZE_V2 &&
(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;
while (nNextIndex < nEndOffset && pBestMatch[nNextIndex].length < MIN_MATCH_SIZE_V2) {
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));
int nReducedPartialSize = lzsa_get_match_varlen_size_v2(pMatch->length + pBestMatch[i + pMatch->length].length - MIN_MATCH_SIZE_V2);
if (nNextIndex < nEndOffset) {
const int nNextOffset = pBestMatch[nNextIndex].offset;
if (nNextOffset != pBestMatch[i + pMatch->length].offset)
nCurPartialSize += (nNextOffset <= 32) ? 4 : ((nNextOffset <= 512) ? 8 : ((nNextOffset <= (8192 + 512)) ? 12 : 16));
if (nNextOffset != pMatch->offset)
nReducedPartialSize += (nNextOffset <= 32) ? 4 : ((nNextOffset <= 512) ? 8 : ((nNextOffset <= (8192 + 512)) ? 12 : 16));
}
if (nCurPartialSize >= nReducedPartialSize) {
const int nMatchLen = pMatch->length;
/* Join */
pMatch->length += pBestMatch[i + nMatchLen].length;
pBestMatch[i + nMatchLen].length = 0;
pBestMatch[i + nMatchLen].offset = 0;
nDidReduce = 1;
continue;
}
}
nPrevRepMatchOffset = nRepMatchOffset;
nRepMatchLen = pMatch->length;
nRepMatchOffset = pMatch->offset;
nRepIndex = i;
i += pMatch->length;
nNumLiterals = 0;
}
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(lzsa_compressor *pCompressor, const unsigned char *pInWindow, const int nStartOffset, const int nEndOffset, unsigned char *pOutData, const int nMaxOutDataSize) {
const lzsa_match *pBestMatch = pCompressor->best_match - nStartOffset;
int i;
int nNumLiterals = 0;
int nInFirstLiteralOffset = 0;
int nOutOffset = 0;
int nCurNibbleOffset = -1;
int nRepMatchOffset = 0;
for (i = nStartOffset; i < nEndOffset; ) {
const lzsa_match *pMatch = pBestMatch + i;
if (pMatch->length >= MIN_MATCH_SIZE_V2) {
const int nMatchLen = pMatch->length;
const int nMatchOffset = pMatch->offset;
const int nEncodedMatchLen = nMatchLen - MIN_MATCH_SIZE_V2;
const int nTokenLiteralsLen = (nNumLiterals >= LITERALS_RUN_LEN_V2) ? LITERALS_RUN_LEN_V2 : nNumLiterals;
const 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;
}
}
const 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, 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, ((-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, ((-(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, 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) {
const 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++;
}
}
{
const int nTokenLiteralsLen = (nNumLiterals >= LITERALS_RUN_LEN_V2) ? LITERALS_RUN_LEN_V2 : nNumLiterals;
const 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) | 0xe7;
else
pOutData[nOutOffset++] = (nTokenLiteralsLen << 3) /* | 0x00 */;
nOutOffset = lzsa_write_literals_varlen_v2(pOutData, nOutOffset, nMaxOutDataSize, &nCurNibbleOffset, 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;
}
if (pCompressor->flags & LZSA_FLAG_RAW_BLOCK) {
const 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;
nOutOffset = lzsa_write_nibble_v2(pOutData, nOutOffset, nMaxOutDataSize, &nCurNibbleOffset, 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, 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;
const int nNumLiterals = nEndOffset - nStartOffset;
const int nTokenLiteralsLen = (nNumLiterals >= LITERALS_RUN_LEN_V2) ? LITERALS_RUN_LEN_V2 : nNumLiterals;
int nOutOffset = 0;
const int nCommandSize = 8 /* token */ + lzsa_get_literals_varlen_size_v2(nNumLiterals) + (nNumLiterals << 3) + 4 + 8;
if ((nOutOffset + ((nCommandSize + 7) >> 3)) > nMaxOutDataSize)
return -1;
pCompressor->num_commands = 0;
pOutData[nOutOffset++] = (nTokenLiteralsLen << 3) | 0xe7;
nOutOffset = lzsa_write_literals_varlen_v2(pOutData, nOutOffset, nMaxOutDataSize, &nCurNibbleOffset, nNumLiterals);
if (nOutOffset < 0) return -1;
if (nNumLiterals != 0) {
memcpy(pOutData + nOutOffset, pInWindow + nStartOffset, nNumLiterals);
nOutOffset += nNumLiterals;
}
/* Emit EOD marker for raw block */
nOutOffset = lzsa_write_nibble_v2(pOutData, nOutOffset, nMaxOutDataSize, &nCurNibbleOffset, 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, 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) {
const int nEndOffset = nPreviousBlockSize + nInDataSize;
const int nArrivalsPerPosition = (nInDataSize < 65536) ? NARRIVALS_PER_POSITION_V2_BIG : NARRIVALS_PER_POSITION_V2_SMALL;
int nResult;
int *rle_len = (int*)pCompressor->intervals /* reuse */;
int i, nDidReduce, nPasses;
i = 0;
while (i < nEndOffset) {
int nRangeStartIdx = i;
const unsigned char c = pInWindow[nRangeStartIdx];
do {
i++;
} while (i < nEndOffset && pInWindow[i] == c);
while (nRangeStartIdx < i) {
rle_len[nRangeStartIdx] = i - nRangeStartIdx;
nRangeStartIdx++;
}
}
/* 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, nPreviousBlockSize, nEndOffset, 0 /* reduce */, (nInDataSize < 65536) ? 1 : 0 /* insert forward reps */, nArrivalsPerPosition);
if (nInDataSize < 65536) {
int* first_offset_for_byte = pCompressor->first_offset_for_byte;
int* next_offset_for_pos = pCompressor->next_offset_for_pos;
int* offset_cache = pCompressor->offset_cache;
int nPosition;
/* Supplement small matches */
memset(first_offset_for_byte, 0xff, sizeof(int) * 65536);
memset(next_offset_for_pos, 0xff, sizeof(int) * nInDataSize);
for (nPosition = nPreviousBlockSize; nPosition < nEndOffset - 1; nPosition++) {
next_offset_for_pos[nPosition - nPreviousBlockSize] = first_offset_for_byte[((unsigned int)pInWindow[nPosition]) | (((unsigned int)pInWindow[nPosition + 1]) << 8)];
first_offset_for_byte[((unsigned int)pInWindow[nPosition]) | (((unsigned int)pInWindow[nPosition + 1]) << 8)] = nPosition;
}
for (nPosition = nPreviousBlockSize + 1; nPosition < (nEndOffset - 1); nPosition++) {
const int nMaxMatchLen = ((nPosition + 16) < nEndOffset) ? 16 : (nEndOffset - nPosition);
lzsa_match* match = pCompressor->match + ((nPosition - nPreviousBlockSize) << MATCHES_PER_INDEX_SHIFT_V2);
int m = 0, nInserted = 0;
int nMatchPos;
while (m < 15 && match[m].length)
m++;
for (nMatchPos = next_offset_for_pos[nPosition - nPreviousBlockSize]; m < 15 && nMatchPos >= 0; nMatchPos = next_offset_for_pos[nMatchPos - nPreviousBlockSize]) {
const int nMatchOffset = nPosition - nMatchPos;
int nAlreadyExists = 0;
int nExistingMatchIdx;
for (nExistingMatchIdx = 0; nExistingMatchIdx < m; nExistingMatchIdx++) {
if (match[nExistingMatchIdx].offset == nMatchOffset) {
nAlreadyExists = 1;
break;
}
}
if (!nAlreadyExists) {
int nMatchLen = 2;
while ((nMatchLen + 8) < nMaxMatchLen && !memcmp(pInWindow + nPosition + nMatchLen, pInWindow + nMatchPos + nMatchLen, 8))
nMatchLen += 8;
while ((nMatchLen + 4) < nMaxMatchLen && !memcmp(pInWindow + nPosition + nMatchLen, pInWindow + nMatchPos + nMatchLen, 4))
nMatchLen += 4;
while (nMatchLen < nMaxMatchLen && pInWindow[nPosition + nMatchLen] == pInWindow[nMatchPos + nMatchLen])
nMatchLen++;
match[m].length = nMatchLen;
match[m].offset = nMatchOffset;
m++;
nInserted++;
if (nInserted >= 12)
break;
}
}
}
/* Supplement matches further */
memset(offset_cache, 0xff, sizeof(int) * 2048);
for (nPosition = nPreviousBlockSize + 1; nPosition < (nEndOffset - 1); nPosition++) {
lzsa_match* match = pCompressor->match + ((nPosition - nPreviousBlockSize) << MATCHES_PER_INDEX_SHIFT_V2);
if (match[0].length < 5) {
const int nMaxMatchLen = ((nPosition + 16) < nEndOffset) ? 16 : (nEndOffset - nPosition);
int m = 0, nInserted = 0;
int nMatchPos;
int nMaxForwardPos = nPosition + 2 + 1 + 2;
if (nMaxForwardPos > (nEndOffset - 2))
nMaxForwardPos = nEndOffset - 2;
while (m < 46 && match[m].length) {
offset_cache[match[m].offset & 2047] = nPosition;
m++;
}
for (nMatchPos = next_offset_for_pos[nPosition - nPreviousBlockSize]; m < 46 && nMatchPos >= 0; nMatchPos = next_offset_for_pos[nMatchPos - nPreviousBlockSize]) {
const int nMatchOffset = nPosition - nMatchPos;
if (nMatchOffset <= MAX_OFFSET) {
int nAlreadyExists = 0;
if (offset_cache[nMatchOffset & 2047] == nPosition) {
int nExistingMatchIdx;
for (nExistingMatchIdx = 0; nExistingMatchIdx < m; nExistingMatchIdx++) {
if (match[nExistingMatchIdx].offset == nMatchOffset) {
nAlreadyExists = 1;
break;
}
}
}
if (!nAlreadyExists) {
int nForwardPos = nPosition + 2;
if (nForwardPos >= nMatchOffset) {
int nGotMatch = 0;
while (nForwardPos < nMaxForwardPos) {
if (!memcmp(pInWindow + nForwardPos, pInWindow + nForwardPos - nMatchOffset, 2)) {
nGotMatch = 1;
break;
}
nForwardPos++;
}
if (nGotMatch) {
int nMatchLen = 2;
while ((nMatchLen + 8) < nMaxMatchLen && !memcmp(pInWindow + nPosition + nMatchLen, pInWindow + nMatchPos + nMatchLen, 8))
nMatchLen += 8;
while ((nMatchLen + 4) < nMaxMatchLen && !memcmp(pInWindow + nPosition + nMatchLen, pInWindow + nMatchPos + nMatchLen, 4))
nMatchLen += 4;
while (nMatchLen < nMaxMatchLen && pInWindow[nPosition + nMatchLen] == pInWindow[nMatchPos + nMatchLen])
nMatchLen++;
match[m].length = nMatchLen | 0x8000;
match[m].offset = nMatchOffset;
m++;
lzsa_insert_forward_match_v2(pCompressor, pInWindow, nPosition, nMatchOffset, nPreviousBlockSize, nEndOffset, 8);
nInserted++;
if (nInserted >= 3)
break;
}
}
}
}
else {
break;
}
}
}
}
for (nPosition = nPreviousBlockSize + 1; nPosition < (nEndOffset - 1); nPosition++) {
lzsa_match* match = pCompressor->match + ((nPosition - nPreviousBlockSize) << MATCHES_PER_INDEX_SHIFT_V2);
if (match[0].length < 8) {
const int nMaxMatchLen = ((nPosition + 16) < nEndOffset) ? 16 : (nEndOffset - nPosition);
int m = 0, nInserted = 0;
int nMatchPos;
int nMaxForwardPos = nPosition + 2 + 1 + 6;
if (nMaxForwardPos > (nEndOffset - 2))
nMaxForwardPos = nEndOffset - 2;
while (m < 63 && match[m].length) {
offset_cache[match[m].offset & 2047] = nPosition;
m++;
}
for (nMatchPos = next_offset_for_pos[nPosition - nPreviousBlockSize]; m < 63 && nMatchPos >= 0; nMatchPos = next_offset_for_pos[nMatchPos - nPreviousBlockSize]) {
const int nMatchOffset = nPosition - nMatchPos;
if (nMatchOffset <= MAX_OFFSET) {
int nAlreadyExists = 0;
if (offset_cache[nMatchOffset & 2047] == nPosition) {
int nExistingMatchIdx;
for (nExistingMatchIdx = 0; nExistingMatchIdx < m; nExistingMatchIdx++) {
if (match[nExistingMatchIdx].offset == nMatchOffset) {
nAlreadyExists = 1;
break;
}
}
}
if (!nAlreadyExists) {
int nForwardPos = nPosition + 2;
if (nForwardPos >= nMatchOffset) {
int nGotMatch = 0;
while (nForwardPos < nMaxForwardPos) {
if (!memcmp(pInWindow + nForwardPos, pInWindow + nForwardPos - nMatchOffset, 2)) {
nGotMatch = 1;
break;
}
nForwardPos++;
}
if (nGotMatch) {
int nMatchLen = 2;
while ((nMatchLen + 8) < nMaxMatchLen && !memcmp(pInWindow + nPosition + nMatchLen, pInWindow + nMatchPos + nMatchLen, 8))
nMatchLen += 8;
while ((nMatchLen + 4) < nMaxMatchLen && !memcmp(pInWindow + nPosition + nMatchLen, pInWindow + nMatchPos + nMatchLen, 4))
nMatchLen += 4;
while (nMatchLen < nMaxMatchLen && pInWindow[nPosition + nMatchLen] == pInWindow[nMatchPos + nMatchLen] )
nMatchLen++;
match[m].length = nMatchLen;
match[m].offset = nMatchOffset;
m++;
lzsa_insert_forward_match_v2(pCompressor, pInWindow, nPosition, nMatchOffset, nPreviousBlockSize, nEndOffset, 8);
nInserted++;
if (nInserted >= 12)
break;
}
}
}
}
else {
break;
}
}
}
}
/* Compress optimally and do break ties in favor of less tokens */
lzsa_optimize_forward_v2(pCompressor, pInWindow, nPreviousBlockSize, nEndOffset, 1 /* reduce */, 0 /* use forward reps */, NARRIVALS_PER_POSITION_V2_MAX);
}
/* Try to reduce final command set, wherever possible */
nPasses = 0;
do {
nDidReduce = lzsa_optimize_command_count_v2(pCompressor, pInWindow, nPreviousBlockSize, nEndOffset);
nPasses++;
} while (nDidReduce && nPasses < 20);
/* Write compressed block */
nResult = lzsa_write_block_v2(pCompressor, pInWindow, nPreviousBlockSize, nEndOffset, pOutData, nMaxOutDataSize);
if (nResult < 0 && (pCompressor->flags & LZSA_FLAG_RAW_BLOCK)) {
nResult = lzsa_write_raw_uncompressed_block_v2(pCompressor, pInWindow, nPreviousBlockSize, nEndOffset, pOutData, nMaxOutDataSize);
}
return nResult;
}
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