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Compress LZSA2 faster, clean code up

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Emmanuel Marty 2020-07-13 19:34:07 +02:00 committed by GitHub
parent 4864f3c184
commit c39158eea8
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GPG Key ID: 4AEE18F83AFDEB23
3 changed files with 74 additions and 48 deletions
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8
src/shrink_block_v1.c
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@ -217,8 +217,8 @@ static void lzsa_optimize_forward_v1(lzsa_compressor *pCompressor, lzsa_match *p
int nMatchOffsetCost = lzsa_get_offset_cost_v1(match[m].offset);
int nStartingMatchLen, k;
if ((i + nMatchLen) > (nEndOffset - LAST_LITERALS))
nMatchLen = nEndOffset - LAST_LITERALS - i;
if ((i + nMatchLen) > nEndOffset)
nMatchLen = nEndOffset - i;
if (nMatchLen >= LEAVE_ALONE_MATCH_SIZE)
nStartingMatchLen = nMatchLen;
@ -308,12 +308,12 @@ static int lzsa_optimize_command_count_v1(lzsa_compressor *pCompressor, const un
lzsa_match *pMatch = pBestMatch + i;
if (pMatch->length == 0 &&
(i + 1) < (nEndOffset - LAST_LITERALS) &&
(i + 1) < nEndOffset &&
pBestMatch[i + 1].length >= MIN_MATCH_SIZE_V1 &&
pBestMatch[i + 1].length < MAX_VARLEN &&
pBestMatch[i + 1].offset &&
i >= pBestMatch[i + 1].offset &&
(i + pBestMatch[i + 1].length + 1) <= (nEndOffset - LAST_LITERALS) &&
(i + pBestMatch[i + 1].length + 1) <= nEndOffset &&
!memcmp(pInWindow + i - (pBestMatch[i + 1].offset), pInWindow + i, pBestMatch[i + 1].length + 1)) {
int nCurLenSize = lzsa_get_match_varlen_size_v1(pBestMatch[i + 1].length - MIN_MATCH_SIZE_V1);
int nReducedLenSize = lzsa_get_match_varlen_size_v1(pBestMatch[i + 1].length + 1 - MIN_MATCH_SIZE_V1);

112
src/shrink_block_v2.c
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@ -194,6 +194,7 @@ static inline int lzsa_write_match_varlen_v2(unsigned char *pOutData, int nOutOf
*/
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) {
lzsa_arrival *arrival = pCompressor->arrival + ((i - nStartOffset) << MATCHES_PER_ARRIVAL_SHIFT);
const int *rle_end = (int*)pCompressor->intervals /* reuse */;
int j;
int nPrevRepPos = -1, nPrevPrevRepPos = -1;
@ -205,45 +206,55 @@ static void lzsa_insert_forward_match_v2(lzsa_compressor *pCompressor, const uns
int nRepLen = arrival[j].rep_len;
if (nRepPos > nMatchOffset &&
(nRepPos - nMatchOffset + nRepLen) <= (nEndOffset - LAST_LITERALS) &&
(nRepPos - nMatchOffset + nRepLen) <= nEndOffset &&
pCompressor->match[((nRepPos - nStartOffset) << MATCHES_PER_INDEX_SHIFT_V2) + NMATCHES_PER_INDEX_V2 - 1].length == 0) {
if (nPrevRepPos != nRepPos && nPrevPrevRepPos != nRepPos) {
if (!memcmp(pInWindow + nRepPos, pInWindow + nRepPos - nMatchOffset, nRepLen)) {
int nCurRepLen = nRepLen;
if (pInWindow[nRepPos] == pInWindow[nRepPos - nMatchOffset]) {
int nLen0 = rle_end[nRepPos - nMatchOffset] - (nRepPos - nMatchOffset);
int nLen1 = rle_end[nRepPos] - (nRepPos);
int nMinLen = (nLen0 < nLen1) ? nLen0 : nLen1;
nPrevPrevRepPos = nPrevRepPos;
nPrevRepPos = nRepPos;
if (nMinLen >= nRepLen || !memcmp(pInWindow + nRepPos + nMinLen, pInWindow + nRepPos + nMinLen - nMatchOffset, nRepLen - nMinLen)) {
nPrevPrevRepPos = nPrevRepPos;
nPrevRepPos = nRepPos;
int nMaxRepLen = nEndOffset - nRepPos;
if (nMaxRepLen > LCP_MAX)
nMaxRepLen = LCP_MAX;
while ((nCurRepLen + 8) < nMaxRepLen && !memcmp(pInWindow + nRepPos + nCurRepLen, pInWindow + nRepPos - nMatchOffset + nCurRepLen, 8))
nCurRepLen += 8;
while ((nCurRepLen + 4) < nMaxRepLen && !memcmp(pInWindow + nRepPos + nCurRepLen, pInWindow + nRepPos - nMatchOffset + nCurRepLen, 4))
nCurRepLen += 4;
while (nCurRepLen < nMaxRepLen && pInWindow[nRepPos + nCurRepLen] == pInWindow[nRepPos - nMatchOffset + nCurRepLen])
nCurRepLen++;
int nMaxRepLen = nEndOffset - nRepPos;
if (nMaxRepLen > LCP_MAX)
nMaxRepLen = LCP_MAX;
int nCurRepLen = (nMinLen > nRepLen) ? nMinLen : nRepLen;
if (nCurRepLen > nMaxRepLen)
nCurRepLen = nMaxRepLen;
const unsigned char *pInWindowMax = pInWindow + nRepPos + nMaxRepLen;
const unsigned char *pInWindowAtRepPos = pInWindow + nRepPos + nCurRepLen;
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++;
lzsa_match* fwd_match = pCompressor->match + ((nRepPos - nStartOffset) << MATCHES_PER_INDEX_SHIFT_V2);
int r;
nCurRepLen = (int)(pInWindowAtRepPos - (pInWindow + nRepPos));
lzsa_match* fwd_match = pCompressor->match + ((nRepPos - nStartOffset) << MATCHES_PER_INDEX_SHIFT_V2);
int r;
for (r = 0; r < NMATCHES_PER_INDEX_V2 && fwd_match[r].length >= MIN_MATCH_SIZE_V2; r++) {
if (fwd_match[r].offset == nMatchOffset) {
if (fwd_match[r].length < nCurRepLen)
fwd_match[r].length = nCurRepLen;
for (r = 0; r < NMATCHES_PER_INDEX_V2 && fwd_match[r].length >= MIN_MATCH_SIZE_V2; r++) {
if (fwd_match[r].offset == nMatchOffset) {
if (fwd_match[r].length < nCurRepLen)
fwd_match[r].length = nCurRepLen;
r = NMATCHES_PER_INDEX_V2;
break;
r = NMATCHES_PER_INDEX_V2;
break;
}
}
}
if (r < NMATCHES_PER_INDEX_V2) {
fwd_match[r].offset = nMatchOffset;
fwd_match[r].length = nCurRepLen;
if (r < NMATCHES_PER_INDEX_V2) {
fwd_match[r].offset = nMatchOffset;
fwd_match[r].length = nCurRepLen;
if (nDepth < 9)
lzsa_insert_forward_match_v2(pCompressor, pInWindow, nRepPos, nMatchOffset, nStartOffset, nEndOffset, nMatchesPerArrival, nDepth + 1);
if (nDepth < 9)
lzsa_insert_forward_match_v2(pCompressor, pInWindow, nRepPos, nMatchOffset, nStartOffset, nEndOffset, nMatchesPerArrival, nDepth + 1);
}
}
}
}
@ -381,8 +392,8 @@ static void lzsa_optimize_forward_v2(lzsa_compressor *pCompressor, const unsigne
int nStartingMatchLen, nMaxOverallRepLen = 0, k;
int nMaxRepLen[NMATCHES_PER_ARRIVAL_V2_BIG];
if ((i + nMatchLen) > (nEndOffset - LAST_LITERALS))
nMatchLen = nEndOffset - LAST_LITERALS - i;
if ((i + nMatchLen) > nEndOffset)
nMatchLen = nEndOffset - i;
for (j = 0; j < nMatchesPerArrival && cur_arrival[j].from_slot; j++) {
int nRepOffset = cur_arrival[j].rep_offset;
@ -393,14 +404,17 @@ static void lzsa_optimize_forward_v2(lzsa_compressor *pCompressor, const unsigne
nCurMaxRepLen = nMatchLen;
else {
if (i > nRepOffset &&
(i - nRepOffset + nMatchLen) <= (nEndOffset - LAST_LITERALS)) {
(i - nRepOffset + nMatchLen) <= nEndOffset) {
nCurMaxRepLen = nMinRepLen[j];
while ((nCurMaxRepLen + 8) < nMatchLen && !memcmp(pInWindow + i - nRepOffset + nCurMaxRepLen, pInWindow + i + nCurMaxRepLen, 8))
nCurMaxRepLen += 8;
while ((nCurMaxRepLen + 4) < nMatchLen && !memcmp(pInWindow + i - nRepOffset + nCurMaxRepLen, pInWindow + i + nCurMaxRepLen, 4))
nCurMaxRepLen += 4;
while (nCurMaxRepLen < nMatchLen && pInWindow[i - nRepOffset + nCurMaxRepLen] == pInWindow[i + nCurMaxRepLen])
nCurMaxRepLen++;
const unsigned char *pInWindowAtPos = pInWindow + i + nCurMaxRepLen;
const unsigned char *pInWindowMax = pInWindow + i + nMatchLen;
while ((pInWindowAtPos + 8) < pInWindowMax && !memcmp(pInWindowAtPos - nRepOffset, pInWindowAtPos, 8))
pInWindowAtPos += 8;
while ((pInWindowAtPos + 4) < pInWindowMax && !memcmp(pInWindowAtPos - nRepOffset, pInWindowAtPos, 4))
pInWindowAtPos += 4;
while (pInWindowAtPos < pInWindowMax && pInWindowAtPos[-nRepOffset] == pInWindowAtPos[0])
pInWindowAtPos++;
nCurMaxRepLen = (int)(pInWindowAtPos - (pInWindow + i));
nMinRepLen[j] = nCurMaxRepLen;
}
}
@ -636,12 +650,12 @@ static int lzsa_optimize_command_count_v2(lzsa_compressor *pCompressor, const un
lzsa_match *pMatch = pBestMatch + i;
if (pMatch->length == 0 &&
(i + 1) < (nEndOffset - LAST_LITERALS) &&
(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 - LAST_LITERALS) &&
(i + pBestMatch[i + 1].length + 1) <= nEndOffset &&
!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 - MIN_MATCH_SIZE_V2);
int nReducedLenSize = lzsa_get_match_varlen_size_v2(pBestMatch[i + 1].length + 1 - MIN_MATCH_SIZE_V2);
@ -677,7 +691,7 @@ static int lzsa_optimize_command_count_v2(lzsa_compressor *pCompressor, const un
* 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) &&
(i - nRepMatchOffset + pMatch->length) <= nEndOffset &&
!memcmp(pInWindow + i - nRepMatchOffset, pInWindow + i - pMatch->offset, pMatch->length)) {
pMatch->offset = nRepMatchOffset;
nDidReduce = 1;
@ -686,7 +700,7 @@ static int lzsa_optimize_command_count_v2(lzsa_compressor *pCompressor, const un
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)) {
if (i > pBestMatch[nNextIndex].offset && (i - pBestMatch[nNextIndex].offset + pMatch->length) <= nEndOffset) {
int nMaxLen = 0;
while (nMaxLen < pMatch->length && pInWindow[i - pBestMatch[nNextIndex].offset + nMaxLen] == pInWindow[i - pMatch->offset + nMaxLen])
nMaxLen++;
@ -742,7 +756,7 @@ static int lzsa_optimize_command_count_v2(lzsa_compressor *pCompressor, const un
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) &&
(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;
@ -1191,6 +1205,20 @@ static int lzsa_write_raw_uncompressed_block_v2(lzsa_compressor *pCompressor, co
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_V2_BIG : NMATCHES_PER_ARRIVAL_V2_SMALL;
int *rle_end = (int*)pCompressor->intervals /* reuse */;
int i;
i = 0;
while (i < (nPreviousBlockSize + nInDataSize)) {
int nRangeStartIdx = i;
unsigned char c = pInWindow[nRangeStartIdx];
do {
i++;
} while (i < (nPreviousBlockSize + nInDataSize) && pInWindow[i] == c);
while (nRangeStartIdx < i) {
rle_end[nRangeStartIdx++] = i;
}
}
/* Compress optimally without breaking ties in favor of less tokens */

2
src/shrink_context.h
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@ -63,8 +63,6 @@ extern "C" {
#define LEAVE_ALONE_MATCH_SIZE 300
#define LEAVE_ALONE_MATCH_SIZE_SMALL 1000
#define LAST_LITERALS 0
#define MODESWITCH_PENALTY 3
/** One match */