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Generalize merging very large matches

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Emmanuel Marty 2019-10-24 13:05:32 +02:00 committed by GitHub
parent f4cf97f176
commit 53fcd3b1a8
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2 changed files with 22 additions and 7 deletions
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18
src/shrink_block_v1.c
View File

@ -284,13 +284,14 @@ static void lzsa_optimize_forward_v1(lzsa_compressor *pCompressor, lzsa_match *p
* 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 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 non-zero if the number of tokens was reduced, 0 if it wasn't
*/
static int lzsa_optimize_command_count_v1(lzsa_compressor *pCompressor, lzsa_match *pBestMatch, const int nStartOffset, const int nEndOffset) {
static int lzsa_optimize_command_count_v1(lzsa_compressor *pCompressor, const unsigned char *pInWindow, lzsa_match *pBestMatch, const int nStartOffset, const int nEndOffset) {
int i;
int nNumLiterals = 0;
int nDidReduce = 0;
@ -327,8 +328,15 @@ static int lzsa_optimize_command_count_v1(lzsa_compressor *pCompressor, lzsa_mat
}
if ((i + pMatch->length) < nEndOffset && pMatch->length >= LCP_MAX &&
pMatch->offset && pMatch->offset <= 32 && pBestMatch[i + pMatch->length].offset == pMatch->offset && (pMatch->length % pMatch->offset) == 0 &&
(pMatch->length + pBestMatch[i + pMatch->length].length) <= MAX_VARLEN) {
pBestMatch[i + pMatch->length].offset &&
pBestMatch[i + pMatch->length].length >= MIN_MATCH_SIZE_V1 &&
pBestMatch[i + pMatch->length].offset <= pMatch->length &&
(pMatch->length + pBestMatch[i + pMatch->length].length) <= MAX_VARLEN &&
(i + pMatch->length) > pMatch->offset &&
(i - pMatch->offset + 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 nMatchLen = pMatch->length;
/* Join */
@ -625,7 +633,7 @@ int lzsa_optimize_and_write_block_v1(lzsa_compressor *pCompressor, const unsigne
int nDidReduce;
int nPasses = 0;
do {
nDidReduce = lzsa_optimize_command_count_v1(pCompressor, pCompressor->best_match, nPreviousBlockSize, nPreviousBlockSize + nInDataSize);
nDidReduce = lzsa_optimize_command_count_v1(pCompressor, pInWindow, pCompressor->best_match, nPreviousBlockSize, nPreviousBlockSize + nInDataSize);
nPasses++;
} while (nDidReduce && nPasses < 20);
@ -640,7 +648,7 @@ int lzsa_optimize_and_write_block_v1(lzsa_compressor *pCompressor, const unsigne
nPasses = 0;
do {
nDidReduce = lzsa_optimize_command_count_v1(pCompressor, pCompressor->improved_match, nPreviousBlockSize, nPreviousBlockSize + nInDataSize);
nDidReduce = lzsa_optimize_command_count_v1(pCompressor, pInWindow, pCompressor->improved_match, nPreviousBlockSize, nPreviousBlockSize + nInDataSize);
nPasses++;
} while (nDidReduce && nPasses < 20);

11
src/shrink_block_v2.c
View File

@ -584,8 +584,15 @@ static int lzsa_optimize_command_count_v2(lzsa_compressor *pCompressor, const un
}
if ((i + pMatch->length) < nEndOffset && pMatch->length >= LCP_MAX &&
pMatch->offset && pMatch->offset <= 32 && pBestMatch[i + pMatch->length].offset == pMatch->offset && (pMatch->length % pMatch->offset) == 0 &&
(pMatch->length + pBestMatch[i + pMatch->length].length) <= MAX_VARLEN) {
pBestMatch[i + pMatch->length].offset &&
pBestMatch[i + pMatch->length].length >= MIN_MATCH_SIZE_V2 &&
pBestMatch[i + pMatch->length].offset <= pMatch->length &&
(pMatch->length + pBestMatch[i + pMatch->length].length) <= MAX_VARLEN &&
(i + pMatch->length) > pMatch->offset &&
(i - pMatch->offset + 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 nMatchLen = pMatch->length;
/* Join */