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Don't systematically encode last byte as literal

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Emmanuel Marty 2019-11-26 20:48:13 +01:00 committed by GitHub
parent 88f563d84c
commit 78ad147799
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4 changed files with 13 additions and 16 deletions
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11
src/shrink_block_v1.c
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@ -165,11 +165,11 @@ static void lzsa_optimize_forward_v1(lzsa_compressor *pCompressor, lzsa_match *p
if ((nEndOffset - nStartOffset) > BLOCK_SIZE) return;
memset(arrival + (nStartOffset << MATCHES_PER_ARRIVAL_SHIFT), 0, sizeof(lzsa_arrival) * ((nEndOffset - nStartOffset) << MATCHES_PER_ARRIVAL_SHIFT));
memset(arrival + (nStartOffset << MATCHES_PER_ARRIVAL_SHIFT), 0, sizeof(lzsa_arrival) * ((nEndOffset - nStartOffset + 1) << MATCHES_PER_ARRIVAL_SHIFT));
arrival[nStartOffset << MATCHES_PER_ARRIVAL_SHIFT].from_slot = -1;
for (i = nStartOffset; i != (nEndOffset - 1); i++) {
for (i = nStartOffset; i != nEndOffset; i++) {
int m;
for (j = 0; j < NMATCHES_PER_ARRIVAL_SMALL && arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].from_slot; j++) {
@ -270,10 +270,9 @@ static void lzsa_optimize_forward_v1(lzsa_compressor *pCompressor, lzsa_match *p
}
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) {
if (end_arrival->from_pos >= nEndOffset) return;
pBestMatch[end_arrival->from_pos].length = end_arrival->match_len;
pBestMatch[end_arrival->from_pos].offset = end_arrival->match_offset;
@ -351,14 +350,14 @@ static int lzsa_optimize_command_count_v1(lzsa_compressor *pCompressor, const un
}
}
if ((i + pMatch->length) < nEndOffset && pMatch->offset > 0 && pMatch->length >= MIN_MATCH_SIZE_V1 &&
if ((i + pMatch->length) <= nEndOffset && pMatch->offset > 0 && pMatch->length >= MIN_MATCH_SIZE_V1 &&
pBestMatch[i + pMatch->length].offset > 0 &&
pBestMatch[i + pMatch->length].length >= MIN_MATCH_SIZE_V1 &&
(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 &&
(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)) {

13
src/shrink_block_v2.c
View File

@ -254,15 +254,15 @@ static void lzsa_optimize_forward_v2(lzsa_compressor *pCompressor, const unsigne
if ((nEndOffset - nStartOffset) > BLOCK_SIZE) return;
memset(arrival + (nStartOffset << MATCHES_PER_ARRIVAL_SHIFT), 0, sizeof(lzsa_arrival) * ((nEndOffset - nStartOffset) << MATCHES_PER_ARRIVAL_SHIFT));
memset(arrival + (nStartOffset << MATCHES_PER_ARRIVAL_SHIFT), 0, sizeof(lzsa_arrival) * ((nEndOffset - nStartOffset + 1) << MATCHES_PER_ARRIVAL_SHIFT));
for (i = (nStartOffset << MATCHES_PER_ARRIVAL_SHIFT); i != (nEndOffset << MATCHES_PER_ARRIVAL_SHIFT); i++) {
for (i = (nStartOffset << MATCHES_PER_ARRIVAL_SHIFT); i != ((nEndOffset + 1) << MATCHES_PER_ARRIVAL_SHIFT); i++) {
arrival[i].cost = 0x40000000;
}
arrival[nStartOffset << MATCHES_PER_ARRIVAL_SHIFT].from_slot = -1;
for (i = nStartOffset; i != (nEndOffset - 1); i++) {
for (i = nStartOffset; i != nEndOffset; i++) {
int m;
for (j = 0; j < nMatchesPerArrival && arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].from_slot; j++) {
@ -481,10 +481,9 @@ static void lzsa_optimize_forward_v2(lzsa_compressor *pCompressor, const unsigne
}
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) {
if (end_arrival->from_pos >= nEndOffset) return;
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)];
@ -650,14 +649,14 @@ static int lzsa_optimize_command_count_v2(lzsa_compressor *pCompressor, const un
}
}
if ((i + pMatch->length) < nEndOffset && pMatch->offset > 0 && pMatch->length >= MIN_MATCH_SIZE_V2 &&
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 &&
(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)) {

2
src/shrink_context.c
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@ -89,7 +89,7 @@ int lzsa_compressor_init(lzsa_compressor *pCompressor, const int nMaxWindowSize,
pCompressor->open_intervals = (unsigned int *)malloc((LCP_AND_TAG_MAX + 1) * sizeof(unsigned int));
if (pCompressor->open_intervals) {
pCompressor->arrival = (lzsa_arrival *)malloc(BLOCK_SIZE * NMATCHES_PER_ARRIVAL_BIG * sizeof(lzsa_arrival));
pCompressor->arrival = (lzsa_arrival *)malloc((BLOCK_SIZE + 1) * NMATCHES_PER_ARRIVAL_BIG * sizeof(lzsa_arrival));
if (pCompressor->arrival) {
pCompressor->best_match = (lzsa_match *)malloc(BLOCK_SIZE * sizeof(lzsa_match));

3
src/shrink_context.h
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@ -61,8 +61,7 @@ extern "C" {
#define LEAVE_ALONE_MATCH_SIZE 1000
#define LAST_MATCH_OFFSET 4
#define LAST_LITERALS 1
#define LAST_LITERALS 0
#define MODESWITCH_PENALTY 3