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Faster LZSA2 compression

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Emmanuel Marty 2020-05-28 18:38:19 +02:00 committed by GitHub
parent 231f6580c5
commit 278fcc0256
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GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 54 additions and 38 deletions
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92
src/shrink_block_v2.c
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@ -272,12 +272,13 @@ static void lzsa_optimize_forward_v2(lzsa_compressor *pCompressor, const unsigne
arrival[nStartOffset << MATCHES_PER_ARRIVAL_SHIFT].from_slot = -1;
for (i = nStartOffset; i != nEndOffset; i++) {
lzsa_arrival *cur_arrival = &arrival[i << MATCHES_PER_ARRIVAL_SHIFT];
int m;
for (j = 0; j < nMatchesPerArrival && arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].from_slot; j++) {
const int nPrevCost = arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].cost & 0x3fffffff;
for (j = 0; j < nMatchesPerArrival && cur_arrival[j].from_slot; j++) {
const int nPrevCost = cur_arrival[j].cost & 0x3fffffff;
int nCodingChoiceCost = nPrevCost + 8 /* literal */;
int nNumLiterals = arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].num_literals + 1;
int nNumLiterals = cur_arrival[j].num_literals + 1;
if (nNumLiterals == LITERALS_RUN_LEN_V2) {
nCodingChoiceCost += 4;
@ -294,47 +295,62 @@ static void lzsa_optimize_forward_v2(lzsa_compressor *pCompressor, const unsigne
lzsa_arrival *pDestSlots = &arrival[(i + 1) << MATCHES_PER_ARRIVAL_SHIFT];
if (nCodingChoiceCost <= pDestSlots[nMatchesPerArrival - 1].cost) {
int nRepOffset = cur_arrival[j].rep_offset;
int exists = 0;
for (n = 0;
n < nMatchesPerArrival && pDestSlots[n].cost <= nCodingChoiceCost;
n < nMatchesPerArrival && pDestSlots[n].cost < nCodingChoiceCost;
n++) {
if (pDestSlots[n].rep_offset == arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].rep_offset) {
if (pDestSlots[n].rep_offset == nRepOffset) {
exists = 1;
break;
}
}
if (!exists) {
int nScore = arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].score + 1;
for (n = 0; n < nMatchesPerArrival; n++) {
lzsa_arrival *pDestArrival = &pDestSlots[n];
if (nCodingChoiceCost < pDestArrival->cost ||
(nCodingChoiceCost == pDestArrival->cost && nScore < (pDestArrival->score + nDisableScore))) {
int nn;
if (pDestArrival->from_slot) {
int z;
for (nn = n;
nn < nMatchesPerArrival && pDestSlots[nn].cost == nCodingChoiceCost;
nn++) {
if (pDestSlots[nn].rep_offset == nRepOffset) {
exists = 1;
break;
}
}
for (z = n; z < nMatchesPerArrival - 1; z++) {
if (pDestSlots[z].rep_offset == arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].rep_offset)
break;
if (!exists) {
int nScore = cur_arrival[j].score + 1;
for (; n < nMatchesPerArrival; n++) {
lzsa_arrival* pDestArrival = &pDestSlots[n];
if (nCodingChoiceCost < pDestArrival->cost || nScore < (pDestArrival->score + nDisableScore)) {
if (pDestArrival->from_slot) {
int z;
for (z = n; z < nMatchesPerArrival - 1; z++) {
if (pDestSlots[z].rep_offset == nRepOffset)
break;
}
memmove(&pDestSlots[n + 1],
&pDestSlots[n],
sizeof(lzsa_arrival) * (z - n));
}
memmove(&pDestSlots[n + 1],
&pDestSlots[n],
sizeof(lzsa_arrival) * (z - n));
pDestArrival->cost = nCodingChoiceCost;
pDestArrival->from_pos = i;
pDestArrival->from_slot = j + 1;
pDestArrival->match_offset = 0;
pDestArrival->match_len = 0;
pDestArrival->num_literals = nNumLiterals;
pDestArrival->score = nScore;
pDestArrival->rep_offset = nRepOffset;
pDestArrival->rep_pos = cur_arrival[j].rep_pos;
pDestArrival->rep_len = cur_arrival[j].rep_len;
break;
}
pDestArrival->cost = nCodingChoiceCost;
pDestArrival->from_pos = i;
pDestArrival->from_slot = j + 1;
pDestArrival->match_offset = 0;
pDestArrival->match_len = 0;
pDestArrival->num_literals = nNumLiterals;
pDestArrival->score = nScore;
pDestArrival->rep_offset = arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].rep_offset;
pDestArrival->rep_pos = arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].rep_pos;
pDestArrival->rep_len = arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].rep_len;
break;
}
}
}
@ -357,8 +373,8 @@ static void lzsa_optimize_forward_v2(lzsa_compressor *pCompressor, const unsigne
if ((i + nMatchLen) > (nEndOffset - LAST_LITERALS))
nMatchLen = nEndOffset - LAST_LITERALS - i;
for (j = 0; j < nMatchesPerArrival && arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].from_slot; j++) {
int nRepOffset = arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].rep_offset;
for (j = 0; j < nMatchesPerArrival && cur_arrival[j].from_slot; j++) {
int nRepOffset = cur_arrival[j].rep_offset;
int nCurMaxRepLen = 0;
if (nRepOffset) {
@ -413,17 +429,17 @@ static void lzsa_optimize_forward_v2(lzsa_compressor *pCompressor, const unsigne
lzsa_arrival *pDestSlots = &arrival[(i + k) << MATCHES_PER_ARRIVAL_SHIFT];
int nInsertedNoRepMatchCandidate = 0;
for (j = 0; j < nMatchesPerArrival && arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].from_slot; j++) {
const int nPrevCost = arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].cost & 0x3fffffff;
for (j = 0; j < nMatchesPerArrival && cur_arrival[j].from_slot; j++) {
const int nPrevCost = cur_arrival[j].cost & 0x3fffffff;
int nRepCodingChoiceCost = nPrevCost + 8 /* token */ /* the actual cost of the literals themselves accumulates up the chain */ + nMatchLenCost;
if (nRepCodingChoiceCost <= pDestSlots[nMatchesPerArrival - 1].cost) {
int nRepOffset = arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].rep_offset;
int nRepOffset = cur_arrival[j].rep_offset;
if (nMatchOffset != nRepOffset && !nInsertedNoRepMatchCandidate) {
int nCodingChoiceCost = nRepCodingChoiceCost + nNoRepmatchOffsetCost;
if (!nFavorRatio && !arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].num_literals)
if (!nFavorRatio && !cur_arrival[j].num_literals)
nCodingChoiceCost += MODESWITCH_PENALTY;
if (nCodingChoiceCost <= pDestSlots[nMatchesPerArrival - 2].cost) {
@ -440,7 +456,7 @@ static void lzsa_optimize_forward_v2(lzsa_compressor *pCompressor, const unsigne
}
if (!exists) {
int nScore = arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].score + 3 + nScorePenalty;
int nScore = cur_arrival[j].score + 3 + nScorePenalty;
int nn;
for (nn = n;
@ -514,7 +530,7 @@ static void lzsa_optimize_forward_v2(lzsa_compressor *pCompressor, const unsigne
}
if (!exists) {
int nScore = arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].score + 2;
int nScore = cur_arrival[j].score + 2;
for (n = 0; n < nMatchesPerArrival; n++) {
lzsa_arrival *pDestArrival = &pDestSlots[n];