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Compress LZSA1 a little faster

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Emmanuel Marty 2020-07-10 17:45:13 +02:00 committed by GitHub
parent 8ed768aafc
commit 4864f3c184
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GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 38 additions and 31 deletions
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69
src/shrink_block_v1.c
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@ -160,6 +160,7 @@ static void lzsa_optimize_forward_v1(lzsa_compressor *pCompressor, lzsa_match *p
lzsa_arrival *arrival = pCompressor->arrival - (nStartOffset << MATCHES_PER_ARRIVAL_SHIFT);
const int nMinMatchSize = pCompressor->min_match_size;
const int nFavorRatio = (pCompressor->flags & LZSA_FLAG_FAVOR_RATIO) ? 1 : 0;
const int nModeSwitchPenalty = nFavorRatio ? 0 : MODESWITCH_PENALTY;
const int nDisableScore = nReduce ? 0 : (2 * BLOCK_SIZE);
int i, j, n;
@ -170,20 +171,21 @@ static void lzsa_optimize_forward_v1(lzsa_compressor *pCompressor, lzsa_match *p
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 < NMATCHES_PER_ARRIVAL_V1 && arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].from_slot; j++) {
int nPrevCost = arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].cost;
for (j = 0; j < NMATCHES_PER_ARRIVAL_V1 && cur_arrival[j].from_slot; j++) {
int nPrevCost = cur_arrival[j].cost;
int nCodingChoiceCost = nPrevCost + 8 /* literal */;
int nScore = arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].score + 1;
int nNumLiterals = arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].num_literals + 1;
int nScore = cur_arrival[j].score + 1;
int nNumLiterals = cur_arrival[j].num_literals + 1;
if (nNumLiterals == LITERALS_RUN_LEN_V1 || nNumLiterals == 256 || nNumLiterals == 512) {
nCodingChoiceCost += 8;
}
if (!nFavorRatio && nNumLiterals == 1)
nCodingChoiceCost += MODESWITCH_PENALTY;
if (nNumLiterals == 1)
nCodingChoiceCost += nModeSwitchPenalty;
for (n = 0; n < NMATCHES_PER_ARRIVAL_V1 /* we only need the literals + short match cost + long match cost cases */; n++) {
lzsa_arrival *pDestArrival = &arrival[((i + 1) << MATCHES_PER_ARRIVAL_SHIFT) + n];
@ -202,7 +204,7 @@ static void lzsa_optimize_forward_v1(lzsa_compressor *pCompressor, lzsa_match *p
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_offset = cur_arrival[j].rep_offset;
break;
}
}
@ -225,43 +227,48 @@ static void lzsa_optimize_forward_v1(lzsa_compressor *pCompressor, lzsa_match *p
for (k = nStartingMatchLen; k <= nMatchLen; k++) {
int nMatchLenCost = lzsa_get_match_varlen_size_v1(k - MIN_MATCH_SIZE_V1);
for (j = 0; j < NMATCHES_PER_ARRIVAL_V1 && arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].from_slot; j++) {
int nPrevCost = arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].cost;
lzsa_arrival *pDestSlots = &arrival[(i + k) << MATCHES_PER_ARRIVAL_SHIFT];
for (j = 0; j < NMATCHES_PER_ARRIVAL_V1 && cur_arrival[j].from_slot; j++) {
int nPrevCost = cur_arrival[j].cost;
int nCodingChoiceCost = nPrevCost + 8 /* token */ /* the actual cost of the literals themselves accumulates up the chain */ + nMatchOffsetCost + nMatchLenCost;
int nScore = arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].score + 5;
int exists = 0;
if (!nFavorRatio && !arrival[(i << MATCHES_PER_ARRIVAL_SHIFT) + j].num_literals)
nCodingChoiceCost += MODESWITCH_PENALTY;
if (!cur_arrival[j].num_literals)
nCodingChoiceCost += nModeSwitchPenalty;
for (n = 0;
n < NMATCHES_PER_ARRIVAL_V1 && arrival[((i + k) << MATCHES_PER_ARRIVAL_SHIFT) + n].from_slot && arrival[((i + k) << MATCHES_PER_ARRIVAL_SHIFT) + n].cost <= nCodingChoiceCost;
n < NMATCHES_PER_ARRIVAL_V1 && pDestSlots[n].from_slot && pDestSlots[n].cost <= nCodingChoiceCost;
n++) {
if (lzsa_get_offset_cost_v1(arrival[((i + k) << MATCHES_PER_ARRIVAL_SHIFT) + n].rep_offset) == lzsa_get_offset_cost_v1(match[m].offset)) {
if (lzsa_get_offset_cost_v1(pDestSlots[n].rep_offset) == lzsa_get_offset_cost_v1(match[m].offset)) {
exists = 1;
break;
}
}
for (n = 0; !exists && n < NMATCHES_PER_ARRIVAL_V1 /* we only need the literals + short match cost + long match cost cases */; n++) {
lzsa_arrival *pDestArrival = &arrival[((i + k) << MATCHES_PER_ARRIVAL_SHIFT) + n];
if (!exists) {
int nScore = cur_arrival[j].score + 5;
if (pDestArrival->from_slot == 0 ||
nCodingChoiceCost < pDestArrival->cost ||
(nCodingChoiceCost == pDestArrival->cost && nScore < (pDestArrival->score + nDisableScore))) {
memmove(&arrival[((i + k) << MATCHES_PER_ARRIVAL_SHIFT) + n + 1],
&arrival[((i + k) << MATCHES_PER_ARRIVAL_SHIFT) + n],
sizeof(lzsa_arrival) * (NMATCHES_PER_ARRIVAL_V1 - n - 1));
for (n = 0; n < NMATCHES_PER_ARRIVAL_V1 /* we only need the literals + short match cost + long match cost cases */; n++) {
lzsa_arrival *pDestArrival = &pDestSlots[n];
pDestArrival->cost = nCodingChoiceCost;
pDestArrival->from_pos = i;
pDestArrival->from_slot = j + 1;
pDestArrival->match_offset = match[m].offset;
pDestArrival->match_len = k;
pDestArrival->num_literals = 0;
pDestArrival->score = nScore;
pDestArrival->rep_offset = match[m].offset;
break;
if (pDestArrival->from_slot == 0 ||
nCodingChoiceCost < pDestArrival->cost ||
(nCodingChoiceCost == pDestArrival->cost && nScore < (pDestArrival->score + nDisableScore))) {
memmove(&pDestSlots[n + 1],
&pDestSlots[n],
sizeof(lzsa_arrival) * (NMATCHES_PER_ARRIVAL_V1 - n - 1));
pDestArrival->cost = nCodingChoiceCost;
pDestArrival->from_pos = i;
pDestArrival->from_slot = j + 1;
pDestArrival->match_offset = match[m].offset;
pDestArrival->match_len = k;
pDestArrival->num_literals = 0;
pDestArrival->score = nScore;
pDestArrival->rep_offset = match[m].offset;
break;
}
}
}
}