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Faster LZSA1 compression

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Emmanuel Marty 2020-08-18 11:51:24 +02:00 committed by GitHub
parent 5a0da16874
commit e3fd315541
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GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 5 additions and 3 deletions
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src/shrink_block_v1.c
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@ -187,8 +187,9 @@ static void lzsa_optimize_forward_v1(lzsa_compressor *pCompressor, lzsa_match *p
if (nNumLiterals == 1)
nCodingChoiceCost += nModeSwitchPenalty;
lzsa_arrival *pDestSlots = &arrival[(i + 1) << ARRIVALS_PER_POSITION_SHIFT];
for (n = 0; n < NARRIVALS_PER_POSITION_V1 /* we only need the literals + short match cost + long match cost cases */; n++) {
lzsa_arrival *pDestArrival = &arrival[((i + 1) << ARRIVALS_PER_POSITION_SHIFT) + n];
lzsa_arrival *pDestArrival = &pDestSlots[n];
if (pDestArrival->from_slot == 0 ||
nCodingChoiceCost < pDestArrival->cost ||
@ -210,6 +211,7 @@ static void lzsa_optimize_forward_v1(lzsa_compressor *pCompressor, lzsa_match *p
}
const lzsa_match *match = pCompressor->match + ((i - nStartOffset) << MATCHES_PER_INDEX_SHIFT_V1);
int nNumArrivalsForThisPos = j;
for (m = 0; m < NMATCHES_PER_INDEX_V1 && match[m].length; m++) {
int nMatchLen = match[m].length;
@ -228,7 +230,7 @@ static void lzsa_optimize_forward_v1(lzsa_compressor *pCompressor, lzsa_match *p
lzsa_arrival *pDestSlots = &arrival[(i + k) << ARRIVALS_PER_POSITION_SHIFT];
for (j = 0; j < NARRIVALS_PER_POSITION_V1 && cur_arrival[j].from_slot; j++) {
for (j = 0; j < nNumArrivalsForThisPos; 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 exists = 0;
@ -239,7 +241,7 @@ static void lzsa_optimize_forward_v1(lzsa_compressor *pCompressor, lzsa_match *p
for (n = 0;
n < NARRIVALS_PER_POSITION_V1 && pDestSlots[n].from_slot && pDestSlots[n].cost <= nCodingChoiceCost;
n++) {
if (lzsa_get_offset_cost_v1(pDestSlots[n].rep_offset) == lzsa_get_offset_cost_v1(match[m].offset)) {
if (lzsa_get_offset_cost_v1(pDestSlots[n].rep_offset) == nMatchOffsetCost) {
exists = 1;
break;
}