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Add early-out, speed LZSA2 compression up further

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This commit is contained in:
Emmanuel Marty
2019-10-08 16:23:33 +02:00
committed by GitHub
parent bfb383befd
commit 44df8f3d2d
1 changed files with 103 additions and 97 deletions
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200
src/shrink_block_v2.c
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@@ -215,35 +215,37 @@ static void lzsa_optimize_forward_v2(lzsa_compressor *pCompressor, const unsigne
if (!nFavorRatio && nNumLiterals == 1) if (!nFavorRatio && nNumLiterals == 1)
nCodingChoiceCost += MODESWITCH_PENALTY; nCodingChoiceCost += MODESWITCH_PENALTY;
int exists = 0; if (arrival[((i + 1) << MATCHES_PER_OFFSET_SHIFT) + NMATCHES_PER_OFFSET - 1].from_slot == 0 || nCodingChoiceCost <= arrival[((i + 1) << MATCHES_PER_OFFSET_SHIFT) + NMATCHES_PER_OFFSET - 1].cost) {
for (n = 0; int exists = 0;
n < NMATCHES_PER_OFFSET && arrival[((i + 1) << MATCHES_PER_OFFSET_SHIFT) + n].from_slot && arrival[((i + 1) << MATCHES_PER_OFFSET_SHIFT) + n].cost <= nCodingChoiceCost; for (n = 0;
n++) { n < NMATCHES_PER_OFFSET && arrival[((i + 1) << MATCHES_PER_OFFSET_SHIFT) + n].from_slot && arrival[((i + 1) << MATCHES_PER_OFFSET_SHIFT) + n].cost <= nCodingChoiceCost;
if (arrival[((i + 1) << MATCHES_PER_OFFSET_SHIFT) + n].rep_offset == arrival[(i << MATCHES_PER_OFFSET_SHIFT) + j].rep_offset) { n++) {
exists = 1; if (arrival[((i + 1) << MATCHES_PER_OFFSET_SHIFT) + n].rep_offset == arrival[(i << MATCHES_PER_OFFSET_SHIFT) + j].rep_offset) {
break; exists = 1;
} break;
}
for (n = 0; !exists && n < NMATCHES_PER_OFFSET; n++) {
lzsa_arrival *pDestArrival = &arrival[((i + 1) << MATCHES_PER_OFFSET_SHIFT) + n];
if (pDestArrival->from_slot == 0 ||
nCodingChoiceCost <= pDestArrival->cost) {
if (pDestArrival->from_slot) {
memmove(&arrival[((i + 1) << MATCHES_PER_OFFSET_SHIFT) + n + 1],
&arrival[((i + 1) << MATCHES_PER_OFFSET_SHIFT) + n],
sizeof(lzsa_arrival) * (NMATCHES_PER_OFFSET - n - 1));
} }
}
pDestArrival->cost = nCodingChoiceCost; for (n = 0; !exists && n < NMATCHES_PER_OFFSET; n++) {
pDestArrival->from_pos = i; lzsa_arrival *pDestArrival = &arrival[((i + 1) << MATCHES_PER_OFFSET_SHIFT) + n];
pDestArrival->from_slot = j + 1; if (pDestArrival->from_slot == 0 ||
pDestArrival->match_offset = 0; nCodingChoiceCost <= pDestArrival->cost) {
pDestArrival->match_len = 0;
pDestArrival->num_literals = nNumLiterals; if (pDestArrival->from_slot) {
pDestArrival->rep_offset = arrival[(i << MATCHES_PER_OFFSET_SHIFT) + j].rep_offset; memmove(&arrival[((i + 1) << MATCHES_PER_OFFSET_SHIFT) + n + 1],
break; &arrival[((i + 1) << MATCHES_PER_OFFSET_SHIFT) + n],
sizeof(lzsa_arrival) * (NMATCHES_PER_OFFSET - n - 1));
}
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->rep_offset = arrival[(i << MATCHES_PER_OFFSET_SHIFT) + j].rep_offset;
break;
}
} }
} }
} }
@@ -291,83 +293,87 @@ static void lzsa_optimize_forward_v2(lzsa_compressor *pCompressor, const unsigne
int nRepOffset = arrival[(i << MATCHES_PER_OFFSET_SHIFT) + j].rep_offset; int nRepOffset = arrival[(i << MATCHES_PER_OFFSET_SHIFT) + j].rep_offset;
int nMatchOffsetCost = (nMatchOffset == nRepOffset) ? 0 : nNoRepmatchOffsetCost; int nMatchOffsetCost = (nMatchOffset == nRepOffset) ? 0 : nNoRepmatchOffsetCost;
int nCodingChoiceCost = nPrevCost + 8 /* token */ /* the actual cost of the literals themselves accumulates up the chain */ + nMatchOffsetCost + nMatchLenCost; int nRepCodingChoiceCost = nPrevCost + 8 /* token */ /* the actual cost of the literals themselves accumulates up the chain */ + nMatchLenCost;
int nCodingChoiceCost = nRepCodingChoiceCost + nMatchOffsetCost;
int exists = 0; int exists = 0;
if (!nFavorRatio && !arrival[(i << MATCHES_PER_OFFSET_SHIFT) + j].num_literals) if (!nFavorRatio && !arrival[(i << MATCHES_PER_OFFSET_SHIFT) + j].num_literals)
nCodingChoiceCost += MODESWITCH_PENALTY; nCodingChoiceCost += MODESWITCH_PENALTY;
for (n = 0; if (pDestSlots[NMATCHES_PER_OFFSET - 1].from_slot == 0 || nRepCodingChoiceCost <= pDestSlots[NMATCHES_PER_OFFSET - 1].cost) {
n < NMATCHES_PER_OFFSET && pDestSlots[n].from_slot && pDestSlots[n].cost <= nCodingChoiceCost; if (pDestSlots[NMATCHES_PER_OFFSET - 1].from_slot == 0 || nCodingChoiceCost <= pDestSlots[NMATCHES_PER_OFFSET - 1].cost) {
n++) { for (n = 0;
if (pDestSlots[n].rep_offset == nMatchOffset) { n < NMATCHES_PER_OFFSET && pDestSlots[n].from_slot && pDestSlots[n].cost <= nCodingChoiceCost;
exists = 1; n++) {
break; if (pDestSlots[n].rep_offset == nMatchOffset) {
} exists = 1;
} break;
for (n = 0; !exists && n < NMATCHES_PER_OFFSET; n++) {
lzsa_arrival *pDestArrival = &pDestSlots[n];
if (pDestArrival->from_slot == 0 ||
nCodingChoiceCost <= pDestArrival->cost) {
if (pDestArrival->from_slot) {
memmove(&pDestSlots[n + 1],
&pDestSlots[n],
sizeof(lzsa_arrival) * (NMATCHES_PER_OFFSET - n - 1));
}
pDestArrival->cost = nCodingChoiceCost;
pDestArrival->from_pos = i;
pDestArrival->from_slot = j + 1;
pDestArrival->match_offset = nMatchOffset;
pDestArrival->match_len = k;
pDestArrival->num_literals = 0;
pDestArrival->rep_offset = nMatchOffset;
break;
}
}
/* If this coding choice doesn't rep-match, see if we still get a match by using the current repmatch offset for this arrival. This can occur (and not have the
* matchfinder offer the offset in the first place, or have too many choices with the same cost to retain the repmatchable offset) when compressing regions
* of identical bytes, for instance. Checking for this provides a big compression win on some files. */
if (nMaxRepLen[j] >= k) {
/* A match is possible at the rep offset; insert the extra coding choice. */
nCodingChoiceCost = nPrevCost + 8 /* token */ /* the actual cost of the literals themselves accumulates up the chain */ + /* rep match - no offset cost */ nMatchLenCost;
exists = 0;
for (n = 0;
n < NMATCHES_PER_OFFSET && pDestSlots[n].from_slot && pDestSlots[n].cost <= nCodingChoiceCost;
n++) {
if (pDestSlots[n].rep_offset == nRepOffset) {
exists = 1;
break;
}
}
for (n = 0; !exists && n < NMATCHES_PER_OFFSET; n++) {
lzsa_arrival *pDestArrival = &pDestSlots[n];
if (pDestArrival->from_slot == 0 ||
nCodingChoiceCost <= pDestArrival->cost) {
if (pDestArrival->from_slot) {
memmove(&pDestSlots[n + 1],
&pDestSlots[n],
sizeof(lzsa_arrival) * (NMATCHES_PER_OFFSET - n - 1));
} }
}
pDestArrival->cost = nCodingChoiceCost; for (n = 0; !exists && n < NMATCHES_PER_OFFSET; n++) {
pDestArrival->from_pos = i; lzsa_arrival *pDestArrival = &pDestSlots[n];
pDestArrival->from_slot = j + 1;
pDestArrival->match_offset = nRepOffset; if (pDestArrival->from_slot == 0 ||
pDestArrival->match_len = k; nCodingChoiceCost <= pDestArrival->cost) {
pDestArrival->num_literals = 0;
pDestArrival->rep_offset = nRepOffset; if (pDestArrival->from_slot) {
break; memmove(&pDestSlots[n + 1],
&pDestSlots[n],
sizeof(lzsa_arrival) * (NMATCHES_PER_OFFSET - n - 1));
}
pDestArrival->cost = nCodingChoiceCost;
pDestArrival->from_pos = i;
pDestArrival->from_slot = j + 1;
pDestArrival->match_offset = nMatchOffset;
pDestArrival->match_len = k;
pDestArrival->num_literals = 0;
pDestArrival->rep_offset = nMatchOffset;
break;
}
}
}
/* If this coding choice doesn't rep-match, see if we still get a match by using the current repmatch offset for this arrival. This can occur (and not have the
* matchfinder offer the offset in the first place, or have too many choices with the same cost to retain the repmatchable offset) when compressing regions
* of identical bytes, for instance. Checking for this provides a big compression win on some files. */
if (nMaxRepLen[j] >= k) {
/* A match is possible at the rep offset; insert the extra coding choice. */
exists = 0;
for (n = 0;
n < NMATCHES_PER_OFFSET && pDestSlots[n].from_slot && pDestSlots[n].cost <= nRepCodingChoiceCost;
n++) {
if (pDestSlots[n].rep_offset == nRepOffset) {
exists = 1;
break;
}
}
for (n = 0; !exists && n < NMATCHES_PER_OFFSET; n++) {
lzsa_arrival *pDestArrival = &pDestSlots[n];
if (pDestArrival->from_slot == 0 ||
nRepCodingChoiceCost <= pDestArrival->cost) {
if (pDestArrival->from_slot) {
memmove(&pDestSlots[n + 1],
&pDestSlots[n],
sizeof(lzsa_arrival) * (NMATCHES_PER_OFFSET - n - 1));
}
pDestArrival->cost = nRepCodingChoiceCost;
pDestArrival->from_pos = i;
pDestArrival->from_slot = j + 1;
pDestArrival->match_offset = nRepOffset;
pDestArrival->match_len = k;
pDestArrival->num_literals = 0;
pDestArrival->rep_offset = nRepOffset;
break;
}
} }
} }
} }