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Simplify Match Limit Checks

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Seems like a ~1.25% speedup.
This commit is contained in:
W. Felix Handte
2020-09-10 22:10:02 -04:00
parent 06d240b8a7
commit ed43832770
1 changed files with 7 additions and 7 deletions
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lib/compress/zstd_lazy.c
+7 -7
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@@ -535,8 +535,7 @@ void ZSTD_dedicatedDictSearch_lazy_loadDictionary(ZSTD_matchState_t* ms, const B
if (count == cacheSize) { if (count == cacheSize) {
for (count = 0; count < chainLimit;) { for (count = 0; count < chainLimit;) {
if (i < minChain) { if (i < minChain) {
countBeyondMinChain++; if (!i || countBeyondMinChain++ > cacheSize) {
if (countBeyondMinChain > cacheSize) {
/* only allow pulling `cacheSize` number of entries /* only allow pulling `cacheSize` number of entries
* into the cache or chainTable beyond `minChain`, * into the cache or chainTable beyond `minChain`,
* to replace the entries pulled out of the * to replace the entries pulled out of the
@@ -688,10 +687,13 @@ size_t ZSTD_HcFindBestMatch_generic (
matchIndex = dms->hashTable[ddsIdx + ddsAttempt]; matchIndex = dms->hashTable[ddsIdx + ddsAttempt];
match = ddsBase + matchIndex; match = ddsBase + matchIndex;
if (matchIndex < ddsLowestIndex) { if (!matchIndex) {
return ml; return ml;
} }
/* guaranteed by table construction */
(void)ddsLowestIndex;
assert(matchIndex >= ddsLowestIndex);
assert(match+4 <= ddsEnd); assert(match+4 <= ddsEnd);
if (MEM_read32(match) == MEM_read32(ip)) { if (MEM_read32(match) == MEM_read32(ip)) {
/* assumption : matchIndex <= dictLimit-4 (by table construction) */ /* assumption : matchIndex <= dictLimit-4 (by table construction) */
@@ -727,10 +729,8 @@ size_t ZSTD_HcFindBestMatch_generic (
matchIndex = dms->chainTable[chainIndex]; matchIndex = dms->chainTable[chainIndex];
match = ddsBase + matchIndex; match = ddsBase + matchIndex;
if (matchIndex < ddsLowestIndex) { /* guaranteed by table construction */
break; assert(matchIndex >= ddsLowestIndex);
}
assert(match+4 <= ddsEnd); assert(match+4 <= ddsEnd);
if (MEM_read32(match) == MEM_read32(ip)) { if (MEM_read32(match) == MEM_read32(ip)) {
/* assumption : matchIndex <= dictLimit-4 (by table construction) */ /* assumption : matchIndex <= dictLimit-4 (by table construction) */