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Truncate Chain at Last Possible Attempt

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Make the chain table denser?
This commit is contained in:
W. Felix Handte 2020-09-03 13:58:11 -04:00
parent 20a020edbc
commit f42c5bddd9
1 changed files with 4 additions and 2 deletions
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6
lib/compress/zstd_lazy.c
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@ -487,7 +487,9 @@ void ZSTD_dedicatedDictSearch_lazy_loadDictionary(ZSTD_matchState_t* ms, const B
U32 const chainMask = chainSize - 1; U32 const chainMask = chainSize - 1;
U32 idx = ms->nextToUpdate; U32 idx = ms->nextToUpdate;
U32 const minChain = chainSize < target ? target - chainSize : idx; U32 const minChain = chainSize < target ? target - chainSize : idx;
U32 bucketSize = 1 << ZSTD_LAZY_DDSS_BUCKET_LOG; U32 const bucketSize = 1 << ZSTD_LAZY_DDSS_BUCKET_LOG;
U32 const nbAttempts = (1 << ms->cParams.searchLog) - bucketSize + 1;
U32 const chainLimit = nbAttempts > 255 ? 255 : nbAttempts;
U32* const chains = (U32*)malloc(chainSize * sizeof(U32)); U32* const chains = (U32*)malloc(chainSize * sizeof(U32));
assert(chains != NULL); assert(chains != NULL);
assert(idx != 0); assert(idx != 0);
@ -517,7 +519,7 @@ void ZSTD_dedicatedDictSearch_lazy_loadDictionary(ZSTD_matchState_t* ms, const B
while (i) { while (i) {
chainTable[chainPos++] = i; chainTable[chainPos++] = i;
count++; count++;
if (i < minChain || count >= 255) { if (i < minChain || count >= chainLimit) {
break; break;
} }
i = chains[i & chainMask]; i = chains[i & chainMask];