AuroraMiddleware/lz4
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re-inserted last byte test in widerMatch

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This commit is contained in:
Yann Collet 2017-10-09 01:44:05 -07:00
parent bdca63ed69
commit 97c18f5f0e
1 changed files with 22 additions and 19 deletions
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41
lib/lz4hc.c
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@ -181,6 +181,7 @@ LZ4_FORCE_INLINE int LZ4HC_InsertAndGetWiderMatch (
const BYTE* const lowPrefixPtr = base + dictLimit; const BYTE* const lowPrefixPtr = base + dictLimit;
const U32 lowLimit = (hc4->lowLimit + 64 KB > (U32)(ip-base)) ? hc4->lowLimit : (U32)(ip - base) - MAX_DISTANCE; const U32 lowLimit = (hc4->lowLimit + 64 KB > (U32)(ip-base)) ? hc4->lowLimit : (U32)(ip - base) - MAX_DISTANCE;
const BYTE* const dictBase = hc4->dictBase; const BYTE* const dictBase = hc4->dictBase;
int const delta = (int)(ip-iLowLimit);
int nbAttempts = maxNbAttempts; int nbAttempts = maxNbAttempts;
reg_t const pattern = LZ4_read_ARCH(ip); reg_t const pattern = LZ4_read_ARCH(ip);
U32 matchIndex; U32 matchIndex;
@ -196,26 +197,28 @@ LZ4_FORCE_INLINE int LZ4HC_InsertAndGetWiderMatch (
nbAttempts--; nbAttempts--;
if (matchIndex >= dictLimit) { if (matchIndex >= dictLimit) {
const BYTE* const matchPtr = base + matchIndex; const BYTE* const matchPtr = base + matchIndex;
if (LZ4_read32(matchPtr) == (U32)pattern) { if (*(iLowLimit + longest) == *(matchPtr - delta + longest)) {
int mlt = MINMATCH + LZ4_count(ip+MINMATCH, matchPtr+MINMATCH, iHighLimit); if (LZ4_read32(matchPtr) == (U32)pattern) {
#if 0 int mlt = MINMATCH + LZ4_count(ip+MINMATCH, matchPtr+MINMATCH, iHighLimit);
/* more generic but unfortunately slower ... */ #if 0
int const back = LZ4HC_countBack(ip, matchPtr, iLowLimit, lowPrefixPtr); /* more generic but unfortunately slower ... */
#else int const back = LZ4HC_countBack(ip, matchPtr, iLowLimit, lowPrefixPtr);
int back = 0; #else
while ( (ip+back > iLowLimit) int back = 0;
&& (matchPtr+back > lowPrefixPtr) while ( (ip+back > iLowLimit)
&& (ip[back-1] == matchPtr[back-1])) { && (matchPtr+back > lowPrefixPtr)
back--; && (ip[back-1] == matchPtr[back-1])) {
} back--;
#endif }
mlt -= back; #endif
mlt -= back;
if (mlt > longest) { if (mlt > longest) {
longest = mlt; longest = mlt;
*matchpos = matchPtr+back; *matchpos = matchPtr+back;
*startpos = ip+back; *startpos = ip+back;
} } } }
}
} else { /* matchIndex < dictLimit */ } else { /* matchIndex < dictLimit */
const BYTE* const matchPtr = dictBase + matchIndex; const BYTE* const matchPtr = dictBase + matchIndex;
if (LZ4_read32(matchPtr) == (U32)pattern) { if (LZ4_read32(matchPtr) == (U32)pattern) {