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| author | Yann Collet <Cyan4973@users.noreply.github.com> | 2022-01-29 05:26:24 (GMT) |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2022-01-29 05:26:24 (GMT) |
| commit | 49e4c671c8d17363170f209614c9fc9f594c77a4 (patch) | |
| tree | 4dbfdcc5b8b0ff3cd90c9482201e4748ff85a011 | |
| parent | 573fa33d1d2793da996eb6edad820c67439ce6a0 (diff) | |
| parent | e4f5a34d1613b3cce97124539c3a8b6b2ed42310 (diff) | |
| download | lz4-49e4c671c8d17363170f209614c9fc9f594c77a4.zip lz4-49e4c671c8d17363170f209614c9fc9f594c77a4.tar.gz lz4-49e4c671c8d17363170f209614c9fc9f594c77a4.tar.bz2 | |
Merge pull request #1056 from lz4/fix_opt12
fixed bug in optimal parser
| -rw-r--r-- | lib/lz4hc.c | 36 | ||||
| -rw-r--r-- | tests/Makefile | 1 |
2 files changed, 18 insertions, 19 deletions
diff --git a/lib/lz4hc.c b/lib/lz4hc.c index e71ce94..ee6fc41 100644 --- a/lib/lz4hc.c +++ b/lib/lz4hc.c @@ -193,8 +193,7 @@ LZ4HC_countPattern(const BYTE* ip, const BYTE* const iEnd, U32 const pattern32) BYTE const byte = (BYTE)(pattern >> bitOffset); if (*ip != byte) break; ip ++; bitOffset -= 8; - } - } + } } return (unsigned)(ip - iStart); } @@ -234,18 +233,16 @@ typedef enum { favorCompressionRatio=0, favorDecompressionSpeed } HCfavor_e; LZ4_FORCE_INLINE int LZ4HC_InsertAndGetWiderMatch ( - LZ4HC_CCtx_internal* hc4, - const BYTE* const ip, - const BYTE* const iLowLimit, - const BYTE* const iHighLimit, - int longest, - const BYTE** matchpos, - const BYTE** startpos, - const int maxNbAttempts, - const int patternAnalysis, - const int chainSwap, - const dictCtx_directive dict, - const HCfavor_e favorDecSpeed) + LZ4HC_CCtx_internal* const hc4, + const BYTE* const ip, + const BYTE* const iLowLimit, const BYTE* const iHighLimit, + int longest, + const BYTE** matchpos, + const BYTE** startpos, + const int maxNbAttempts, + const int patternAnalysis, const int chainSwap, + const dictCtx_directive dict, + const HCfavor_e favorDecSpeed) { U16* const chainTable = hc4->chainTable; U32* const HashTable = hc4->hashTable; @@ -254,7 +251,8 @@ LZ4HC_InsertAndGetWiderMatch ( const U32 dictLimit = hc4->dictLimit; const BYTE* const lowPrefixPtr = base + dictLimit; const U32 ipIndex = (U32)(ip - base); - const U32 lowestMatchIndex = (hc4->lowLimit + (LZ4_DISTANCE_MAX + 1) > ipIndex) ? hc4->lowLimit : ipIndex - LZ4_DISTANCE_MAX; + const int withinStartDistance = (hc4->lowLimit + (LZ4_DISTANCE_MAX + 1) > ipIndex); + const U32 lowestMatchIndex = (withinStartDistance) ? hc4->lowLimit : ipIndex - LZ4_DISTANCE_MAX; const BYTE* const dictBase = hc4->dictBase; int const lookBackLength = (int)(ip-iLowLimit); int nbAttempts = maxNbAttempts; @@ -294,7 +292,8 @@ LZ4HC_InsertAndGetWiderMatch ( } } } } else { /* lowestMatchIndex <= matchIndex < dictLimit */ const BYTE* const matchPtr = dictBase + matchIndex; - if (LZ4_read32(matchPtr) == pattern) { + if ( likely(matchIndex <= dictLimit - 4) + && (LZ4_read32(matchPtr) == pattern) ) { const BYTE* const dictStart = dictBase + hc4->lowLimit; int back = 0; const BYTE* vLimit = ip + (dictLimit - matchIndex); @@ -310,7 +309,7 @@ LZ4HC_InsertAndGetWiderMatch ( *startpos = ip + back; } } } - if (chainSwap && matchLength==longest) { /* better match => select a better chain */ + if (chainSwap && matchLength==longest) { /* better match => select a better chain */ assert(lookBackLength==0); /* search forward only */ if (matchIndex + (U32)longest <= ipIndex) { int const kTrigger = 4; @@ -326,8 +325,7 @@ LZ4HC_InsertAndGetWiderMatch ( distanceToNextMatch = candidateDist; matchChainPos = (U32)pos; accel = 1 << kTrigger; - } - } + } } if (distanceToNextMatch > 1) { if (distanceToNextMatch > matchIndex) break; /* avoid overflow */ matchIndex -= distanceToNextMatch; diff --git a/tests/Makefile b/tests/Makefile index d75fabe..b4df3e3 100644 --- a/tests/Makefile +++ b/tests/Makefile @@ -449,6 +449,7 @@ test-lz4-opt-parser: lz4 datagen $(DATAGEN) -g256K | $(LZ4) -12B4D | $(LZ4) -t $(DATAGEN) -g512K -P25 | $(LZ4) -12BD | $(LZ4) -t $(DATAGEN) -g1M | $(LZ4) -12B5 | $(LZ4) -t + $(DATAGEN) -g1M -s2 | $(LZ4) -12B4D | $(LZ4) -t $(DATAGEN) -g2M -P99 | $(LZ4) -11B4D | $(LZ4) -t $(DATAGEN) -g4M | $(LZ4) -11vq | $(LZ4) -qt $(DATAGEN) -g8M | $(LZ4) -11B4 | $(LZ4) -t |