ddidderr/zstd-rs
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simplified chain

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This commit is contained in:
Yann Collet
2015-10-27 03:06:40 +01:00
parent 8b91abec18
commit d55a7e0e4d
1 changed files with 3 additions and 4 deletions
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lib/zstdhc.c
+3 -4
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@@ -143,7 +143,7 @@ static void ZSTD_HC_resetCCtx_advanced (ZSTD_HC_CCtx* zc,
***************************************/ ***************************************/
#define KNUTH 2654435761U #define KNUTH 2654435761U
static U32 ZSTD_HC_hash(U32 u, U32 h) { return (u * KNUTH) >> (32-h) ; } static U32 ZSTD_HC_hash(U32 u, U32 h) { return (u * KNUTH) >> (32-h) ; }
#define DELTANEXT(d) chainTable[(d) & chainMask] /* flexible, CHAINSIZE dependent */ #define NEXT_IN_CHAIN(d) chainTable[(d) & chainMask] /* flexible, CHAINSIZE dependent */
static U32 ZSTD_HC_hashPtr(const void* ptr, U32 h) { return ZSTD_HC_hash(MEM_read32(ptr), h); } static U32 ZSTD_HC_hashPtr(const void* ptr, U32 h) { return ZSTD_HC_hash(MEM_read32(ptr), h); }
@@ -165,8 +165,7 @@ static void ZSTD_HC_insert (ZSTD_HC_CCtx* zc, const BYTE* ip)
while(idx < target) while(idx < target)
{ {
U32 h = ZSTD_HC_hashPtr(base+idx, hashLog); U32 h = ZSTD_HC_hashPtr(base+idx, hashLog);
size_t delta = idx - hashTable[h]; NEXT_IN_CHAIN(idx) = hashTable[h];
DELTANEXT(idx) = (U32)delta;
hashTable[h] = idx; hashTable[h] = idx;
idx++; idx++;
} }
@@ -229,7 +228,7 @@ static size_t ZSTD_HC_insertAndFindBestMatch (
} }
if (base + matchIndex <= ip - chainSize) break; if (base + matchIndex <= ip - chainSize) break;
matchIndex -= DELTANEXT(matchIndex); matchIndex = NEXT_IN_CHAIN(matchIndex);
} }
return ml; return ml;