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fixed Huff0 quad-symbols decoder (#173)

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This commit is contained in:
Yann Collet
2016-05-05 12:41:36 +02:00
parent ddb8ebd5b3
commit 6d1d25299a
2 changed files with 87 additions and 77 deletions
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lib/common/huf_static.h
+19 -20
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@@ -76,7 +76,7 @@ extern "C" {
******************************************/
size_t HUF_decompress4X2 (void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize); /* single-symbol decoder */
size_t HUF_decompress4X4 (void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize); /* double-symbols decoder */
size_t HUF_decompress4X6 (void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize); /* quad-symbols decoder */
size_t HUF_decompress4X6 (void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize); /* quad-symbols decoder, only works for dstSize >= 64 */
/* ****************************************
@@ -122,7 +122,7 @@ size_t HUF_compress1X_usingCTable(void* dst, size_t dstSize, const void* src, si
size_t HUF_decompress1X2 (void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize); /* single-symbol decoder */
size_t HUF_decompress1X4 (void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize); /* double-symbol decoder */
size_t HUF_decompress1X6 (void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize); /* quad-symbol decoder */
size_t HUF_decompress1X6 (void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize); /* quad-symbols decoder, only works for dstSize >= 64 */
size_t HUF_decompress1X2_usingDTable(void* dst, size_t maxDstSize, const void* cSrc, size_t cSrcSize, const unsigned short* DTable);
size_t HUF_decompress1X4_usingDTable(void* dst, size_t maxDstSize, const void* cSrc, size_t cSrcSize, const unsigned* DTable);
@@ -157,7 +157,6 @@ MEM_STATIC size_t HUF_readStats(BYTE* huffWeight, size_t hwSize, U32* rankStats,
const void* src, size_t srcSize)
{
U32 weightTotal;
U32 tableLog;
const BYTE* ip = (const BYTE*) src;
size_t iSize = ip[0];
size_t oSize;
@@ -191,31 +190,31 @@ MEM_STATIC size_t HUF_readStats(BYTE* huffWeight, size_t hwSize, U32* rankStats,
/* collect weight stats */
memset(rankStats, 0, (HUF_ABSOLUTEMAX_TABLELOG + 1) * sizeof(U32));
weightTotal = 0;
{ U32 n; for (n=0; n<oSize; n++) {
if (huffWeight[n] >= HUF_ABSOLUTEMAX_TABLELOG) return ERROR(corruption_detected);
rankStats[huffWeight[n]]++;
weightTotal += (1 << huffWeight[n]) >> 1;
}}
{ U32 n; for (n=0; n<oSize; n++) {
if (huffWeight[n] >= HUF_ABSOLUTEMAX_TABLELOG) return ERROR(corruption_detected);
rankStats[huffWeight[n]]++;
weightTotal += (1 << huffWeight[n]) >> 1;
} }
/* get last non-null symbol weight (implied, total must be 2^n) */
tableLog = BIT_highbit32(weightTotal) + 1;
if (tableLog > HUF_ABSOLUTEMAX_TABLELOG) return ERROR(corruption_detected);
/* determine last weight */
{ U32 const total = 1 << tableLog;
U32 const rest = total - weightTotal;
U32 const verif = 1 << BIT_highbit32(rest);
U32 const lastWeight = BIT_highbit32(rest) + 1;
if (verif != rest) return ERROR(corruption_detected); /* last value must be a clean power of 2 */
huffWeight[oSize] = (BYTE)lastWeight;
rankStats[lastWeight]++;
}
{ U32 const tableLog = BIT_highbit32(weightTotal) + 1;
if (tableLog > HUF_ABSOLUTEMAX_TABLELOG) return ERROR(corruption_detected);
*tableLogPtr = tableLog;
/* determine last weight */
{ U32 const total = 1 << tableLog;
U32 const rest = total - weightTotal;
U32 const verif = 1 << BIT_highbit32(rest);
U32 const lastWeight = BIT_highbit32(rest) + 1;
if (verif != rest) return ERROR(corruption_detected); /* last value must be a clean power of 2 */
huffWeight[oSize] = (BYTE)lastWeight;
rankStats[lastWeight]++;
} }
/* check tree construction validity */
if ((rankStats[1] < 2) || (rankStats[1] & 1)) return ERROR(corruption_detected); /* by construction : at least 2 elts of rank 1, must be even */
/* results */
*nbSymbolsPtr = (U32)(oSize+1);
*tableLogPtr = tableLog;
return iSize+1;
}