ddidderr/zstd-rs
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updated fse

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This commit is contained in:
Yann Collet
2015-08-21 03:59:31 +01:00
parent 997f9ee2ef
commit d02114e0e1
1 changed files with 13 additions and 5 deletions
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lib/fse.c
+13 -5
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@@ -703,7 +703,7 @@ static short FSE_abs(short a)
****************************************************************/ ****************************************************************/
size_t FSE_NCountWriteBound(unsigned maxSymbolValue, unsigned tableLog) size_t FSE_NCountWriteBound(unsigned maxSymbolValue, unsigned tableLog)
{ {
size_t maxHeaderSize = (((maxSymbolValue+1) * tableLog) >> 3) + 3; size_t maxHeaderSize = (((maxSymbolValue+1) * tableLog) >> 3) + 3;
return maxSymbolValue ? maxHeaderSize : FSE_NCOUNTBOUND; /* maxSymbolValue==0 ? use default */ return maxSymbolValue ? maxHeaderSize : FSE_NCOUNTBOUND; /* maxSymbolValue==0 ? use default */
} }
@@ -964,14 +964,22 @@ void FSE_freeCTable (FSE_CTable* ct)
} }
unsigned FSE_optimalTableLog(unsigned maxTableLog, size_t srcSize, unsigned maxSymbolValue) /* provides the minimum logSize to safely represent a distribution */
static unsigned FSE_minTableLog(size_t srcSize, unsigned maxSymbolValue)
{ {
U32 tableLog = maxTableLog;
U32 minBitsSrc = FSE_highbit32((U32)(srcSize - 1)) + 1; U32 minBitsSrc = FSE_highbit32((U32)(srcSize - 1)) + 1;
U32 minBitsSymbols = FSE_highbit32(maxSymbolValue) + 2; U32 minBitsSymbols = FSE_highbit32(maxSymbolValue) + 2;
U32 minBits = minBitsSrc < minBitsSymbols ? minBitsSrc : minBitsSymbols; U32 minBits = minBitsSrc < minBitsSymbols ? minBitsSrc : minBitsSymbols;
return minBits;
}
unsigned FSE_optimalTableLog(unsigned maxTableLog, size_t srcSize, unsigned maxSymbolValue)
{
U32 maxBitsSrc = FSE_highbit32((U32)(srcSize - 1)) - 2;
U32 tableLog = maxTableLog;
U32 minBits = FSE_minTableLog(srcSize, maxSymbolValue);
if (tableLog==0) tableLog = FSE_DEFAULT_TABLELOG; if (tableLog==0) tableLog = FSE_DEFAULT_TABLELOG;
if (minBitsSrc < tableLog + 3) tableLog = minBitsSrc-3; /* Accuracy can be reduced */ if (maxBitsSrc < tableLog) tableLog = maxBitsSrc; /* Accuracy can be reduced */
if (minBits > tableLog) tableLog = minBits; /* Need a minimum to safely represent all symbol values */ if (minBits > tableLog) tableLog = minBits; /* Need a minimum to safely represent all symbol values */
if (tableLog < FSE_MIN_TABLELOG) tableLog = FSE_MIN_TABLELOG; if (tableLog < FSE_MIN_TABLELOG) tableLog = FSE_MIN_TABLELOG;
if (tableLog > FSE_MAX_TABLELOG) tableLog = FSE_MAX_TABLELOG; if (tableLog > FSE_MAX_TABLELOG) tableLog = FSE_MAX_TABLELOG;
@@ -1079,7 +1087,7 @@ size_t FSE_normalizeCount (short* normalizedCounter, unsigned tableLog,
if (tableLog==0) tableLog = FSE_DEFAULT_TABLELOG; if (tableLog==0) tableLog = FSE_DEFAULT_TABLELOG;
if (tableLog < FSE_MIN_TABLELOG) return (size_t)-FSE_ERROR_GENERIC; /* Unsupported size */ if (tableLog < FSE_MIN_TABLELOG) return (size_t)-FSE_ERROR_GENERIC; /* Unsupported size */
if (tableLog > FSE_MAX_TABLELOG) return (size_t)-FSE_ERROR_GENERIC; /* Unsupported size */ if (tableLog > FSE_MAX_TABLELOG) return (size_t)-FSE_ERROR_GENERIC; /* Unsupported size */
//if ((1U<<tableLog) <= maxSymbolValue) return (size_t)-FSE_ERROR_GENERIC; /* Too small tableLog, compression potentially impossible */ if (tableLog < FSE_minTableLog(total, maxSymbolValue)) return (size_t)-FSE_ERROR_GENERIC; /* Too small tableLog, compression potentially impossible */
{ {
U32 const rtbTable[] = { 0, 473195, 504333, 520860, 550000, 700000, 750000, 830000 }; U32 const rtbTable[] = { 0, 473195, 504333, 520860, 550000, 700000, 750000, 830000 };