AuroraMiddleware/zstd
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updated FSE

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This commit is contained in:
Yann Collet 2015-02-24 09:05:58 +01:00
parent a3c75bad5a
commit 26aa1ec946
1 changed files with 9 additions and 12 deletions
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21
lib/fse.c
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@ -560,8 +560,6 @@ int FSE_compareRankT(const void* r1, const void* r2)
return 2 * (R1->count < R2->count) - 1;
}
static U32 g_tableLog_test =0;
static U32 g_total_test = 0;
#if 0
static size_t FSE_adjustNormSlow(short* norm, int pointsToRemove, const unsigned* count, U32 maxSymbolValue)
@ -607,16 +605,16 @@ static size_t FSE_adjustNormSlow(short* norm, int pointsToRemove, const unsigned
#else
static size_t FSE_adjustNormSlow(short* norm, int pointsToRemove, const unsigned* count, U32 maxSymbolValue)
/* Secondary normalization method.
To be used when primary method fails. */
static size_t FSE_normalizeM2(short* norm, U32 tableLog, const unsigned* count, size_t total, U32 maxSymbolValue)
{
U32 s;
U32 total = g_total_test;
U32 tableLog = g_tableLog_test;
U32 distributed = 0;
U32 ToDistribute;
/* Init */
(void)pointsToRemove;
U32 lowThreshold = (U32)(total >> tableLog);
U32 lowOne = (U32)((total * 3) >> (tableLog + 1));
@ -664,8 +662,9 @@ static size_t FSE_adjustNormSlow(short* norm, int pointsToRemove, const unsigned
if (distributed == maxSymbolValue+1)
{
/* all values are pretty poor; probably incompressible data (should have already been detected);
find max, then give all remaining to max */
/* all values are pretty poor;
probably incompressible data (should have already been detected);
find max, then give all remaining points to max */
U32 maxV = 0, maxC =0;
for (s=0; s<=maxSymbolValue; s++)
if (count[s] > maxC) maxV=s, maxC=count[s];
@ -750,12 +749,10 @@ size_t FSE_normalizeCount (short* normalizedCounter, unsigned tableLog,
stillToDistribute -= proba;
}
}
g_tableLog_test = tableLog;
g_total_test = total;
if (-stillToDistribute >= (normalizedCounter[largest] >> 1))
{
/* corner case, need to converge towards normalization with caution */
size_t errorCode = FSE_adjustNormSlow(normalizedCounter, -stillToDistribute, count, maxSymbolValue);
/* corner case, need another normalization method */
size_t errorCode = FSE_normalizeM2(normalizedCounter, tableLog, count, total, maxSymbolValue);
if (FSE_isError(errorCode)) return errorCode;
}
else normalizedCounter[largest] += (short)stillToDistribute;