updated fse
diff --git a/lib/fse.c b/lib/fse.c
index a577e81..2c55a56 100644
--- a/lib/fse.c
+++ b/lib/fse.c
@@ -703,7 +703,7 @@
****************************************************************/
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 */
}
@@ -964,14 +964,22 @@
}
-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 minBitsSymbols = FSE_highbit32(maxSymbolValue) + 2;
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 (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 (tableLog < FSE_MIN_TABLELOG) tableLog = FSE_MIN_TABLELOG;
if (tableLog > FSE_MAX_TABLELOG) tableLog = FSE_MAX_TABLELOG;
@@ -1079,7 +1087,7 @@
if (tableLog==0) tableLog = FSE_DEFAULT_TABLELOG;
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 ((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 };