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optimized counting of small segments

dev
Yann Collet 2016-01-28 03:24:53 +01:00
parent e618f8e221
commit 4ddb1f5566
3 changed files with 159 additions and 158 deletions
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299
lib/fse.c
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@ -141,102 +141,6 @@ typedef U32 DTable_max_t[FSE_DTABLE_SIZE_U32(FSE_MAX_TABLELOG)];
/* Function templates */
size_t FSE_count_generic(unsigned* count, unsigned* maxSymbolValuePtr, const FSE_FUNCTION_TYPE* source, size_t sourceSize, unsigned safe)
{
const FSE_FUNCTION_TYPE* ip = source;
const FSE_FUNCTION_TYPE* const iend = ip+sourceSize;
unsigned maxSymbolValue = *maxSymbolValuePtr;
unsigned max=0;
int s;
U32 Counting1[FSE_MAX_SYMBOL_VALUE+1] = { 0 };
U32 Counting2[FSE_MAX_SYMBOL_VALUE+1] = { 0 };
U32 Counting3[FSE_MAX_SYMBOL_VALUE+1] = { 0 };
U32 Counting4[FSE_MAX_SYMBOL_VALUE+1] = { 0 };
/* safety checks */
if (!sourceSize)
{
memset(count, 0, (maxSymbolValue + 1) * sizeof(FSE_FUNCTION_TYPE));
*maxSymbolValuePtr = 0;
return 0;
}
if (maxSymbolValue > FSE_MAX_SYMBOL_VALUE) return ERROR(GENERIC); /* maxSymbolValue too large : unsupported */
if (!maxSymbolValue) maxSymbolValue = FSE_MAX_SYMBOL_VALUE; /* 0 == default */
if ((safe) || (sizeof(FSE_FUNCTION_TYPE)>1))
{
/* check input values, to avoid count table overflow */
while (ip < iend-3)
{
if (*ip>maxSymbolValue) return ERROR(GENERIC); Counting1[*ip++]++;
if (*ip>maxSymbolValue) return ERROR(GENERIC); Counting2[*ip++]++;
if (*ip>maxSymbolValue) return ERROR(GENERIC); Counting3[*ip++]++;
if (*ip>maxSymbolValue) return ERROR(GENERIC); Counting4[*ip++]++;
}
}
else
{
U32 cached = MEM_read32(ip); ip += 4;
while (ip < iend-15)
{
U32 c = cached; cached = MEM_read32(ip); ip += 4;
Counting1[(BYTE) c ]++;
Counting2[(BYTE)(c>>8) ]++;
Counting3[(BYTE)(c>>16)]++;
Counting4[ c>>24 ]++;
c = cached; cached = MEM_read32(ip); ip += 4;
Counting1[(BYTE) c ]++;
Counting2[(BYTE)(c>>8) ]++;
Counting3[(BYTE)(c>>16)]++;
Counting4[ c>>24 ]++;
c = cached; cached = MEM_read32(ip); ip += 4;
Counting1[(BYTE) c ]++;
Counting2[(BYTE)(c>>8) ]++;
Counting3[(BYTE)(c>>16)]++;
Counting4[ c>>24 ]++;
c = cached; cached = MEM_read32(ip); ip += 4;
Counting1[(BYTE) c ]++;
Counting2[(BYTE)(c>>8) ]++;
Counting3[(BYTE)(c>>16)]++;
Counting4[ c>>24 ]++;
}
ip-=4;
}
/* finish last symbols */
while (ip<iend) { if ((safe) && (*ip>maxSymbolValue)) return ERROR(GENERIC); Counting1[*ip++]++; }
for (s=0; s<=(int)maxSymbolValue; s++)
{
count[s] = Counting1[s] + Counting2[s] + Counting3[s] + Counting4[s];
if (count[s] > max) max = count[s];
}
while (!count[maxSymbolValue]) maxSymbolValue--;
*maxSymbolValuePtr = maxSymbolValue;
return (size_t)max;
}
/* hidden fast variant (unsafe) */
size_t FSE_FUNCTION_NAME(FSE_countFast, FSE_FUNCTION_EXTENSION)
(unsigned* count, unsigned* maxSymbolValuePtr, const FSE_FUNCTION_TYPE* source, size_t sourceSize)
{
return FSE_count_generic(count, maxSymbolValuePtr, source, sourceSize, 0);
}
size_t FSE_FUNCTION_NAME(FSE_count, FSE_FUNCTION_EXTENSION)
(unsigned* count, unsigned* maxSymbolValuePtr, const FSE_FUNCTION_TYPE* source, size_t sourceSize)
{
if ((sizeof(FSE_FUNCTION_TYPE)==1) && (*maxSymbolValuePtr >= 255))
{
*maxSymbolValuePtr = 255;
return FSE_count_generic(count, maxSymbolValuePtr, source, sourceSize, 0);
}
return FSE_count_generic(count, maxSymbolValuePtr, source, sourceSize, 1);
}
static U32 FSE_tableStep(U32 tableSize) { return (tableSize>>1) + (tableSize>>3) + 3; }
size_t FSE_buildCTable(FSE_CTable* ct, const short* normalizedCounter, unsigned maxSymbolValue, unsigned tableLog)
@ -264,35 +168,28 @@ size_t FSE_buildCTable(FSE_CTable* ct, const short* normalizedCounter, unsigned
/* symbol start positions */
cumul[0] = 0;
for (i=1; i<=maxSymbolValue+1; i++)
{
if (normalizedCounter[i-1]==-1) /* Low proba symbol */
{
for (i=1; i<=maxSymbolValue+1; i++) {
if (normalizedCounter[i-1]==-1) { /* Low proba symbol */
cumul[i] = cumul[i-1] + 1;
tableSymbol[highThreshold--] = (FSE_FUNCTION_TYPE)(i-1);
}
else
} else {
cumul[i] = cumul[i-1] + normalizedCounter[i-1];
}
} }
cumul[maxSymbolValue+1] = tableSize+1;
/* Spread symbols */
for (symbol=0; symbol<=maxSymbolValue; symbol++)
{
for (symbol=0; symbol<=maxSymbolValue; symbol++) {
int nbOccurences;
for (nbOccurences=0; nbOccurences<normalizedCounter[symbol]; nbOccurences++)
{
for (nbOccurences=0; nbOccurences<normalizedCounter[symbol]; nbOccurences++) {
tableSymbol[position] = (FSE_FUNCTION_TYPE)symbol;
position = (position + step) & tableMask;
while (position > highThreshold) position = (position + step) & tableMask; /* Low proba area */
}
}
} }
if (position!=0) return ERROR(GENERIC); /* Must have gone through all positions */
/* Build table */
for (i=0; i<tableSize; i++)
{
for (i=0; i<tableSize; i++) {
FSE_FUNCTION_TYPE s = tableSymbol[i]; /* note : static analyzer may not understand tableSymbol is properly initialized */
tableU16[cumul[s]++] = (U16) (tableSize+i); /* TableU16 : sorted by symbol order; gives next state value */
}
@ -301,8 +198,7 @@ size_t FSE_buildCTable(FSE_CTable* ct, const short* normalizedCounter, unsigned
{
unsigned s;
unsigned total = 0;
for (s=0; s<=maxSymbolValue; s++)
{
for (s=0; s<=maxSymbolValue; s++) {
switch (normalizedCounter[s])
{
case 0:
@ -323,7 +219,7 @@ size_t FSE_buildCTable(FSE_CTable* ct, const short* normalizedCounter, unsigned
}
}
}
}
} /* Build Symbol Transformation Table */
return 0;
}
@ -361,45 +257,35 @@ size_t FSE_buildDTable(FSE_DTable* dt, const short* normalizedCounter, unsigned
/* Init, lay down lowprob symbols */
DTableH.tableLog = (U16)tableLog;
for (s=0; s<=maxSymbolValue; s++)
{
if (normalizedCounter[s]==-1)
{
for (s=0; s<=maxSymbolValue; s++) {
if (normalizedCounter[s]==-1) {
tableDecode[highThreshold--].symbol = (FSE_FUNCTION_TYPE)s;
symbolNext[s] = 1;
}
else
{
} else {
if (normalizedCounter[s] >= largeLimit) noLarge=0;
symbolNext[s] = normalizedCounter[s];
}
}
} }
/* Spread symbols */
for (s=0; s<=maxSymbolValue; s++)
{
for (s=0; s<=maxSymbolValue; s++) {
int i;
for (i=0; i<normalizedCounter[s]; i++)
{
for (i=0; i<normalizedCounter[s]; i++) {
tableDecode[position].symbol = (FSE_FUNCTION_TYPE)s;
position = (position + step) & tableMask;
while (position > highThreshold) position = (position + step) & tableMask; /* lowprob area */
}
}
} }
if (position!=0) return ERROR(GENERIC); /* position must reach all cells once, otherwise normalizedCounter is incorrect */
/* Build Decoding table */
{
U32 i;
for (i=0; i<tableSize; i++)
{
for (i=0; i<tableSize; i++) {
FSE_FUNCTION_TYPE symbol = (FSE_FUNCTION_TYPE)(tableDecode[i].symbol);
U16 nextState = symbolNext[symbol]++;
tableDecode[i].nbBits = (BYTE) (tableLog - BIT_highbit32 ((U32)nextState) );
tableDecode[i].newState = (U16) ( (nextState << tableDecode[i].nbBits) - tableSize);
}
}
} }
DTableH.fastMode = (U16)noLarge;
memcpy(dt, &DTableH, sizeof(DTableH));
@ -408,7 +294,7 @@ size_t FSE_buildDTable(FSE_DTable* dt, const short* normalizedCounter, unsigned
#ifndef FSE_COMMONDEFS_ONLY
/******************************************
/*-****************************************
* FSE helper functions
******************************************/
unsigned FSE_isError(size_t code) { return ERR_isError(code); }
@ -416,7 +302,7 @@ unsigned FSE_isError(size_t code) { return ERR_isError(code); }
const char* FSE_getErrorName(size_t code) { return ERR_getErrorName(code); }
/****************************************************************
/*-**************************************************************
* FSE NCount encoding-decoding
****************************************************************/
size_t FSE_NCountWriteBound(unsigned maxSymbolValue, unsigned tableLog)
@ -623,10 +509,131 @@ size_t FSE_readNCount (short* normalizedCounter, unsigned* maxSVPtr, unsigned* t
}
/****************************************************************
/*-**************************************************************
* Counting histogram
****************************************************************/
/*! FSE_count_simple
This function just counts byte values within @src,
and store the histogram into @count.
This function is unsafe : it doesn't check that all values within @src can fit into @count.
For this reason, prefer using a table @count with 256 elements.
@return : highest count for a single element
*/
static size_t FSE_count_simple(unsigned* count, unsigned* maxSymbolValuePtr,
const void* src, size_t srcSize)
{
const BYTE* ip = (const BYTE*)src;
const BYTE* const end = ip + srcSize;
unsigned maxSymbolValue = *maxSymbolValuePtr;
unsigned max=0;
U32 s;
memset(count, 0, (maxSymbolValue+1)*sizeof(*count));
if (srcSize==0) { *maxSymbolValuePtr = 0; return 0; }
while (ip<end) count[*ip++]++;
while (!count[maxSymbolValue]) maxSymbolValue--;
*maxSymbolValuePtr = maxSymbolValue;
for (s=0; s<=maxSymbolValue; s++) if (count[s] > max) max = count[s];
return (size_t)max;
}
static size_t FSE_count_parallel(unsigned* count, unsigned* maxSymbolValuePtr,
const void* source, size_t sourceSize,
unsigned checkMax)
{
const BYTE* ip = (const BYTE*)source;
const BYTE* const iend = ip+sourceSize;
unsigned maxSymbolValue = *maxSymbolValuePtr;
unsigned max=0;
U32 s;
U32 Counting1[256] = { 0 };
U32 Counting2[256] = { 0 };
U32 Counting3[256] = { 0 };
U32 Counting4[256] = { 0 };
/* safety checks */
if (!sourceSize) {
memset(count, 0, maxSymbolValue + 1);
*maxSymbolValuePtr = 0;
return 0;
}
if (!maxSymbolValue) maxSymbolValue = 255; /* 0 == default */
{ /* by stripes of 16 bytes */
U32 cached = MEM_read32(ip); ip += 4;
while (ip < iend-15) {
U32 c = cached; cached = MEM_read32(ip); ip += 4;
Counting1[(BYTE) c ]++;
Counting2[(BYTE)(c>>8) ]++;
Counting3[(BYTE)(c>>16)]++;
Counting4[ c>>24 ]++;
c = cached; cached = MEM_read32(ip); ip += 4;
Counting1[(BYTE) c ]++;
Counting2[(BYTE)(c>>8) ]++;
Counting3[(BYTE)(c>>16)]++;
Counting4[ c>>24 ]++;
c = cached; cached = MEM_read32(ip); ip += 4;
Counting1[(BYTE) c ]++;
Counting2[(BYTE)(c>>8) ]++;
Counting3[(BYTE)(c>>16)]++;
Counting4[ c>>24 ]++;
c = cached; cached = MEM_read32(ip); ip += 4;
Counting1[(BYTE) c ]++;
Counting2[(BYTE)(c>>8) ]++;
Counting3[(BYTE)(c>>16)]++;
Counting4[ c>>24 ]++;
}
ip-=4;
}
/* finish last symbols */
while (ip<iend) Counting1[*ip++]++;
if (checkMax) { /* verify stats will fit into destination table */
for (s=255; s>maxSymbolValue; s--)
{
Counting1[s] += Counting2[s] + Counting3[s] + Counting4[s];
if (Counting1[s]) return ERROR(maxSymbolValue_tooSmall);
} }
for (s=0; s<=maxSymbolValue; s++) {
count[s] = Counting1[s] + Counting2[s] + Counting3[s] + Counting4[s];
if (count[s] > max) max = count[s];
}
while (!count[maxSymbolValue]) maxSymbolValue--;
*maxSymbolValuePtr = maxSymbolValue;
return (size_t)max;
}
/* fast variant (unsafe : won't check if src contains values beyond count[] limit) */
size_t FSE_countFast(unsigned* count, unsigned* maxSymbolValuePtr,
const void* source, size_t sourceSize)
{
if (sourceSize < 1500) return FSE_count_simple(count, maxSymbolValuePtr, source, sourceSize);
return FSE_count_parallel(count, maxSymbolValuePtr, source, sourceSize, 0);
}
size_t FSE_count(unsigned* count, unsigned* maxSymbolValuePtr,
const void* source, size_t sourceSize)
{
if (*maxSymbolValuePtr <255)
return FSE_count_parallel(count, maxSymbolValuePtr, source, sourceSize, 1);
*maxSymbolValuePtr = 255;
return FSE_countFast(count, maxSymbolValuePtr, source, sourceSize);
}
/*-**************************************************************
* FSE Compression Code
****************************************************************/
/*
/*!
FSE_CTable is a variable size structure which contains :
U16 tableLog;
U16 maxSymbolValue;
@ -657,7 +664,6 @@ void FSE_freeCTable (FSE_CTable* ct)
free(ct);
}
/* provides the minimum logSize to safely represent a distribution */
static unsigned FSE_minTableLog(size_t srcSize, unsigned maxSymbolValue)
{
@ -872,10 +878,8 @@ size_t FSE_buildCTable_rle (FSE_CTable* ct, BYTE symbolValue)
tableU16[1] = 0; /* just in case */
/* Build Symbol Transformation Table */
{
symbolTT[symbolValue].deltaNbBits = 0;
symbolTT[symbolValue].deltaFindState = 0;
}
symbolTT[symbolValue].deltaNbBits = 0;
symbolTT[symbolValue].deltaFindState = 0;
return 0;
}
@ -905,15 +909,13 @@ static size_t FSE_compress_usingCTable_generic (void* dst, size_t dstSize,
#define FSE_FLUSHBITS(s) (fast ? BIT_flushBitsFast(s) : BIT_flushBits(s))
/* join to even */
if (srcSize & 1)
{
if (srcSize & 1) {
FSE_encodeSymbol(&bitC, &CState1, *--ip);
FSE_FLUSHBITS(&bitC);
}
/* join to mod 4 */
if ((sizeof(bitC.bitContainer)*8 > FSE_MAX_TABLELOG*4+7 ) && (srcSize & 2)) /* test bit 2 */
{
if ((sizeof(bitC.bitContainer)*8 > FSE_MAX_TABLELOG*4+7 ) && (srcSize & 2)) { /* test bit 2 */
FSE_encodeSymbol(&bitC, &CState2, *--ip);
FSE_encodeSymbol(&bitC, &CState1, *--ip);
FSE_FLUSHBITS(&bitC);
@ -929,8 +931,7 @@ static size_t FSE_compress_usingCTable_generic (void* dst, size_t dstSize,
FSE_encodeSymbol(&bitC, &CState1, *--ip);
if (sizeof(bitC.bitContainer)*8 > FSE_MAX_TABLELOG*4+7 ) /* this test must be static */
{
if (sizeof(bitC.bitContainer)*8 > FSE_MAX_TABLELOG*4+7 ) { /* this test must be static */
FSE_encodeSymbol(&bitC, &CState2, *--ip);
FSE_encodeSymbol(&bitC, &CState1, *--ip);
}
@ -1013,7 +1014,7 @@ size_t FSE_compress (void* dst, size_t dstSize, const void* src, size_t srcSize)
}
/*********************************************************
/*-*******************************************************
* Decompression (Byte symbols)
*********************************************************/
size_t FSE_buildDTable_rle (FSE_DTable* dt, BYTE symbolValue)

14
lib/fse.h
View File

@ -124,13 +124,13 @@ or to save and provide normalized distribution using external method.
/*!
FSE_count():
Provides the precise count of each symbol within a table 'count'
'count' is a table of unsigned int, of minimum size (maxSymbolValuePtr[0]+1).
maxSymbolValuePtr[0] will be updated if detected smaller than initially expected
return : the count of the most frequent symbol (which is not identified)
if return == srcSize, there is only one symbol.
if FSE_isError(return), it's an error code. */
size_t FSE_count(unsigned* count, unsigned* maxSymbolValuePtr, const unsigned char* src, size_t srcSize);
Provides the precise count of each byte within a table 'count'
'count' is a table of unsigned int, of minimum size (*maxSymbolValuePtr+1).
*maxSymbolValuePtr will be updated if detected smaller than initial value.
@return : the count of the most frequent symbol (which is not identified)
if return == srcSize, there is only one symbol.
Can also return an error code, which can be tested with FSE_isError() */
size_t FSE_count(unsigned* count, unsigned* maxSymbolValuePtr, const void* src, size_t srcSize);
/*!
FSE_optimalTableLog():

4
lib/fse_static.h
View File

@ -63,8 +63,8 @@ extern "C" {
/* *****************************************
* FSE advanced API
*******************************************/
size_t FSE_countFast(unsigned* count, unsigned* maxSymbolValuePtr, const unsigned char* src, size_t srcSize);
/* same as FSE_count(), but blindly trust that all values within src are <= *maxSymbolValuePtr */
size_t FSE_countFast(unsigned* count, unsigned* maxSymbolValuePtr, const void* src, size_t srcSize);
/* same as FSE_count(), but blindly trusts that all byte values within src are <= *maxSymbolValuePtr */
size_t FSE_buildCTable_raw (FSE_CTable* ct, unsigned nbBits);
/* build a fake FSE_CTable, designed to not compress an input, where each symbol uses nbBits */