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| -rw-r--r-- | src/zstd/lib/compress/fse_compress.c | 841 |
1 files changed, 841 insertions, 0 deletions
diff --git a/src/zstd/lib/compress/fse_compress.c b/src/zstd/lib/compress/fse_compress.c new file mode 100644 index 00000000..549c115d --- /dev/null +++ b/src/zstd/lib/compress/fse_compress.c @@ -0,0 +1,841 @@ +/* ****************************************************************** + FSE : Finite State Entropy encoder + Copyright (C) 2013-2015, Yann Collet. + + BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php) + + Redistribution and use in source and binary forms, with or without + modification, are permitted provided that the following conditions are + met: + + * Redistributions of source code must retain the above copyright + notice, this list of conditions and the following disclaimer. + * Redistributions in binary form must reproduce the above + copyright notice, this list of conditions and the following disclaimer + in the documentation and/or other materials provided with the + distribution. + + THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + + You can contact the author at : + - FSE source repository : https://github.com/Cyan4973/FiniteStateEntropy + - Public forum : https://groups.google.com/forum/#!forum/lz4c +****************************************************************** */ + +/* ************************************************************** +* Includes +****************************************************************/ +#include <stdlib.h> /* malloc, free, qsort */ +#include <string.h> /* memcpy, memset */ +#include <stdio.h> /* printf (debug) */ +#include "bitstream.h" +#include "compiler.h" +#define FSE_STATIC_LINKING_ONLY +#include "fse.h" +#include "error_private.h" + + +/* ************************************************************** +* Error Management +****************************************************************/ +#define FSE_isError ERR_isError +#define FSE_STATIC_ASSERT(c) { enum { FSE_static_assert = 1/(int)(!!(c)) }; } /* use only *after* variable declarations */ + + +/* ************************************************************** +* Templates +****************************************************************/ +/* + designed to be included + for type-specific functions (template emulation in C) + Objective is to write these functions only once, for improved maintenance +*/ + +/* safety checks */ +#ifndef FSE_FUNCTION_EXTENSION +# error "FSE_FUNCTION_EXTENSION must be defined" +#endif +#ifndef FSE_FUNCTION_TYPE +# error "FSE_FUNCTION_TYPE must be defined" +#endif + +/* Function names */ +#define FSE_CAT(X,Y) X##Y +#define FSE_FUNCTION_NAME(X,Y) FSE_CAT(X,Y) +#define FSE_TYPE_NAME(X,Y) FSE_CAT(X,Y) + + +/* Function templates */ + +/* FSE_buildCTable_wksp() : + * Same as FSE_buildCTable(), but using an externally allocated scratch buffer (`workSpace`). + * wkspSize should be sized to handle worst case situation, which is `1<<max_tableLog * sizeof(FSE_FUNCTION_TYPE)` + * workSpace must also be properly aligned with FSE_FUNCTION_TYPE requirements + */ +size_t FSE_buildCTable_wksp(FSE_CTable* ct, const short* normalizedCounter, unsigned maxSymbolValue, unsigned tableLog, void* workSpace, size_t wkspSize) +{ + U32 const tableSize = 1 << tableLog; + U32 const tableMask = tableSize - 1; + void* const ptr = ct; + U16* const tableU16 = ( (U16*) ptr) + 2; + void* const FSCT = ((U32*)ptr) + 1 /* header */ + (tableLog ? tableSize>>1 : 1) ; + FSE_symbolCompressionTransform* const symbolTT = (FSE_symbolCompressionTransform*) (FSCT); + U32 const step = FSE_TABLESTEP(tableSize); + U32 cumul[FSE_MAX_SYMBOL_VALUE+2]; + + FSE_FUNCTION_TYPE* const tableSymbol = (FSE_FUNCTION_TYPE*)workSpace; + U32 highThreshold = tableSize-1; + + /* CTable header */ + if (((size_t)1 << tableLog) * sizeof(FSE_FUNCTION_TYPE) > wkspSize) return ERROR(tableLog_tooLarge); + tableU16[-2] = (U16) tableLog; + tableU16[-1] = (U16) maxSymbolValue; + + /* For explanations on how to distribute symbol values over the table : + * http://fastcompression.blogspot.fr/2014/02/fse-distributing-symbol-values.html */ + + /* symbol start positions */ + { U32 u; + cumul[0] = 0; + for (u=1; u<=maxSymbolValue+1; u++) { + if (normalizedCounter[u-1]==-1) { /* Low proba symbol */ + cumul[u] = cumul[u-1] + 1; + tableSymbol[highThreshold--] = (FSE_FUNCTION_TYPE)(u-1); + } else { + cumul[u] = cumul[u-1] + normalizedCounter[u-1]; + } } + cumul[maxSymbolValue+1] = tableSize+1; + } + + /* Spread symbols */ + { U32 position = 0; + U32 symbol; + for (symbol=0; symbol<=maxSymbolValue; symbol++) { + int 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 */ + { U32 u; for (u=0; u<tableSize; u++) { + FSE_FUNCTION_TYPE s = tableSymbol[u]; /* note : static analyzer may not understand tableSymbol is properly initialized */ + tableU16[cumul[s]++] = (U16) (tableSize+u); /* TableU16 : sorted by symbol order; gives next state value */ + } } + + /* Build Symbol Transformation Table */ + { unsigned total = 0; + unsigned s; + for (s=0; s<=maxSymbolValue; s++) { + switch (normalizedCounter[s]) + { + case 0: break; + + case -1: + case 1: + symbolTT[s].deltaNbBits = (tableLog << 16) - (1<<tableLog); + symbolTT[s].deltaFindState = total - 1; + total ++; + break; + default : + { + U32 const maxBitsOut = tableLog - BIT_highbit32 (normalizedCounter[s]-1); + U32 const minStatePlus = normalizedCounter[s] << maxBitsOut; + symbolTT[s].deltaNbBits = (maxBitsOut << 16) - minStatePlus; + symbolTT[s].deltaFindState = total - normalizedCounter[s]; + total += normalizedCounter[s]; + } } } } + + return 0; +} + + +size_t FSE_buildCTable(FSE_CTable* ct, const short* normalizedCounter, unsigned maxSymbolValue, unsigned tableLog) +{ + FSE_FUNCTION_TYPE tableSymbol[FSE_MAX_TABLESIZE]; /* memset() is not necessary, even if static analyzer complain about it */ + return FSE_buildCTable_wksp(ct, normalizedCounter, maxSymbolValue, tableLog, tableSymbol, sizeof(tableSymbol)); +} + + + +#ifndef FSE_COMMONDEFS_ONLY + +/*-************************************************************** +* FSE NCount encoding-decoding +****************************************************************/ +size_t FSE_NCountWriteBound(unsigned maxSymbolValue, unsigned tableLog) +{ + size_t const maxHeaderSize = (((maxSymbolValue+1) * tableLog) >> 3) + 3; + return maxSymbolValue ? maxHeaderSize : FSE_NCOUNTBOUND; /* maxSymbolValue==0 ? use default */ +} + +static size_t FSE_writeNCount_generic (void* header, size_t headerBufferSize, + const short* normalizedCounter, unsigned maxSymbolValue, unsigned tableLog, + unsigned writeIsSafe) +{ + BYTE* const ostart = (BYTE*) header; + BYTE* out = ostart; + BYTE* const oend = ostart + headerBufferSize; + int nbBits; + const int tableSize = 1 << tableLog; + int remaining; + int threshold; + U32 bitStream; + int bitCount; + unsigned charnum = 0; + int previous0 = 0; + + bitStream = 0; + bitCount = 0; + /* Table Size */ + bitStream += (tableLog-FSE_MIN_TABLELOG) << bitCount; + bitCount += 4; + + /* Init */ + remaining = tableSize+1; /* +1 for extra accuracy */ + threshold = tableSize; + nbBits = tableLog+1; + + while (remaining>1) { /* stops at 1 */ + if (previous0) { + unsigned start = charnum; + while (!normalizedCounter[charnum]) charnum++; + while (charnum >= start+24) { + start+=24; + bitStream += 0xFFFFU << bitCount; + if ((!writeIsSafe) && (out > oend-2)) return ERROR(dstSize_tooSmall); /* Buffer overflow */ + out[0] = (BYTE) bitStream; + out[1] = (BYTE)(bitStream>>8); + out+=2; + bitStream>>=16; + } + while (charnum >= start+3) { + start+=3; + bitStream += 3 << bitCount; + bitCount += 2; + } + bitStream += (charnum-start) << bitCount; + bitCount += 2; + if (bitCount>16) { + if ((!writeIsSafe) && (out > oend - 2)) return ERROR(dstSize_tooSmall); /* Buffer overflow */ + out[0] = (BYTE)bitStream; + out[1] = (BYTE)(bitStream>>8); + out += 2; + bitStream >>= 16; + bitCount -= 16; + } } + { int count = normalizedCounter[charnum++]; + int const max = (2*threshold-1)-remaining; + remaining -= count < 0 ? -count : count; + count++; /* +1 for extra accuracy */ + if (count>=threshold) count += max; /* [0..max[ [max..threshold[ (...) [threshold+max 2*threshold[ */ + bitStream += count << bitCount; + bitCount += nbBits; + bitCount -= (count<max); + previous0 = (count==1); + if (remaining<1) return ERROR(GENERIC); + while (remaining<threshold) nbBits--, threshold>>=1; + } + if (bitCount>16) { + if ((!writeIsSafe) && (out > oend - 2)) return ERROR(dstSize_tooSmall); /* Buffer overflow */ + out[0] = (BYTE)bitStream; + out[1] = (BYTE)(bitStream>>8); + out += 2; + bitStream >>= 16; + bitCount -= 16; + } } + + /* flush remaining bitStream */ + if ((!writeIsSafe) && (out > oend - 2)) return ERROR(dstSize_tooSmall); /* Buffer overflow */ + out[0] = (BYTE)bitStream; + out[1] = (BYTE)(bitStream>>8); + out+= (bitCount+7) /8; + + if (charnum > maxSymbolValue + 1) return ERROR(GENERIC); + + return (out-ostart); +} + + +size_t FSE_writeNCount (void* buffer, size_t bufferSize, const short* normalizedCounter, unsigned maxSymbolValue, unsigned tableLog) +{ + if (tableLog > FSE_MAX_TABLELOG) return ERROR(tableLog_tooLarge); /* Unsupported */ + if (tableLog < FSE_MIN_TABLELOG) return ERROR(GENERIC); /* Unsupported */ + + if (bufferSize < FSE_NCountWriteBound(maxSymbolValue, tableLog)) + return FSE_writeNCount_generic(buffer, bufferSize, normalizedCounter, maxSymbolValue, tableLog, 0); + + return FSE_writeNCount_generic(buffer, bufferSize, normalizedCounter, maxSymbolValue, tableLog, 1); +} + + + +/*-************************************************************** +* Counting histogram +****************************************************************/ +/*! FSE_count_simple + This function counts byte values within `src`, and store the histogram into table `count`. + It doesn't use any additional memory. + But 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 : count of most numerous element +*/ +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; + + 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; + + { U32 s; for (s=0; s<=maxSymbolValue; s++) if (count[s] > max) max = count[s]; } + + return (size_t)max; +} + + +/* FSE_count_parallel_wksp() : + * Same as FSE_count_parallel(), but using an externally provided scratch buffer. + * `workSpace` size must be a minimum of `1024 * sizeof(unsigned)`` */ +static size_t FSE_count_parallel_wksp( + unsigned* count, unsigned* maxSymbolValuePtr, + const void* source, size_t sourceSize, + unsigned checkMax, unsigned* const workSpace) +{ + const BYTE* ip = (const BYTE*)source; + const BYTE* const iend = ip+sourceSize; + unsigned maxSymbolValue = *maxSymbolValuePtr; + unsigned max=0; + U32* const Counting1 = workSpace; + U32* const Counting2 = Counting1 + 256; + U32* const Counting3 = Counting2 + 256; + U32* const Counting4 = Counting3 + 256; + + memset(Counting1, 0, 4*256*sizeof(unsigned)); + + /* 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 */ + U32 s; for (s=255; s>maxSymbolValue; s--) { + Counting1[s] += Counting2[s] + Counting3[s] + Counting4[s]; + if (Counting1[s]) return ERROR(maxSymbolValue_tooSmall); + } } + + { U32 s; 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; +} + +/* FSE_countFast_wksp() : + * Same as FSE_countFast(), but using an externally provided scratch buffer. + * `workSpace` size must be table of >= `1024` unsigned */ +size_t FSE_countFast_wksp(unsigned* count, unsigned* maxSymbolValuePtr, + const void* source, size_t sourceSize, unsigned* workSpace) +{ + if (sourceSize < 1500) return FSE_count_simple(count, maxSymbolValuePtr, source, sourceSize); + return FSE_count_parallel_wksp(count, maxSymbolValuePtr, source, sourceSize, 0, workSpace); +} + +/* 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) +{ + unsigned tmpCounters[1024]; + return FSE_countFast_wksp(count, maxSymbolValuePtr, source, sourceSize, tmpCounters); +} + +/* FSE_count_wksp() : + * Same as FSE_count(), but using an externally provided scratch buffer. + * `workSpace` size must be table of >= `1024` unsigned */ +size_t FSE_count_wksp(unsigned* count, unsigned* maxSymbolValuePtr, + const void* source, size_t sourceSize, unsigned* workSpace) +{ + if (*maxSymbolValuePtr < 255) + return FSE_count_parallel_wksp(count, maxSymbolValuePtr, source, sourceSize, 1, workSpace); + *maxSymbolValuePtr = 255; + return FSE_countFast_wksp(count, maxSymbolValuePtr, source, sourceSize, workSpace); +} + +size_t FSE_count(unsigned* count, unsigned* maxSymbolValuePtr, + const void* src, size_t srcSize) +{ + unsigned tmpCounters[1024]; + return FSE_count_wksp(count, maxSymbolValuePtr, src, srcSize, tmpCounters); +} + + + +/*-************************************************************** +* FSE Compression Code +****************************************************************/ +/*! FSE_sizeof_CTable() : + FSE_CTable is a variable size structure which contains : + `U16 tableLog;` + `U16 maxSymbolValue;` + `U16 nextStateNumber[1 << tableLog];` // This size is variable + `FSE_symbolCompressionTransform symbolTT[maxSymbolValue+1];` // This size is variable +Allocation is manual (C standard does not support variable-size structures). +*/ +size_t FSE_sizeof_CTable (unsigned maxSymbolValue, unsigned tableLog) +{ + if (tableLog > FSE_MAX_TABLELOG) return ERROR(tableLog_tooLarge); + return FSE_CTABLE_SIZE_U32 (tableLog, maxSymbolValue) * sizeof(U32); +} + +FSE_CTable* FSE_createCTable (unsigned maxSymbolValue, unsigned tableLog) +{ + size_t size; + if (tableLog > FSE_TABLELOG_ABSOLUTE_MAX) tableLog = FSE_TABLELOG_ABSOLUTE_MAX; + size = FSE_CTABLE_SIZE_U32 (tableLog, maxSymbolValue) * sizeof(U32); + return (FSE_CTable*)malloc(size); +} + +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) +{ + U32 minBitsSrc = BIT_highbit32((U32)(srcSize - 1)) + 1; + U32 minBitsSymbols = BIT_highbit32(maxSymbolValue) + 2; + U32 minBits = minBitsSrc < minBitsSymbols ? minBitsSrc : minBitsSymbols; + assert(srcSize > 1); /* Not supported, RLE should be used instead */ + return minBits; +} + +unsigned FSE_optimalTableLog_internal(unsigned maxTableLog, size_t srcSize, unsigned maxSymbolValue, unsigned minus) +{ + U32 maxBitsSrc = BIT_highbit32((U32)(srcSize - 1)) - minus; + U32 tableLog = maxTableLog; + U32 minBits = FSE_minTableLog(srcSize, maxSymbolValue); + assert(srcSize > 1); /* Not supported, RLE should be used instead */ + if (tableLog==0) tableLog = FSE_DEFAULT_TABLELOG; + 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; + return tableLog; +} + +unsigned FSE_optimalTableLog(unsigned maxTableLog, size_t srcSize, unsigned maxSymbolValue) +{ + return FSE_optimalTableLog_internal(maxTableLog, srcSize, maxSymbolValue, 2); +} + + +/* 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) +{ + short const NOT_YET_ASSIGNED = -2; + U32 s; + U32 distributed = 0; + U32 ToDistribute; + + /* Init */ + U32 const lowThreshold = (U32)(total >> tableLog); + U32 lowOne = (U32)((total * 3) >> (tableLog + 1)); + + for (s=0; s<=maxSymbolValue; s++) { + if (count[s] == 0) { + norm[s]=0; + continue; + } + if (count[s] <= lowThreshold) { + norm[s] = -1; + distributed++; + total -= count[s]; + continue; + } + if (count[s] <= lowOne) { + norm[s] = 1; + distributed++; + total -= count[s]; + continue; + } + + norm[s]=NOT_YET_ASSIGNED; + } + ToDistribute = (1 << tableLog) - distributed; + + if ((total / ToDistribute) > lowOne) { + /* risk of rounding to zero */ + lowOne = (U32)((total * 3) / (ToDistribute * 2)); + for (s=0; s<=maxSymbolValue; s++) { + if ((norm[s] == NOT_YET_ASSIGNED) && (count[s] <= lowOne)) { + norm[s] = 1; + distributed++; + total -= count[s]; + continue; + } } + ToDistribute = (1 << tableLog) - distributed; + } + + if (distributed == maxSymbolValue+1) { + /* 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]; + norm[maxV] += (short)ToDistribute; + return 0; + } + + if (total == 0) { + /* all of the symbols were low enough for the lowOne or lowThreshold */ + for (s=0; ToDistribute > 0; s = (s+1)%(maxSymbolValue+1)) + if (norm[s] > 0) ToDistribute--, norm[s]++; + return 0; + } + + { U64 const vStepLog = 62 - tableLog; + U64 const mid = (1ULL << (vStepLog-1)) - 1; + U64 const rStep = ((((U64)1<<vStepLog) * ToDistribute) + mid) / total; /* scale on remaining */ + U64 tmpTotal = mid; + for (s=0; s<=maxSymbolValue; s++) { + if (norm[s]==NOT_YET_ASSIGNED) { + U64 const end = tmpTotal + (count[s] * rStep); + U32 const sStart = (U32)(tmpTotal >> vStepLog); + U32 const sEnd = (U32)(end >> vStepLog); + U32 const weight = sEnd - sStart; + if (weight < 1) + return ERROR(GENERIC); + norm[s] = (short)weight; + tmpTotal = end; + } } } + + return 0; +} + + +size_t FSE_normalizeCount (short* normalizedCounter, unsigned tableLog, + const unsigned* count, size_t total, + unsigned maxSymbolValue) +{ + /* Sanity checks */ + if (tableLog==0) tableLog = FSE_DEFAULT_TABLELOG; + if (tableLog < FSE_MIN_TABLELOG) return ERROR(GENERIC); /* Unsupported size */ + if (tableLog > FSE_MAX_TABLELOG) return ERROR(tableLog_tooLarge); /* Unsupported size */ + if (tableLog < FSE_minTableLog(total, maxSymbolValue)) return ERROR(GENERIC); /* Too small tableLog, compression potentially impossible */ + + { static U32 const rtbTable[] = { 0, 473195, 504333, 520860, 550000, 700000, 750000, 830000 }; + U64 const scale = 62 - tableLog; + U64 const step = ((U64)1<<62) / total; /* <== here, one division ! */ + U64 const vStep = 1ULL<<(scale-20); + int stillToDistribute = 1<<tableLog; + unsigned s; + unsigned largest=0; + short largestP=0; + U32 lowThreshold = (U32)(total >> tableLog); + + for (s=0; s<=maxSymbolValue; s++) { + if (count[s] == total) return 0; /* rle special case */ + if (count[s] == 0) { normalizedCounter[s]=0; continue; } + if (count[s] <= lowThreshold) { + normalizedCounter[s] = -1; + stillToDistribute--; + } else { + short proba = (short)((count[s]*step) >> scale); + if (proba<8) { + U64 restToBeat = vStep * rtbTable[proba]; + proba += (count[s]*step) - ((U64)proba<<scale) > restToBeat; + } + if (proba > largestP) largestP=proba, largest=s; + normalizedCounter[s] = proba; + stillToDistribute -= proba; + } } + if (-stillToDistribute >= (normalizedCounter[largest] >> 1)) { + /* corner case, need another normalization method */ + size_t const errorCode = FSE_normalizeM2(normalizedCounter, tableLog, count, total, maxSymbolValue); + if (FSE_isError(errorCode)) return errorCode; + } + else normalizedCounter[largest] += (short)stillToDistribute; + } + +#if 0 + { /* Print Table (debug) */ + U32 s; + U32 nTotal = 0; + for (s=0; s<=maxSymbolValue; s++) + printf("%3i: %4i \n", s, normalizedCounter[s]); + for (s=0; s<=maxSymbolValue; s++) + nTotal += abs(normalizedCounter[s]); + if (nTotal != (1U<<tableLog)) + printf("Warning !!! Total == %u != %u !!!", nTotal, 1U<<tableLog); + getchar(); + } +#endif + + return tableLog; +} + + +/* fake FSE_CTable, for raw (uncompressed) input */ +size_t FSE_buildCTable_raw (FSE_CTable* ct, unsigned nbBits) +{ + const unsigned tableSize = 1 << nbBits; + const unsigned tableMask = tableSize - 1; + const unsigned maxSymbolValue = tableMask; + void* const ptr = ct; + U16* const tableU16 = ( (U16*) ptr) + 2; + void* const FSCT = ((U32*)ptr) + 1 /* header */ + (tableSize>>1); /* assumption : tableLog >= 1 */ + FSE_symbolCompressionTransform* const symbolTT = (FSE_symbolCompressionTransform*) (FSCT); + unsigned s; + + /* Sanity checks */ + if (nbBits < 1) return ERROR(GENERIC); /* min size */ + + /* header */ + tableU16[-2] = (U16) nbBits; + tableU16[-1] = (U16) maxSymbolValue; + + /* Build table */ + for (s=0; s<tableSize; s++) + tableU16[s] = (U16)(tableSize + s); + + /* Build Symbol Transformation Table */ + { const U32 deltaNbBits = (nbBits << 16) - (1 << nbBits); + for (s=0; s<=maxSymbolValue; s++) { + symbolTT[s].deltaNbBits = deltaNbBits; + symbolTT[s].deltaFindState = s-1; + } } + + return 0; +} + +/* fake FSE_CTable, for rle input (always same symbol) */ +size_t FSE_buildCTable_rle (FSE_CTable* ct, BYTE symbolValue) +{ + void* ptr = ct; + U16* tableU16 = ( (U16*) ptr) + 2; + void* FSCTptr = (U32*)ptr + 2; + FSE_symbolCompressionTransform* symbolTT = (FSE_symbolCompressionTransform*) FSCTptr; + + /* header */ + tableU16[-2] = (U16) 0; + tableU16[-1] = (U16) symbolValue; + + /* Build table */ + tableU16[0] = 0; + tableU16[1] = 0; /* just in case */ + + /* Build Symbol Transformation Table */ + symbolTT[symbolValue].deltaNbBits = 0; + symbolTT[symbolValue].deltaFindState = 0; + + return 0; +} + + +static size_t FSE_compress_usingCTable_generic (void* dst, size_t dstSize, + const void* src, size_t srcSize, + const FSE_CTable* ct, const unsigned fast) +{ + const BYTE* const istart = (const BYTE*) src; + const BYTE* const iend = istart + srcSize; + const BYTE* ip=iend; + + BIT_CStream_t bitC; + FSE_CState_t CState1, CState2; + + /* init */ + if (srcSize <= 2) return 0; + { size_t const initError = BIT_initCStream(&bitC, dst, dstSize); + if (FSE_isError(initError)) return 0; /* not enough space available to write a bitstream */ } + +#define FSE_FLUSHBITS(s) (fast ? BIT_flushBitsFast(s) : BIT_flushBits(s)) + + if (srcSize & 1) { + FSE_initCState2(&CState1, ct, *--ip); + FSE_initCState2(&CState2, ct, *--ip); + FSE_encodeSymbol(&bitC, &CState1, *--ip); + FSE_FLUSHBITS(&bitC); + } else { + FSE_initCState2(&CState2, ct, *--ip); + FSE_initCState2(&CState1, ct, *--ip); + } + + /* join to mod 4 */ + srcSize -= 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); + } + + /* 2 or 4 encoding per loop */ + while ( ip>istart ) { + + FSE_encodeSymbol(&bitC, &CState2, *--ip); + + if (sizeof(bitC.bitContainer)*8 < FSE_MAX_TABLELOG*2+7 ) /* this test must be static */ + FSE_FLUSHBITS(&bitC); + + FSE_encodeSymbol(&bitC, &CState1, *--ip); + + 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); + } + + FSE_FLUSHBITS(&bitC); + } + + FSE_flushCState(&bitC, &CState2); + FSE_flushCState(&bitC, &CState1); + return BIT_closeCStream(&bitC); +} + +size_t FSE_compress_usingCTable (void* dst, size_t dstSize, + const void* src, size_t srcSize, + const FSE_CTable* ct) +{ + unsigned const fast = (dstSize >= FSE_BLOCKBOUND(srcSize)); + + if (fast) + return FSE_compress_usingCTable_generic(dst, dstSize, src, srcSize, ct, 1); + else + return FSE_compress_usingCTable_generic(dst, dstSize, src, srcSize, ct, 0); +} + + +size_t FSE_compressBound(size_t size) { return FSE_COMPRESSBOUND(size); } + +#define CHECK_V_F(e, f) size_t const e = f; if (ERR_isError(e)) return e +#define CHECK_F(f) { CHECK_V_F(_var_err__, f); } + +/* FSE_compress_wksp() : + * Same as FSE_compress2(), but using an externally allocated scratch buffer (`workSpace`). + * `wkspSize` size must be `(1<<tableLog)`. + */ +size_t FSE_compress_wksp (void* dst, size_t dstSize, const void* src, size_t srcSize, unsigned maxSymbolValue, unsigned tableLog, void* workSpace, size_t wkspSize) +{ + BYTE* const ostart = (BYTE*) dst; + BYTE* op = ostart; + BYTE* const oend = ostart + dstSize; + + U32 count[FSE_MAX_SYMBOL_VALUE+1]; + S16 norm[FSE_MAX_SYMBOL_VALUE+1]; + FSE_CTable* CTable = (FSE_CTable*)workSpace; + size_t const CTableSize = FSE_CTABLE_SIZE_U32(tableLog, maxSymbolValue); + void* scratchBuffer = (void*)(CTable + CTableSize); + size_t const scratchBufferSize = wkspSize - (CTableSize * sizeof(FSE_CTable)); + + /* init conditions */ + if (wkspSize < FSE_WKSP_SIZE_U32(tableLog, maxSymbolValue)) return ERROR(tableLog_tooLarge); + if (srcSize <= 1) return 0; /* Not compressible */ + if (!maxSymbolValue) maxSymbolValue = FSE_MAX_SYMBOL_VALUE; + if (!tableLog) tableLog = FSE_DEFAULT_TABLELOG; + + /* Scan input and build symbol stats */ + { CHECK_V_F(maxCount, FSE_count_wksp(count, &maxSymbolValue, src, srcSize, (unsigned*)scratchBuffer) ); + if (maxCount == srcSize) return 1; /* only a single symbol in src : rle */ + if (maxCount == 1) return 0; /* each symbol present maximum once => not compressible */ + if (maxCount < (srcSize >> 7)) return 0; /* Heuristic : not compressible enough */ + } + + tableLog = FSE_optimalTableLog(tableLog, srcSize, maxSymbolValue); + CHECK_F( FSE_normalizeCount(norm, tableLog, count, srcSize, maxSymbolValue) ); + + /* Write table description header */ + { CHECK_V_F(nc_err, FSE_writeNCount(op, oend-op, norm, maxSymbolValue, tableLog) ); + op += nc_err; + } + + /* Compress */ + CHECK_F( FSE_buildCTable_wksp(CTable, norm, maxSymbolValue, tableLog, scratchBuffer, scratchBufferSize) ); + { CHECK_V_F(cSize, FSE_compress_usingCTable(op, oend - op, src, srcSize, CTable) ); + if (cSize == 0) return 0; /* not enough space for compressed data */ + op += cSize; + } + + /* check compressibility */ + if ( (size_t)(op-ostart) >= srcSize-1 ) return 0; + + return op-ostart; +} + +typedef struct { + FSE_CTable CTable_max[FSE_CTABLE_SIZE_U32(FSE_MAX_TABLELOG, FSE_MAX_SYMBOL_VALUE)]; + BYTE scratchBuffer[1 << FSE_MAX_TABLELOG]; +} fseWkspMax_t; + +size_t FSE_compress2 (void* dst, size_t dstCapacity, const void* src, size_t srcSize, unsigned maxSymbolValue, unsigned tableLog) +{ + fseWkspMax_t scratchBuffer; + FSE_STATIC_ASSERT(sizeof(scratchBuffer) >= FSE_WKSP_SIZE_U32(FSE_MAX_TABLELOG, FSE_MAX_SYMBOL_VALUE)); /* compilation failures here means scratchBuffer is not large enough */ + if (tableLog > FSE_MAX_TABLELOG) return ERROR(tableLog_tooLarge); + return FSE_compress_wksp(dst, dstCapacity, src, srcSize, maxSymbolValue, tableLog, &scratchBuffer, sizeof(scratchBuffer)); +} + +size_t FSE_compress (void* dst, size_t dstCapacity, const void* src, size_t srcSize) +{ + return FSE_compress2(dst, dstCapacity, src, srcSize, FSE_MAX_SYMBOL_VALUE, FSE_DEFAULT_TABLELOG); +} + + +#endif /* FSE_COMMONDEFS_ONLY */ |