comparison contrib/python-zstandard/zstd/compress/fse_compress.c @ 40121:73fef626dae3

zstandard: vendor python-zstandard 0.10.1

This was just released.

The upstream source distribution from PyPI was extracted. Unwanted
files were removed.

The clang-format ignore list was updated to reflect the new source
of files.

setup.py was updated to pass a new argument to python-zstandard's
function for returning an Extension instance. Upstream had to change
to use relative paths because Python 3.7's packaging doesn't
seem to like absolute paths when defining sources, includes, etc.
The default relative path calculation is relative to setup_zstd.py
which is different from the directory of Mercurial's setup.py.

The project contains a vendored copy of zstandard 1.3.6. The old
version was 1.3.4.

The API should be backwards compatible and nothing in core should
need adjusted. However, there is a new "chunker" API that we
may find useful in places where we want to emit compressed chunks
of a fixed size.

There are a pair of bug fixes in 0.10.0 with regards to
compressobj() and decompressobj() when block flushing is used. I
actually found these bugs when introducing these APIs in Mercurial!
But existing Mercurial code is not affected because we don't
perform block flushing.

# no-check-commit because 3rd party code has different style guidelines

Differential Revision: https://phab.mercurial-scm.org/D4911

40120:89742f1fa6cb

/* ******************************************************************
   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

/* **************************************************************
*  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
****************************************************************/

/* 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;

    /* 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++) {

    /* 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 */

    {   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;

                    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)

#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) {
        assert(*ip <= maxSymbolValue);
        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)`.
 * @return : largest histogram frequency, or an error code (notably when histogram would be larger than *maxSymbolValuePtr). */
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(workSpace, 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;
        if (maxSymbolValue > 255) maxSymbolValue = 255;
        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) /* heuristic threshold */
        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;

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;
}

        }

        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 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;

    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 */
    }

} 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)

40121:73fef626dae3

/* ******************************************************************
   FSE : Finite State Entropy encoder
   Copyright (C) 2013-present, 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

/* **************************************************************
*  Includes
****************************************************************/
#include <stdlib.h>     /* malloc, free, qsort */
#include <string.h>     /* memcpy, memset */
#include "compiler.h"
#include "mem.h"        /* U32, U16, etc. */
#include "debug.h"      /* assert, DEBUGLOG */
#include "hist.h"       /* HIST_count_wksp */
#include "bitstream.h"
#define FSE_STATIC_LINKING_ONLY
#include "fse.h"
#include "error_private.h"


/* **************************************************************
*  Error Management
****************************************************************/
#define FSE_isError ERR_isError


/* **************************************************************
*  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;

    /* CTable header */
    if (((size_t)1 << tableLog) * sizeof(FSE_FUNCTION_TYPE) > wkspSize) return ERROR(tableLog_tooLarge);
    tableU16[-2] = (U16) tableLog;
    tableU16[-1] = (U16) maxSymbolValue;
    assert(tableLog < 16);   /* required for threshold strategy to work */

    /* For explanations on how to distribute symbol values over the table :
     * http://fastcompression.blogspot.fr/2014/02/fse-distributing-symbol-values.html */

     #ifdef __clang_analyzer__
     memset(tableSymbol, 0, sizeof(*tableSymbol) * tableSize);   /* useless initialization, just to keep scan-build happy */
     #endif

    /* symbol start positions */
    {   U32 u;
        cumul[0] = 0;
        for (u=1; u<=maxSymbolValue+1; u++) {

    /* Spread symbols */
    {   U32 position = 0;
        U32 symbol;
        for (symbol=0; symbol<=maxSymbolValue; symbol++) {
            int nbOccurences;
            int const freq = normalizedCounter[symbol];
            for (nbOccurences=0; nbOccurences<freq; nbOccurences++) {
                tableSymbol[position] = (FSE_FUNCTION_TYPE)symbol;
                position = (position + step) & tableMask;
                while (position > highThreshold)
                    position = (position + step) & tableMask;   /* Low proba area */
        }   }

        assert(position==0);  /* Must have initialized 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 */

    {   unsigned total = 0;
        unsigned s;
        for (s=0; s<=maxSymbolValue; s++) {
            switch (normalizedCounter[s])
            {
            case  0:
                /* filling nonetheless, for compatibility with FSE_getMaxNbBits() */
                symbolTT[s].deltaNbBits = ((tableLog+1) << 16) - (1<<tableLog);
                break;

            case -1:
            case  1:
                symbolTT[s].deltaNbBits = (tableLog << 16) - (1<<tableLog);
                symbolTT[s].deltaFindState = total - 1;

                    symbolTT[s].deltaNbBits = (maxBitsOut << 16) - minStatePlus;
                    symbolTT[s].deltaFindState = total - normalizedCounter[s];
                    total +=  normalizedCounter[s];
    }   }   }   }

#if 0  /* debug : symbol costs */
    DEBUGLOG(5, "\n --- table statistics : ");
    {   U32 symbol;
        for (symbol=0; symbol<=maxSymbolValue; symbol++) {
            DEBUGLOG(5, "%3u: w=%3i,   maxBits=%u, fracBits=%.2f",
                symbol, normalizedCounter[symbol],
                FSE_getMaxNbBits(symbolTT, symbol),
                (double)FSE_bitCost(symbolTT, tableLog, symbol, 8) / 256);
        }
    }
#endif

    return 0;
}


size_t FSE_buildCTable(FSE_CTable* ct, const short* normalizedCounter, unsigned maxSymbolValue, unsigned tableLog)

#ifndef FSE_COMMONDEFS_ONLY


/*-**************************************************************
*  FSE NCount encoding
****************************************************************/
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 = 0;
    int bitCount = 0;
    unsigned symbol = 0;
    unsigned const alphabetSize = maxSymbolValue + 1;
    int previousIs0 = 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 ((symbol < alphabetSize) && (remaining>1)) {  /* stops at 1 */
        if (previousIs0) {
            unsigned start = symbol;
            while ((symbol < alphabetSize) && !normalizedCounter[symbol]) symbol++;
            if (symbol == alphabetSize) break;   /* incorrect distribution */
            while (symbol >= 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 (symbol >= start+3) {
                start+=3;
                bitStream += 3 << bitCount;
                bitCount += 2;
            }
            bitStream += (symbol-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[symbol++];
            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);
            previousIs0  = (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;
    }   }

    if (remaining != 1)
        return ERROR(GENERIC);  /* incorrect normalized distribution */
    assert(symbol <= alphabetSize);

    /* 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;

    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 /* write in buffer is safe */);
}


/*-**************************************************************
*  FSE Compression Code
****************************************************************/

FSE_CTable* FSE_createCTable (unsigned maxSymbolValue, unsigned tableLog)
{
    size_t size;
    if (tableLog > FSE_TABLELOG_ABSOLUTE_MAX) tableLog = FSE_TABLELOG_ABSOLUTE_MAX;

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;
    U32 minBitsSymbols = BIT_highbit32(maxSymbolValue) + 2;
    U32 minBits = minBitsSrc < minBitsSymbols ? minBitsSrc : minBitsSymbols;
    assert(srcSize > 1); /* Not supported, RLE should be used instead */
    return minBits;
}

        }

        norm[s]=NOT_YET_ASSIGNED;
    }
    ToDistribute = (1 << tableLog) - distributed;

    if (ToDistribute == 0)
        return 0;

    if ((total / ToDistribute) > lowOne) {
        /* risk of rounding to zero */
        lowOne = (U32)((total * 3) / (ToDistribute * 2));
        for (s=0; s<=maxSymbolValue; s++) {

#if 0
    {   /* Print Table (debug) */
        U32 s;
        U32 nTotal = 0;
        for (s=0; s<=maxSymbolValue; s++)
            RAWLOG(2, "%3i: %4i \n", s, normalizedCounter[s]);
        for (s=0; s<=maxSymbolValue; s++)
            nTotal += abs(normalizedCounter[s]);
        if (nTotal != (1U<<tableLog))
            RAWLOG(2, "Warning !!! Total == %u != %u !!!", nTotal, 1U<<tableLog);
        getchar();
    }
#endif

    return tableLog;

    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, HIST_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 */
    }

} fseWkspMax_t;

size_t FSE_compress2 (void* dst, size_t dstCapacity, const void* src, size_t srcSize, unsigned maxSymbolValue, unsigned tableLog)
{
    fseWkspMax_t scratchBuffer;
    DEBUG_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)