FreeBSD/Linux Kernel Cross Reference
sys/contrib/openzfs/module/zstd/lib/compress/huf_compress.c

     /* ******************************************************************
      * Huffman encoder, part of New Generation Entropy library
      * Copyright (c) 2013-2020, Yann Collet, Facebook, Inc.
      *
      *  You can contact the author at :
      *  - FSE+HUF source repository : https://github.com/Cyan4973/FiniteStateEntropy
      *  - Public forum : https://groups.google.com/forum/#!forum/lz4c
      *
      * This source code is licensed under both the BSD-style license (found in the
     * LICENSE file in the root directory of this source tree) and the GPLv2 (found
     * in the COPYING file in the root directory of this source tree).
     * You may select, at your option, one of the above-listed licenses.
    ****************************************************************** */
    
    /* **************************************************************
    *  Compiler specifics
    ****************************************************************/
    #ifdef _MSC_VER    /* Visual Studio */
    #  pragma warning(disable : 4127)        /* disable: C4127: conditional expression is constant */
    #endif
    
    
    /* **************************************************************
    *  Includes
    ****************************************************************/
    #include <string.h>     /* memcpy, memset */
    #include <stdio.h>      /* printf (debug) */
    #include "../common/compiler.h"
    #include "../common/bitstream.h"
    #include "hist.h"
    #define FSE_STATIC_LINKING_ONLY   /* FSE_optimalTableLog_internal */
    #include "../common/fse.h"        /* header compression */
    #define HUF_STATIC_LINKING_ONLY
    #include "../common/huf.h"
    #include "../common/error_private.h"
    
    
    /* **************************************************************
    *  Error Management
    ****************************************************************/
    #define HUF_isError ERR_isError
    #define HUF_STATIC_ASSERT(c) DEBUG_STATIC_ASSERT(c)   /* use only *after* variable declarations */
    
    
    /* **************************************************************
    *  Utils
    ****************************************************************/
    unsigned HUF_optimalTableLog(unsigned maxTableLog, size_t srcSize, unsigned maxSymbolValue)
    {
        return FSE_optimalTableLog_internal(maxTableLog, srcSize, maxSymbolValue, 1);
    }
    
    
    /* *******************************************************
    *  HUF : Huffman block compression
    *********************************************************/
    /* HUF_compressWeights() :
     * Same as FSE_compress(), but dedicated to huff0's weights compression.
     * The use case needs much less stack memory.
     * Note : all elements within weightTable are supposed to be <= HUF_TABLELOG_MAX.
     */
    #define MAX_FSE_TABLELOG_FOR_HUFF_HEADER 6
    static size_t HUF_compressWeights (void* dst, size_t dstSize, const void* weightTable, size_t wtSize)
    {
        BYTE* const ostart = (BYTE*) dst;
        BYTE* op = ostart;
        BYTE* const oend = ostart + dstSize;
    
        unsigned maxSymbolValue = HUF_TABLELOG_MAX;
        U32 tableLog = MAX_FSE_TABLELOG_FOR_HUFF_HEADER;
    
        FSE_CTable CTable[FSE_CTABLE_SIZE_U32(MAX_FSE_TABLELOG_FOR_HUFF_HEADER, HUF_TABLELOG_MAX)];
        BYTE scratchBuffer[1<<MAX_FSE_TABLELOG_FOR_HUFF_HEADER];
    
        unsigned count[HUF_TABLELOG_MAX+1];
        S16 norm[HUF_TABLELOG_MAX+1];
    
        /* init conditions */
        if (wtSize <= 1) return 0;  /* Not compressible */
    
        /* Scan input and build symbol stats */
        {   unsigned const maxCount = HIST_count_simple(count, &maxSymbolValue, weightTable, wtSize);   /* never fails */
            if (maxCount == wtSize) return 1;   /* only a single symbol in src : rle */
            if (maxCount == 1) return 0;        /* each symbol present maximum once => not compressible */
        }
    
        tableLog = FSE_optimalTableLog(tableLog, wtSize, maxSymbolValue);
        CHECK_F( FSE_normalizeCount(norm, tableLog, count, wtSize, maxSymbolValue) );
    
        /* Write table description header */
        {   CHECK_V_F(hSize, FSE_writeNCount(op, (size_t)(oend-op), norm, maxSymbolValue, tableLog) );
            op += hSize;
        }
    
        /* Compress */
        CHECK_F( FSE_buildCTable_wksp(CTable, norm, maxSymbolValue, tableLog, scratchBuffer, sizeof(scratchBuffer)) );
        {   CHECK_V_F(cSize, FSE_compress_usingCTable(op, (size_t)(oend - op), weightTable, wtSize, CTable) );
            if (cSize == 0) return 0;   /* not enough space for compressed data */
            op += cSize;
       }
   
       return (size_t)(op-ostart);
   }
   
   
   struct HUF_CElt_s {
     U16  val;
     BYTE nbBits;
   };   /* typedef'd to HUF_CElt within "huf.h" */
   
   /*! HUF_writeCTable() :
       `CTable` : Huffman tree to save, using huf representation.
       @return : size of saved CTable */
   size_t HUF_writeCTable (void* dst, size_t maxDstSize,
                           const HUF_CElt* CTable, unsigned maxSymbolValue, unsigned huffLog)
   {
       BYTE bitsToWeight[HUF_TABLELOG_MAX + 1];   /* precomputed conversion table */
       BYTE huffWeight[HUF_SYMBOLVALUE_MAX];
       BYTE* op = (BYTE*)dst;
       U32 n;
   
        /* check conditions */
       if (maxSymbolValue > HUF_SYMBOLVALUE_MAX) return ERROR(maxSymbolValue_tooLarge);
   
       /* convert to weight */
       bitsToWeight[0] = 0;
       for (n=1; n<huffLog+1; n++)
           bitsToWeight[n] = (BYTE)(huffLog + 1 - n);
       for (n=0; n<maxSymbolValue; n++)
           huffWeight[n] = bitsToWeight[CTable[n].nbBits];
   
       /* attempt weights compression by FSE */
       {   CHECK_V_F(hSize, HUF_compressWeights(op+1, maxDstSize-1, huffWeight, maxSymbolValue) );
           if ((hSize>1) & (hSize < maxSymbolValue/2)) {   /* FSE compressed */
               op[0] = (BYTE)hSize;
               return hSize+1;
       }   }
   
       /* write raw values as 4-bits (max : 15) */
       if (maxSymbolValue > (256-128)) return ERROR(GENERIC);   /* should not happen : likely means source cannot be compressed */
       if (((maxSymbolValue+1)/2) + 1 > maxDstSize) return ERROR(dstSize_tooSmall);   /* not enough space within dst buffer */
       op[0] = (BYTE)(128 /*special case*/ + (maxSymbolValue-1));
       huffWeight[maxSymbolValue] = 0;   /* to be sure it doesn't cause msan issue in final combination */
       for (n=0; n<maxSymbolValue; n+=2)
           op[(n/2)+1] = (BYTE)((huffWeight[n] << 4) + huffWeight[n+1]);
       return ((maxSymbolValue+1)/2) + 1;
   }
   
   
   size_t HUF_readCTable (HUF_CElt* CTable, unsigned* maxSymbolValuePtr, const void* src, size_t srcSize, unsigned* hasZeroWeights)
   {
       BYTE huffWeight[HUF_SYMBOLVALUE_MAX + 1];   /* init not required, even though some static analyzer may complain */
       U32 rankVal[HUF_TABLELOG_ABSOLUTEMAX + 1];   /* large enough for values from 0 to 16 */
       U32 tableLog = 0;
       U32 nbSymbols = 0;
   
       /* get symbol weights */
       CHECK_V_F(readSize, HUF_readStats(huffWeight, HUF_SYMBOLVALUE_MAX+1, rankVal, &nbSymbols, &tableLog, src, srcSize));
   
       /* check result */
       if (tableLog > HUF_TABLELOG_MAX) return ERROR(tableLog_tooLarge);
       if (nbSymbols > *maxSymbolValuePtr+1) return ERROR(maxSymbolValue_tooSmall);
   
       /* Prepare base value per rank */
       {   U32 n, nextRankStart = 0;
           for (n=1; n<=tableLog; n++) {
               U32 current = nextRankStart;
               nextRankStart += (rankVal[n] << (n-1));
               rankVal[n] = current;
       }   }
   
       /* fill nbBits */
       *hasZeroWeights = 0;
       {   U32 n; for (n=0; n<nbSymbols; n++) {
               const U32 w = huffWeight[n];
               *hasZeroWeights |= (w == 0);
               CTable[n].nbBits = (BYTE)(tableLog + 1 - w) & -(w != 0);
       }   }
   
       /* fill val */
       {   U16 nbPerRank[HUF_TABLELOG_MAX+2]  = {0};  /* support w=0=>n=tableLog+1 */
           U16 valPerRank[HUF_TABLELOG_MAX+2] = {0};
           { U32 n; for (n=0; n<nbSymbols; n++) nbPerRank[CTable[n].nbBits]++; }
           /* determine stating value per rank */
           valPerRank[tableLog+1] = 0;   /* for w==0 */
           {   U16 min = 0;
               U32 n; for (n=tableLog; n>0; n--) {  /* start at n=tablelog <-> w=1 */
                   valPerRank[n] = min;     /* get starting value within each rank */
                   min += nbPerRank[n];
                   min >>= 1;
           }   }
           /* assign value within rank, symbol order */
           { U32 n; for (n=0; n<nbSymbols; n++) CTable[n].val = valPerRank[CTable[n].nbBits]++; }
       }
   
       *maxSymbolValuePtr = nbSymbols - 1;
       return readSize;
   }
   
   U32 HUF_getNbBits(const void* symbolTable, U32 symbolValue)
   {
       const HUF_CElt* table = (const HUF_CElt*)symbolTable;
       assert(symbolValue <= HUF_SYMBOLVALUE_MAX);
       return table[symbolValue].nbBits;
   }
   
   
   typedef struct nodeElt_s {
       U32 count;
       U16 parent;
       BYTE byte;
       BYTE nbBits;
   } nodeElt;
   
   static U32 HUF_setMaxHeight(nodeElt* huffNode, U32 lastNonNull, U32 maxNbBits)
   {
       const U32 largestBits = huffNode[lastNonNull].nbBits;
       if (largestBits <= maxNbBits) return largestBits;   /* early exit : no elt > maxNbBits */
   
       /* there are several too large elements (at least >= 2) */
       {   int totalCost = 0;
           const U32 baseCost = 1 << (largestBits - maxNbBits);
           int n = (int)lastNonNull;
   
           while (huffNode[n].nbBits > maxNbBits) {
               totalCost += baseCost - (1 << (largestBits - huffNode[n].nbBits));
               huffNode[n].nbBits = (BYTE)maxNbBits;
               n --;
           }  /* n stops at huffNode[n].nbBits <= maxNbBits */
           while (huffNode[n].nbBits == maxNbBits) n--;   /* n end at index of smallest symbol using < maxNbBits */
   
           /* renorm totalCost */
           totalCost >>= (largestBits - maxNbBits);  /* note : totalCost is necessarily a multiple of baseCost */
   
           /* repay normalized cost */
           {   U32 const noSymbol = 0xF0F0F0F0;
               U32 rankLast[HUF_TABLELOG_MAX+2];
   
               /* Get pos of last (smallest) symbol per rank */
               memset(rankLast, 0xF0, sizeof(rankLast));
               {   U32 currentNbBits = maxNbBits;
                   int pos;
                   for (pos=n ; pos >= 0; pos--) {
                       if (huffNode[pos].nbBits >= currentNbBits) continue;
                       currentNbBits = huffNode[pos].nbBits;   /* < maxNbBits */
                       rankLast[maxNbBits-currentNbBits] = (U32)pos;
               }   }
   
               while (totalCost > 0) {
                   U32 nBitsToDecrease = BIT_highbit32((U32)totalCost) + 1;
                   for ( ; nBitsToDecrease > 1; nBitsToDecrease--) {
                       U32 const highPos = rankLast[nBitsToDecrease];
                       U32 const lowPos = rankLast[nBitsToDecrease-1];
                       if (highPos == noSymbol) continue;
                       if (lowPos == noSymbol) break;
                       {   U32 const highTotal = huffNode[highPos].count;
                           U32 const lowTotal = 2 * huffNode[lowPos].count;
                           if (highTotal <= lowTotal) break;
                   }   }
                   /* only triggered when no more rank 1 symbol left => find closest one (note : there is necessarily at least one !) */
                   /* HUF_MAX_TABLELOG test just to please gcc 5+; but it should not be necessary */
                   while ((nBitsToDecrease<=HUF_TABLELOG_MAX) && (rankLast[nBitsToDecrease] == noSymbol))
                       nBitsToDecrease ++;
                   totalCost -= 1 << (nBitsToDecrease-1);
                   if (rankLast[nBitsToDecrease-1] == noSymbol)
                       rankLast[nBitsToDecrease-1] = rankLast[nBitsToDecrease];   /* this rank is no longer empty */
                   huffNode[rankLast[nBitsToDecrease]].nbBits ++;
                   if (rankLast[nBitsToDecrease] == 0)    /* special case, reached largest symbol */
                       rankLast[nBitsToDecrease] = noSymbol;
                   else {
                       rankLast[nBitsToDecrease]--;
                       if (huffNode[rankLast[nBitsToDecrease]].nbBits != maxNbBits-nBitsToDecrease)
                           rankLast[nBitsToDecrease] = noSymbol;   /* this rank is now empty */
               }   }   /* while (totalCost > 0) */
   
               while (totalCost < 0) {  /* Sometimes, cost correction overshoot */
                   if (rankLast[1] == noSymbol) {  /* special case : no rank 1 symbol (using maxNbBits-1); let's create one from largest rank 0 (using maxNbBits) */
                       while (huffNode[n].nbBits == maxNbBits) n--;
                       huffNode[n+1].nbBits--;
                       assert(n >= 0);
                       rankLast[1] = (U32)(n+1);
                       totalCost++;
                       continue;
                   }
                   huffNode[ rankLast[1] + 1 ].nbBits--;
                   rankLast[1]++;
                   totalCost ++;
       }   }   }   /* there are several too large elements (at least >= 2) */
   
       return maxNbBits;
   }
   
   typedef struct {
       U32 base;
       U32 current;
   } rankPos;
   
   typedef nodeElt huffNodeTable[HUF_CTABLE_WORKSPACE_SIZE_U32];
   
   #define RANK_POSITION_TABLE_SIZE 32
   
   typedef struct {
     huffNodeTable huffNodeTbl;
     rankPos rankPosition[RANK_POSITION_TABLE_SIZE];
   } HUF_buildCTable_wksp_tables;
   
   static void HUF_sort(nodeElt* huffNode, const unsigned* count, U32 maxSymbolValue, rankPos* rankPosition)
   {
       U32 n;
   
       memset(rankPosition, 0, sizeof(*rankPosition) * RANK_POSITION_TABLE_SIZE);
       for (n=0; n<=maxSymbolValue; n++) {
           U32 r = BIT_highbit32(count[n] + 1);
           rankPosition[r].base ++;
       }
       for (n=30; n>0; n--) rankPosition[n-1].base += rankPosition[n].base;
       for (n=0; n<32; n++) rankPosition[n].current = rankPosition[n].base;
       for (n=0; n<=maxSymbolValue; n++) {
           U32 const c = count[n];
           U32 const r = BIT_highbit32(c+1) + 1;
           U32 pos = rankPosition[r].current++;
           while ((pos > rankPosition[r].base) && (c > huffNode[pos-1].count)) {
               huffNode[pos] = huffNode[pos-1];
               pos--;
           }
           huffNode[pos].count = c;
           huffNode[pos].byte  = (BYTE)n;
       }
   }
   
   
   /** HUF_buildCTable_wksp() :
    *  Same as HUF_buildCTable(), but using externally allocated scratch buffer.
    *  `workSpace` must be aligned on 4-bytes boundaries, and be at least as large as sizeof(HUF_buildCTable_wksp_tables).
    */
   #define STARTNODE (HUF_SYMBOLVALUE_MAX+1)
   
   size_t HUF_buildCTable_wksp (HUF_CElt* tree, const unsigned* count, U32 maxSymbolValue, U32 maxNbBits, void* workSpace, size_t wkspSize)
   {
       HUF_buildCTable_wksp_tables* const wksp_tables = (HUF_buildCTable_wksp_tables*)workSpace;
       nodeElt* const huffNode0 = wksp_tables->huffNodeTbl;
       nodeElt* const huffNode = huffNode0+1;
       int nonNullRank;
       int lowS, lowN;
       int nodeNb = STARTNODE;
       int n, nodeRoot;
   
       /* safety checks */
       if (((size_t)workSpace & 3) != 0) return ERROR(GENERIC);  /* must be aligned on 4-bytes boundaries */
       if (wkspSize < sizeof(HUF_buildCTable_wksp_tables))
         return ERROR(workSpace_tooSmall);
       if (maxNbBits == 0) maxNbBits = HUF_TABLELOG_DEFAULT;
       if (maxSymbolValue > HUF_SYMBOLVALUE_MAX)
         return ERROR(maxSymbolValue_tooLarge);
       memset(huffNode0, 0, sizeof(huffNodeTable));
   
       /* sort, decreasing order */
       HUF_sort(huffNode, count, maxSymbolValue, wksp_tables->rankPosition);
   
       /* init for parents */
       nonNullRank = (int)maxSymbolValue;
       while(huffNode[nonNullRank].count == 0) nonNullRank--;
       lowS = nonNullRank; nodeRoot = nodeNb + lowS - 1; lowN = nodeNb;
       huffNode[nodeNb].count = huffNode[lowS].count + huffNode[lowS-1].count;
       huffNode[lowS].parent = huffNode[lowS-1].parent = (U16)nodeNb;
       nodeNb++; lowS-=2;
       for (n=nodeNb; n<=nodeRoot; n++) huffNode[n].count = (U32)(1U<<30);
       huffNode0[0].count = (U32)(1U<<31);  /* fake entry, strong barrier */
   
       /* create parents */
       while (nodeNb <= nodeRoot) {
           int const n1 = (huffNode[lowS].count < huffNode[lowN].count) ? lowS-- : lowN++;
           int const n2 = (huffNode[lowS].count < huffNode[lowN].count) ? lowS-- : lowN++;
           huffNode[nodeNb].count = huffNode[n1].count + huffNode[n2].count;
           huffNode[n1].parent = huffNode[n2].parent = (U16)nodeNb;
           nodeNb++;
       }
   
       /* distribute weights (unlimited tree height) */
       huffNode[nodeRoot].nbBits = 0;
       for (n=nodeRoot-1; n>=STARTNODE; n--)
           huffNode[n].nbBits = huffNode[ huffNode[n].parent ].nbBits + 1;
       for (n=0; n<=nonNullRank; n++)
           huffNode[n].nbBits = huffNode[ huffNode[n].parent ].nbBits + 1;
   
       /* enforce maxTableLog */
       maxNbBits = HUF_setMaxHeight(huffNode, (U32)nonNullRank, maxNbBits);
   
       /* fill result into tree (val, nbBits) */
       {   U16 nbPerRank[HUF_TABLELOG_MAX+1] = {0};
           U16 valPerRank[HUF_TABLELOG_MAX+1] = {0};
           int const alphabetSize = (int)(maxSymbolValue + 1);
           if (maxNbBits > HUF_TABLELOG_MAX) return ERROR(GENERIC);   /* check fit into table */
           for (n=0; n<=nonNullRank; n++)
               nbPerRank[huffNode[n].nbBits]++;
           /* determine stating value per rank */
           {   U16 min = 0;
               for (n=(int)maxNbBits; n>0; n--) {
                   valPerRank[n] = min;      /* get starting value within each rank */
                   min += nbPerRank[n];
                   min >>= 1;
           }   }
           for (n=0; n<alphabetSize; n++)
               tree[huffNode[n].byte].nbBits = huffNode[n].nbBits;   /* push nbBits per symbol, symbol order */
           for (n=0; n<alphabetSize; n++)
               tree[n].val = valPerRank[tree[n].nbBits]++;   /* assign value within rank, symbol order */
       }
   
       return maxNbBits;
   }
   
   /** HUF_buildCTable() :
    * @return : maxNbBits
    *  Note : count is used before tree is written, so they can safely overlap
    */
   size_t HUF_buildCTable (HUF_CElt* tree, const unsigned* count, unsigned maxSymbolValue, unsigned maxNbBits)
   {
       HUF_buildCTable_wksp_tables workspace;
       return HUF_buildCTable_wksp(tree, count, maxSymbolValue, maxNbBits, &workspace, sizeof(workspace));
   }
   
   size_t HUF_estimateCompressedSize(const HUF_CElt* CTable, const unsigned* count, unsigned maxSymbolValue)
   {
       size_t nbBits = 0;
       int s;
       for (s = 0; s <= (int)maxSymbolValue; ++s) {
           nbBits += CTable[s].nbBits * count[s];
       }
       return nbBits >> 3;
   }
   
   int HUF_validateCTable(const HUF_CElt* CTable, const unsigned* count, unsigned maxSymbolValue) {
     int bad = 0;
     int s;
     for (s = 0; s <= (int)maxSymbolValue; ++s) {
       bad |= (count[s] != 0) & (CTable[s].nbBits == 0);
     }
     return !bad;
   }
   
   size_t HUF_compressBound(size_t size) { return HUF_COMPRESSBOUND(size); }
   
   FORCE_INLINE_TEMPLATE void
   HUF_encodeSymbol(BIT_CStream_t* bitCPtr, U32 symbol, const HUF_CElt* CTable)
   {
       BIT_addBitsFast(bitCPtr, CTable[symbol].val, CTable[symbol].nbBits);
   }
   
   #define HUF_FLUSHBITS(s)  BIT_flushBits(s)
   
   #define HUF_FLUSHBITS_1(stream) \
       if (sizeof((stream)->bitContainer)*8 < HUF_TABLELOG_MAX*2+7) HUF_FLUSHBITS(stream)
   
   #define HUF_FLUSHBITS_2(stream) \
       if (sizeof((stream)->bitContainer)*8 < HUF_TABLELOG_MAX*4+7) HUF_FLUSHBITS(stream)
   
   FORCE_INLINE_TEMPLATE size_t
   HUF_compress1X_usingCTable_internal_body(void* dst, size_t dstSize,
                                      const void* src, size_t srcSize,
                                      const HUF_CElt* CTable)
   {
       const BYTE* ip = (const BYTE*) src;
       BYTE* const ostart = (BYTE*)dst;
       BYTE* const oend = ostart + dstSize;
       BYTE* op = ostart;
       size_t n;
       BIT_CStream_t bitC;
   
       /* init */
       if (dstSize < 8) return 0;   /* not enough space to compress */
       { size_t const initErr = BIT_initCStream(&bitC, op, (size_t)(oend-op));
         if (HUF_isError(initErr)) return 0; }
   
       n = srcSize & ~3;  /* join to mod 4 */
       switch (srcSize & 3)
       {
           case 3 : HUF_encodeSymbol(&bitC, ip[n+ 2], CTable);
                    HUF_FLUSHBITS_2(&bitC);
                    /* fall-through */
           case 2 : HUF_encodeSymbol(&bitC, ip[n+ 1], CTable);
                    HUF_FLUSHBITS_1(&bitC);
                    /* fall-through */
           case 1 : HUF_encodeSymbol(&bitC, ip[n+ 0], CTable);
                    HUF_FLUSHBITS(&bitC);
                    /* fall-through */
           case 0 : /* fall-through */
           default: break;
       }
   
       for (; n>0; n-=4) {  /* note : n&3==0 at this stage */
           HUF_encodeSymbol(&bitC, ip[n- 1], CTable);
           HUF_FLUSHBITS_1(&bitC);
           HUF_encodeSymbol(&bitC, ip[n- 2], CTable);
           HUF_FLUSHBITS_2(&bitC);
           HUF_encodeSymbol(&bitC, ip[n- 3], CTable);
           HUF_FLUSHBITS_1(&bitC);
           HUF_encodeSymbol(&bitC, ip[n- 4], CTable);
           HUF_FLUSHBITS(&bitC);
       }
   
       return BIT_closeCStream(&bitC);
   }
   
   #if DYNAMIC_BMI2
   
   static TARGET_ATTRIBUTE("bmi2") size_t
   HUF_compress1X_usingCTable_internal_bmi2(void* dst, size_t dstSize,
                                      const void* src, size_t srcSize,
                                      const HUF_CElt* CTable)
   {
       return HUF_compress1X_usingCTable_internal_body(dst, dstSize, src, srcSize, CTable);
   }
   
   static size_t
   HUF_compress1X_usingCTable_internal_default(void* dst, size_t dstSize,
                                         const void* src, size_t srcSize,
                                         const HUF_CElt* CTable)
   {
       return HUF_compress1X_usingCTable_internal_body(dst, dstSize, src, srcSize, CTable);
   }
   
   static size_t
   HUF_compress1X_usingCTable_internal(void* dst, size_t dstSize,
                                 const void* src, size_t srcSize,
                                 const HUF_CElt* CTable, const int bmi2)
   {
       if (bmi2) {
           return HUF_compress1X_usingCTable_internal_bmi2(dst, dstSize, src, srcSize, CTable);
       }
       return HUF_compress1X_usingCTable_internal_default(dst, dstSize, src, srcSize, CTable);
   }
   
   #else
   
   static size_t
   HUF_compress1X_usingCTable_internal(void* dst, size_t dstSize,
                                 const void* src, size_t srcSize,
                                 const HUF_CElt* CTable, const int bmi2)
   {
       (void)bmi2;
       return HUF_compress1X_usingCTable_internal_body(dst, dstSize, src, srcSize, CTable);
   }
   
   #endif
   
   size_t HUF_compress1X_usingCTable(void* dst, size_t dstSize, const void* src, size_t srcSize, const HUF_CElt* CTable)
   {
       return HUF_compress1X_usingCTable_internal(dst, dstSize, src, srcSize, CTable, /* bmi2 */ 0);
   }
   
   
   static size_t
   HUF_compress4X_usingCTable_internal(void* dst, size_t dstSize,
                                 const void* src, size_t srcSize,
                                 const HUF_CElt* CTable, int bmi2)
   {
       size_t const segmentSize = (srcSize+3)/4;   /* first 3 segments */
       const BYTE* ip = (const BYTE*) src;
       const BYTE* const iend = ip + srcSize;
       BYTE* const ostart = (BYTE*) dst;
       BYTE* const oend = ostart + dstSize;
       BYTE* op = ostart;
   
       if (dstSize < 6 + 1 + 1 + 1 + 8) return 0;   /* minimum space to compress successfully */
       if (srcSize < 12) return 0;   /* no saving possible : too small input */
       op += 6;   /* jumpTable */
   
       assert(op <= oend);
       {   CHECK_V_F(cSize, HUF_compress1X_usingCTable_internal(op, (size_t)(oend-op), ip, segmentSize, CTable, bmi2) );
           if (cSize==0) return 0;
           assert(cSize <= 65535);
           MEM_writeLE16(ostart, (U16)cSize);
           op += cSize;
       }
   
       ip += segmentSize;
       assert(op <= oend);
       {   CHECK_V_F(cSize, HUF_compress1X_usingCTable_internal(op, (size_t)(oend-op), ip, segmentSize, CTable, bmi2) );
           if (cSize==0) return 0;
           assert(cSize <= 65535);
           MEM_writeLE16(ostart+2, (U16)cSize);
           op += cSize;
       }
   
       ip += segmentSize;
       assert(op <= oend);
       {   CHECK_V_F(cSize, HUF_compress1X_usingCTable_internal(op, (size_t)(oend-op), ip, segmentSize, CTable, bmi2) );
           if (cSize==0) return 0;
           assert(cSize <= 65535);
           MEM_writeLE16(ostart+4, (U16)cSize);
           op += cSize;
       }
   
       ip += segmentSize;
       assert(op <= oend);
       assert(ip <= iend);
       {   CHECK_V_F(cSize, HUF_compress1X_usingCTable_internal(op, (size_t)(oend-op), ip, (size_t)(iend-ip), CTable, bmi2) );
           if (cSize==0) return 0;
           op += cSize;
       }
   
       return (size_t)(op-ostart);
   }
   
   size_t HUF_compress4X_usingCTable(void* dst, size_t dstSize, const void* src, size_t srcSize, const HUF_CElt* CTable)
   {
       return HUF_compress4X_usingCTable_internal(dst, dstSize, src, srcSize, CTable, /* bmi2 */ 0);
   }
   
   typedef enum { HUF_singleStream, HUF_fourStreams } HUF_nbStreams_e;
   
   static size_t HUF_compressCTable_internal(
                   BYTE* const ostart, BYTE* op, BYTE* const oend,
                   const void* src, size_t srcSize,
                   HUF_nbStreams_e nbStreams, const HUF_CElt* CTable, const int bmi2)
   {
       size_t const cSize = (nbStreams==HUF_singleStream) ?
                            HUF_compress1X_usingCTable_internal(op, (size_t)(oend - op), src, srcSize, CTable, bmi2) :
                            HUF_compress4X_usingCTable_internal(op, (size_t)(oend - op), src, srcSize, CTable, bmi2);
       if (HUF_isError(cSize)) { return cSize; }
       if (cSize==0) { return 0; }   /* uncompressible */
       op += cSize;
       /* check compressibility */
       assert(op >= ostart);
       if ((size_t)(op-ostart) >= srcSize-1) { return 0; }
       return (size_t)(op-ostart);
   }
   
   typedef struct {
       unsigned count[HUF_SYMBOLVALUE_MAX + 1];
       HUF_CElt CTable[HUF_SYMBOLVALUE_MAX + 1];
       HUF_buildCTable_wksp_tables buildCTable_wksp;
   } HUF_compress_tables_t;
   
   /* HUF_compress_internal() :
    * `workSpace` must a table of at least HUF_WORKSPACE_SIZE_U32 unsigned */
   static size_t
   HUF_compress_internal (void* dst, size_t dstSize,
                    const void* src, size_t srcSize,
                          unsigned maxSymbolValue, unsigned huffLog,
                          HUF_nbStreams_e nbStreams,
                          void* workSpace, size_t wkspSize,
                          HUF_CElt* oldHufTable, HUF_repeat* repeat, int preferRepeat,
                    const int bmi2)
   {
       HUF_compress_tables_t* const table = (HUF_compress_tables_t*)workSpace;
       BYTE* const ostart = (BYTE*)dst;
       BYTE* const oend = ostart + dstSize;
       BYTE* op = ostart;
   
       HUF_STATIC_ASSERT(sizeof(*table) <= HUF_WORKSPACE_SIZE);
   
       /* checks & inits */
       if (((size_t)workSpace & 3) != 0) return ERROR(GENERIC);  /* must be aligned on 4-bytes boundaries */
       if (wkspSize < HUF_WORKSPACE_SIZE) return ERROR(workSpace_tooSmall);
       if (!srcSize) return 0;  /* Uncompressed */
       if (!dstSize) return 0;  /* cannot fit anything within dst budget */
       if (srcSize > HUF_BLOCKSIZE_MAX) return ERROR(srcSize_wrong);   /* current block size limit */
       if (huffLog > HUF_TABLELOG_MAX) return ERROR(tableLog_tooLarge);
       if (maxSymbolValue > HUF_SYMBOLVALUE_MAX) return ERROR(maxSymbolValue_tooLarge);
       if (!maxSymbolValue) maxSymbolValue = HUF_SYMBOLVALUE_MAX;
       if (!huffLog) huffLog = HUF_TABLELOG_DEFAULT;
   
       /* Heuristic : If old table is valid, use it for small inputs */
       if (preferRepeat && repeat && *repeat == HUF_repeat_valid) {
           return HUF_compressCTable_internal(ostart, op, oend,
                                              src, srcSize,
                                              nbStreams, oldHufTable, bmi2);
       }
   
       /* Scan input and build symbol stats */
       {   CHECK_V_F(largest, HIST_count_wksp (table->count, &maxSymbolValue, (const BYTE*)src, srcSize, workSpace, wkspSize) );
           if (largest == srcSize) { *ostart = ((const BYTE*)src)[0]; return 1; }   /* single symbol, rle */
           if (largest <= (srcSize >> 7)+4) return 0;   /* heuristic : probably not compressible enough */
       }
   
       /* Check validity of previous table */
       if ( repeat
         && *repeat == HUF_repeat_check
         && !HUF_validateCTable(oldHufTable, table->count, maxSymbolValue)) {
           *repeat = HUF_repeat_none;
       }
       /* Heuristic : use existing table for small inputs */
       if (preferRepeat && repeat && *repeat != HUF_repeat_none) {
           return HUF_compressCTable_internal(ostart, op, oend,
                                              src, srcSize,
                                              nbStreams, oldHufTable, bmi2);
       }
   
       /* Build Huffman Tree */
       huffLog = HUF_optimalTableLog(huffLog, srcSize, maxSymbolValue);
       {   size_t const maxBits = HUF_buildCTable_wksp(table->CTable, table->count,
                                               maxSymbolValue, huffLog,
                                               &table->buildCTable_wksp, sizeof(table->buildCTable_wksp));
           CHECK_F(maxBits);
           huffLog = (U32)maxBits;
           /* Zero unused symbols in CTable, so we can check it for validity */
           memset(table->CTable + (maxSymbolValue + 1), 0,
                  sizeof(table->CTable) - ((maxSymbolValue + 1) * sizeof(HUF_CElt)));
       }
   
       /* Write table description header */
       {   CHECK_V_F(hSize, HUF_writeCTable (op, dstSize, table->CTable, maxSymbolValue, huffLog) );
           /* Check if using previous huffman table is beneficial */
           if (repeat && *repeat != HUF_repeat_none) {
               size_t const oldSize = HUF_estimateCompressedSize(oldHufTable, table->count, maxSymbolValue);
               size_t const newSize = HUF_estimateCompressedSize(table->CTable, table->count, maxSymbolValue);
               if (oldSize <= hSize + newSize || hSize + 12 >= srcSize) {
                   return HUF_compressCTable_internal(ostart, op, oend,
                                                      src, srcSize,
                                                      nbStreams, oldHufTable, bmi2);
           }   }
   
           /* Use the new huffman table */
           if (hSize + 12ul >= srcSize) { return 0; }
           op += hSize;
           if (repeat) { *repeat = HUF_repeat_none; }
           if (oldHufTable)
               memcpy(oldHufTable, table->CTable, sizeof(table->CTable));  /* Save new table */
       }
       return HUF_compressCTable_internal(ostart, op, oend,
                                          src, srcSize,
                                          nbStreams, table->CTable, bmi2);
   }
   
   
   size_t HUF_compress1X_wksp (void* dst, size_t dstSize,
                         const void* src, size_t srcSize,
                         unsigned maxSymbolValue, unsigned huffLog,
                         void* workSpace, size_t wkspSize)
   {
       return HUF_compress_internal(dst, dstSize, src, srcSize,
                                    maxSymbolValue, huffLog, HUF_singleStream,
                                    workSpace, wkspSize,
                                    NULL, NULL, 0, 0 /*bmi2*/);
   }
   
   size_t HUF_compress1X_repeat (void* dst, size_t dstSize,
                         const void* src, size_t srcSize,
                         unsigned maxSymbolValue, unsigned huffLog,
                         void* workSpace, size_t wkspSize,
                         HUF_CElt* hufTable, HUF_repeat* repeat, int preferRepeat, int bmi2)
   {
       return HUF_compress_internal(dst, dstSize, src, srcSize,
                                    maxSymbolValue, huffLog, HUF_singleStream,
                                    workSpace, wkspSize, hufTable,
                                    repeat, preferRepeat, bmi2);
   }
   
   size_t HUF_compress1X (void* dst, size_t dstSize,
                    const void* src, size_t srcSize,
                    unsigned maxSymbolValue, unsigned huffLog)
   {
       unsigned workSpace[HUF_WORKSPACE_SIZE_U32];
       return HUF_compress1X_wksp(dst, dstSize, src, srcSize, maxSymbolValue, huffLog, workSpace, sizeof(workSpace));
   }
   
   /* HUF_compress4X_repeat():
    * compress input using 4 streams.
    * provide workspace to generate compression tables */
   size_t HUF_compress4X_wksp (void* dst, size_t dstSize,
                         const void* src, size_t srcSize,
                         unsigned maxSymbolValue, unsigned huffLog,
                         void* workSpace, size_t wkspSize)
   {
       return HUF_compress_internal(dst, dstSize, src, srcSize,
                                    maxSymbolValue, huffLog, HUF_fourStreams,
                                    workSpace, wkspSize,
                                    NULL, NULL, 0, 0 /*bmi2*/);
   }
   
   /* HUF_compress4X_repeat():
    * compress input using 4 streams.
    * re-use an existing huffman compression table */
   size_t HUF_compress4X_repeat (void* dst, size_t dstSize,
                         const void* src, size_t srcSize,
                         unsigned maxSymbolValue, unsigned huffLog,
                         void* workSpace, size_t wkspSize,
                         HUF_CElt* hufTable, HUF_repeat* repeat, int preferRepeat, int bmi2)
   {
       return HUF_compress_internal(dst, dstSize, src, srcSize,
                                    maxSymbolValue, huffLog, HUF_fourStreams,
                                    workSpace, wkspSize,
                                    hufTable, repeat, preferRepeat, bmi2);
   }
   
   size_t HUF_compress2 (void* dst, size_t dstSize,
                   const void* src, size_t srcSize,
                   unsigned maxSymbolValue, unsigned huffLog)
   {
       unsigned workSpace[HUF_WORKSPACE_SIZE_U32];
       return HUF_compress4X_wksp(dst, dstSize, src, srcSize, maxSymbolValue, huffLog, workSpace, sizeof(workSpace));
   }
   
   size_t HUF_compress (void* dst, size_t maxDstSize, const void* src, size_t srcSize)
   {
       return HUF_compress2(dst, maxDstSize, src, srcSize, 255, HUF_TABLELOG_DEFAULT);
   }

Cache object: 27b0b7463868717b2ce7ebcebba9976e