FreeBSD/Linux Kernel Cross Reference
sys/contrib/zstd/zlibWrapper/zstd_zlibwrapper.c

     /*
      * Copyright (c) 2016-2021, Przemyslaw Skibinski, Yann Collet, Facebook, Inc.
      * All rights reserved.
      *
      * 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.
      */
    
    
    /* ===   Tuning parameters   === */
    #ifndef ZWRAP_USE_ZSTD
        #define ZWRAP_USE_ZSTD 0
    #endif
    
    
    /* ===   Dependencies   === */
    #include <stdlib.h>
    #include <stdio.h>                 /* vsprintf */
    #include <stdarg.h>                /* va_list, for z_gzprintf */
    #include <string.h>
    #define NO_DUMMY_DECL
    #define ZLIB_CONST
    #include <zlib.h>                  /* without #define Z_PREFIX */
    #include "zstd_zlibwrapper.h"
    #define ZSTD_STATIC_LINKING_ONLY   /* ZSTD_isFrame, ZSTD_MAGICNUMBER, ZSTD_customMem */
    #include "zstd.h"
    
    
    /* ===   Constants   === */
    #define Z_INFLATE_SYNC              8
    #define ZLIB_HEADERSIZE             4
    #define ZSTD_HEADERSIZE             ZSTD_FRAMEHEADERSIZE_MIN(ZSTD_f_zstd1)
    #define ZWRAP_DEFAULT_CLEVEL        3   /* Z_DEFAULT_COMPRESSION is translated to ZWRAP_DEFAULT_CLEVEL for zstd */
    
    
    /* ===   Debug   === */
    #define LOG_WRAPPERC(...)  /* fprintf(stderr, __VA_ARGS__) */
    #define LOG_WRAPPERD(...)  /* fprintf(stderr, __VA_ARGS__) */
    
    #define FINISH_WITH_GZ_ERR(msg) { (void)msg; return Z_STREAM_ERROR; }
    #define FINISH_WITH_NULL_ERR(msg) { (void)msg; return NULL; }
    
    /* ===   Utility   === */
    
    #define MIN(x,y) ((x) < (y) ? (x) : (y))
    
    static unsigned ZWRAP_isLittleEndian(void)
    {
        const union { unsigned u; char c[4]; } one = { 1 };   /* don't use static : performance detrimental  */
        return one.c[0];
    }
    
    #ifndef __has_builtin
    # define __has_builtin(x) 0
    #endif
    
    static unsigned ZWRAP_swap32(unsigned in)
    {
    #if defined(_MSC_VER)     /* Visual Studio */
        return _byteswap_ulong(in);
    #elif (defined (__GNUC__) && (__GNUC__ * 100 + __GNUC_MINOR__ >= 403)) \
      || (defined(__clang__) && __has_builtin(__builtin_bswap32))
        return __builtin_bswap32(in);
    #else
        return  ((in << 24) & 0xff000000 ) |
                ((in <<  8) & 0x00ff0000 ) |
                ((in >>  8) & 0x0000ff00 ) |
                ((in >> 24) & 0x000000ff );
    #endif
    }
    
    static unsigned ZWRAP_readLE32(const void* ptr)
    {
        unsigned value;
        memcpy(&value, ptr, sizeof(value));
        if (ZWRAP_isLittleEndian())
            return value;
        else
            return ZWRAP_swap32(value);
    }
    
    
    /* ===   Wrapper   === */
    static int g_ZWRAP_useZSTDcompression = ZWRAP_USE_ZSTD; /* 0 = don't use ZSTD */
    
    void ZWRAP_useZSTDcompression(int turn_on) { g_ZWRAP_useZSTDcompression = turn_on; }
    
    int ZWRAP_isUsingZSTDcompression(void) { return g_ZWRAP_useZSTDcompression; }
    
    
    
    static ZWRAP_decompress_type g_ZWRAPdecompressionType = ZWRAP_AUTO;
    
    void ZWRAP_setDecompressionType(ZWRAP_decompress_type type) { g_ZWRAPdecompressionType = type; }
    
    ZWRAP_decompress_type ZWRAP_getDecompressionType(void) { return g_ZWRAPdecompressionType; }
    
   
   
   const char * zstdVersion(void) { return ZSTD_VERSION_STRING; }
   
   ZEXTERN const char * ZEXPORT z_zlibVersion OF((void)) { return zlibVersion();  }
   
   static void* ZWRAP_allocFunction(void* opaque, size_t size)
   {
       z_streamp strm = (z_streamp) opaque;
       void* address = strm->zalloc(strm->opaque, 1, (uInt)size);
       /* LOG_WRAPPERC("ZWRAP alloc %p, %d \n", address, (int)size); */
       return address;
   }
   
   static void ZWRAP_freeFunction(void* opaque, void* address)
   {
       z_streamp strm = (z_streamp) opaque;
       strm->zfree(strm->opaque, address);
      /* if (address) LOG_WRAPPERC("ZWRAP free %p \n", address); */
   }
   
   static void* ZWRAP_customMalloc(size_t size, ZSTD_customMem customMem)
   {
       if (customMem.customAlloc)
           return customMem.customAlloc(customMem.opaque, size);
       return malloc(size);
   }
   
   static void* ZWRAP_customCalloc(size_t size, ZSTD_customMem customMem)
   {
       if (customMem.customAlloc) {
           /* calloc implemented as malloc+memset;
            * not as efficient as calloc, but next best guess for custom malloc */
           void* const ptr = customMem.customAlloc(customMem.opaque, size);
           memset(ptr, 0, size);
           return ptr;
       }
       return calloc(1, size);
   }
   
   static void ZWRAP_customFree(void* ptr, ZSTD_customMem customMem)
   {
       if (ptr!=NULL) {
           if (customMem.customFree)
               customMem.customFree(customMem.opaque, ptr);
           else
               free(ptr);
       }
   }
   
   
   
   /* ===   Compression   === */
   typedef enum { ZWRAP_useInit, ZWRAP_useReset, ZWRAP_streamEnd } ZWRAP_state_t;
   
   typedef struct {
       ZSTD_CStream* zbc;
       int compressionLevel;
       int streamEnd; /* a flag to signal the end of a stream */
       unsigned long long totalInBytes; /* we need it as strm->total_in can be reset by user */
       ZSTD_customMem customMem;
       z_stream allocFunc; /* copy of zalloc, zfree, opaque */
       ZSTD_inBuffer inBuffer;
       ZSTD_outBuffer outBuffer;
       ZWRAP_state_t comprState;
       unsigned long long pledgedSrcSize;
   } ZWRAP_CCtx;
   
   /* typedef ZWRAP_CCtx internal_state; */
   
   
   
   static size_t ZWRAP_freeCCtx(ZWRAP_CCtx* zwc)
   {
       if (zwc==NULL) return 0;   /* support free on NULL */
       ZSTD_freeCStream(zwc->zbc);
       ZWRAP_customFree(zwc, zwc->customMem);
       return 0;
   }
   
   
   static ZWRAP_CCtx* ZWRAP_createCCtx(z_streamp strm)
   {
       ZWRAP_CCtx* zwc;
       ZSTD_customMem customMem = { NULL, NULL, NULL };
   
       if (strm->zalloc && strm->zfree) {
           customMem.customAlloc = ZWRAP_allocFunction;
           customMem.customFree = ZWRAP_freeFunction;
       }
       customMem.opaque = strm;
   
       zwc = (ZWRAP_CCtx*)ZWRAP_customCalloc(sizeof(ZWRAP_CCtx), customMem);
       if (zwc == NULL) return NULL;
       zwc->allocFunc = *strm;
       customMem.opaque = &zwc->allocFunc;
       zwc->customMem = customMem;
   
       return zwc;
   }
   
   
   static int ZWRAP_initializeCStream(ZWRAP_CCtx* zwc, const void* dict, size_t dictSize, unsigned long long pledgedSrcSize)
   {
       LOG_WRAPPERC("- ZWRAP_initializeCStream=%p\n", zwc);
       if (zwc == NULL || zwc->zbc == NULL) return Z_STREAM_ERROR;
   
       if (!pledgedSrcSize) pledgedSrcSize = zwc->pledgedSrcSize;
       {   unsigned initErr = 0;
           ZSTD_parameters const params = ZSTD_getParams(zwc->compressionLevel, pledgedSrcSize, dictSize);
           ZSTD_CCtx_params* cctxParams = ZSTD_createCCtxParams();
           if (!cctxParams) return Z_STREAM_ERROR;
           LOG_WRAPPERC("pledgedSrcSize=%d windowLog=%d chainLog=%d hashLog=%d searchLog=%d minMatch=%d strategy=%d\n",
                       (int)pledgedSrcSize, params.cParams.windowLog, params.cParams.chainLog, params.cParams.hashLog, params.cParams.searchLog, params.cParams.minMatch, params.cParams.strategy);
   
           initErr |= ZSTD_isError(ZSTD_CCtx_reset(zwc->zbc, ZSTD_reset_session_only));
           initErr |= ZSTD_isError(ZSTD_CCtxParams_init_advanced(cctxParams, params));
           initErr |= ZSTD_isError(ZSTD_CCtx_setParametersUsingCCtxParams(zwc->zbc, cctxParams));
           initErr |= ZSTD_isError(ZSTD_CCtx_setPledgedSrcSize(zwc->zbc, pledgedSrcSize));
           initErr |= ZSTD_isError(ZSTD_CCtx_loadDictionary(zwc->zbc, dict, dictSize));
   
           ZSTD_freeCCtxParams(cctxParams);
           if (initErr) return Z_STREAM_ERROR;
       }
   
       return Z_OK;
   }
   
   
   static int ZWRAPC_finishWithError(ZWRAP_CCtx* zwc, z_streamp strm, int error)
   {
       LOG_WRAPPERC("- ZWRAPC_finishWithError=%d\n", error);
       if (zwc) ZWRAP_freeCCtx(zwc);
       if (strm) strm->state = NULL;
       return (error) ? error : Z_STREAM_ERROR;
   }
   
   
   static int ZWRAPC_finishWithErrorMsg(z_streamp strm, char* message)
   {
       ZWRAP_CCtx* zwc = (ZWRAP_CCtx*) strm->state;
       strm->msg = message;
       if (zwc == NULL) return Z_STREAM_ERROR;
   
       return ZWRAPC_finishWithError(zwc, strm, 0);
   }
   
   
   int ZWRAP_setPledgedSrcSize(z_streamp strm, unsigned long long pledgedSrcSize)
   {
       ZWRAP_CCtx* zwc = (ZWRAP_CCtx*) strm->state;
       if (zwc == NULL) return Z_STREAM_ERROR;
   
       zwc->pledgedSrcSize = pledgedSrcSize;
       zwc->comprState = ZWRAP_useInit;
       return Z_OK;
   }
   
   static struct internal_state* convert_into_sis(void* ptr)
   {
       return (struct internal_state*) ptr;
   }
   
   ZEXTERN int ZEXPORT z_deflateInit_ OF((z_streamp strm, int level,
                                        const char *version, int stream_size))
   {
       ZWRAP_CCtx* zwc;
   
       LOG_WRAPPERC("- deflateInit level=%d\n", level);
       if (!g_ZWRAP_useZSTDcompression) {
           return deflateInit_((strm), (level), version, stream_size);
       }
   
       zwc = ZWRAP_createCCtx(strm);
       if (zwc == NULL) return Z_MEM_ERROR;
   
       if (level == Z_DEFAULT_COMPRESSION)
           level = ZWRAP_DEFAULT_CLEVEL;
   
       zwc->streamEnd = 0;
       zwc->totalInBytes = 0;
       zwc->compressionLevel = level;
       strm->state = convert_into_sis(zwc); /* use state which in not used by user */
       strm->total_in = 0;
       strm->total_out = 0;
       strm->adler = 0;
       return Z_OK;
   }
   
   
   ZEXTERN int ZEXPORT z_deflateInit2_ OF((z_streamp strm, int level, int method,
                                         int windowBits, int memLevel,
                                         int strategy, const char *version,
                                         int stream_size))
   {
       if (!g_ZWRAP_useZSTDcompression)
           return deflateInit2_(strm, level, method, windowBits, memLevel, strategy, version, stream_size);
   
       return z_deflateInit_ (strm, level, version, stream_size);
   }
   
   
   int ZWRAP_deflateReset_keepDict(z_streamp strm)
   {
       LOG_WRAPPERC("- ZWRAP_deflateReset_keepDict\n");
       if (!g_ZWRAP_useZSTDcompression)
           return deflateReset(strm);
   
       { ZWRAP_CCtx* zwc = (ZWRAP_CCtx*) strm->state;
         if (zwc) {
             zwc->streamEnd = 0;
             zwc->totalInBytes = 0;
         }
       }
   
       strm->total_in = 0;
       strm->total_out = 0;
       strm->adler = 0;
       return Z_OK;
   }
   
   
   ZEXTERN int ZEXPORT z_deflateReset OF((z_streamp strm))
   {
       LOG_WRAPPERC("- deflateReset\n");
       if (!g_ZWRAP_useZSTDcompression)
           return deflateReset(strm);
   
       ZWRAP_deflateReset_keepDict(strm);
   
       { ZWRAP_CCtx* zwc = (ZWRAP_CCtx*) strm->state;
         if (zwc) zwc->comprState = ZWRAP_useInit;
       }
       return Z_OK;
   }
   
   
   ZEXTERN int ZEXPORT z_deflateSetDictionary OF((z_streamp strm,
                                                const Bytef *dictionary,
                                                uInt  dictLength))
   {
       if (!g_ZWRAP_useZSTDcompression) {
           LOG_WRAPPERC("- deflateSetDictionary\n");
           return deflateSetDictionary(strm, dictionary, dictLength);
       }
   
       {   ZWRAP_CCtx* zwc = (ZWRAP_CCtx*) strm->state;
           LOG_WRAPPERC("- deflateSetDictionary level=%d\n", (int)zwc->compressionLevel);
           if (!zwc) return Z_STREAM_ERROR;
           if (zwc->zbc == NULL) {
               zwc->zbc = ZSTD_createCStream_advanced(zwc->customMem);
               if (zwc->zbc == NULL) return ZWRAPC_finishWithError(zwc, strm, 0);
           }
           { int res = ZWRAP_initializeCStream(zwc, dictionary, dictLength, ZSTD_CONTENTSIZE_UNKNOWN);
             if (res != Z_OK) return ZWRAPC_finishWithError(zwc, strm, res); }
           zwc->comprState = ZWRAP_useReset;
       }
   
       return Z_OK;
   }
   
   
   ZEXTERN int ZEXPORT z_deflate OF((z_streamp strm, int flush))
   {
       ZWRAP_CCtx* zwc;
   
       if (!g_ZWRAP_useZSTDcompression) {
           LOG_WRAPPERC("- deflate1 flush=%d avail_in=%d avail_out=%d total_in=%d total_out=%d\n",
                       (int)flush, (int)strm->avail_in, (int)strm->avail_out, (int)strm->total_in, (int)strm->total_out);
           return deflate(strm, flush);
       }
   
       zwc = (ZWRAP_CCtx*) strm->state;
       if (zwc == NULL) { LOG_WRAPPERC("zwc == NULL\n"); return Z_STREAM_ERROR; }
   
       if (zwc->zbc == NULL) {
           zwc->zbc = ZSTD_createCStream_advanced(zwc->customMem);
           if (zwc->zbc == NULL) return ZWRAPC_finishWithError(zwc, strm, 0);
           { int const initErr = ZWRAP_initializeCStream(zwc, NULL, 0, (flush == Z_FINISH) ? strm->avail_in : ZSTD_CONTENTSIZE_UNKNOWN);
             if (initErr != Z_OK) return ZWRAPC_finishWithError(zwc, strm, initErr); }
           if (flush != Z_FINISH) zwc->comprState = ZWRAP_useReset;
       } else {
           if (zwc->totalInBytes == 0) {
               if (zwc->comprState == ZWRAP_useReset) {
                   size_t resetErr = ZSTD_CCtx_reset(zwc->zbc, ZSTD_reset_session_only);
                   if (ZSTD_isError(resetErr)) {
                       LOG_WRAPPERC("ERROR: ZSTD_CCtx_reset errorCode=%s\n",
                                   ZSTD_getErrorName(resetErr));
                       return ZWRAPC_finishWithError(zwc, strm, 0);
                   }
                   resetErr = ZSTD_CCtx_setPledgedSrcSize(zwc->zbc, (flush == Z_FINISH) ? strm->avail_in : zwc->pledgedSrcSize);
                   if (ZSTD_isError(resetErr)) {
                       LOG_WRAPPERC("ERROR: ZSTD_CCtx_setPledgedSrcSize errorCode=%s\n",
                                   ZSTD_getErrorName(resetErr));
                       return ZWRAPC_finishWithError(zwc, strm, 0);
                   }
               } else {
                   int const res = ZWRAP_initializeCStream(zwc, NULL, 0, (flush == Z_FINISH) ? strm->avail_in : ZSTD_CONTENTSIZE_UNKNOWN);
                   if (res != Z_OK) return ZWRAPC_finishWithError(zwc, strm, res);
                   if (flush != Z_FINISH) zwc->comprState = ZWRAP_useReset;
               }
           }  /* (zwc->totalInBytes == 0) */
       }  /* ! (zwc->zbc == NULL) */
   
       LOG_WRAPPERC("- deflate2 flush=%d avail_in=%d avail_out=%d total_in=%d total_out=%d\n", (int)flush, (int)strm->avail_in, (int)strm->avail_out, (int)strm->total_in, (int)strm->total_out);
       if (strm->avail_in > 0) {
           zwc->inBuffer.src = strm->next_in;
           zwc->inBuffer.size = strm->avail_in;
           zwc->inBuffer.pos = 0;
           zwc->outBuffer.dst = strm->next_out;
           zwc->outBuffer.size = strm->avail_out;
           zwc->outBuffer.pos = 0;
           { size_t const cErr = ZSTD_compressStream(zwc->zbc, &zwc->outBuffer, &zwc->inBuffer);
             LOG_WRAPPERC("deflate ZSTD_compressStream srcSize=%d dstCapacity=%d\n", (int)zwc->inBuffer.size, (int)zwc->outBuffer.size);
             if (ZSTD_isError(cErr)) return ZWRAPC_finishWithError(zwc, strm, 0);
           }
           strm->next_out += zwc->outBuffer.pos;
           strm->total_out += zwc->outBuffer.pos;
           strm->avail_out -= zwc->outBuffer.pos;
           strm->total_in += zwc->inBuffer.pos;
           zwc->totalInBytes += zwc->inBuffer.pos;
           strm->next_in += zwc->inBuffer.pos;
           strm->avail_in -= zwc->inBuffer.pos;
       }
   
       if (flush == Z_FULL_FLUSH
   #if ZLIB_VERNUM >= 0x1240
           || flush == Z_TREES
   #endif
           || flush == Z_BLOCK)
           return ZWRAPC_finishWithErrorMsg(strm, "Z_FULL_FLUSH, Z_BLOCK and Z_TREES are not supported!");
   
       if (flush == Z_FINISH) {
           size_t bytesLeft;
           if (zwc->streamEnd) return Z_STREAM_END;
           zwc->outBuffer.dst = strm->next_out;
           zwc->outBuffer.size = strm->avail_out;
           zwc->outBuffer.pos = 0;
           bytesLeft = ZSTD_endStream(zwc->zbc, &zwc->outBuffer);
           LOG_WRAPPERC("deflate ZSTD_endStream dstCapacity=%d bytesLeft=%d\n", (int)strm->avail_out, (int)bytesLeft);
           if (ZSTD_isError(bytesLeft)) return ZWRAPC_finishWithError(zwc, strm, 0);
           strm->next_out += zwc->outBuffer.pos;
           strm->total_out += zwc->outBuffer.pos;
           strm->avail_out -= zwc->outBuffer.pos;
           if (bytesLeft == 0) {
               zwc->streamEnd = 1;
               LOG_WRAPPERC("Z_STREAM_END2 strm->total_in=%d strm->avail_out=%d strm->total_out=%d\n",
                           (int)strm->total_in, (int)strm->avail_out, (int)strm->total_out);
               return Z_STREAM_END;
       }   }
       else
       if (flush == Z_SYNC_FLUSH || flush == Z_PARTIAL_FLUSH) {
           size_t bytesLeft;
           zwc->outBuffer.dst = strm->next_out;
           zwc->outBuffer.size = strm->avail_out;
           zwc->outBuffer.pos = 0;
           bytesLeft = ZSTD_flushStream(zwc->zbc, &zwc->outBuffer);
           LOG_WRAPPERC("deflate ZSTD_flushStream dstCapacity=%d bytesLeft=%d\n", (int)strm->avail_out, (int)bytesLeft);
           if (ZSTD_isError(bytesLeft)) return ZWRAPC_finishWithError(zwc, strm, 0);
           strm->next_out += zwc->outBuffer.pos;
           strm->total_out += zwc->outBuffer.pos;
           strm->avail_out -= zwc->outBuffer.pos;
       }
       LOG_WRAPPERC("- deflate3 flush=%d avail_in=%d avail_out=%d total_in=%d total_out=%d\n", (int)flush, (int)strm->avail_in, (int)strm->avail_out, (int)strm->total_in, (int)strm->total_out);
       return Z_OK;
   }
   
   
   ZEXTERN int ZEXPORT z_deflateEnd OF((z_streamp strm))
   {
       if (!g_ZWRAP_useZSTDcompression) {
           LOG_WRAPPERC("- deflateEnd\n");
           return deflateEnd(strm);
       }
       LOG_WRAPPERC("- deflateEnd total_in=%d total_out=%d\n", (int)(strm->total_in), (int)(strm->total_out));
       {   size_t errorCode;
           ZWRAP_CCtx* zwc = (ZWRAP_CCtx*) strm->state;
           if (zwc == NULL) return Z_OK;  /* structures are already freed */
           strm->state = NULL;
           errorCode = ZWRAP_freeCCtx(zwc);
           if (ZSTD_isError(errorCode)) return Z_STREAM_ERROR;
       }
       return Z_OK;
   }
   
   
   ZEXTERN uLong ZEXPORT z_deflateBound OF((z_streamp strm,
                                          uLong sourceLen))
   {
       if (!g_ZWRAP_useZSTDcompression)
           return deflateBound(strm, sourceLen);
   
       return ZSTD_compressBound(sourceLen);
   }
   
   
   ZEXTERN int ZEXPORT z_deflateParams OF((z_streamp strm,
                                         int level,
                                         int strategy))
   {
       if (!g_ZWRAP_useZSTDcompression) {
           LOG_WRAPPERC("- deflateParams level=%d strategy=%d\n", level, strategy);
           return deflateParams(strm, level, strategy);
       }
   
       return Z_OK;
   }
   
   
   
   
   
   /* ===   Decompression   === */
   
   typedef enum { ZWRAP_ZLIB_STREAM, ZWRAP_ZSTD_STREAM, ZWRAP_UNKNOWN_STREAM } ZWRAP_stream_type;
   
   typedef struct {
       ZSTD_DStream* zbd;
       char headerBuf[16];   /* must be >= ZSTD_frameHeaderSize_min */
       int errorCount;
       unsigned long long totalInBytes; /* we need it as strm->total_in can be reset by user */
       ZWRAP_state_t decompState;
       ZSTD_inBuffer inBuffer;
       ZSTD_outBuffer outBuffer;
   
       /* zlib params */
       int stream_size;
       char *version;
       int windowBits;
       ZSTD_customMem customMem;
       z_stream allocFunc; /* just to copy zalloc, zfree, opaque */
   } ZWRAP_DCtx;
   
   
   static void ZWRAP_initDCtx(ZWRAP_DCtx* zwd)
   {
       zwd->errorCount = 0;
       zwd->outBuffer.pos = 0;
       zwd->outBuffer.size = 0;
   }
   
   static ZWRAP_DCtx* ZWRAP_createDCtx(z_streamp strm)
   {
       ZWRAP_DCtx* zwd;
       ZSTD_customMem customMem = { NULL, NULL, NULL };
   
       if (strm->zalloc && strm->zfree) {
           customMem.customAlloc = ZWRAP_allocFunction;
           customMem.customFree = ZWRAP_freeFunction;
       }
       customMem.opaque = strm;
   
       zwd = (ZWRAP_DCtx*)ZWRAP_customCalloc(sizeof(ZWRAP_DCtx), customMem);
       if (zwd == NULL) return NULL;
       zwd->allocFunc = *strm;
       customMem.opaque = &zwd->allocFunc;
       zwd->customMem = customMem;
   
       ZWRAP_initDCtx(zwd);
       return zwd;
   }
   
   static size_t ZWRAP_freeDCtx(ZWRAP_DCtx* zwd)
   {
       if (zwd==NULL) return 0;   /* support free on null */
       ZSTD_freeDStream(zwd->zbd);
       ZWRAP_customFree(zwd->version, zwd->customMem);
       ZWRAP_customFree(zwd, zwd->customMem);
       return 0;
   }
   
   
   int ZWRAP_isUsingZSTDdecompression(z_streamp strm)
   {
       if (strm == NULL) return 0;
       return (strm->reserved == ZWRAP_ZSTD_STREAM);
   }
   
   
   static int ZWRAPD_finishWithError(ZWRAP_DCtx* zwd, z_streamp strm, int error)
   {
       LOG_WRAPPERD("- ZWRAPD_finishWithError=%d\n", error);
       ZWRAP_freeDCtx(zwd);
       strm->state = NULL;
       return (error) ? error : Z_STREAM_ERROR;
   }
   
   static int ZWRAPD_finishWithErrorMsg(z_streamp strm, char* message)
   {
       ZWRAP_DCtx* const zwd = (ZWRAP_DCtx*) strm->state;
       strm->msg = message;
       if (zwd == NULL) return Z_STREAM_ERROR;
   
       return ZWRAPD_finishWithError(zwd, strm, 0);
   }
   
   
   ZEXTERN int ZEXPORT z_inflateInit_ OF((z_streamp strm,
                                        const char* version, int stream_size))
   {
       if (g_ZWRAPdecompressionType == ZWRAP_FORCE_ZLIB) {
           strm->reserved = ZWRAP_ZLIB_STREAM;
           return inflateInit(strm);
       }
   
       {   ZWRAP_DCtx* const zwd = ZWRAP_createDCtx(strm);
           LOG_WRAPPERD("- inflateInit\n");
           if (zwd == NULL) return ZWRAPD_finishWithError(zwd, strm, 0);
   
           zwd->version = (char*)ZWRAP_customMalloc(strlen(version)+1, zwd->customMem);
           if (zwd->version == NULL) return ZWRAPD_finishWithError(zwd, strm, 0);
           strcpy(zwd->version, version);
   
           zwd->stream_size = stream_size;
           zwd->totalInBytes = 0;
           strm->state = convert_into_sis(zwd);
           strm->total_in = 0;
           strm->total_out = 0;
           strm->reserved = ZWRAP_UNKNOWN_STREAM;
           strm->adler = 0;
       }
   
       return Z_OK;
   }
   
   
   ZEXTERN int ZEXPORT z_inflateInit2_ OF((z_streamp strm, int  windowBits,
                                         const char *version, int stream_size))
   {
       if (g_ZWRAPdecompressionType == ZWRAP_FORCE_ZLIB) {
           return inflateInit2_(strm, windowBits, version, stream_size);
       }
   
       {   int const ret = z_inflateInit_ (strm, version, stream_size);
           LOG_WRAPPERD("- inflateInit2 windowBits=%d\n", windowBits);
           if (ret == Z_OK) {
               ZWRAP_DCtx* const zwd = (ZWRAP_DCtx*)strm->state;
               if (zwd == NULL) return Z_STREAM_ERROR;
               zwd->windowBits = windowBits;
           }
           return ret;
       }
   }
   
   int ZWRAP_inflateReset_keepDict(z_streamp strm)
   {
       LOG_WRAPPERD("- ZWRAP_inflateReset_keepDict\n");
       if (g_ZWRAPdecompressionType == ZWRAP_FORCE_ZLIB || !strm->reserved)
           return inflateReset(strm);
   
       {   ZWRAP_DCtx* const zwd = (ZWRAP_DCtx*) strm->state;
           if (zwd == NULL) return Z_STREAM_ERROR;
           ZWRAP_initDCtx(zwd);
           zwd->decompState = ZWRAP_useReset;
           zwd->totalInBytes = 0;
       }
   
       strm->total_in = 0;
       strm->total_out = 0;
       return Z_OK;
   }
   
   
   ZEXTERN int ZEXPORT z_inflateReset OF((z_streamp strm))
   {
       LOG_WRAPPERD("- inflateReset\n");
       if (g_ZWRAPdecompressionType == ZWRAP_FORCE_ZLIB || !strm->reserved)
           return inflateReset(strm);
   
       { int const ret = ZWRAP_inflateReset_keepDict(strm);
         if (ret != Z_OK) return ret; }
   
       { ZWRAP_DCtx* const zwd = (ZWRAP_DCtx*) strm->state;
         if (zwd == NULL) return Z_STREAM_ERROR;
         zwd->decompState = ZWRAP_useInit; }
   
       return Z_OK;
   }
   
   
   #if ZLIB_VERNUM >= 0x1240
   ZEXTERN int ZEXPORT z_inflateReset2 OF((z_streamp strm,
                                         int windowBits))
   {
       if (g_ZWRAPdecompressionType == ZWRAP_FORCE_ZLIB || !strm->reserved)
           return inflateReset2(strm, windowBits);
   
       {   int const ret = z_inflateReset (strm);
           if (ret == Z_OK) {
               ZWRAP_DCtx* const zwd = (ZWRAP_DCtx*)strm->state;
               if (zwd == NULL) return Z_STREAM_ERROR;
               zwd->windowBits = windowBits;
           }
           return ret;
       }
   }
   #endif
   
   
   ZEXTERN int ZEXPORT z_inflateSetDictionary OF((z_streamp strm,
                                                const Bytef *dictionary,
                                                uInt  dictLength))
   {
       LOG_WRAPPERD("- inflateSetDictionary\n");
       if (g_ZWRAPdecompressionType == ZWRAP_FORCE_ZLIB || !strm->reserved)
           return inflateSetDictionary(strm, dictionary, dictLength);
   
       {   ZWRAP_DCtx* const zwd = (ZWRAP_DCtx*) strm->state;
           if (zwd == NULL || zwd->zbd == NULL) return Z_STREAM_ERROR;
           { size_t const initErr = ZSTD_initDStream_usingDict(zwd->zbd, dictionary, dictLength);
             if (ZSTD_isError(initErr)) return ZWRAPD_finishWithError(zwd, strm, 0); }
           zwd->decompState = ZWRAP_useReset;
   
           if (zwd->totalInBytes == ZSTD_HEADERSIZE) {
               zwd->inBuffer.src = zwd->headerBuf;
               zwd->inBuffer.size = zwd->totalInBytes;
               zwd->inBuffer.pos = 0;
               zwd->outBuffer.dst = strm->next_out;
               zwd->outBuffer.size = 0;
               zwd->outBuffer.pos = 0;
               {   size_t const errorCode = ZSTD_decompressStream(zwd->zbd, &zwd->outBuffer, &zwd->inBuffer);
                   LOG_WRAPPERD("inflateSetDictionary ZSTD_decompressStream errorCode=%d srcSize=%d dstCapacity=%d\n",
                                (int)errorCode, (int)zwd->inBuffer.size, (int)zwd->outBuffer.size);
                   if (zwd->inBuffer.pos < zwd->outBuffer.size || ZSTD_isError(errorCode)) {
                       LOG_WRAPPERD("ERROR: ZSTD_decompressStream %s\n",
                                    ZSTD_getErrorName(errorCode));
                       return ZWRAPD_finishWithError(zwd, strm, 0);
       }   }   }   }
   
       return Z_OK;
   }
   
   
   ZEXTERN int ZEXPORT z_inflate OF((z_streamp strm, int flush))
   {
       ZWRAP_DCtx* zwd;
   
       if (g_ZWRAPdecompressionType == ZWRAP_FORCE_ZLIB || !strm->reserved) {
           int const result = inflate(strm, flush);
           LOG_WRAPPERD("- inflate2 flush=%d avail_in=%d avail_out=%d total_in=%d total_out=%d res=%d\n",
                        (int)flush, (int)strm->avail_in, (int)strm->avail_out, (int)strm->total_in, (int)strm->total_out, result);
           return result;
       }
   
       if (strm->avail_in <= 0) return Z_OK;
   
       zwd = (ZWRAP_DCtx*) strm->state;
       LOG_WRAPPERD("- inflate1 flush=%d avail_in=%d avail_out=%d total_in=%d total_out=%d\n",
                    (int)flush, (int)strm->avail_in, (int)strm->avail_out, (int)strm->total_in, (int)strm->total_out);
   
       if (zwd == NULL) return Z_STREAM_ERROR;
       if (zwd->decompState == ZWRAP_streamEnd) return Z_STREAM_END;
   
       if (zwd->totalInBytes < ZLIB_HEADERSIZE) {
           if (zwd->totalInBytes == 0 && strm->avail_in >= ZLIB_HEADERSIZE) {
               if (ZWRAP_readLE32(strm->next_in) != ZSTD_MAGICNUMBER) {
                   {   int const initErr = (zwd->windowBits) ?
                                   inflateInit2_(strm, zwd->windowBits, zwd->version, zwd->stream_size) :
                                   inflateInit_(strm, zwd->version, zwd->stream_size);
                       LOG_WRAPPERD("ZLIB inflateInit errorCode=%d\n", initErr);
                       if (initErr != Z_OK) return ZWRAPD_finishWithError(zwd, strm, initErr);
                   }
   
                   strm->reserved = ZWRAP_ZLIB_STREAM;
                   { size_t const freeErr = ZWRAP_freeDCtx(zwd);
                     if (ZSTD_isError(freeErr)) goto error; }
   
                   {   int const result = (flush == Z_INFLATE_SYNC) ?
                                           inflateSync(strm) :
                                           inflate(strm, flush);
                       LOG_WRAPPERD("- inflate3 flush=%d avail_in=%d avail_out=%d total_in=%d total_out=%d res=%d\n",
                                    (int)flush, (int)strm->avail_in, (int)strm->avail_out, (int)strm->total_in, (int)strm->total_out, res);
                       return result;
               }   }
           } else {  /* ! (zwd->totalInBytes == 0 && strm->avail_in >= ZLIB_HEADERSIZE) */
               size_t const srcSize = MIN(strm->avail_in, ZLIB_HEADERSIZE - zwd->totalInBytes);
               memcpy(zwd->headerBuf+zwd->totalInBytes, strm->next_in, srcSize);
               strm->total_in += srcSize;
               zwd->totalInBytes += srcSize;
               strm->next_in += srcSize;
               strm->avail_in -= srcSize;
               if (zwd->totalInBytes < ZLIB_HEADERSIZE) return Z_OK;
   
               if (ZWRAP_readLE32(zwd->headerBuf) != ZSTD_MAGICNUMBER) {
                   z_stream strm2;
                   strm2.next_in = strm->next_in;
                   strm2.avail_in = strm->avail_in;
                   strm2.next_out = strm->next_out;
                   strm2.avail_out = strm->avail_out;
   
                   {   int const initErr = (zwd->windowBits) ?
                                   inflateInit2_(strm, zwd->windowBits, zwd->version, zwd->stream_size) :
                                   inflateInit_(strm, zwd->version, zwd->stream_size);
                       LOG_WRAPPERD("ZLIB inflateInit errorCode=%d\n", initErr);
                       if (initErr != Z_OK) return ZWRAPD_finishWithError(zwd, strm, initErr);
                   }
   
                   /* inflate header */
                   strm->next_in = (unsigned char*)zwd->headerBuf;
                   strm->avail_in = ZLIB_HEADERSIZE;
                   strm->avail_out = 0;
                   {   int const dErr = inflate(strm, Z_NO_FLUSH);
                       LOG_WRAPPERD("ZLIB inflate errorCode=%d strm->avail_in=%d\n",
                                     dErr, (int)strm->avail_in);
                       if (dErr != Z_OK)
                           return ZWRAPD_finishWithError(zwd, strm, dErr);
                   }
                   if (strm->avail_in > 0) goto error;
   
                   strm->next_in = strm2.next_in;
                   strm->avail_in = strm2.avail_in;
                   strm->next_out = strm2.next_out;
                   strm->avail_out = strm2.avail_out;
   
                   strm->reserved = ZWRAP_ZLIB_STREAM; /* mark as zlib stream */
                   { size_t const freeErr = ZWRAP_freeDCtx(zwd);
                     if (ZSTD_isError(freeErr)) goto error; }
   
                   {   int const result = (flush == Z_INFLATE_SYNC) ?
                                          inflateSync(strm) :
                                          inflate(strm, flush);
                       LOG_WRAPPERD("- inflate2 flush=%d avail_in=%d avail_out=%d total_in=%d total_out=%d res=%d\n",
                                    (int)flush, (int)strm->avail_in, (int)strm->avail_out, (int)strm->total_in, (int)strm->total_out, res);
                       return result;
           }   }   }  /* if ! (zwd->totalInBytes == 0 && strm->avail_in >= ZLIB_HEADERSIZE) */
       }  /* (zwd->totalInBytes < ZLIB_HEADERSIZE) */
   
       strm->reserved = ZWRAP_ZSTD_STREAM; /* mark as zstd steam */
   
       if (flush == Z_INFLATE_SYNC) { strm->msg = "inflateSync is not supported!"; goto error; }
   
       if (!zwd->zbd) {
           zwd->zbd = ZSTD_createDStream_advanced(zwd->customMem);
           if (zwd->zbd == NULL) { LOG_WRAPPERD("ERROR: ZSTD_createDStream_advanced\n"); goto error; }
           zwd->decompState = ZWRAP_useInit;
       }
   
       if (zwd->totalInBytes < ZSTD_HEADERSIZE) {
           if (zwd->totalInBytes == 0 && strm->avail_in >= ZSTD_HEADERSIZE) {
               if (zwd->decompState == ZWRAP_useInit) {
                   size_t const initErr = ZSTD_initDStream(zwd->zbd);
                   if (ZSTD_isError(initErr)) {
                       LOG_WRAPPERD("ERROR: ZSTD_initDStream errorCode=%s\n",
                                    ZSTD_getErrorName(initErr));
                       goto error;
                   }
               } else {
                   size_t const resetErr = ZSTD_DCtx_reset(zwd->zbd, ZSTD_reset_session_only);
                   if (ZSTD_isError(resetErr)) goto error;
               }
           } else {
               size_t const srcSize = MIN(strm->avail_in, ZSTD_HEADERSIZE - zwd->totalInBytes);
               memcpy(zwd->headerBuf+zwd->totalInBytes, strm->next_in, srcSize);
               strm->total_in += srcSize;
               zwd->totalInBytes += srcSize;
               strm->next_in += srcSize;
               strm->avail_in -= srcSize;
               if (zwd->totalInBytes < ZSTD_HEADERSIZE) return Z_OK;
   
               if (zwd->decompState == ZWRAP_useInit) {
                   size_t const initErr = ZSTD_initDStream(zwd->zbd);
                   if (ZSTD_isError(initErr)) {
                       LOG_WRAPPERD("ERROR: ZSTD_initDStream errorCode=%s\n",
                                   ZSTD_getErrorName(initErr));
                       goto error;
                   }
               } else {
                   size_t const resetErr = ZSTD_DCtx_reset(zwd->zbd, ZSTD_reset_session_only);
                   if (ZSTD_isError(resetErr)) goto error;
               }
   
               zwd->inBuffer.src = zwd->headerBuf;
               zwd->inBuffer.size = ZSTD_HEADERSIZE;
               zwd->inBuffer.pos = 0;
               zwd->outBuffer.dst = strm->next_out;
               zwd->outBuffer.size = 0;
               zwd->outBuffer.pos = 0;
               {   size_t const dErr = ZSTD_decompressStream(zwd->zbd, &zwd->outBuffer, &zwd->inBuffer);
                   LOG_WRAPPERD("inflate ZSTD_decompressStream1 errorCode=%d srcSize=%d dstCapacity=%d\n",
                               (int)dErr, (int)zwd->inBuffer.size, (int)zwd->outBuffer.size);
                   if (ZSTD_isError(dErr)) {
                       LOG_WRAPPERD("ERROR: ZSTD_decompressStream1 %s\n", ZSTD_getErrorName(dErr));
                       goto error;
               }   }
               if (zwd->inBuffer.pos != zwd->inBuffer.size) goto error; /* not consumed */
           }
       }   /* (zwd->totalInBytes < ZSTD_HEADERSIZE) */
   
       zwd->inBuffer.src = strm->next_in;
       zwd->inBuffer.size = strm->avail_in;
       zwd->inBuffer.pos = 0;
       zwd->outBuffer.dst = strm->next_out;
       zwd->outBuffer.size = strm->avail_out;
       zwd->outBuffer.pos = 0;
       {   size_t const dErr = ZSTD_decompressStream(zwd->zbd, &zwd->outBuffer, &zwd->inBuffer);
           LOG_WRAPPERD("inflate ZSTD_decompressStream2 errorCode=%d srcSize=%d dstCapacity=%d\n",
                       (int)dErr, (int)strm->avail_in, (int)strm->avail_out);
           if (ZSTD_isError(dErr)) {
               zwd->errorCount++;
               LOG_WRAPPERD("ERROR: ZSTD_decompressStream2 %s zwd->errorCount=%d\n",
                           ZSTD_getErrorName(dErr), zwd->errorCount);
               if (zwd->errorCount<=1) return Z_NEED_DICT; else goto error;
           }
           LOG_WRAPPERD("inflate inBuffer.pos=%d inBuffer.size=%d outBuffer.pos=%d outBuffer.size=%d o\n",
                       (int)zwd->inBuffer.pos, (int)zwd->inBuffer.size, (int)zwd->outBuffer.pos, (int)zwd->outBuffer.size);
           strm->next_out += zwd->outBuffer.pos;
           strm->total_out += zwd->outBuffer.pos;
           strm->avail_out -= zwd->outBuffer.pos;
           strm->total_in += zwd->inBuffer.pos;
           zwd->totalInBytes += zwd->inBuffer.pos;
           strm->next_in += zwd->inBuffer.pos;
           strm->avail_in -= zwd->inBuffer.pos;
           if (dErr == 0) {
               LOG_WRAPPERD("inflate Z_STREAM_END1 avail_in=%d avail_out=%d total_in=%d total_out=%d\n",
                           (int)strm->avail_in, (int)strm->avail_out, (int)strm->total_in, (int)strm->total_out);
               zwd->decompState = ZWRAP_streamEnd;
               return Z_STREAM_END;
           }
       }  /* dErr lifetime */
   
       LOG_WRAPPERD("- inflate2 flush=%d avail_in=%d avail_out=%d total_in=%d total_out=%d res=%d\n",
                   (int)flush, (int)strm->avail_in, (int)strm->avail_out, (int)strm->total_in, (int)strm->total_out, Z_OK);
       return Z_OK;
   
   error:
       return ZWRAPD_finishWithError(zwd, strm, 0);
   }
   
   
   ZEXTERN int ZEXPORT z_inflateEnd OF((z_streamp strm))
   {
       if (g_ZWRAPdecompressionType == ZWRAP_FORCE_ZLIB || !strm->reserved)
           return inflateEnd(strm);
   
       LOG_WRAPPERD("- inflateEnd total_in=%d total_out=%d\n",
                   (int)(strm->total_in), (int)(strm->total_out));
       {   ZWRAP_DCtx* const zwd = (ZWRAP_DCtx*) strm->state;
           if (zwd == NULL) return Z_OK;  /* structures are already freed */
           { size_t const freeErr = ZWRAP_freeDCtx(zwd);
             if (ZSTD_isError(freeErr)) return Z_STREAM_ERROR; }
           strm->state = NULL;
       }
       return Z_OK;
   }
   
   
   ZEXTERN int ZEXPORT z_inflateSync OF((z_streamp strm))
   {
       if (g_ZWRAPdecompressionType == ZWRAP_FORCE_ZLIB || !strm->reserved) {
           return inflateSync(strm);
       }
   
       return z_inflate(strm, Z_INFLATE_SYNC);
   }
   
   
   
   /* Advanced compression functions */
   ZEXTERN int ZEXPORT z_deflateCopy OF((z_streamp dest,
                                       z_streamp source))
   {
       if (!g_ZWRAP_useZSTDcompression)
           return deflateCopy(dest, source);
       return ZWRAPC_finishWithErrorMsg(source, "deflateCopy is not supported!");
   }
   
   
   ZEXTERN int ZEXPORT z_deflateTune OF((z_streamp strm,
                                       int good_length,
                                       int max_lazy,
                                       int nice_length,
                                       int max_chain))
   {
       if (!g_ZWRAP_useZSTDcompression)
           return deflateTune(strm, good_length, max_lazy, nice_length, max_chain);
       return ZWRAPC_finishWithErrorMsg(strm, "deflateTune is not supported!");
   }
   
   
   #if ZLIB_VERNUM >= 0x1260
   ZEXTERN int ZEXPORT z_deflatePending OF((z_streamp strm,
                                          unsigned *pending,
                                          int *bits))
   {
       if (!g_ZWRAP_useZSTDcompression)
           return deflatePending(strm, pending, bits);
       return ZWRAPC_finishWithErrorMsg(strm, "deflatePending is not supported!");
   }
   #endif
   
   
   ZEXTERN int ZEXPORT z_deflatePrime OF((z_streamp strm,
                                        int bits,
                                        int value))
   {
       if (!g_ZWRAP_useZSTDcompression)
           return deflatePrime(strm, bits, value);
       return ZWRAPC_finishWithErrorMsg(strm, "deflatePrime is not supported!");
   }
   
  
  ZEXTERN int ZEXPORT z_deflateSetHeader OF((z_streamp strm,
                                           gz_headerp head))
  {
      if (!g_ZWRAP_useZSTDcompression)
          return deflateSetHeader(strm, head);
      return ZWRAPC_finishWithErrorMsg(strm, "deflateSetHeader is not supported!");
  }
  
  
  
  
  /* Advanced decompression functions */
  #if ZLIB_VERNUM >= 0x1280
  ZEXTERN int ZEXPORT z_inflateGetDictionary OF((z_streamp strm,
                                               Bytef *dictionary,
                                               uInt  *dictLength))
  {
      if (g_ZWRAPdecompressionType == ZWRAP_FORCE_ZLIB || !strm->reserved)
          return inflateGetDictionary(strm, dictionary, dictLength);
      return ZWRAPD_finishWithErrorMsg(strm, "inflateGetDictionary is not supported!");
  }
  #endif
  
  
  ZEXTERN int ZEXPORT z_inflateCopy OF((z_streamp dest,
                                      z_streamp source))
  {
      if (g_ZWRAPdecompressionType == ZWRAP_FORCE_ZLIB || !source->reserved)
          return inflateCopy(dest, source);
      return ZWRAPD_finishWithErrorMsg(source, "inflateCopy is not supported!");
  }
  
  
  #if ZLIB_VERNUM >= 0x1240
  ZEXTERN long ZEXPORT z_inflateMark OF((z_streamp strm))
  {
      if (g_ZWRAPdecompressionType == ZWRAP_FORCE_ZLIB || !strm->reserved)
          return inflateMark(strm);
      return ZWRAPD_finishWithErrorMsg(strm, "inflateMark is not supported!");
  }
  #endif
  
  
  ZEXTERN int ZEXPORT z_inflatePrime OF((z_streamp strm,
                                       int bits,
                                       int value))
  {
      if (g_ZWRAPdecompressionType == ZWRAP_FORCE_ZLIB || !strm->reserved)
          return inflatePrime(strm, bits, value);
      return ZWRAPD_finishWithErrorMsg(strm, "inflatePrime is not supported!");
  }
  
  
  ZEXTERN int ZEXPORT z_inflateGetHeader OF((z_streamp strm,
                                           gz_headerp head))
  {
      if (g_ZWRAPdecompressionType == ZWRAP_FORCE_ZLIB || !strm->reserved)
          return inflateGetHeader(strm, head);
      return ZWRAPD_finishWithErrorMsg(strm, "inflateGetHeader is not supported!");
  }
  
  
  ZEXTERN int ZEXPORT z_inflateBackInit_ OF((z_streamp strm, int windowBits,
                                           unsigned char FAR *window,
                                           const char *version,
                                           int stream_size))
  {
      if (g_ZWRAPdecompressionType == ZWRAP_FORCE_ZLIB || !strm->reserved)
          return inflateBackInit_(strm, windowBits, window, version, stream_size);
      return ZWRAPD_finishWithErrorMsg(strm, "inflateBackInit is not supported!");
  }
  
  
  ZEXTERN int ZEXPORT z_inflateBack OF((z_streamp strm,
                                      in_func in, void FAR *in_desc,
                                      out_func out, void FAR *out_desc))
  {
      if (g_ZWRAPdecompressionType == ZWRAP_FORCE_ZLIB || !strm->reserved)
          return inflateBack(strm, in, in_desc, out, out_desc);
      return ZWRAPD_finishWithErrorMsg(strm, "inflateBack is not supported!");
  }
  
  
  ZEXTERN int ZEXPORT z_inflateBackEnd OF((z_streamp strm))
  {
      if (g_ZWRAPdecompressionType == ZWRAP_FORCE_ZLIB || !strm->reserved)
          return inflateBackEnd(strm);
      return ZWRAPD_finishWithErrorMsg(strm, "inflateBackEnd is not supported!");
  }
  
  
  ZEXTERN uLong ZEXPORT z_zlibCompileFlags OF((void)) { return zlibCompileFlags(); }
  
  
  
                      /* ===   utility functions  === */
  #ifndef Z_SOLO
  
  ZEXTERN int ZEXPORT z_compress OF((Bytef *dest,   uLongf *destLen,
                                   const Bytef *source, uLong sourceLen))
  {
      if (!g_ZWRAP_useZSTDcompression)
          return compress(dest, destLen, source, sourceLen);
  
      {   size_t dstCapacity = *destLen;
          size_t const cSize = ZSTD_compress(dest, dstCapacity,
                                             source, sourceLen,
                                             ZWRAP_DEFAULT_CLEVEL);
          LOG_WRAPPERD("z_compress sourceLen=%d dstCapacity=%d\n",
                      (int)sourceLen, (int)dstCapacity);
          if (ZSTD_isError(cSize)) return Z_STREAM_ERROR;
          *destLen = cSize;
      }
      return Z_OK;
  }
  
  
  ZEXTERN int ZEXPORT z_compress2 OF((Bytef *dest,   uLongf *destLen,
                                    const Bytef *source, uLong sourceLen,
                                    int level))
  {
      if (!g_ZWRAP_useZSTDcompression)
          return compress2(dest, destLen, source, sourceLen, level);
  
      { size_t dstCapacity = *destLen;
        size_t const cSize = ZSTD_compress(dest, dstCapacity, source, sourceLen, level);
        if (ZSTD_isError(cSize)) return Z_STREAM_ERROR;
        *destLen = cSize;
      }
      return Z_OK;
  }
  
  
  ZEXTERN uLong ZEXPORT z_compressBound OF((uLong sourceLen))
  {
      if (!g_ZWRAP_useZSTDcompression)
          return compressBound(sourceLen);
  
      return ZSTD_compressBound(sourceLen);
  }
  
  
  ZEXTERN int ZEXPORT z_uncompress OF((Bytef *dest,   uLongf *destLen,
                                     const Bytef *source, uLong sourceLen))
  {
      if (!ZSTD_isFrame(source, sourceLen))
          return uncompress(dest, destLen, source, sourceLen);
  
      { size_t dstCapacity = *destLen;
        size_t const dSize = ZSTD_decompress(dest, dstCapacity, source, sourceLen);
        if (ZSTD_isError(dSize)) return Z_STREAM_ERROR;
        *destLen = dSize;
       }
      return Z_OK;
  }
  
  #endif /* !Z_SOLO */
  
  
                          /* checksum functions */
  
  ZEXTERN uLong ZEXPORT z_adler32 OF((uLong adler, const Bytef *buf, uInt len))
  {
      return adler32(adler, buf, len);
  }
  
  ZEXTERN uLong ZEXPORT z_crc32   OF((uLong crc, const Bytef *buf, uInt len))
  {
      return crc32(crc, buf, len);
  }
  
  
  #if ZLIB_VERNUM >= 0x12B0
  ZEXTERN uLong ZEXPORT z_adler32_z OF((uLong adler, const Bytef *buf, z_size_t len))
  {
      return adler32_z(adler, buf, len);
  }
  
  ZEXTERN uLong ZEXPORT z_crc32_z OF((uLong crc, const Bytef *buf, z_size_t len))
  {
      return crc32_z(crc, buf, len);
  }
  #endif
  
  
  #if ZLIB_VERNUM >= 0x1270
  ZEXTERN const z_crc_t FAR * ZEXPORT z_get_crc_table    OF((void))
  {
      return get_crc_table();
  }
  #endif
  
                          /* Error function */
  ZEXTERN const char * ZEXPORT z_zError OF((int err))
  {
      /* Just use zlib Error function */
      return zError(err);
  }

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