FreeBSD/Linux Kernel Cross Reference
sys/contrib/zstd/examples/dictionary_compression.c

     /*
      * Copyright (c) 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.
      */
    #include <stdio.h>     // printf
    #include <stdlib.h>    // free
    #include <string.h>    // memset, strcat
    #include <zstd.h>      // presumes zstd library is installed
    #include "common.h"    // Helper functions, CHECK(), and CHECK_ZSTD()
    
    /* createDict() :
       `dictFileName` is supposed to have been created using `zstd --train` */
    static ZSTD_CDict* createCDict_orDie(const char* dictFileName, int cLevel)
    {
        size_t dictSize;
        printf("loading dictionary %s \n", dictFileName);
        void* const dictBuffer = mallocAndLoadFile_orDie(dictFileName, &dictSize);
        ZSTD_CDict* const cdict = ZSTD_createCDict(dictBuffer, dictSize, cLevel);
        CHECK(cdict != NULL, "ZSTD_createCDict() failed!");
        free(dictBuffer);
        return cdict;
    }
    
    
    static void compress(const char* fname, const char* oname, const ZSTD_CDict* cdict)
    {
        size_t fSize;
        void* const fBuff = mallocAndLoadFile_orDie(fname, &fSize);
        size_t const cBuffSize = ZSTD_compressBound(fSize);
        void* const cBuff = malloc_orDie(cBuffSize);
    
        /* Compress using the dictionary.
         * This function writes the dictionary id, and content size into the header.
         * But, it doesn't use a checksum. You can control these options using the
         * advanced API: ZSTD_CCtx_setParameter(), ZSTD_CCtx_refCDict(),
         * and ZSTD_compress2().
         */
        ZSTD_CCtx* const cctx = ZSTD_createCCtx();
        CHECK(cctx != NULL, "ZSTD_createCCtx() failed!");
        size_t const cSize = ZSTD_compress_usingCDict(cctx, cBuff, cBuffSize, fBuff, fSize, cdict);
        CHECK_ZSTD(cSize);
    
        saveFile_orDie(oname, cBuff, cSize);
    
        /* success */
        printf("%25s : %6u -> %7u - %s \n", fname, (unsigned)fSize, (unsigned)cSize, oname);
    
        ZSTD_freeCCtx(cctx);   /* never fails */
        free(fBuff);
        free(cBuff);
    }
    
    
    static char* createOutFilename_orDie(const char* filename)
    {
        size_t const inL = strlen(filename);
        size_t const outL = inL + 5;
        void* outSpace = malloc_orDie(outL);
        memset(outSpace, 0, outL);
        strcat(outSpace, filename);
        strcat(outSpace, ".zst");
        return (char*)outSpace;
    }
    
    int main(int argc, const char** argv)
    {
        const char* const exeName = argv[0];
        int const cLevel = 3;
    
        if (argc<3) {
            fprintf(stderr, "wrong arguments\n");
            fprintf(stderr, "usage:\n");
            fprintf(stderr, "%s [FILES] dictionary\n", exeName);
            return 1;
        }
    
        /* load dictionary only once */
        const char* const dictName = argv[argc-1];
        ZSTD_CDict* const dictPtr = createCDict_orDie(dictName, cLevel);
    
        int u;
        for (u=1; u<argc-1; u++) {
            const char* inFilename = argv[u];
            char* const outFilename = createOutFilename_orDie(inFilename);
            compress(inFilename, outFilename, dictPtr);
            free(outFilename);
        }
    
        ZSTD_freeCDict(dictPtr);
        printf("All %u files compressed. \n", argc-2);
        return 0;
    }

Cache object: 250eb70dca67bc70609765fcbf0b7973