FreeBSD/Linux Kernel Cross Reference
sys/contrib/zstd/examples/multiple_simple_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>    // memcpy, strlen
    #include <zstd.h>      // presumes zstd library is installed
    #include "common.h"    // Helper functions, CHECK(), and CHECK_ZSTD()
    
    typedef struct {
        void* fBuffer;
        void* cBuffer;
        size_t fBufferSize;
        size_t cBufferSize;
        ZSTD_CCtx* cctx;
    } resources;
    
    /*
     * allocate memory for buffers big enough to compress all files
     * as well as memory for output file name (ofn)
     */
    static resources createResources_orDie(int argc, const char** argv, char **ofn, size_t* ofnBufferLen)
    {
        size_t maxFilenameLength=0;
        size_t maxFileSize = 0;
    
        int argNb;
        for (argNb = 1; argNb < argc; argNb++) {
          const char* const filename = argv[argNb];
          size_t const filenameLength = strlen(filename);
          size_t const fileSize = fsize_orDie(filename);
    
          if (filenameLength > maxFilenameLength) maxFilenameLength = filenameLength;
          if (fileSize > maxFileSize) maxFileSize = fileSize;
        }
    
        resources ress;
        ress.fBufferSize = maxFileSize;
        ress.cBufferSize = ZSTD_compressBound(maxFileSize);
    
        *ofnBufferLen = maxFilenameLength + 5;
        *ofn = (char*)malloc_orDie(*ofnBufferLen);
        ress.fBuffer = malloc_orDie(ress.fBufferSize);
        ress.cBuffer = malloc_orDie(ress.cBufferSize);
        ress.cctx = ZSTD_createCCtx();
        CHECK(ress.cctx != NULL, "ZSTD_createCCtx() failed!");
        return ress;
    }
    
    static void freeResources(resources ress, char *outFilename)
    {
        free(ress.fBuffer);
        free(ress.cBuffer);
        ZSTD_freeCCtx(ress.cctx);   /* never fails */
        free(outFilename);
    }
    
    /* compress with pre-allocated context (ZSTD_CCtx) and input/output buffers*/
    static void compressFile_orDie(resources ress, const char* fname, const char* oname)
    {
        size_t fSize = loadFile_orDie(fname, ress.fBuffer, ress.fBufferSize);
    
        /* Compress using the context.
         * If you need more control over parameters, use the advanced API:
         * ZSTD_CCtx_setParameter(), and ZSTD_compress2().
         */
        size_t const cSize = ZSTD_compressCCtx(ress.cctx, ress.cBuffer, ress.cBufferSize, ress.fBuffer, fSize, 1);
        CHECK_ZSTD(cSize);
    
        saveFile_orDie(oname, ress.cBuffer, cSize);
    
        /* success */
        printf("%25s : %6u -> %7u - %s \n", fname, (unsigned)fSize, (unsigned)cSize, oname);
    }
    
    int main(int argc, const char** argv)
    {
        const char* const exeName = argv[0];
    
        if (argc<2) {
            printf("wrong arguments\n");
            printf("usage:\n");
            printf("%s FILE(s)\n", exeName);
            return 1;
        }
    
        /* memory allocation for outFilename and resources */
        char* outFilename;
        size_t outFilenameBufferLen;
        resources const ress = createResources_orDie(argc, argv, &outFilename, &outFilenameBufferLen);
    
        /* compress files with shared context, input and output buffers */
       int argNb;
       for (argNb = 1; argNb < argc; argNb++) {
           const char* const inFilename = argv[argNb];
           size_t const inFilenameLen = strlen(inFilename);
           CHECK(inFilenameLen + 5 <= outFilenameBufferLen, "File name too long!");
           memcpy(outFilename, inFilename, inFilenameLen);
           memcpy(outFilename+inFilenameLen, ".zst", 5);
           compressFile_orDie(ress, inFilename, outFilename);
       }
   
       /* free memory */
       freeResources(ress,outFilename);
   
       printf("compressed %i files \n", argc-1);
   
       return 0;
   }

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