ceph/src/zstd/examples/simple_decompression.c

   1 /**
   2  * Copyright 2016-present, Yann Collet, Facebook, Inc.
   3  * All rights reserved.
   4  *
   5  * This source code is licensed under the license found in the
   6  * LICENSE-examples file in the root directory of this source tree.
   7  */
   8
   9
  10
  11 #include <stdlib.h>    // malloc, exit
  12 #include <stdio.h>     // printf
  13 #include <string.h>    // strerror
  14 #include <errno.h>     // errno
  15 #include <sys/stat.h>  // stat
  16 #include <zstd.h>      // presumes zstd library is installed
  17
  18
  19 static off_t fsize_X(const char *filename)
  20 {
  21     struct stat st;
  22     if (stat(filename, &st) == 0) return st.st_size;
  23     /* error */
  24     printf("stat: %s : %s \n", filename, strerror(errno));
  25     exit(1);
  26 }
  27
  28 static FILE* fopen_X(const char *filename, const char *instruction)
  29 {
  30     FILE* const inFile = fopen(filename, instruction);
  31     if (inFile) return inFile;
  32     /* error */
  33     printf("fopen: %s : %s \n", filename, strerror(errno));
  34     exit(2);
  35 }
  36
  37 static void* malloc_X(size_t size)
  38 {
  39     void* const buff = malloc(size);
  40     if (buff) return buff;
  41     /* error */
  42     printf("malloc: %s \n", strerror(errno));
  43     exit(3);
  44 }
  45
  46 static void* loadFile_X(const char* fileName, size_t* size)
  47 {
  48     off_t const buffSize = fsize_X(fileName);
  49     FILE* const inFile = fopen_X(fileName, "rb");
  50     void* const buffer = malloc_X(buffSize);
  51     size_t const readSize = fread(buffer, 1, buffSize, inFile);
  52     if (readSize != (size_t)buffSize) {
  53         printf("fread: %s : %s \n", fileName, strerror(errno));
  54         exit(4);
  55     }
  56     fclose(inFile);   /* can't fail (read only) */
  57     *size = buffSize;
  58     return buffer;
  59 }
  60
  61
  62 static void decompress(const char* fname)
  63 {
  64     size_t cSize;
  65     void* const cBuff = loadFile_X(fname, &cSize);
  66     unsigned long long const rSize = ZSTD_getDecompressedSize(cBuff, cSize);
  67     if (rSize==0) {
  68         printf("%s : original size unknown. Use streaming decompression instead. \n", fname);
  69         exit(5);
  70     }
  71     void* const rBuff = malloc_X((size_t)rSize);
  72
  73     size_t const dSize = ZSTD_decompress(rBuff, rSize, cBuff, cSize);
  74
  75     if (dSize != rSize) {
  76         printf("error decoding %s : %s \n", fname, ZSTD_getErrorName(dSize));
  77         exit(7);
  78     }
  79
  80     /* success */
  81     printf("%25s : %6u -> %7u \n", fname, (unsigned)cSize, (unsigned)rSize);
  82
  83     free(rBuff);
  84     free(cBuff);
  85 }
  86
  87
  88 int main(int argc, const char** argv)
  89 {
  90     const char* const exeName = argv[0];
  91
  92     if (argc!=2) {
  93         printf("wrong arguments\n");
  94         printf("usage:\n");
  95         printf("%s FILE\n", exeName);
  96         return 1;
  97     }
  98
  99     decompress(argv[1]);
 100
 101     printf("%s correctly decoded (in memory). \n", argv[1]);
 102
 103     return 0;
 104 }