common/dist/zlib/examples/zpipe.c

   1 /*      $NetBSD: zpipe.c,v 1.1.1.1 2006/01/14 20:11:09 christos Exp $   */
   2
   3 /* zpipe.c: example of proper use of zlib's inflate() and deflate()
   4    Not copyrighted -- provided to the public domain
   5    Version 1.2  9 November 2004  Mark Adler */
   6
   7 /* Version history:
   8    1.0  30 Oct 2004  First version
   9    1.1   8 Nov 2004  Add void casting for unused return values
  10                      Use switch statement for inflate() return values
  11    1.2   9 Nov 2004  Add assertions to document zlib guarantees
  12    1.3   6 Apr 2005  Remove incorrect assertion in inf()
  13  */
  14
  15 #include <stdio.h>
  16 #include <string.h>
  17 #include <assert.h>
  18 #include "zlib.h"
  19
  20 #define CHUNK 16384
  21
  22 /* Compress from file source to file dest until EOF on source.
  23    def() returns Z_OK on success, Z_MEM_ERROR if memory could not be
  24    allocated for processing, Z_STREAM_ERROR if an invalid compression
  25    level is supplied, Z_VERSION_ERROR if the version of zlib.h and the
  26    version of the library linked do not match, or Z_ERRNO if there is
  27    an error reading or writing the files. */
  28 int def(FILE *source, FILE *dest, int level)
  29 {
  30     int ret, flush;
  31     unsigned have;
  32     z_stream strm;
  33     char in[CHUNK];
  34     char out[CHUNK];
  35
  36     /* allocate deflate state */
  37     strm.zalloc = Z_NULL;
  38     strm.zfree = Z_NULL;
  39     strm.opaque = Z_NULL;
  40     ret = deflateInit(&strm, level);
  41     if (ret != Z_OK)
  42         return ret;
  43
  44     /* compress until end of file */
  45     do {
  46         strm.avail_in = fread(in, 1, CHUNK, source);
  47         if (ferror(source)) {
  48             (void)deflateEnd(&strm);
  49             return Z_ERRNO;
  50         }
  51         flush = feof(source) ? Z_FINISH : Z_NO_FLUSH;
  52         strm.next_in = in;
  53
  54         /* run deflate() on input until output buffer not full, finish
  55            compression if all of source has been read in */
  56         do {
  57             strm.avail_out = CHUNK;
  58             strm.next_out = out;
  59             ret = deflate(&strm, flush);    /* no bad return value */
  60             assert(ret != Z_STREAM_ERROR);  /* state not clobbered */
  61             have = CHUNK - strm.avail_out;
  62             if (fwrite(out, 1, have, dest) != have || ferror(dest)) {
  63                 (void)deflateEnd(&strm);
  64                 return Z_ERRNO;
  65             }
  66         } while (strm.avail_out == 0);
  67         assert(strm.avail_in == 0);     /* all input will be used */
  68
  69         /* done when last data in file processed */
  70     } while (flush != Z_FINISH);
  71     assert(ret == Z_STREAM_END);        /* stream will be complete */
  72
  73     /* clean up and return */
  74     (void)deflateEnd(&strm);
  75     return Z_OK;
  76 }
  77
  78 /* Decompress from file source to file dest until stream ends or EOF.
  79    inf() returns Z_OK on success, Z_MEM_ERROR if memory could not be
  80    allocated for processing, Z_DATA_ERROR if the deflate data is
  81    invalid or incomplete, Z_VERSION_ERROR if the version of zlib.h and
  82    the version of the library linked do not match, or Z_ERRNO if there
  83    is an error reading or writing the files. */
  84 int inf(FILE *source, FILE *dest)
  85 {
  86     int ret;
  87     unsigned have;
  88     z_stream strm;
  89     char in[CHUNK];
  90     char out[CHUNK];
  91
  92     /* allocate inflate state */
  93     strm.zalloc = Z_NULL;
  94     strm.zfree = Z_NULL;
  95     strm.opaque = Z_NULL;
  96     strm.avail_in = 0;
  97     strm.next_in = Z_NULL;
  98     ret = inflateInit(&strm);
  99     if (ret != Z_OK)
 100         return ret;
 101
 102     /* decompress until deflate stream ends or end of file */
 103     do {
 104         strm.avail_in = fread(in, 1, CHUNK, source);
 105         if (ferror(source)) {
 106             (void)inflateEnd(&strm);
 107             return Z_ERRNO;
 108         }
 109         if (strm.avail_in == 0)
 110             break;
 111         strm.next_in = in;
 112
 113         /* run inflate() on input until output buffer not full */
 114         do {
 115             strm.avail_out = CHUNK;
 116             strm.next_out = out;
 117             ret = inflate(&strm, Z_NO_FLUSH);
 118             assert(ret != Z_STREAM_ERROR);  /* state not clobbered */
 119             switch (ret) {
 120             case Z_NEED_DICT:
 121                 ret = Z_DATA_ERROR;     /* and fall through */
 122             case Z_DATA_ERROR:
 123             case Z_MEM_ERROR:
 124                 (void)inflateEnd(&strm);
 125                 return ret;
 126             }
 127             have = CHUNK - strm.avail_out;
 128             if (fwrite(out, 1, have, dest) != have || ferror(dest)) {
 129                 (void)inflateEnd(&strm);
 130                 return Z_ERRNO;
 131             }
 132         } while (strm.avail_out == 0);
 133
 134         /* done when inflate() says it's done */
 135     } while (ret != Z_STREAM_END);
 136
 137     /* clean up and return */
 138     (void)inflateEnd(&strm);
 139     return ret == Z_STREAM_END ? Z_OK : Z_DATA_ERROR;
 140 }
 141
 142 /* report a zlib or i/o error */
 143 void zerr(int ret)
 144 {
 145     fputs("zpipe: ", stderr);
 146     switch (ret) {
 147     case Z_ERRNO:
 148         if (ferror(stdin))
 149             fputs("error reading stdin\n", stderr);
 150         if (ferror(stdout))
 151             fputs("error writing stdout\n", stderr);
 152         break;
 153     case Z_STREAM_ERROR:
 154         fputs("invalid compression level\n", stderr);
 155         break;
 156     case Z_DATA_ERROR:
 157         fputs("invalid or incomplete deflate data\n", stderr);
 158         break;
 159     case Z_MEM_ERROR:
 160         fputs("out of memory\n", stderr);
 161         break;
 162     case Z_VERSION_ERROR:
 163         fputs("zlib version mismatch!\n", stderr);
 164     }
 165 }
 166
 167 /* compress or decompress from stdin to stdout */
 168 int main(int argc, char **argv)
 169 {
 170     int ret;
 171
 172     /* do compression if no arguments */
 173     if (argc == 1) {
 174         ret = def(stdin, stdout, Z_DEFAULT_COMPRESSION);
 175         if (ret != Z_OK)
 176             zerr(ret);
 177         return ret;
 178     }
 179
 180     /* do decompression if -d specified */
 181     else if (argc == 2 && strcmp(argv[1], "-d") == 0) {
 182         ret = inf(stdin, stdout);
 183         if (ret != Z_OK)
 184             zerr(ret);
 185         return ret;
 186     }
 187
 188     /* otherwise, report usage */
 189     else {
 190         fputs("zpipe usage: zpipe [-d] < source > dest\n", stderr);
 191         return 1;
 192     }
 193 }