1  /* zpipe.c: example of proper use of zlib's inflate() and deflate()
2     Not copyrighted -- provided to the public domain
3     Version 1.4  11 December 2005  Mark Adler */
4  
5  /* Version history:
6     1.0  30 Oct 2004  First version
7     1.1   8 Nov 2004  Add void casting for unused return values
8                       Use switch statement for inflate() return values
9     1.2   9 Nov 2004  Add assertions to document zlib guarantees
10     1.3   6 Apr 2005  Remove incorrect assertion in inf()
11     1.4  11 Dec 2005  Add hack to avoid MSDOS end-of-line conversions
12                       Avoid some compiler warnings for input and output buffers
13   */
14  
15  #include <stdio.h>
16  #include <string.h>
17  #include <assert.h>
18  #include "zlib.h"
19  
20  #if defined(MSDOS) || defined(OS2) || defined(WIN32) || defined(__CYGWIN__)
21  #  include <fcntl.h>
22  #  include <io.h>
23  #  define SET_BINARY_MODE(file) setmode(fileno(file), O_BINARY)
24  #else
25  #  define SET_BINARY_MODE(file)
26  #endif
27  
28  #define CHUNK 16384
29  
30  /* Compress from file source to file dest until EOF on source.
31     def() returns Z_OK on success, Z_MEM_ERROR if memory could not be
32     allocated for processing, Z_STREAM_ERROR if an invalid compression
33     level is supplied, Z_VERSION_ERROR if the version of zlib.h and the
34     version of the library linked do not match, or Z_ERRNO if there is
35     an error reading or writing the files. */
def(FILE * source,FILE * dest,int level)36  int def(FILE *source, FILE *dest, int level)
37  {
38      int ret, flush;
39      unsigned have;
40      z_stream strm;
41      unsigned char in[CHUNK];
42      unsigned char out[CHUNK];
43  
44      /* allocate deflate state */
45      strm.zalloc = Z_NULL;
46      strm.zfree = Z_NULL;
47      strm.opaque = Z_NULL;
48      ret = deflateInit(&strm, level);
49      if (ret != Z_OK)
50          return ret;
51  
52      /* compress until end of file */
53      do {
54          strm.avail_in = fread(in, 1, CHUNK, source);
55          if (ferror(source)) {
56              (void)deflateEnd(&strm);
57              return Z_ERRNO;
58          }
59          flush = feof(source) ? Z_FINISH : Z_NO_FLUSH;
60          strm.next_in = in;
61  
62          /* run deflate() on input until output buffer not full, finish
63             compression if all of source has been read in */
64          do {
65              strm.avail_out = CHUNK;
66              strm.next_out = out;
67              ret = deflate(&strm, flush);    /* no bad return value */
68              assert(ret != Z_STREAM_ERROR);  /* state not clobbered */
69              have = CHUNK - strm.avail_out;
70              if (fwrite(out, 1, have, dest) != have || ferror(dest)) {
71                  (void)deflateEnd(&strm);
72                  return Z_ERRNO;
73              }
74          } while (strm.avail_out == 0);
75          assert(strm.avail_in == 0);     /* all input will be used */
76  
77          /* done when last data in file processed */
78      } while (flush != Z_FINISH);
79      assert(ret == Z_STREAM_END);        /* stream will be complete */
80  
81      /* clean up and return */
82      (void)deflateEnd(&strm);
83      return Z_OK;
84  }
85  
86  /* Decompress from file source to file dest until stream ends or EOF.
87     inf() returns Z_OK on success, Z_MEM_ERROR if memory could not be
88     allocated for processing, Z_DATA_ERROR if the deflate data is
89     invalid or incomplete, Z_VERSION_ERROR if the version of zlib.h and
90     the version of the library linked do not match, or Z_ERRNO if there
91     is an error reading or writing the files. */
inf(FILE * source,FILE * dest)92  int inf(FILE *source, FILE *dest)
93  {
94      int ret;
95      unsigned have;
96      z_stream strm;
97      unsigned char in[CHUNK];
98      unsigned char out[CHUNK];
99  
100      /* allocate inflate state */
101      strm.zalloc = Z_NULL;
102      strm.zfree = Z_NULL;
103      strm.opaque = Z_NULL;
104      strm.avail_in = 0;
105      strm.next_in = Z_NULL;
106      ret = inflateInit(&strm);
107      if (ret != Z_OK)
108          return ret;
109  
110      /* decompress until deflate stream ends or end of file */
111      do {
112          strm.avail_in = fread(in, 1, CHUNK, source);
113          if (ferror(source)) {
114              (void)inflateEnd(&strm);
115              return Z_ERRNO;
116          }
117          if (strm.avail_in == 0)
118              break;
119          strm.next_in = in;
120  
121          /* run inflate() on input until output buffer not full */
122          do {
123              strm.avail_out = CHUNK;
124              strm.next_out = out;
125              ret = inflate(&strm, Z_NO_FLUSH);
126              assert(ret != Z_STREAM_ERROR);  /* state not clobbered */
127              switch (ret) {
128              case Z_NEED_DICT:
129                  ret = Z_DATA_ERROR;     /* and fall through */
130              case Z_DATA_ERROR:
131              case Z_MEM_ERROR:
132                  (void)inflateEnd(&strm);
133                  return ret;
134              }
135              have = CHUNK - strm.avail_out;
136              if (fwrite(out, 1, have, dest) != have || ferror(dest)) {
137                  (void)inflateEnd(&strm);
138                  return Z_ERRNO;
139              }
140          } while (strm.avail_out == 0);
141  
142          /* done when inflate() says it's done */
143      } while (ret != Z_STREAM_END);
144  
145      /* clean up and return */
146      (void)inflateEnd(&strm);
147      return ret == Z_STREAM_END ? Z_OK : Z_DATA_ERROR;
148  }
149  
150  /* report a zlib or i/o error */
zerr(int ret)151  void zerr(int ret)
152  {
153      fputs("zpipe: ", stderr);
154      switch (ret) {
155      case Z_ERRNO:
156          if (ferror(stdin))
157              fputs("error reading stdin\n", stderr);
158          if (ferror(stdout))
159              fputs("error writing stdout\n", stderr);
160          break;
161      case Z_STREAM_ERROR:
162          fputs("invalid compression level\n", stderr);
163          break;
164      case Z_DATA_ERROR:
165          fputs("invalid or incomplete deflate data\n", stderr);
166          break;
167      case Z_MEM_ERROR:
168          fputs("out of memory\n", stderr);
169          break;
170      case Z_VERSION_ERROR:
171          fputs("zlib version mismatch!\n", stderr);
172      }
173  }
174  
175  /* compress or decompress from stdin to stdout */
main(int argc,char ** argv)176  int main(int argc, char **argv)
177  {
178      int ret;
179  
180      /* avoid end-of-line conversions */
181      SET_BINARY_MODE(stdin);
182      SET_BINARY_MODE(stdout);
183  
184      /* do compression if no arguments */
185      if (argc == 1) {
186          ret = def(stdin, stdout, Z_DEFAULT_COMPRESSION);
187          if (ret != Z_OK)
188              zerr(ret);
189          return ret;
190      }
191  
192      /* do decompression if -d specified */
193      else if (argc == 2 && strcmp(argv[1], "-d") == 0) {
194          ret = inf(stdin, stdout);
195          if (ret != Z_OK)
196              zerr(ret);
197          return ret;
198      }
199  
200      /* otherwise, report usage */
201      else {
202          fputs("zpipe usage: zpipe [-d] < source > dest\n", stderr);
203          return 1;
204      }
205  }
206