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 */
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
20 #if defined(MSDOS) || defined(OS2) || defined(WIN32) || defined(__CYGWIN__)
23 # define SET_BINARY_MODE(file) setmode(fileno(file), O_BINARY)
25 # define SET_BINARY_MODE(file)
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. */
36 int def(FILE *source, FILE *dest, int level)
41 unsigned char in[CHUNK];
42 unsigned char out[CHUNK];
44 /* allocate deflate state */
48 ret = deflateInit(&strm, level);
52 /* compress until end of file */
54 strm.avail_in = fread(in, 1, CHUNK, source);
56 (void)deflateEnd(&strm);
59 flush = feof(source) ? Z_FINISH : Z_NO_FLUSH;
62 /* run deflate() on input until output buffer not full, finish
63 compression if all of source has been read in */
65 strm.avail_out = CHUNK;
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);
74 } while (strm.avail_out == 0);
75 assert(strm.avail_in == 0); /* all input will be used */
77 /* done when last data in file processed */
78 } while (flush != Z_FINISH);
79 assert(ret == Z_STREAM_END); /* stream will be complete */
81 /* clean up and return */
82 (void)deflateEnd(&strm);
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. */
92 int inf(FILE *source, FILE *dest)
97 unsigned char in[CHUNK];
98 unsigned char out[CHUNK];
100 /* allocate inflate state */
101 strm.zalloc = Z_NULL;
103 strm.opaque = Z_NULL;
105 strm.next_in = Z_NULL;
106 ret = inflateInit(&strm);
110 /* decompress until deflate stream ends or end of file */
112 strm.avail_in = fread(in, 1, CHUNK, source);
113 if (ferror(source)) {
114 (void)inflateEnd(&strm);
117 if (strm.avail_in == 0)
121 /* run inflate() on input until output buffer not full */
123 strm.avail_out = CHUNK;
125 ret = inflate(&strm, Z_NO_FLUSH);
126 assert(ret != Z_STREAM_ERROR); /* state not clobbered */
129 ret = Z_DATA_ERROR; /* and fall through */
132 (void)inflateEnd(&strm);
135 have = CHUNK - strm.avail_out;
136 if (fwrite(out, 1, have, dest) != have || ferror(dest)) {
137 (void)inflateEnd(&strm);
140 } while (strm.avail_out == 0);
142 /* done when inflate() says it's done */
143 } while (ret != Z_STREAM_END);
145 /* clean up and return */
146 (void)inflateEnd(&strm);
147 return ret == Z_STREAM_END ? Z_OK : Z_DATA_ERROR;
150 /* report a zlib or i/o error */
153 fputs("zpipe: ", stderr);
157 fputs("error reading stdin\n", stderr);
159 fputs("error writing stdout\n", stderr);
162 fputs("invalid compression level\n", stderr);
165 fputs("invalid or incomplete deflate data\n", stderr);
168 fputs("out of memory\n", stderr);
170 case Z_VERSION_ERROR:
171 fputs("zlib version mismatch!\n", stderr);
175 /* compress or decompress from stdin to stdout */
176 int main(int argc, char **argv)
180 /* avoid end-of-line conversions */
181 SET_BINARY_MODE(stdin);
182 SET_BINARY_MODE(stdout);
184 /* do compression if no arguments */
186 ret = def(stdin, stdout, Z_DEFAULT_COMPRESSION);
192 /* do decompression if -d specified */
193 else if (argc == 2 && strcmp(argv[1], "-d") == 0) {
194 ret = inf(stdin, stdout);
200 /* otherwise, report usage */
202 fputs("zpipe usage: zpipe [-d] < source > dest\n", stderr);