1 /* zpipe.c: example of proper use of zlib's inflate() and deflate()
2 Not copyrighted -- provided to the public domain
3 Version 1.2 9 November 2004 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()
20 /* Compress from file source to file dest until EOF on source.
21 def() returns Z_OK on success, Z_MEM_ERROR if memory could not be
22 allocated for processing, Z_STREAM_ERROR if an invalid compression
23 level is supplied, Z_VERSION_ERROR if the version of zlib.h and the
24 version of the library linked do not match, or Z_ERRNO if there is
25 an error reading or writing the files. */
26 int def(FILE *source, FILE *dest, int level)
34 /* allocate deflate state */
38 ret = deflateInit(&strm, level);
42 /* compress until end of file */
44 strm.avail_in = fread(in, 1, CHUNK, source);
46 (void)deflateEnd(&strm);
49 flush = feof(source) ? Z_FINISH : Z_NO_FLUSH;
52 /* run deflate() on input until output buffer not full, finish
53 compression if all of source has been read in */
55 strm.avail_out = CHUNK;
57 ret = deflate(&strm, flush); /* no bad return value */
58 assert(ret != Z_STREAM_ERROR); /* state not clobbered */
59 have = CHUNK - strm.avail_out;
60 if (fwrite(out, 1, have, dest) != have || ferror(dest)) {
61 (void)deflateEnd(&strm);
64 } while (strm.avail_out == 0);
65 assert(strm.avail_in == 0); /* all input will be used */
67 /* done when last data in file processed */
68 } while (flush != Z_FINISH);
69 assert(ret == Z_STREAM_END); /* stream will be complete */
71 /* clean up and return */
72 (void)deflateEnd(&strm);
76 /* Decompress from file source to file dest until stream ends or EOF.
77 inf() returns Z_OK on success, Z_MEM_ERROR if memory could not be
78 allocated for processing, Z_DATA_ERROR if the deflate data is
79 invalid or incomplete, Z_VERSION_ERROR if the version of zlib.h and
80 the version of the library linked do not match, or Z_ERRNO if there
81 is an error reading or writing the files. */
82 int inf(FILE *source, FILE *dest)
90 /* allocate inflate state */
95 strm.next_in = Z_NULL;
96 ret = inflateInit(&strm);
100 /* decompress until deflate stream ends or end of file */
102 strm.avail_in = fread(in, 1, CHUNK, source);
103 if (ferror(source)) {
104 (void)inflateEnd(&strm);
107 if (strm.avail_in == 0)
111 /* run inflate() on input until output buffer not full */
113 strm.avail_out = CHUNK;
115 ret = inflate(&strm, Z_NO_FLUSH);
116 assert(ret != Z_STREAM_ERROR); /* state not clobbered */
119 ret = Z_DATA_ERROR; /* and fall through */
122 (void)inflateEnd(&strm);
125 have = CHUNK - strm.avail_out;
126 if (fwrite(out, 1, have, dest) != have || ferror(dest)) {
127 (void)inflateEnd(&strm);
130 } while (strm.avail_out == 0);
132 /* done when inflate() says it's done */
133 } while (ret != Z_STREAM_END);
135 /* clean up and return */
136 (void)inflateEnd(&strm);
137 return ret == Z_STREAM_END ? Z_OK : Z_DATA_ERROR;
140 /* report a zlib or i/o error */
143 fputs("zpipe: ", stderr);
147 fputs("error reading stdin\n", stderr);
149 fputs("error writing stdout\n", stderr);
152 fputs("invalid compression level\n", stderr);
155 fputs("invalid or incomplete deflate data\n", stderr);
158 fputs("out of memory\n", stderr);
160 case Z_VERSION_ERROR:
161 fputs("zlib version mismatch!\n", stderr);
165 /* compress or decompress from stdin to stdout */
166 int main(int argc, char **argv)
170 /* do compression if no arguments */
172 ret = def(stdin, stdout, Z_DEFAULT_COMPRESSION);
178 /* do decompression if -d specified */
179 else if (argc == 2 && strcmp(argv[1], "-d") == 0) {
180 ret = inf(stdin, stdout);
186 /* otherwise, report usage */
188 fputs("zpipe usage: zpipe [-d] < source > dest\n", stderr);