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