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 #if defined(_WIN32) && !defined(_CRT_NONSTDC_NO_DEPRECATE)
16 # define _CRT_NONSTDC_NO_DEPRECATE
17 #endif
18
19 #include <stdio.h>
20 #include <string.h>
21 #include <assert.h>
22 #include "zlib.h"
23
24 #if defined(MSDOS) || defined(OS2) || defined(WIN32) || defined(__CYGWIN__)
25 # include <fcntl.h>
26 # include <io.h>
27 # define SET_BINARY_MODE(file) setmode(fileno(file), O_BINARY)
28 #else
29 # define SET_BINARY_MODE(file)
30 #endif
31
32 #define CHUNK 16384
33
34 /* Compress from file source to file dest until EOF on source.
35 def() returns Z_OK on success, Z_MEM_ERROR if memory could not be
36 allocated for processing, Z_STREAM_ERROR if an invalid compression
37 level is supplied, Z_VERSION_ERROR if the version of zlib.h and the
38 version of the library linked do not match, or Z_ERRNO if there is
39 an error reading or writing the files. */
def(FILE * source,FILE * dest,int level)40 int def(FILE *source, FILE *dest, int level)
41 {
42 int ret, flush;
43 unsigned have;
44 z_stream strm;
45 unsigned char in[CHUNK];
46 unsigned char out[CHUNK];
47
48 /* allocate deflate state */
49 strm.zalloc = Z_NULL;
50 strm.zfree = Z_NULL;
51 strm.opaque = Z_NULL;
52 ret = deflateInit(&strm, level);
53 if (ret != Z_OK)
54 return ret;
55
56 /* compress until end of file */
57 do {
58 strm.avail_in = fread(in, 1, CHUNK, source);
59 if (ferror(source)) {
60 (void)deflateEnd(&strm);
61 return Z_ERRNO;
62 }
63 flush = feof(source) ? Z_FINISH : Z_NO_FLUSH;
64 strm.next_in = in;
65
66 /* run deflate() on input until output buffer not full, finish
67 compression if all of source has been read in */
68 do {
69 strm.avail_out = CHUNK;
70 strm.next_out = out;
71 ret = deflate(&strm, flush); /* no bad return value */
72 assert(ret != Z_STREAM_ERROR); /* state not clobbered */
73 have = CHUNK - strm.avail_out;
74 if (fwrite(out, 1, have, dest) != have || ferror(dest)) {
75 (void)deflateEnd(&strm);
76 return Z_ERRNO;
77 }
78 } while (strm.avail_out == 0);
79 assert(strm.avail_in == 0); /* all input will be used */
80
81 /* done when last data in file processed */
82 } while (flush != Z_FINISH);
83 assert(ret == Z_STREAM_END); /* stream will be complete */
84
85 /* clean up and return */
86 (void)deflateEnd(&strm);
87 return Z_OK;
88 }
89
90 /* Decompress from file source to file dest until stream ends or EOF.
91 inf() returns Z_OK on success, Z_MEM_ERROR if memory could not be
92 allocated for processing, Z_DATA_ERROR if the deflate data is
93 invalid or incomplete, Z_VERSION_ERROR if the version of zlib.h and
94 the version of the library linked do not match, or Z_ERRNO if there
95 is an error reading or writing the files. */
inf(FILE * source,FILE * dest)96 int inf(FILE *source, FILE *dest)
97 {
98 int ret;
99 unsigned have;
100 z_stream strm;
101 unsigned char in[CHUNK];
102 unsigned char out[CHUNK];
103
104 /* allocate inflate state */
105 strm.zalloc = Z_NULL;
106 strm.zfree = Z_NULL;
107 strm.opaque = Z_NULL;
108 strm.avail_in = 0;
109 strm.next_in = Z_NULL;
110 ret = inflateInit(&strm);
111 if (ret != Z_OK)
112 return ret;
113
114 /* decompress until deflate stream ends or end of file */
115 do {
116 strm.avail_in = fread(in, 1, CHUNK, source);
117 if (ferror(source)) {
118 (void)inflateEnd(&strm);
119 return Z_ERRNO;
120 }
121 if (strm.avail_in == 0)
122 break;
123 strm.next_in = in;
124
125 /* run inflate() on input until output buffer not full */
126 do {
127 strm.avail_out = CHUNK;
128 strm.next_out = out;
129 ret = inflate(&strm, Z_NO_FLUSH);
130 assert(ret != Z_STREAM_ERROR); /* state not clobbered */
131 switch (ret) {
132 case Z_NEED_DICT:
133 ret = Z_DATA_ERROR; /* and fall through */
134 case Z_DATA_ERROR:
135 case Z_MEM_ERROR:
136 (void)inflateEnd(&strm);
137 return ret;
138 }
139 have = CHUNK - strm.avail_out;
140 if (fwrite(out, 1, have, dest) != have || ferror(dest)) {
141 (void)inflateEnd(&strm);
142 return Z_ERRNO;
143 }
144 } while (strm.avail_out == 0);
145
146 /* done when inflate() says it's done */
147 } while (ret != Z_STREAM_END);
148
149 /* clean up and return */
150 (void)inflateEnd(&strm);
151 return ret == Z_STREAM_END ? Z_OK : Z_DATA_ERROR;
152 }
153
154 /* report a zlib or i/o error */
zerr(int ret)155 void zerr(int ret)
156 {
157 fputs("zpipe: ", stderr);
158 switch (ret) {
159 case Z_ERRNO:
160 if (ferror(stdin))
161 fputs("error reading stdin\n", stderr);
162 if (ferror(stdout))
163 fputs("error writing stdout\n", stderr);
164 break;
165 case Z_STREAM_ERROR:
166 fputs("invalid compression level\n", stderr);
167 break;
168 case Z_DATA_ERROR:
169 fputs("invalid or incomplete deflate data\n", stderr);
170 break;
171 case Z_MEM_ERROR:
172 fputs("out of memory\n", stderr);
173 break;
174 case Z_VERSION_ERROR:
175 fputs("zlib version mismatch!\n", stderr);
176 }
177 }
178
179 /* compress or decompress from stdin to stdout */
main(int argc,char ** argv)180 int main(int argc, char **argv)
181 {
182 int ret;
183
184 /* avoid end-of-line conversions */
185 SET_BINARY_MODE(stdin);
186 SET_BINARY_MODE(stdout);
187
188 /* do compression if no arguments */
189 if (argc == 1) {
190 ret = def(stdin, stdout, Z_DEFAULT_COMPRESSION);
191 if (ret != Z_OK)
192 zerr(ret);
193 return ret;
194 }
195
196 /* do decompression if -d specified */
197 else if (argc == 2 && strcmp(argv[1], "-d") == 0) {
198 ret = inf(stdin, stdout);
199 if (ret != Z_OK)
200 zerr(ret);
201 return ret;
202 }
203
204 /* otherwise, report usage */
205 else {
206 fputs("zpipe usage: zpipe [-d] < source > dest\n", stderr);
207 return 1;
208 }
209 }
210