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5ca28f79 L |
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. */ | |
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. */ | |
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 */ | |
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 */ | |
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 | } |