9e052883 |
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 | } |