| 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 | } |