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| 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 | +} |
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