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 } 206
