1/* zpipe.c: example of proper use of zlib's inflate() and deflate() 2 Not copyrighted -- provided to the public domain 3 Version 1.2 9 November 2004 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 */ 12 13#include <stdio.h> 14#include <string.h> 15#include <assert.h> 16#include "zlib.h" 17 18#define CHUNK 16384 19 20/* Compress from file source to file dest until EOF on source. 21 def() returns Z_OK on success, Z_MEM_ERROR if memory could not be 22 allocated for processing, Z_STREAM_ERROR if an invalid compression 23 level is supplied, Z_VERSION_ERROR if the version of zlib.h and the 24 version of the library linked do not match, or Z_ERRNO if there is 25 an error reading or writing the files. */ 26int def(FILE *source, FILE *dest, int level) 27{ 28 int ret, flush; 29 unsigned have; 30 z_stream strm; 31 char in[CHUNK]; 32 char out[CHUNK]; 33 34 /* allocate deflate state */ 35 strm.zalloc = Z_NULL; 36 strm.zfree = Z_NULL; 37 strm.opaque = Z_NULL; 38 ret = deflateInit(&strm, level); 39 if (ret != Z_OK) 40 return ret; 41 42 /* compress until end of file */ 43 do { 44 strm.avail_in = fread(in, 1, CHUNK, source); 45 if (ferror(source)) { 46 (void)deflateEnd(&strm); 47 return Z_ERRNO; 48 } 49 flush = feof(source) ? Z_FINISH : Z_NO_FLUSH; 50 strm.next_in = in; 51 52 /* run deflate() on input until output buffer not full, finish 53 compression if all of source has been read in */ 54 do { 55 strm.avail_out = CHUNK; 56 strm.next_out = out; 57 ret = deflate(&strm, flush); /* no bad return value */ 58 assert(ret != Z_STREAM_ERROR); /* state not clobbered */ 59 have = CHUNK - strm.avail_out; 60 if (fwrite(out, 1, have, dest) != have || ferror(dest)) { 61 (void)deflateEnd(&strm); 62 return Z_ERRNO; 63 } 64 } while (strm.avail_out == 0); 65 assert(strm.avail_in == 0); /* all input will be used */ 66 67 /* done when last data in file processed */ 68 } while (flush != Z_FINISH); 69 assert(ret == Z_STREAM_END); /* stream will be complete */ 70 71 /* clean up and return */ 72 (void)deflateEnd(&strm); 73 return Z_OK; 74} 75 76/* Decompress from file source to file dest until stream ends or EOF. 77 inf() returns Z_OK on success, Z_MEM_ERROR if memory could not be 78 allocated for processing, Z_DATA_ERROR if the deflate data is 79 invalid or incomplete, Z_VERSION_ERROR if the version of zlib.h and 80 the version of the library linked do not match, or Z_ERRNO if there 81 is an error reading or writing the files. */ 82int inf(FILE *source, FILE *dest) 83{ 84 int ret; 85 unsigned have; 86 z_stream strm; 87 char in[CHUNK]; 88 char out[CHUNK]; 89 90 /* allocate inflate state */ 91 strm.zalloc = Z_NULL; 92 strm.zfree = Z_NULL; 93 strm.opaque = Z_NULL; 94 strm.avail_in = 0; 95 strm.next_in = Z_NULL; 96 ret = inflateInit(&strm); 97 if (ret != Z_OK) 98 return ret; 99 100 /* decompress until deflate stream ends or end of file */ 101 do { 102 strm.avail_in = fread(in, 1, CHUNK, source); 103 if (ferror(source)) { 104 (void)inflateEnd(&strm); 105 return Z_ERRNO; 106 } 107 if (strm.avail_in == 0) 108 break; 109 strm.next_in = in; 110 111 /* run inflate() on input until output buffer not full */ 112 do { 113 strm.avail_out = CHUNK; 114 strm.next_out = out; 115 ret = inflate(&strm, Z_NO_FLUSH); 116 assert(ret != Z_STREAM_ERROR); /* state not clobbered */ 117 switch (ret) { 118 case Z_NEED_DICT: 119 ret = Z_DATA_ERROR; /* and fall through */ 120 case Z_DATA_ERROR: 121 case Z_MEM_ERROR: 122 (void)inflateEnd(&strm); 123 return ret; 124 } 125 have = CHUNK - strm.avail_out; 126 if (fwrite(out, 1, have, dest) != have || ferror(dest)) { 127 (void)inflateEnd(&strm); 128 return Z_ERRNO; 129 } 130 } while (strm.avail_out == 0); 131 132 /* done when inflate() says it's done */ 133 } while (ret != Z_STREAM_END); 134 135 /* clean up and return */ 136 (void)inflateEnd(&strm); 137 return ret == Z_STREAM_END ? Z_OK : Z_DATA_ERROR; 138} 139 140/* report a zlib or i/o error */ 141void zerr(int ret) 142{ 143 fputs("zpipe: ", stderr); 144 switch (ret) { 145 case Z_ERRNO: 146 if (ferror(stdin)) 147 fputs("error reading stdin\n", stderr); 148 if (ferror(stdout)) 149 fputs("error writing stdout\n", stderr); 150 break; 151 case Z_STREAM_ERROR: 152 fputs("invalid compression level\n", stderr); 153 break; 154 case Z_DATA_ERROR: 155 fputs("invalid or incomplete deflate data\n", stderr); 156 break; 157 case Z_MEM_ERROR: 158 fputs("out of memory\n", stderr); 159 break; 160 case Z_VERSION_ERROR: 161 fputs("zlib version mismatch!\n", stderr); 162 } 163} 164 165/* compress or decompress from stdin to stdout */ 166int main(int argc, char **argv) 167{ 168 int ret; 169 170 /* do compression if no arguments */ 171 if (argc == 1) { 172 ret = def(stdin, stdout, Z_DEFAULT_COMPRESSION); 173 if (ret != Z_OK) 174 zerr(ret); 175 return ret; 176 } 177 178 /* do decompression if -d specified */ 179 else if (argc == 2 && strcmp(argv[1], "-d") == 0) { 180 ret = inf(stdin, stdout); 181 if (ret != Z_OK) 182 zerr(ret); 183 return ret; 184 } 185 186 /* otherwise, report usage */ 187 else { 188 fputs("zpipe usage: zpipe [-d] < source > dest\n", stderr); 189 return 1; 190 } 191} 192