zlib/example.c

   1 /* example.c -- usage example of the zlib compression library
   2  * Copyright (C) 1995-2003 Jean-loup Gailly.
   3  * For conditions of distribution and use, see copyright notice in zlib.h
   4  */
   5
   6 /* @(#) $Id: example.c,v 1.1.1.2 2002/03/11 21:53:23 tromey Exp $ */
   7
   8 #include <stdio.h>
   9 #include "zlib.h"
  10
  11 #ifdef STDC
  12 #  include <string.h>
  13 #  include <stdlib.h>
  14 #else
  15    extern void exit  OF((int));
  16 #endif
  17
  18 #if defined(VMS) || defined(RISCOS)
  19 #  define TESTFILE "foo-gz"
  20 #else
  21 #  define TESTFILE "foo.gz"
  22 #endif
  23
  24 #define CHECK_ERR(err, msg) { \
  25     if (err != Z_OK) { \
  26         fprintf(stderr, "%s error: %d\n", msg, err); \
  27         exit(1); \
  28     } \
  29 }
  30
  31 const char hello[] = "hello, hello!";
  32 /* "hello world" would be more standard, but the repeated "hello"
  33  * stresses the compression code better, sorry...
  34  */
  35
  36 const char dictionary[] = "hello";
  37 uLong dictId; /* Adler32 value of the dictionary */
  38
  39 void test_compress      OF((Byte *compr, uLong comprLen,
  40                             Byte *uncompr, uLong uncomprLen));
  41 void test_gzio          OF((const char *fname,
  42                             Byte *uncompr, uLong uncomprLen));
  43 void test_deflate       OF((Byte *compr, uLong comprLen));
  44 void test_inflate       OF((Byte *compr, uLong comprLen,
  45                             Byte *uncompr, uLong uncomprLen));
  46 void test_large_deflate OF((Byte *compr, uLong comprLen,
  47                             Byte *uncompr, uLong uncomprLen));
  48 void test_large_inflate OF((Byte *compr, uLong comprLen,
  49                             Byte *uncompr, uLong uncomprLen));
  50 void test_flush         OF((Byte *compr, uLong *comprLen));
  51 void test_sync          OF((Byte *compr, uLong comprLen,
  52                             Byte *uncompr, uLong uncomprLen));
  53 void test_dict_deflate  OF((Byte *compr, uLong comprLen));
  54 void test_dict_inflate  OF((Byte *compr, uLong comprLen,
  55                             Byte *uncompr, uLong uncomprLen));
  56 int  main               OF((int argc, char *argv[]));
  57
  58 /* ===========================================================================
  59  * Test compress() and uncompress()
  60  */
  61 void test_compress(compr, comprLen, uncompr, uncomprLen)
  62     Byte *compr, *uncompr;
  63     uLong comprLen, uncomprLen;
  64 {
  65     int err;
  66     uLong len = (uLong)strlen(hello)+1;
  67
  68     err = compress(compr, &comprLen, (const Bytef*)hello, len);
  69     CHECK_ERR(err, "compress");
  70
  71     strcpy((char*)uncompr, "garbage");
  72
  73     err = uncompress(uncompr, &uncomprLen, compr, comprLen);
  74     CHECK_ERR(err, "uncompress");
  75
  76     if (strcmp((char*)uncompr, hello)) {
  77         fprintf(stderr, "bad uncompress\n");
  78         exit(1);
  79     } else {
  80         printf("uncompress(): %s\n", (char *)uncompr);
  81     }
  82 }
  83
  84 /* ===========================================================================
  85  * Test read/write of .gz files
  86  */
  87 void test_gzio(fname, uncompr, uncomprLen)
  88     const char *fname; /* compressed file name */
  89     Byte *uncompr;
  90     uLong uncomprLen;
  91 {
  92 #ifdef NO_GZCOMPRESS
  93     fprintf(stderr, "NO_GZCOMPRESS -- gz* functions cannot compress\n");
  94 #else
  95     int err;
  96     int len = (int)strlen(hello)+1;
  97     gzFile file;
  98     z_off_t pos;
  99
 100     file = gzopen(fname, "wb");
 101     if (file == NULL) {
 102         fprintf(stderr, "gzopen error\n");
 103         exit(1);
 104     }
 105     gzputc(file, 'h');
 106     if (gzputs(file, "ello") != 4) {
 107         fprintf(stderr, "gzputs err: %s\n", gzerror(file, &err));
 108         exit(1);
 109     }
 110     if (gzprintf(file, ", %s!", "hello") != 8) {
 111         fprintf(stderr, "gzprintf err: %s\n", gzerror(file, &err));
 112         exit(1);
 113     }
 114     gzseek(file, 1L, SEEK_CUR); /* add one zero byte */
 115     gzclose(file);
 116
 117     file = gzopen(fname, "rb");
 118     if (file == NULL) {
 119         fprintf(stderr, "gzopen error\n");
 120         exit(1);
 121     }
 122     strcpy((char*)uncompr, "garbage");
 123
 124     if (gzread(file, uncompr, (unsigned)uncomprLen) != len) {
 125         fprintf(stderr, "gzread err: %s\n", gzerror(file, &err));
 126         exit(1);
 127     }
 128     if (strcmp((char*)uncompr, hello)) {
 129         fprintf(stderr, "bad gzread: %s\n", (char*)uncompr);
 130         exit(1);
 131     } else {
 132         printf("gzread(): %s\n", (char*)uncompr);
 133     }
 134
 135     pos = gzseek(file, -8L, SEEK_CUR);
 136     if (pos != 6 || gztell(file) != pos) {
 137         fprintf(stderr, "gzseek error, pos=%ld, gztell=%ld\n",
 138                 (long)pos, (long)gztell(file));
 139         exit(1);
 140     }
 141
 142     if (gzgetc(file) != ' ') {
 143         fprintf(stderr, "gzgetc error\n");
 144         exit(1);
 145     }
 146
 147     if (gzungetc(' ', file) != ' ') {
 148         fprintf(stderr, "gzungetc error\n");
 149         exit(1);
 150     }
 151
 152     gzgets(file, (char*)uncompr, (int)uncomprLen);
 153     if (strlen((char*)uncompr) != 7) { /* " hello!" */
 154         fprintf(stderr, "gzgets err after gzseek: %s\n", gzerror(file, &err));
 155         exit(1);
 156     }
 157     if (strcmp((char*)uncompr, hello + 6)) {
 158         fprintf(stderr, "bad gzgets after gzseek\n");
 159         exit(1);
 160     } else {
 161         printf("gzgets() after gzseek: %s\n", (char*)uncompr);
 162     }
 163
 164     gzclose(file);
 165 #endif
 166 }
 167
 168 /* ===========================================================================
 169  * Test deflate() with small buffers
 170  */
 171 void test_deflate(compr, comprLen)
 172     Byte *compr;
 173     uLong comprLen;
 174 {
 175     z_stream c_stream; /* compression stream */
 176     int err;
 177     uLong len = (uLong)strlen(hello)+1;
 178
 179     c_stream.zalloc = (alloc_func)0;
 180     c_stream.zfree = (free_func)0;
 181     c_stream.opaque = (voidpf)0;
 182
 183     err = deflateInit(&c_stream, Z_DEFAULT_COMPRESSION);
 184     CHECK_ERR(err, "deflateInit");
 185
 186     c_stream.next_in  = (Bytef*)hello;
 187     c_stream.next_out = compr;
 188
 189     while (c_stream.total_in != len && c_stream.total_out < comprLen) {
 190         c_stream.avail_in = c_stream.avail_out = 1; /* force small buffers */
 191         err = deflate(&c_stream, Z_NO_FLUSH);
 192         CHECK_ERR(err, "deflate");
 193     }
 194     /* Finish the stream, still forcing small buffers: */
 195     for (;;) {
 196         c_stream.avail_out = 1;
 197         err = deflate(&c_stream, Z_FINISH);
 198         if (err == Z_STREAM_END) break;
 199         CHECK_ERR(err, "deflate");
 200     }
 201
 202     err = deflateEnd(&c_stream);
 203     CHECK_ERR(err, "deflateEnd");
 204 }
 205
 206 /* ===========================================================================
 207  * Test inflate() with small buffers
 208  */
 209 void test_inflate(compr, comprLen, uncompr, uncomprLen)
 210     Byte *compr, *uncompr;
 211     uLong comprLen, uncomprLen;
 212 {
 213     int err;
 214     z_stream d_stream; /* decompression stream */
 215
 216     strcpy((char*)uncompr, "garbage");
 217
 218     d_stream.zalloc = (alloc_func)0;
 219     d_stream.zfree = (free_func)0;
 220     d_stream.opaque = (voidpf)0;
 221
 222     d_stream.next_in  = compr;
 223     d_stream.avail_in = 0;
 224     d_stream.next_out = uncompr;
 225
 226     err = inflateInit(&d_stream);
 227     CHECK_ERR(err, "inflateInit");
 228
 229     while (d_stream.total_out < uncomprLen && d_stream.total_in < comprLen) {
 230         d_stream.avail_in = d_stream.avail_out = 1; /* force small buffers */
 231         err = inflate(&d_stream, Z_NO_FLUSH);
 232         if (err == Z_STREAM_END) break;
 233         CHECK_ERR(err, "inflate");
 234     }
 235
 236     err = inflateEnd(&d_stream);
 237     CHECK_ERR(err, "inflateEnd");
 238
 239     if (strcmp((char*)uncompr, hello)) {
 240         fprintf(stderr, "bad inflate\n");
 241         exit(1);
 242     } else {
 243         printf("inflate(): %s\n", (char *)uncompr);
 244     }
 245 }
 246
 247 /* ===========================================================================
 248  * Test deflate() with large buffers and dynamic change of compression level
 249  */
 250 void test_large_deflate(compr, comprLen, uncompr, uncomprLen)
 251     Byte *compr, *uncompr;
 252     uLong comprLen, uncomprLen;
 253 {
 254     z_stream c_stream; /* compression stream */
 255     int err;
 256
 257     c_stream.zalloc = (alloc_func)0;
 258     c_stream.zfree = (free_func)0;
 259     c_stream.opaque = (voidpf)0;
 260
 261     err = deflateInit(&c_stream, Z_BEST_SPEED);
 262     CHECK_ERR(err, "deflateInit");
 263
 264     c_stream.next_out = compr;
 265     c_stream.avail_out = (uInt)comprLen;
 266
 267     /* At this point, uncompr is still mostly zeroes, so it should compress
 268      * very well:
 269      */
 270     c_stream.next_in = uncompr;
 271     c_stream.avail_in = (uInt)uncomprLen;
 272     err = deflate(&c_stream, Z_NO_FLUSH);
 273     CHECK_ERR(err, "deflate");
 274     if (c_stream.avail_in != 0) {
 275         fprintf(stderr, "deflate not greedy\n");
 276         exit(1);
 277     }
 278
 279     /* Feed in already compressed data and switch to no compression: */
 280     deflateParams(&c_stream, Z_NO_COMPRESSION, Z_DEFAULT_STRATEGY);
 281     c_stream.next_in = compr;
 282     c_stream.avail_in = (uInt)comprLen/2;
 283     err = deflate(&c_stream, Z_NO_FLUSH);
 284     CHECK_ERR(err, "deflate");
 285
 286     /* Switch back to compressing mode: */
 287     deflateParams(&c_stream, Z_BEST_COMPRESSION, Z_FILTERED);
 288     c_stream.next_in = uncompr;
 289     c_stream.avail_in = (uInt)uncomprLen;
 290     err = deflate(&c_stream, Z_NO_FLUSH);
 291     CHECK_ERR(err, "deflate");
 292
 293     err = deflate(&c_stream, Z_FINISH);
 294     if (err != Z_STREAM_END) {
 295         fprintf(stderr, "deflate should report Z_STREAM_END\n");
 296         exit(1);
 297     }
 298     err = deflateEnd(&c_stream);
 299     CHECK_ERR(err, "deflateEnd");
 300 }
 301
 302 /* ===========================================================================
 303  * Test inflate() with large buffers
 304  */
 305 void test_large_inflate(compr, comprLen, uncompr, uncomprLen)
 306     Byte *compr, *uncompr;
 307     uLong comprLen, uncomprLen;
 308 {
 309     int err;
 310     z_stream d_stream; /* decompression stream */
 311
 312     strcpy((char*)uncompr, "garbage");
 313
 314     d_stream.zalloc = (alloc_func)0;
 315     d_stream.zfree = (free_func)0;
 316     d_stream.opaque = (voidpf)0;
 317
 318     d_stream.next_in  = compr;
 319     d_stream.avail_in = (uInt)comprLen;
 320
 321     err = inflateInit(&d_stream);
 322     CHECK_ERR(err, "inflateInit");
 323
 324     for (;;) {
 325         d_stream.next_out = uncompr;            /* discard the output */
 326         d_stream.avail_out = (uInt)uncomprLen;
 327         err = inflate(&d_stream, Z_NO_FLUSH);
 328         if (err == Z_STREAM_END) break;
 329         CHECK_ERR(err, "large inflate");
 330     }
 331
 332     err = inflateEnd(&d_stream);
 333     CHECK_ERR(err, "inflateEnd");
 334
 335     if (d_stream.total_out != 2*uncomprLen + comprLen/2) {
 336         fprintf(stderr, "bad large inflate: %ld\n", d_stream.total_out);
 337         exit(1);
 338     } else {
 339         printf("large_inflate(): OK\n");
 340     }
 341 }
 342
 343 /* ===========================================================================
 344  * Test deflate() with full flush
 345  */
 346 void test_flush(compr, comprLen)
 347     Byte *compr;
 348     uLong *comprLen;
 349 {
 350     z_stream c_stream; /* compression stream */
 351     int err;
 352     uInt len = (uInt)strlen(hello)+1;
 353
 354     c_stream.zalloc = (alloc_func)0;
 355     c_stream.zfree = (free_func)0;
 356     c_stream.opaque = (voidpf)0;
 357
 358     err = deflateInit(&c_stream, Z_DEFAULT_COMPRESSION);
 359     CHECK_ERR(err, "deflateInit");
 360
 361     c_stream.next_in  = (Bytef*)hello;
 362     c_stream.next_out = compr;
 363     c_stream.avail_in = 3;
 364     c_stream.avail_out = (uInt)*comprLen;
 365     err = deflate(&c_stream, Z_FULL_FLUSH);
 366     CHECK_ERR(err, "deflate");
 367
 368     compr[3]++; /* force an error in first compressed block */
 369     c_stream.avail_in = len - 3;
 370
 371     err = deflate(&c_stream, Z_FINISH);
 372     if (err != Z_STREAM_END) {
 373         CHECK_ERR(err, "deflate");
 374     }
 375     err = deflateEnd(&c_stream);
 376     CHECK_ERR(err, "deflateEnd");
 377
 378     *comprLen = c_stream.total_out;
 379 }
 380
 381 /* ===========================================================================
 382  * Test inflateSync()
 383  */
 384 void test_sync(compr, comprLen, uncompr, uncomprLen)
 385     Byte *compr, *uncompr;
 386     uLong comprLen, uncomprLen;
 387 {
 388     int err;
 389     z_stream d_stream; /* decompression stream */
 390
 391     strcpy((char*)uncompr, "garbage");
 392
 393     d_stream.zalloc = (alloc_func)0;
 394     d_stream.zfree = (free_func)0;
 395     d_stream.opaque = (voidpf)0;
 396
 397     d_stream.next_in  = compr;
 398     d_stream.avail_in = 2; /* just read the zlib header */
 399
 400     err = inflateInit(&d_stream);
 401     CHECK_ERR(err, "inflateInit");
 402
 403     d_stream.next_out = uncompr;
 404     d_stream.avail_out = (uInt)uncomprLen;
 405
 406     inflate(&d_stream, Z_NO_FLUSH);
 407     CHECK_ERR(err, "inflate");
 408
 409     d_stream.avail_in = (uInt)comprLen-2;   /* read all compressed data */
 410     err = inflateSync(&d_stream);           /* but skip the damaged part */
 411     CHECK_ERR(err, "inflateSync");
 412
 413     err = inflate(&d_stream, Z_FINISH);
 414     if (err != Z_DATA_ERROR) {
 415         fprintf(stderr, "inflate should report DATA_ERROR\n");
 416         /* Because of incorrect adler32 */
 417         exit(1);
 418     }
 419     err = inflateEnd(&d_stream);
 420     CHECK_ERR(err, "inflateEnd");
 421
 422     printf("after inflateSync(): hel%s\n", (char *)uncompr);
 423 }
 424
 425 /* ===========================================================================
 426  * Test deflate() with preset dictionary
 427  */
 428 void test_dict_deflate(compr, comprLen)
 429     Byte *compr;
 430     uLong comprLen;
 431 {
 432     z_stream c_stream; /* compression stream */
 433     int err;
 434
 435     c_stream.zalloc = (alloc_func)0;
 436     c_stream.zfree = (free_func)0;
 437     c_stream.opaque = (voidpf)0;
 438
 439     err = deflateInit(&c_stream, Z_BEST_COMPRESSION);
 440     CHECK_ERR(err, "deflateInit");
 441
 442     err = deflateSetDictionary(&c_stream,
 443                                (const Bytef*)dictionary, sizeof(dictionary));
 444     CHECK_ERR(err, "deflateSetDictionary");
 445
 446     dictId = c_stream.adler;
 447     c_stream.next_out = compr;
 448     c_stream.avail_out = (uInt)comprLen;
 449
 450     c_stream.next_in = (Bytef*)hello;
 451     c_stream.avail_in = (uInt)strlen(hello)+1;
 452
 453     err = deflate(&c_stream, Z_FINISH);
 454     if (err != Z_STREAM_END) {
 455         fprintf(stderr, "deflate should report Z_STREAM_END\n");
 456         exit(1);
 457     }
 458     err = deflateEnd(&c_stream);
 459     CHECK_ERR(err, "deflateEnd");
 460 }
 461
 462 /* ===========================================================================
 463  * Test inflate() with a preset dictionary
 464  */
 465 void test_dict_inflate(compr, comprLen, uncompr, uncomprLen)
 466     Byte *compr, *uncompr;
 467     uLong comprLen, uncomprLen;
 468 {
 469     int err;
 470     z_stream d_stream; /* decompression stream */
 471
 472     strcpy((char*)uncompr, "garbage");
 473
 474     d_stream.zalloc = (alloc_func)0;
 475     d_stream.zfree = (free_func)0;
 476     d_stream.opaque = (voidpf)0;
 477
 478     d_stream.next_in  = compr;
 479     d_stream.avail_in = (uInt)comprLen;
 480
 481     err = inflateInit(&d_stream);
 482     CHECK_ERR(err, "inflateInit");
 483
 484     d_stream.next_out = uncompr;
 485     d_stream.avail_out = (uInt)uncomprLen;
 486
 487     for (;;) {
 488         err = inflate(&d_stream, Z_NO_FLUSH);
 489         if (err == Z_STREAM_END) break;
 490         if (err == Z_NEED_DICT) {
 491             if (d_stream.adler != dictId) {
 492                 fprintf(stderr, "unexpected dictionary");
 493                 exit(1);
 494             }
 495             err = inflateSetDictionary(&d_stream, (const Bytef*)dictionary,
 496                                        sizeof(dictionary));
 497         }
 498         CHECK_ERR(err, "inflate with dict");
 499     }
 500
 501     err = inflateEnd(&d_stream);
 502     CHECK_ERR(err, "inflateEnd");
 503
 504     if (strcmp((char*)uncompr, hello)) {
 505         fprintf(stderr, "bad inflate with dict\n");
 506         exit(1);
 507     } else {
 508         printf("inflate with dictionary: %s\n", (char *)uncompr);
 509     }
 510 }
 511
 512 /* ===========================================================================
 513  * Usage:  example [output.gz  [input.gz]]
 514  */
 515
 516 int main(argc, argv)
 517     int argc;
 518     char *argv[];
 519 {
 520     Byte *compr, *uncompr;
 521     uLong comprLen = 10000*sizeof(int); /* don't overflow on MSDOS */
 522     uLong uncomprLen = comprLen;
 523     static const char* myVersion = ZLIB_VERSION;
 524
 525     if (zlibVersion()[0] != myVersion[0]) {
 526         fprintf(stderr, "incompatible zlib version\n");
 527         exit(1);
 528
 529     } else if (strcmp(zlibVersion(), ZLIB_VERSION) != 0) {
 530         fprintf(stderr, "warning: different zlib version\n");
 531     }
 532
 533     printf("zlib version %s = 0x%04x, compile flags = 0x%lx\n",
 534             ZLIB_VERSION, ZLIB_VERNUM, zlibCompileFlags());
 535
 536     compr    = (Byte*)calloc((uInt)comprLen, 1);
 537     uncompr  = (Byte*)calloc((uInt)uncomprLen, 1);
 538     /* compr and uncompr are cleared to avoid reading uninitialized
 539      * data and to ensure that uncompr compresses well.
 540      */
 541     if (compr == Z_NULL || uncompr == Z_NULL) {
 542         printf("out of memory\n");
 543         exit(1);
 544     }
 545     test_compress(compr, comprLen, uncompr, uncomprLen);
 546
 547     test_gzio((argc > 1 ? argv[1] : TESTFILE),
 548               uncompr, uncomprLen);
 549
 550     test_deflate(compr, comprLen);
 551     test_inflate(compr, comprLen, uncompr, uncomprLen);
 552
 553     test_large_deflate(compr, comprLen, uncompr, uncomprLen);
 554     test_large_inflate(compr, comprLen, uncompr, uncomprLen);
 555
 556     test_flush(compr, &comprLen);
 557     test_sync(compr, comprLen, uncompr, uncomprLen);
 558     comprLen = uncomprLen;
 559
 560     test_dict_deflate(compr, comprLen);
 561     test_dict_inflate(compr, comprLen, uncompr, uncomprLen);
 562
 563     free(compr);
 564     free(uncompr);
 565
 566     return 0;
 567 }