src/zlib/example.c

   1 /* example.c -- usage example of the zlib compression library
   2  * Copyright (C) 1995-1998 Jean-loup Gailly.
   3  * For conditions of distribution and use, see copyright notice in zlib.h
   4  */
   5
   6 /* @(#) $Id$ */
   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 #define CHECK_ERR(err, msg) { \
  19     if (err != Z_OK) { \
  20         fprintf(stderr, "%s error: %d\n", msg, err); \
  21         exit(1); \
  22     } \
  23 }
  24
  25 const char hello[] = "hello, hello!";
  26 /* "hello world" would be more standard, but the repeated "hello"
  27  * stresses the compression code better, sorry...
  28  */
  29
  30 const char dictionary[] = "hello";
  31 uLong dictId; /* Adler32 value of the dictionary */
  32
  33 void test_compress      OF((Byte *compr, uLong comprLen,
  34                             Byte *uncompr, uLong uncomprLen));
  35 void test_gzio          OF((const char *out, const char *in,
  36                             Byte *uncompr, int uncomprLen));
  37 void test_deflate       OF((Byte *compr, uLong comprLen));
  38 void test_inflate       OF((Byte *compr, uLong comprLen,
  39                             Byte *uncompr, uLong uncomprLen));
  40 void test_large_deflate OF((Byte *compr, uLong comprLen,
  41                             Byte *uncompr, uLong uncomprLen));
  42 void test_large_inflate OF((Byte *compr, uLong comprLen,
  43                             Byte *uncompr, uLong uncomprLen));
  44 void test_flush         OF((Byte *compr, uLong *comprLen));
  45 void test_sync          OF((Byte *compr, uLong comprLen,
  46                             Byte *uncompr, uLong uncomprLen));
  47 void test_dict_deflate  OF((Byte *compr, uLong comprLen));
  48 void test_dict_inflate  OF((Byte *compr, uLong comprLen,
  49                             Byte *uncompr, uLong uncomprLen));
  50 int  main               OF((int argc, char *argv[]));
  51
  52 /* ===========================================================================
  53  * Test compress() and uncompress()
  54  */
  55 void test_compress(compr, comprLen, uncompr, uncomprLen)
  56     Byte *compr, *uncompr;
  57     uLong comprLen, uncomprLen;
  58 {
  59     int err;
  60     uLong len = strlen(hello)+1;
  61
  62     err = compress(compr, &comprLen, (const Bytef*)hello, len);
  63     CHECK_ERR(err, "compress");
  64
  65     strcpy((char*)uncompr, "garbage");
  66
  67     err = uncompress(uncompr, &uncomprLen, compr, comprLen);
  68     CHECK_ERR(err, "uncompress");
  69
  70     if (strcmp((char*)uncompr, hello)) {
  71         fprintf(stderr, "bad uncompress\n");
  72         exit(1);
  73     } else {
  74         printf("uncompress(): %s\n", (char *)uncompr);
  75     }
  76 }
  77
  78 /* ===========================================================================
  79  * Test read/write of .gz files
  80  */
  81 void test_gzio(out, in, uncompr, uncomprLen)
  82     const char *out; /* output file */
  83     const char *in;  /* input file */
  84     Byte *uncompr;
  85     int  uncomprLen;
  86 {
  87     int err;
  88     int len = strlen(hello)+1;
  89     gzFile file;
  90     z_off_t pos;
  91
  92     file = gzopen(out, "wb");
  93     if (file == NULL) {
  94         fprintf(stderr, "gzopen error\n");
  95         exit(1);
  96     }
  97     gzputc(file, 'h');
  98     if (gzputs(file, "ello") != 4) {
  99         fprintf(stderr, "gzputs err: %s\n", gzerror(file, &err));
 100         exit(1);
 101     }
 102     if (gzprintf(file, ", %s!", "hello") != 8) {
 103         fprintf(stderr, "gzprintf err: %s\n", gzerror(file, &err));
 104         exit(1);
 105     }
 106     gzseek(file, 1L, SEEK_CUR); /* add one zero byte */
 107     gzclose(file);
 108
 109     file = gzopen(in, "rb");
 110     if (file == NULL) {
 111         fprintf(stderr, "gzopen error\n");
 112     }
 113     strcpy((char*)uncompr, "garbage");
 114
 115     uncomprLen = gzread(file, uncompr, (unsigned)uncomprLen);
 116     if (uncomprLen != len) {
 117         fprintf(stderr, "gzread err: %s\n", gzerror(file, &err));
 118         exit(1);
 119     }
 120     if (strcmp((char*)uncompr, hello)) {
 121         fprintf(stderr, "bad gzread: %s\n", (char*)uncompr);
 122         exit(1);
 123     } else {
 124         printf("gzread(): %s\n", (char *)uncompr);
 125     }
 126
 127     pos = gzseek(file, -8L, SEEK_CUR);
 128     if (pos != 6 || gztell(file) != pos) {
 129         fprintf(stderr, "gzseek error, pos=%ld, gztell=%ld\n",
 130                 (long)pos, (long)gztell(file));
 131         exit(1);
 132     }
 133
 134     if (gzgetc(file) != ' ') {
 135         fprintf(stderr, "gzgetc error\n");
 136         exit(1);
 137     }
 138
 139     gzgets(file, (char*)uncompr, uncomprLen);
 140     uncomprLen = strlen((char*)uncompr);
 141     if (uncomprLen != 6) { /* "hello!" */
 142         fprintf(stderr, "gzgets err after gzseek: %s\n", gzerror(file, &err));
 143         exit(1);
 144     }
 145     if (strcmp((char*)uncompr, hello+7)) {
 146         fprintf(stderr, "bad gzgets after gzseek\n");
 147         exit(1);
 148     } else {
 149         printf("gzgets() after gzseek: %s\n", (char *)uncompr);
 150     }
 151
 152     gzclose(file);
 153 }
 154
 155 /* ===========================================================================
 156  * Test deflate() with small buffers
 157  */
 158 void test_deflate(compr, comprLen)
 159     Byte *compr;
 160     uLong comprLen;
 161 {
 162     z_stream c_stream; /* compression stream */
 163     int err;
 164     int len = strlen(hello)+1;
 165
 166     c_stream.zalloc = (alloc_func)0;
 167     c_stream.zfree = (free_func)0;
 168     c_stream.opaque = (voidpf)0;
 169
 170     err = deflateInit(&c_stream, Z_DEFAULT_COMPRESSION);
 171     CHECK_ERR(err, "deflateInit");
 172
 173     c_stream.next_in  = (Bytef*)hello;
 174     c_stream.next_out = compr;
 175
 176     while (c_stream.total_in != (uLong)len && c_stream.total_out < comprLen) {
 177         c_stream.avail_in = c_stream.avail_out = 1; /* force small buffers */
 178         err = deflate(&c_stream, Z_NO_FLUSH);
 179         CHECK_ERR(err, "deflate");
 180     }
 181     /* Finish the stream, still forcing small buffers: */
 182     for (;;) {
 183         c_stream.avail_out = 1;
 184         err = deflate(&c_stream, Z_FINISH);
 185         if (err == Z_STREAM_END) break;
 186         CHECK_ERR(err, "deflate");
 187     }
 188
 189     err = deflateEnd(&c_stream);
 190     CHECK_ERR(err, "deflateEnd");
 191 }
 192
 193 /* ===========================================================================
 194  * Test inflate() with small buffers
 195  */
 196 void test_inflate(compr, comprLen, uncompr, uncomprLen)
 197     Byte *compr, *uncompr;
 198     uLong comprLen, uncomprLen;
 199 {
 200     int err;
 201     z_stream d_stream; /* decompression stream */
 202
 203     strcpy((char*)uncompr, "garbage");
 204
 205     d_stream.zalloc = (alloc_func)0;
 206     d_stream.zfree = (free_func)0;
 207     d_stream.opaque = (voidpf)0;
 208
 209     d_stream.next_in  = compr;
 210     d_stream.avail_in = 0;
 211     d_stream.next_out = uncompr;
 212
 213     err = inflateInit(&d_stream);
 214     CHECK_ERR(err, "inflateInit");
 215
 216     while (d_stream.total_out < uncomprLen && d_stream.total_in < comprLen) {
 217         d_stream.avail_in = d_stream.avail_out = 1; /* force small buffers */
 218         err = inflate(&d_stream, Z_NO_FLUSH);
 219         if (err == Z_STREAM_END) break;
 220         CHECK_ERR(err, "inflate");
 221     }
 222
 223     err = inflateEnd(&d_stream);
 224     CHECK_ERR(err, "inflateEnd");
 225
 226     if (strcmp((char*)uncompr, hello)) {
 227         fprintf(stderr, "bad inflate\n");
 228         exit(1);
 229     } else {
 230         printf("inflate(): %s\n", (char *)uncompr);
 231     }
 232 }
 233
 234 /* ===========================================================================
 235  * Test deflate() with large buffers and dynamic change of compression level
 236  */
 237 void test_large_deflate(compr, comprLen, uncompr, uncomprLen)
 238     Byte *compr, *uncompr;
 239     uLong comprLen, uncomprLen;
 240 {
 241     z_stream c_stream; /* compression stream */
 242     int err;
 243
 244     c_stream.zalloc = (alloc_func)0;
 245     c_stream.zfree = (free_func)0;
 246     c_stream.opaque = (voidpf)0;
 247
 248     err = deflateInit(&c_stream, Z_BEST_SPEED);
 249     CHECK_ERR(err, "deflateInit");
 250
 251     c_stream.next_out = compr;
 252     c_stream.avail_out = (uInt)comprLen;
 253
 254     /* At this point, uncompr is still mostly zeroes, so it should compress
 255      * very well:
 256      */
 257     c_stream.next_in = uncompr;
 258     c_stream.avail_in = (uInt)uncomprLen;
 259     err = deflate(&c_stream, Z_NO_FLUSH);
 260     CHECK_ERR(err, "deflate");
 261     if (c_stream.avail_in != 0) {
 262         fprintf(stderr, "deflate not greedy\n");
 263         exit(1);
 264     }
 265
 266     /* Feed in already compressed data and switch to no compression: */
 267     deflateParams(&c_stream, Z_NO_COMPRESSION, Z_DEFAULT_STRATEGY);
 268     c_stream.next_in = compr;
 269     c_stream.avail_in = (uInt)comprLen/2;
 270     err = deflate(&c_stream, Z_NO_FLUSH);
 271     CHECK_ERR(err, "deflate");
 272
 273     /* Switch back to compressing mode: */
 274     deflateParams(&c_stream, Z_BEST_COMPRESSION, Z_FILTERED);
 275     c_stream.next_in = uncompr;
 276     c_stream.avail_in = (uInt)uncomprLen;
 277     err = deflate(&c_stream, Z_NO_FLUSH);
 278     CHECK_ERR(err, "deflate");
 279
 280     err = deflate(&c_stream, Z_FINISH);
 281     if (err != Z_STREAM_END) {
 282         fprintf(stderr, "deflate should report Z_STREAM_END\n");
 283         exit(1);
 284     }
 285     err = deflateEnd(&c_stream);
 286     CHECK_ERR(err, "deflateEnd");
 287 }
 288
 289 /* ===========================================================================
 290  * Test inflate() with large buffers
 291  */
 292 void test_large_inflate(compr, comprLen, uncompr, uncomprLen)
 293     Byte *compr, *uncompr;
 294     uLong comprLen, uncomprLen;
 295 {
 296     int err;
 297     z_stream d_stream; /* decompression stream */
 298
 299     strcpy((char*)uncompr, "garbage");
 300
 301     d_stream.zalloc = (alloc_func)0;
 302     d_stream.zfree = (free_func)0;
 303     d_stream.opaque = (voidpf)0;
 304
 305     d_stream.next_in  = compr;
 306     d_stream.avail_in = (uInt)comprLen;
 307
 308     err = inflateInit(&d_stream);
 309     CHECK_ERR(err, "inflateInit");
 310
 311     for (;;) {
 312         d_stream.next_out = uncompr;            /* discard the output */
 313         d_stream.avail_out = (uInt)uncomprLen;
 314         err = inflate(&d_stream, Z_NO_FLUSH);
 315         if (err == Z_STREAM_END) break;
 316         CHECK_ERR(err, "large inflate");
 317     }
 318
 319     err = inflateEnd(&d_stream);
 320     CHECK_ERR(err, "inflateEnd");
 321
 322     if (d_stream.total_out != 2*uncomprLen + comprLen/2) {
 323         fprintf(stderr, "bad large inflate: %ld\n", d_stream.total_out);
 324         exit(1);
 325     } else {
 326         printf("large_inflate(): OK\n");
 327     }
 328 }
 329
 330 /* ===========================================================================
 331  * Test deflate() with full flush
 332  */
 333 void test_flush(compr, comprLen)
 334     Byte *compr;
 335     uLong *comprLen;
 336 {
 337     z_stream c_stream; /* compression stream */
 338     int err;
 339     int len = strlen(hello)+1;
 340
 341     c_stream.zalloc = (alloc_func)0;
 342     c_stream.zfree = (free_func)0;
 343     c_stream.opaque = (voidpf)0;
 344
 345     err = deflateInit(&c_stream, Z_DEFAULT_COMPRESSION);
 346     CHECK_ERR(err, "deflateInit");
 347
 348     c_stream.next_in  = (Bytef*)hello;
 349     c_stream.next_out = compr;
 350     c_stream.avail_in = 3;
 351     c_stream.avail_out = (uInt)*comprLen;
 352     err = deflate(&c_stream, Z_FULL_FLUSH);
 353     CHECK_ERR(err, "deflate");
 354
 355     compr[3]++; /* force an error in first compressed block */
 356     c_stream.avail_in = len - 3;
 357
 358     err = deflate(&c_stream, Z_FINISH);
 359     if (err != Z_STREAM_END) {
 360         CHECK_ERR(err, "deflate");
 361     }
 362     err = deflateEnd(&c_stream);
 363     CHECK_ERR(err, "deflateEnd");
 364
 365     *comprLen = c_stream.total_out;
 366 }
 367
 368 /* ===========================================================================
 369  * Test inflateSync()
 370  */
 371 void test_sync(compr, comprLen, uncompr, uncomprLen)
 372     Byte *compr, *uncompr;
 373     uLong comprLen, uncomprLen;
 374 {
 375     int err;
 376     z_stream d_stream; /* decompression stream */
 377
 378     strcpy((char*)uncompr, "garbage");
 379
 380     d_stream.zalloc = (alloc_func)0;
 381     d_stream.zfree = (free_func)0;
 382     d_stream.opaque = (voidpf)0;
 383
 384     d_stream.next_in  = compr;
 385     d_stream.avail_in = 2; /* just read the zlib header */
 386
 387     err = inflateInit(&d_stream);
 388     CHECK_ERR(err, "inflateInit");
 389
 390     d_stream.next_out = uncompr;
 391     d_stream.avail_out = (uInt)uncomprLen;
 392
 393     inflate(&d_stream, Z_NO_FLUSH);
 394     CHECK_ERR(err, "inflate");
 395
 396     d_stream.avail_in = (uInt)comprLen-2;   /* read all compressed data */
 397     err = inflateSync(&d_stream);           /* but skip the damaged part */
 398     CHECK_ERR(err, "inflateSync");
 399
 400     err = inflate(&d_stream, Z_FINISH);
 401     if (err != Z_DATA_ERROR) {
 402         fprintf(stderr, "inflate should report DATA_ERROR\n");
 403         /* Because of incorrect adler32 */
 404         exit(1);
 405     }
 406     err = inflateEnd(&d_stream);
 407     CHECK_ERR(err, "inflateEnd");
 408
 409     printf("after inflateSync(): hel%s\n", (char *)uncompr);
 410 }
 411
 412 /* ===========================================================================
 413  * Test deflate() with preset dictionary
 414  */
 415 void test_dict_deflate(compr, comprLen)
 416     Byte *compr;
 417     uLong comprLen;
 418 {
 419     z_stream c_stream; /* compression stream */
 420     int err;
 421
 422     c_stream.zalloc = (alloc_func)0;
 423     c_stream.zfree = (free_func)0;
 424     c_stream.opaque = (voidpf)0;
 425
 426     err = deflateInit(&c_stream, Z_BEST_COMPRESSION);
 427     CHECK_ERR(err, "deflateInit");
 428
 429     err = deflateSetDictionary(&c_stream,
 430                                (const Bytef*)dictionary, sizeof(dictionary));
 431     CHECK_ERR(err, "deflateSetDictionary");
 432
 433     dictId = c_stream.adler;
 434     c_stream.next_out = compr;
 435     c_stream.avail_out = (uInt)comprLen;
 436
 437     c_stream.next_in = (Bytef*)hello;
 438     c_stream.avail_in = (uInt)strlen(hello)+1;
 439
 440     err = deflate(&c_stream, Z_FINISH);
 441     if (err != Z_STREAM_END) {
 442         fprintf(stderr, "deflate should report Z_STREAM_END\n");
 443         exit(1);
 444     }
 445     err = deflateEnd(&c_stream);
 446     CHECK_ERR(err, "deflateEnd");
 447 }
 448
 449 /* ===========================================================================
 450  * Test inflate() with a preset dictionary
 451  */
 452 void test_dict_inflate(compr, comprLen, uncompr, uncomprLen)
 453     Byte *compr, *uncompr;
 454     uLong comprLen, uncomprLen;
 455 {
 456     int err;
 457     z_stream d_stream; /* decompression stream */
 458
 459     strcpy((char*)uncompr, "garbage");
 460
 461     d_stream.zalloc = (alloc_func)0;
 462     d_stream.zfree = (free_func)0;
 463     d_stream.opaque = (voidpf)0;
 464
 465     d_stream.next_in  = compr;
 466     d_stream.avail_in = (uInt)comprLen;
 467
 468     err = inflateInit(&d_stream);
 469     CHECK_ERR(err, "inflateInit");
 470
 471     d_stream.next_out = uncompr;
 472     d_stream.avail_out = (uInt)uncomprLen;
 473
 474     for (;;) {
 475         err = inflate(&d_stream, Z_NO_FLUSH);
 476         if (err == Z_STREAM_END) break;
 477         if (err == Z_NEED_DICT) {
 478             if (d_stream.adler != dictId) {
 479                 fprintf(stderr, "unexpected dictionary");
 480                 exit(1);
 481             }
 482             err = inflateSetDictionary(&d_stream, (const Bytef*)dictionary,
 483                                        sizeof(dictionary));
 484         }
 485         CHECK_ERR(err, "inflate with dict");
 486     }
 487
 488     err = inflateEnd(&d_stream);
 489     CHECK_ERR(err, "inflateEnd");
 490
 491     if (strcmp((char*)uncompr, hello)) {
 492         fprintf(stderr, "bad inflate with dict\n");
 493         exit(1);
 494     } else {
 495         printf("inflate with dictionary: %s\n", (char *)uncompr);
 496     }
 497 }
 498
 499 /* ===========================================================================
 500  * Usage:  example [output.gz  [input.gz]]
 501  */
 502
 503 int main(argc, argv)
 504     int argc;
 505     char *argv[];
 506 {
 507     Byte *compr, *uncompr;
 508     uLong comprLen = 10000*sizeof(int); /* don't overflow on MSDOS */
 509     uLong uncomprLen = comprLen;
 510     static const char* myVersion = ZLIB_VERSION;
 511
 512     if (zlibVersion()[0] != myVersion[0]) {
 513         fprintf(stderr, "incompatible zlib version\n");
 514         exit(1);
 515
 516     } else if (strcmp(zlibVersion(), ZLIB_VERSION) != 0) {
 517         fprintf(stderr, "warning: different zlib version\n");
 518     }
 519
 520     compr    = (Byte*)calloc((uInt)comprLen, 1);
 521     uncompr  = (Byte*)calloc((uInt)uncomprLen, 1);
 522     /* compr and uncompr are cleared to avoid reading uninitialized
 523      * data and to ensure that uncompr compresses well.
 524      */
 525     if (compr == Z_NULL || uncompr == Z_NULL) {
 526         printf("out of memory\n");
 527         exit(1);
 528     }
 529     test_compress(compr, comprLen, uncompr, uncomprLen);
 530
 531     test_gzio((argc > 1 ? argv[1] : "foo.gz"),
 532               (argc > 2 ? argv[2] : "foo.gz"),
 533               uncompr, (int)uncomprLen);
 534
 535     test_deflate(compr, comprLen);
 536     test_inflate(compr, comprLen, uncompr, uncomprLen);
 537
 538     test_large_deflate(compr, comprLen, uncompr, uncomprLen);
 539     test_large_inflate(compr, comprLen, uncompr, uncomprLen);
 540
 541     test_flush(compr, &comprLen);
 542     test_sync(compr, comprLen, uncompr, uncomprLen);
 543     comprLen = uncomprLen;
 544
 545     test_dict_deflate(compr, comprLen);
 546     test_dict_inflate(compr, comprLen, uncompr, uncomprLen);
 547
 548     exit(0);
 549     return 0; /* to avoid warning */
 550 }