1 /* example.c -- usage example of the zlib compression library
2 * Copyright (C) 1995-2006, 2011 Jean-loup Gailly.
3 * For conditions of distribution and use, see copyright notice in zlib.h
4 */
5
6 /* @(#) $Id$ */
7
8 #include "zlib.h"
9 #include <stdio.h>
10
11 #ifdef STDC
12 # include <string.h>
13 # include <stdlib.h>
14 #endif
15
16 #if defined(VMS) || defined(RISCOS)
17 # define TESTFILE "foo-gz"
18 #else
19 # define TESTFILE "foo.gz"
20 #endif
21
22 #define CHECK_ERR(err, msg) { \
23 if (err != Z_OK) { \
24 fprintf(stderr, "%s error: %d\n", msg, err); \
25 exit(1); \
26 } \
27 }
28
29 z_const char hello[] = "hello, hello!";
30 /* "hello world" would be more standard, but the repeated "hello"
31 * stresses the compression code better, sorry...
32 */
33
34 const char dictionary[] = "hello";
35 uLong dictId; /* Adler32 value of the dictionary */
36
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 #ifdef Z_SOLO
54
55 void *myalloc OF((void *, unsigned, unsigned));
56 void myfree OF((void *, void *));
57
myalloc(q,n,m)58 void *myalloc(q, n, m)
59 void *q;
60 unsigned n, m;
61 {
62 q = Z_NULL;
63 return calloc(n, m);
64 }
65
myfree(void * q,void * p)66 void myfree(void *q, void *p)
67 {
68 q = Z_NULL;
69 free(p);
70 }
71
72 static alloc_func zalloc = myalloc;
73 static free_func zfree = myfree;
74
75 #else /* !Z_SOLO */
76
77 static alloc_func zalloc = (alloc_func)0;
78 static free_func zfree = (free_func)0;
79
80 void test_compress OF((Byte *compr, uLong comprLen,
81 Byte *uncompr, uLong uncomprLen));
82 void test_gzio OF((const char *fname,
83 Byte *uncompr, uLong uncomprLen));
84
85 /* ===========================================================================
86 * Test compress() and uncompress()
87 */
test_compress(compr,comprLen,uncompr,uncomprLen)88 void test_compress(compr, comprLen, uncompr, uncomprLen)
89 Byte *compr, *uncompr;
90 uLong comprLen, uncomprLen;
91 {
92 int err;
93 uLong len = (uLong)strlen(hello)+1;
94
95 err = compress(compr, &comprLen, (const Bytef*)hello, len);
96 CHECK_ERR(err, "compress");
97
98 strcpy((char*)uncompr, "garbage");
99
100 err = uncompress(uncompr, &uncomprLen, compr, comprLen);
101 CHECK_ERR(err, "uncompress");
102
103 if (strcmp((char*)uncompr, hello)) {
104 fprintf(stderr, "bad uncompress\n");
105 exit(1);
106 } else {
107 printf("uncompress(): %s\n", (char *)uncompr);
108 }
109 }
110
111 /* ===========================================================================
112 * Test read/write of .gz files
113 */
test_gzio(fname,uncompr,uncomprLen)114 void test_gzio(fname, uncompr, uncomprLen)
115 const char *fname; /* compressed file name */
116 Byte *uncompr;
117 uLong uncomprLen;
118 {
119 #ifdef NO_GZCOMPRESS
120 fprintf(stderr, "NO_GZCOMPRESS -- gz* functions cannot compress\n");
121 #else
122 int err;
123 int len = (int)strlen(hello)+1;
124 gzFile file;
125 z_off_t pos;
126
127 file = gzopen(fname, "wb");
128 if (file == NULL) {
129 fprintf(stderr, "gzopen error\n");
130 exit(1);
131 }
132 gzputc(file, 'h');
133 if (gzputs(file, "ello") != 4) {
134 fprintf(stderr, "gzputs err: %s\n", gzerror(file, &err));
135 exit(1);
136 }
137 if (gzprintf(file, ", %s!", "hello") != 8) {
138 fprintf(stderr, "gzprintf err: %s\n", gzerror(file, &err));
139 exit(1);
140 }
141 gzseek(file, 1L, SEEK_CUR); /* add one zero byte */
142 gzclose(file);
143
144 file = gzopen(fname, "rb");
145 if (file == NULL) {
146 fprintf(stderr, "gzopen error\n");
147 exit(1);
148 }
149 strcpy((char*)uncompr, "garbage");
150
151 if (gzread(file, uncompr, (unsigned)uncomprLen) != len) {
152 fprintf(stderr, "gzread err: %s\n", gzerror(file, &err));
153 exit(1);
154 }
155 if (strcmp((char*)uncompr, hello)) {
156 fprintf(stderr, "bad gzread: %s\n", (char*)uncompr);
157 exit(1);
158 } else {
159 printf("gzread(): %s\n", (char*)uncompr);
160 }
161
162 pos = gzseek(file, -8L, SEEK_CUR);
163 if (pos != 6 || gztell(file) != pos) {
164 fprintf(stderr, "gzseek error, pos=%ld, gztell=%ld\n",
165 (long)pos, (long)gztell(file));
166 exit(1);
167 }
168
169 if (gzgetc(file) != ' ') {
170 fprintf(stderr, "gzgetc error\n");
171 exit(1);
172 }
173
174 if (gzungetc(' ', file) != ' ') {
175 fprintf(stderr, "gzungetc error\n");
176 exit(1);
177 }
178
179 gzgets(file, (char*)uncompr, (int)uncomprLen);
180 if (strlen((char*)uncompr) != 7) { /* " hello!" */
181 fprintf(stderr, "gzgets err after gzseek: %s\n", gzerror(file, &err));
182 exit(1);
183 }
184 if (strcmp((char*)uncompr, hello + 6)) {
185 fprintf(stderr, "bad gzgets after gzseek\n");
186 exit(1);
187 } else {
188 printf("gzgets() after gzseek: %s\n", (char*)uncompr);
189 }
190
191 gzclose(file);
192 #endif
193 }
194
195 #endif /* Z_SOLO */
196
197 /* ===========================================================================
198 * Test deflate() with small buffers
199 */
test_deflate(compr,comprLen)200 void test_deflate(compr, comprLen)
201 Byte *compr;
202 uLong comprLen;
203 {
204 z_stream c_stream; /* compression stream */
205 int err;
206 uLong len = (uLong)strlen(hello)+1;
207
208 c_stream.zalloc = zalloc;
209 c_stream.zfree = zfree;
210 c_stream.opaque = (voidpf)0;
211
212 err = deflateInit(&c_stream, Z_DEFAULT_COMPRESSION);
213 CHECK_ERR(err, "deflateInit");
214
215 c_stream.next_in = (z_const unsigned char *)hello;
216 c_stream.next_out = compr;
217
218 while (c_stream.total_in != len && c_stream.total_out < comprLen) {
219 c_stream.avail_in = c_stream.avail_out = 1; /* force small buffers */
220 err = deflate(&c_stream, Z_NO_FLUSH);
221 CHECK_ERR(err, "deflate");
222 }
223 /* Finish the stream, still forcing small buffers: */
224 for (;;) {
225 c_stream.avail_out = 1;
226 err = deflate(&c_stream, Z_FINISH);
227 if (err == Z_STREAM_END) break;
228 CHECK_ERR(err, "deflate");
229 }
230
231 err = deflateEnd(&c_stream);
232 CHECK_ERR(err, "deflateEnd");
233 }
234
235 /* ===========================================================================
236 * Test inflate() with small buffers
237 */
test_inflate(compr,comprLen,uncompr,uncomprLen)238 void test_inflate(compr, comprLen, uncompr, uncomprLen)
239 Byte *compr, *uncompr;
240 uLong comprLen, uncomprLen;
241 {
242 int err;
243 z_stream d_stream; /* decompression stream */
244
245 strcpy((char*)uncompr, "garbage");
246
247 d_stream.zalloc = zalloc;
248 d_stream.zfree = zfree;
249 d_stream.opaque = (voidpf)0;
250
251 d_stream.next_in = compr;
252 d_stream.avail_in = 0;
253 d_stream.next_out = uncompr;
254
255 err = inflateInit(&d_stream);
256 CHECK_ERR(err, "inflateInit");
257
258 while (d_stream.total_out < uncomprLen && d_stream.total_in < comprLen) {
259 d_stream.avail_in = d_stream.avail_out = 1; /* force small buffers */
260 err = inflate(&d_stream, Z_NO_FLUSH);
261 if (err == Z_STREAM_END) break;
262 CHECK_ERR(err, "inflate");
263 }
264
265 err = inflateEnd(&d_stream);
266 CHECK_ERR(err, "inflateEnd");
267
268 if (strcmp((char*)uncompr, hello)) {
269 fprintf(stderr, "bad inflate\n");
270 exit(1);
271 } else {
272 printf("inflate(): %s\n", (char *)uncompr);
273 }
274 }
275
276 /* ===========================================================================
277 * Test deflate() with large buffers and dynamic change of compression level
278 */
test_large_deflate(compr,comprLen,uncompr,uncomprLen)279 void test_large_deflate(compr, comprLen, uncompr, uncomprLen)
280 Byte *compr, *uncompr;
281 uLong comprLen, uncomprLen;
282 {
283 z_stream c_stream; /* compression stream */
284 int err;
285
286 c_stream.zalloc = zalloc;
287 c_stream.zfree = zfree;
288 c_stream.opaque = (voidpf)0;
289
290 err = deflateInit(&c_stream, Z_BEST_SPEED);
291 CHECK_ERR(err, "deflateInit");
292
293 c_stream.next_out = compr;
294 c_stream.avail_out = (uInt)comprLen;
295
296 /* At this point, uncompr is still mostly zeroes, so it should compress
297 * very well:
298 */
299 c_stream.next_in = uncompr;
300 c_stream.avail_in = (uInt)uncomprLen;
301 err = deflate(&c_stream, Z_NO_FLUSH);
302 CHECK_ERR(err, "deflate");
303 if (c_stream.avail_in != 0) {
304 fprintf(stderr, "deflate not greedy\n");
305 exit(1);
306 }
307
308 /* Feed in already compressed data and switch to no compression: */
309 deflateParams(&c_stream, Z_NO_COMPRESSION, Z_DEFAULT_STRATEGY);
310 c_stream.next_in = compr;
311 c_stream.avail_in = (uInt)comprLen/2;
312 err = deflate(&c_stream, Z_NO_FLUSH);
313 CHECK_ERR(err, "deflate");
314
315 /* Switch back to compressing mode: */
316 deflateParams(&c_stream, Z_BEST_COMPRESSION, Z_FILTERED);
317 c_stream.next_in = uncompr;
318 c_stream.avail_in = (uInt)uncomprLen;
319 err = deflate(&c_stream, Z_NO_FLUSH);
320 CHECK_ERR(err, "deflate");
321
322 err = deflate(&c_stream, Z_FINISH);
323 if (err != Z_STREAM_END) {
324 fprintf(stderr, "deflate should report Z_STREAM_END\n");
325 exit(1);
326 }
327 err = deflateEnd(&c_stream);
328 CHECK_ERR(err, "deflateEnd");
329 }
330
331 /* ===========================================================================
332 * Test inflate() with large buffers
333 */
test_large_inflate(compr,comprLen,uncompr,uncomprLen)334 void test_large_inflate(compr, comprLen, uncompr, uncomprLen)
335 Byte *compr, *uncompr;
336 uLong comprLen, uncomprLen;
337 {
338 int err;
339 z_stream d_stream; /* decompression stream */
340
341 strcpy((char*)uncompr, "garbage");
342
343 d_stream.zalloc = zalloc;
344 d_stream.zfree = zfree;
345 d_stream.opaque = (voidpf)0;
346
347 d_stream.next_in = compr;
348 d_stream.avail_in = (uInt)comprLen;
349
350 err = inflateInit(&d_stream);
351 CHECK_ERR(err, "inflateInit");
352
353 for (;;) {
354 d_stream.next_out = uncompr; /* discard the output */
355 d_stream.avail_out = (uInt)uncomprLen;
356 err = inflate(&d_stream, Z_NO_FLUSH);
357 if (err == Z_STREAM_END) break;
358 CHECK_ERR(err, "large inflate");
359 }
360
361 err = inflateEnd(&d_stream);
362 CHECK_ERR(err, "inflateEnd");
363
364 if (d_stream.total_out != 2*uncomprLen + comprLen/2) {
365 fprintf(stderr, "bad large inflate: %ld\n", d_stream.total_out);
366 exit(1);
367 } else {
368 printf("large_inflate(): OK\n");
369 }
370 }
371
372 /* ===========================================================================
373 * Test deflate() with full flush
374 */
test_flush(compr,comprLen)375 void test_flush(compr, comprLen)
376 Byte *compr;
377 uLong *comprLen;
378 {
379 z_stream c_stream; /* compression stream */
380 int err;
381 uInt len = (uInt)strlen(hello)+1;
382
383 c_stream.zalloc = zalloc;
384 c_stream.zfree = zfree;
385 c_stream.opaque = (voidpf)0;
386
387 err = deflateInit(&c_stream, Z_DEFAULT_COMPRESSION);
388 CHECK_ERR(err, "deflateInit");
389
390 c_stream.next_in = (z_const unsigned char *)hello;
391 c_stream.next_out = compr;
392 c_stream.avail_in = 3;
393 c_stream.avail_out = (uInt)*comprLen;
394 err = deflate(&c_stream, Z_FULL_FLUSH);
395 CHECK_ERR(err, "deflate");
396
397 compr[3]++; /* force an error in first compressed block */
398 c_stream.avail_in = len - 3;
399
400 err = deflate(&c_stream, Z_FINISH);
401 if (err != Z_STREAM_END) {
402 CHECK_ERR(err, "deflate");
403 }
404 err = deflateEnd(&c_stream);
405 CHECK_ERR(err, "deflateEnd");
406
407 *comprLen = c_stream.total_out;
408 }
409
410 /* ===========================================================================
411 * Test inflateSync()
412 */
test_sync(compr,comprLen,uncompr,uncomprLen)413 void test_sync(compr, comprLen, uncompr, uncomprLen)
414 Byte *compr, *uncompr;
415 uLong comprLen, uncomprLen;
416 {
417 int err;
418 z_stream d_stream; /* decompression stream */
419
420 strcpy((char*)uncompr, "garbage");
421
422 d_stream.zalloc = zalloc;
423 d_stream.zfree = zfree;
424 d_stream.opaque = (voidpf)0;
425
426 d_stream.next_in = compr;
427 d_stream.avail_in = 2; /* just read the zlib header */
428
429 err = inflateInit(&d_stream);
430 CHECK_ERR(err, "inflateInit");
431
432 d_stream.next_out = uncompr;
433 d_stream.avail_out = (uInt)uncomprLen;
434
435 inflate(&d_stream, Z_NO_FLUSH);
436 CHECK_ERR(err, "inflate");
437
438 d_stream.avail_in = (uInt)comprLen-2; /* read all compressed data */
439 err = inflateSync(&d_stream); /* but skip the damaged part */
440 CHECK_ERR(err, "inflateSync");
441
442 err = inflate(&d_stream, Z_FINISH);
443 if (err != Z_DATA_ERROR) {
444 fprintf(stderr, "inflate should report DATA_ERROR\n");
445 /* Because of incorrect adler32 */
446 exit(1);
447 }
448 err = inflateEnd(&d_stream);
449 CHECK_ERR(err, "inflateEnd");
450
451 printf("after inflateSync(): hel%s\n", (char *)uncompr);
452 }
453
454 /* ===========================================================================
455 * Test deflate() with preset dictionary
456 */
test_dict_deflate(compr,comprLen)457 void test_dict_deflate(compr, comprLen)
458 Byte *compr;
459 uLong comprLen;
460 {
461 z_stream c_stream; /* compression stream */
462 int err;
463
464 c_stream.zalloc = zalloc;
465 c_stream.zfree = zfree;
466 c_stream.opaque = (voidpf)0;
467
468 err = deflateInit(&c_stream, Z_BEST_COMPRESSION);
469 CHECK_ERR(err, "deflateInit");
470
471 err = deflateSetDictionary(&c_stream,
472 (const Bytef*)dictionary, (int)sizeof(dictionary));
473 CHECK_ERR(err, "deflateSetDictionary");
474
475 dictId = c_stream.adler;
476 c_stream.next_out = compr;
477 c_stream.avail_out = (uInt)comprLen;
478
479 c_stream.next_in = (z_const unsigned char *)hello;
480 c_stream.avail_in = (uInt)strlen(hello)+1;
481
482 err = deflate(&c_stream, Z_FINISH);
483 if (err != Z_STREAM_END) {
484 fprintf(stderr, "deflate should report Z_STREAM_END\n");
485 exit(1);
486 }
487 err = deflateEnd(&c_stream);
488 CHECK_ERR(err, "deflateEnd");
489 }
490
491 /* ===========================================================================
492 * Test inflate() with a preset dictionary
493 */
test_dict_inflate(compr,comprLen,uncompr,uncomprLen)494 void test_dict_inflate(compr, comprLen, uncompr, uncomprLen)
495 Byte *compr, *uncompr;
496 uLong comprLen, uncomprLen;
497 {
498 int err;
499 z_stream d_stream; /* decompression stream */
500
501 strcpy((char*)uncompr, "garbage");
502
503 d_stream.zalloc = zalloc;
504 d_stream.zfree = zfree;
505 d_stream.opaque = (voidpf)0;
506
507 d_stream.next_in = compr;
508 d_stream.avail_in = (uInt)comprLen;
509
510 err = inflateInit(&d_stream);
511 CHECK_ERR(err, "inflateInit");
512
513 d_stream.next_out = uncompr;
514 d_stream.avail_out = (uInt)uncomprLen;
515
516 for (;;) {
517 err = inflate(&d_stream, Z_NO_FLUSH);
518 if (err == Z_STREAM_END) break;
519 if (err == Z_NEED_DICT) {
520 if (d_stream.adler != dictId) {
521 fprintf(stderr, "unexpected dictionary");
522 exit(1);
523 }
524 err = inflateSetDictionary(&d_stream, (const Bytef*)dictionary,
525 (int)sizeof(dictionary));
526 }
527 CHECK_ERR(err, "inflate with dict");
528 }
529
530 err = inflateEnd(&d_stream);
531 CHECK_ERR(err, "inflateEnd");
532
533 if (strcmp((char*)uncompr, hello)) {
534 fprintf(stderr, "bad inflate with dict\n");
535 exit(1);
536 } else {
537 printf("inflate with dictionary: %s\n", (char *)uncompr);
538 }
539 }
540
541 /* ===========================================================================
542 * Usage: example [output.gz [input.gz]]
543 */
544
main(argc,argv)545 int main(argc, argv)
546 int argc;
547 char *argv[];
548 {
549 Byte *compr, *uncompr;
550 uLong comprLen = 10000*sizeof(int); /* don't overflow on MSDOS */
551 uLong uncomprLen = comprLen;
552 static const char* myVersion = ZLIB_VERSION;
553
554 if (zlibVersion()[0] != myVersion[0]) {
555 fprintf(stderr, "incompatible zlib version\n");
556 exit(1);
557
558 } else if (strcmp(zlibVersion(), ZLIB_VERSION) != 0) {
559 fprintf(stderr, "warning: different zlib version\n");
560 }
561
562 printf("zlib version %s = 0x%04x, compile flags = 0x%lx\n",
563 ZLIB_VERSION, ZLIB_VERNUM, zlibCompileFlags());
564
565 compr = (Byte*)calloc((uInt)comprLen, 1);
566 uncompr = (Byte*)calloc((uInt)uncomprLen, 1);
567 /* compr and uncompr are cleared to avoid reading uninitialized
568 * data and to ensure that uncompr compresses well.
569 */
570 if (compr == Z_NULL || uncompr == Z_NULL) {
571 printf("out of memory\n");
572 exit(1);
573 }
574
575 #ifdef Z_SOLO
576 argc = strlen(argv[0]);
577 #else
578 test_compress(compr, comprLen, uncompr, uncomprLen);
579
580 test_gzio((argc > 1 ? argv[1] : TESTFILE),
581 uncompr, uncomprLen);
582 #endif
583
584 test_deflate(compr, comprLen);
585 test_inflate(compr, comprLen, uncompr, uncomprLen);
586
587 test_large_deflate(compr, comprLen, uncompr, uncomprLen);
588 test_large_inflate(compr, comprLen, uncompr, uncomprLen);
589
590 test_flush(compr, &comprLen);
591 test_sync(compr, comprLen, uncompr, uncomprLen);
592 comprLen = uncomprLen;
593
594 test_dict_deflate(compr, comprLen);
595 test_dict_inflate(compr, comprLen, uncompr, uncomprLen);
596
597 free(compr);
598 free(uncompr);
599
600 return 0;
601 }
602