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