1 /* example.c -- usage example of the zlib compression library
2 * Copyright (C) 1995-2006, 2011, 2016 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 static 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 static const char dictionary[] = "hello";
35 static uLong dictId; /* Adler32 value of the dictionary */
36
37 #ifdef Z_SOLO
38
myalloc(void *q, unsigned n, unsigned m)39 static void *myalloc(void *q, unsigned n, unsigned m)
40 {
41 (void)q;
42 return calloc(n, m);
43 }
44
myfree(void *q, void *p)45 static void myfree(void *q, void *p)
46 {
47 (void)q;
48 free(p);
49 }
50
51 static alloc_func zalloc = myalloc;
52 static free_func zfree = myfree;
53
54 #else /* !Z_SOLO */
55
56 static alloc_func zalloc = (alloc_func)0;
57 static free_func zfree = (free_func)0;
58
59 /* ===========================================================================
60 * Test compress() and uncompress()
61 */
test_compress(Byte *compr, uLong comprLen, Byte *uncompr, uLong uncomprLen)62 static void test_compress(Byte *compr, uLong comprLen, Byte *uncompr,
63 uLong 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 */
test_gzio(const char *fname, Byte *uncompr, uLong uncomprLen)87 static void test_gzio(const char *fname, Byte *uncompr, uLong uncomprLen)
88 {
89 #ifdef NO_GZCOMPRESS
90 fprintf(stderr, "NO_GZCOMPRESS -- gz* functions cannot compress\n");
91 #else
92 int err;
93 int len = (int)strlen(hello)+1;
94 gzFile file;
95 z_off_t pos;
96
97 file = gzopen(fname, "wb");
98 if (file == NULL) {
99 fprintf(stderr, "gzopen error\n");
100 exit(1);
101 }
102 gzputc(file, 'h');
103 if (gzputs(file, "ello") != 4) {
104 fprintf(stderr, "gzputs err: %s\n", gzerror(file, &err));
105 exit(1);
106 }
107 if (gzprintf(file, ", %s!", "hello") != 8) {
108 fprintf(stderr, "gzprintf err: %s\n", gzerror(file, &err));
109 exit(1);
110 }
111 gzseek(file, 1L, SEEK_CUR); /* add one zero byte */
112 gzclose(file);
113
114 file = gzopen(fname, "rb");
115 if (file == NULL) {
116 fprintf(stderr, "gzopen error\n");
117 exit(1);
118 }
119 strcpy((char*)uncompr, "garbage");
120
121 if (gzread(file, uncompr, (unsigned)uncomprLen) != len) {
122 fprintf(stderr, "gzread err: %s\n", gzerror(file, &err));
123 exit(1);
124 }
125 if (strcmp((char*)uncompr, hello)) {
126 fprintf(stderr, "bad gzread: %s\n", (char*)uncompr);
127 exit(1);
128 } else {
129 printf("gzread(): %s\n", (char*)uncompr);
130 }
131
132 pos = gzseek(file, -8L, SEEK_CUR);
133 if (pos != 6 || gztell(file) != pos) {
134 fprintf(stderr, "gzseek error, pos=%ld, gztell=%ld\n",
135 (long)pos, (long)gztell(file));
136 exit(1);
137 }
138
139 if (gzgetc(file) != ' ') {
140 fprintf(stderr, "gzgetc error\n");
141 exit(1);
142 }
143
144 if (gzungetc(' ', file) != ' ') {
145 fprintf(stderr, "gzungetc error\n");
146 exit(1);
147 }
148
149 gzgets(file, (char*)uncompr, (int)uncomprLen);
150 if (strlen((char*)uncompr) != 7) { /* " hello!" */
151 fprintf(stderr, "gzgets err after gzseek: %s\n", gzerror(file, &err));
152 exit(1);
153 }
154 if (strcmp((char*)uncompr, hello + 6)) {
155 fprintf(stderr, "bad gzgets after gzseek\n");
156 exit(1);
157 } else {
158 printf("gzgets() after gzseek: %s\n", (char*)uncompr);
159 }
160
161 gzclose(file);
162 #endif
163 }
164
165 #endif /* Z_SOLO */
166
167 /* ===========================================================================
168 * Test deflate() with small buffers
169 */
test_deflate(Byte *compr, uLong comprLen)170 static void test_deflate(Byte *compr, uLong comprLen)
171 {
172 z_stream c_stream; /* compression stream */
173 int err;
174 uLong len = (uLong)strlen(hello)+1;
175
176 c_stream.zalloc = zalloc;
177 c_stream.zfree = zfree;
178 c_stream.opaque = (voidpf)0;
179
180 err = deflateInit(&c_stream, Z_DEFAULT_COMPRESSION);
181 CHECK_ERR(err, "deflateInit");
182
183 c_stream.next_in = (z_const unsigned char *)hello;
184 c_stream.next_out = compr;
185
186 while (c_stream.total_in != len && c_stream.total_out < comprLen) {
187 c_stream.avail_in = c_stream.avail_out = 1; /* force small buffers */
188 err = deflate(&c_stream, Z_NO_FLUSH);
189 CHECK_ERR(err, "deflate");
190 }
191 /* Finish the stream, still forcing small buffers: */
192 for (;;) {
193 c_stream.avail_out = 1;
194 err = deflate(&c_stream, Z_FINISH);
195 if (err == Z_STREAM_END)
196 {
197 break;
198 }
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 */
test_inflate(Byte *compr, uLong comprLen, Byte *uncompr, uLong uncomprLen)209 static void test_inflate(Byte *compr, uLong comprLen, Byte *uncompr,
210 uLong uncomprLen)
211 {
212 int err;
213 z_stream d_stream; /* decompression stream */
214
215 strcpy((char*)uncompr, "garbage");
216
217 d_stream.zalloc = zalloc;
218 d_stream.zfree = zfree;
219 d_stream.opaque = (voidpf)0;
220
221 d_stream.next_in = compr;
222 d_stream.avail_in = 0;
223 d_stream.next_out = uncompr;
224
225 err = inflateInit(&d_stream);
226 CHECK_ERR(err, "inflateInit");
227
228 while (d_stream.total_out < uncomprLen && d_stream.total_in < comprLen) {
229 d_stream.avail_in = d_stream.avail_out = 1; /* force small buffers */
230 err = inflate(&d_stream, Z_NO_FLUSH);
231 if (err == Z_STREAM_END)
232 {
233 break;
234 }
235 CHECK_ERR(err, "inflate");
236 }
237
238 err = inflateEnd(&d_stream);
239 CHECK_ERR(err, "inflateEnd");
240
241 if (strcmp((char*)uncompr, hello)) {
242 fprintf(stderr, "bad inflate\n");
243 exit(1);
244 } else {
245 printf("inflate(): %s\n", (char *)uncompr);
246 }
247 }
248
249 /* ===========================================================================
250 * Test deflate() with large buffers and dynamic change of compression level
251 */
test_large_deflate(Byte *compr, uLong comprLen, Byte *uncompr, uLong uncomprLen)252 static void test_large_deflate(Byte *compr, uLong comprLen, Byte *uncompr,
253 uLong uncomprLen)
254 {
255 z_stream c_stream; /* compression stream */
256 int err;
257
258 c_stream.zalloc = zalloc;
259 c_stream.zfree = zfree;
260 c_stream.opaque = (voidpf)0;
261
262 err = deflateInit(&c_stream, Z_BEST_SPEED);
263 CHECK_ERR(err, "deflateInit");
264
265 c_stream.next_out = compr;
266 c_stream.avail_out = (uInt)comprLen;
267
268 /* At this point, uncompr is still mostly zeroes, so it should compress
269 * very well:
270 */
271 c_stream.next_in = uncompr;
272 c_stream.avail_in = (uInt)uncomprLen;
273 err = deflate(&c_stream, Z_NO_FLUSH);
274 CHECK_ERR(err, "deflate");
275 if (c_stream.avail_in != 0) {
276 fprintf(stderr, "deflate not greedy\n");
277 exit(1);
278 }
279
280 /* Feed in already compressed data and switch to no compression: */
281 deflateParams(&c_stream, Z_NO_COMPRESSION, Z_DEFAULT_STRATEGY);
282 c_stream.next_in = compr;
283 c_stream.avail_in = (uInt)uncomprLen/2;
284 err = deflate(&c_stream, Z_NO_FLUSH);
285 CHECK_ERR(err, "deflate");
286
287 /* Switch back to compressing mode: */
288 deflateParams(&c_stream, Z_BEST_COMPRESSION, Z_FILTERED);
289 c_stream.next_in = uncompr;
290 c_stream.avail_in = (uInt)uncomprLen;
291 err = deflate(&c_stream, Z_NO_FLUSH);
292 CHECK_ERR(err, "deflate");
293
294 err = deflate(&c_stream, Z_FINISH);
295 if (err != Z_STREAM_END) {
296 fprintf(stderr, "deflate should report Z_STREAM_END\n");
297 exit(1);
298 }
299 err = deflateEnd(&c_stream);
300 CHECK_ERR(err, "deflateEnd");
301 }
302
303 /* ===========================================================================
304 * Test inflate() with large buffers
305 */
test_large_inflate(Byte *compr, uLong comprLen, Byte *uncompr, uLong uncomprLen)306 static void test_large_inflate(Byte *compr, uLong comprLen, Byte *uncompr,
307 uLong uncomprLen)
308 {
309 int err;
310 z_stream d_stream; /* decompression stream */
311
312 strcpy((char*)uncompr, "garbage");
313
314 d_stream.zalloc = zalloc;
315 d_stream.zfree = zfree;
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)
329 {
330 break;
331 }
332 CHECK_ERR(err, "large inflate");
333 }
334
335 err = inflateEnd(&d_stream);
336 CHECK_ERR(err, "inflateEnd");
337
338 if (d_stream.total_out != 2*uncomprLen + uncomprLen/2) {
339 fprintf(stderr, "bad large inflate: %ld\n", d_stream.total_out);
340 exit(1);
341 } else {
342 printf("large_inflate(): OK\n");
343 }
344 }
345
346 /* ===========================================================================
347 * Test deflate() with full flush
348 */
test_flush(Byte *compr, uLong *comprLen)349 static void test_flush(Byte *compr, uLong *comprLen)
350 {
351 z_stream c_stream; /* compression stream */
352 int err;
353 uInt len = (uInt)strlen(hello)+1;
354
355 c_stream.zalloc = zalloc;
356 c_stream.zfree = zfree;
357 c_stream.opaque = (voidpf)0;
358
359 err = deflateInit(&c_stream, Z_DEFAULT_COMPRESSION);
360 CHECK_ERR(err, "deflateInit");
361
362 c_stream.next_in = (z_const unsigned char *)hello;
363 c_stream.next_out = compr;
364 c_stream.avail_in = 3;
365 c_stream.avail_out = (uInt)*comprLen;
366 err = deflate(&c_stream, Z_FULL_FLUSH);
367 CHECK_ERR(err, "deflate");
368
369 compr[3]++; /* force an error in first compressed block */
370 c_stream.avail_in = len - 3;
371
372 err = deflate(&c_stream, Z_FINISH);
373 if (err != Z_STREAM_END) {
374 CHECK_ERR(err, "deflate");
375 }
376 err = deflateEnd(&c_stream);
377 CHECK_ERR(err, "deflateEnd");
378
379 *comprLen = c_stream.total_out;
380 }
381
382 /* ===========================================================================
383 * Test inflateSync()
384 */
test_sync(Byte *compr, uLong comprLen, Byte *uncompr, uLong uncomprLen)385 static void test_sync(Byte *compr, uLong comprLen, Byte *uncompr,
386 uLong uncomprLen)
387 {
388 int err;
389 z_stream d_stream; /* decompression stream */
390
391 strcpy((char*)uncompr, "garbage");
392
393 d_stream.zalloc = zalloc;
394 d_stream.zfree = zfree;
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 err = 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_STREAM_END) {
415 fprintf(stderr, "inflate should report Z_STREAM_END\n");
416 exit(1);
417 }
418 err = inflateEnd(&d_stream);
419 CHECK_ERR(err, "inflateEnd");
420
421 printf("after inflateSync(): hel%s\n", (char *)uncompr);
422 }
423
424 /* ===========================================================================
425 * Test deflate() with preset dictionary
426 */
test_dict_deflate(Byte *compr, uLong comprLen)427 static void test_dict_deflate(Byte *compr, uLong comprLen)
428 {
429 z_stream c_stream; /* compression stream */
430 int err;
431
432 c_stream.zalloc = zalloc;
433 c_stream.zfree = zfree;
434 c_stream.opaque = (voidpf)0;
435
436 err = deflateInit(&c_stream, Z_BEST_COMPRESSION);
437 CHECK_ERR(err, "deflateInit");
438
439 err = deflateSetDictionary(&c_stream,
440 (const Bytef*)dictionary, (int)sizeof(dictionary));
441 CHECK_ERR(err, "deflateSetDictionary");
442
443 dictId = c_stream.adler;
444 c_stream.next_out = compr;
445 c_stream.avail_out = (uInt)comprLen;
446
447 c_stream.next_in = (z_const unsigned char *)hello;
448 c_stream.avail_in = (uInt)strlen(hello)+1;
449
450 err = deflate(&c_stream, Z_FINISH);
451 if (err != Z_STREAM_END) {
452 fprintf(stderr, "deflate should report Z_STREAM_END\n");
453 exit(1);
454 }
455 err = deflateEnd(&c_stream);
456 CHECK_ERR(err, "deflateEnd");
457 }
458
459 /* ===========================================================================
460 * Test inflate() with a preset dictionary
461 */
test_dict_inflate(Byte *compr, uLong comprLen, Byte *uncompr, uLong uncomprLen)462 static void test_dict_inflate(Byte *compr, uLong comprLen, Byte *uncompr,
463 uLong uncomprLen)
464 {
465 int err;
466 z_stream d_stream; /* decompression stream */
467
468 strcpy((char*)uncompr, "garbage");
469
470 d_stream.zalloc = zalloc;
471 d_stream.zfree = zfree;
472 d_stream.opaque = (voidpf)0;
473
474 d_stream.next_in = compr;
475 d_stream.avail_in = (uInt)comprLen;
476
477 err = inflateInit(&d_stream);
478 CHECK_ERR(err, "inflateInit");
479
480 d_stream.next_out = uncompr;
481 d_stream.avail_out = (uInt)uncomprLen;
482
483 for (;;) {
484 err = inflate(&d_stream, Z_NO_FLUSH);
485 if (err == Z_STREAM_END)
486 {
487 break;
488 }
489 if (err == Z_NEED_DICT) {
490 if (d_stream.adler != dictId) {
491 fprintf(stderr, "unexpected dictionary");
492 exit(1);
493 }
494 err = inflateSetDictionary(&d_stream, (const Bytef*)dictionary,
495 (int)sizeof(dictionary));
496 }
497 CHECK_ERR(err, "inflate with dict");
498 }
499
500 err = inflateEnd(&d_stream);
501 CHECK_ERR(err, "inflateEnd");
502
503 if (strcmp((char*)uncompr, hello)) {
504 fprintf(stderr, "bad inflate with dict\n");
505 exit(1);
506 } else {
507 printf("inflate with dictionary: %s\n", (char *)uncompr);
508 }
509 }
510
511 /* ===========================================================================
512 * Usage: example [output.gz [input.gz]]
513 */
514 #define THREE 3
main(int argc, char *argv[])515 int main(int argc, char *argv[])
516 {
517 Byte *compr, *uncompr;
518 uLong uncomprLen = 20000;
519 uLong comprLen = 3 * uncomprLen;
520 static const char* myVersion = ZLIB_VERSION;
521
522 if (zlibVersion()[0] != myVersion[0]) {
523 fprintf(stderr, "incompatible zlib version\n");
524 exit(1);
525
526 } else if (strcmp(zlibVersion(), ZLIB_VERSION) != 0) {
527 fprintf(stderr, "warning: different zlib version linked: %s\n",
528 zlibVersion());
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
544 #ifdef Z_SOLO
545 (void)argc;
546 (void)argv;
547 #else
548 test_compress(compr, comprLen, uncompr, uncomprLen);
549
550 test_gzio((argc > 1 ? argv[1] : TESTFILE),
551 uncompr, uncomprLen);
552 #endif
553
554 test_deflate(compr, comprLen);
555 test_inflate(compr, comprLen, uncompr, uncomprLen);
556
557 test_large_deflate(compr, comprLen, uncompr, uncomprLen);
558 test_large_inflate(compr, comprLen, uncompr, uncomprLen);
559
560 test_flush(compr, &comprLen);
561 test_sync(compr, comprLen, uncompr, uncomprLen);
562 comprLen = THREE * uncomprLen;
563
564 test_dict_deflate(compr, comprLen);
565 test_dict_inflate(compr, comprLen, uncompr, uncomprLen);
566
567 free(compr);
568 free(uncompr);
569
570 return 0;
571 }
572