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
16 #if defined(VMS) || defined(RISCOS)
17 # define TESTFILE "foo-gz"
19 # define TESTFILE "foo.gz"
22 #define CHECK_ERR(err, msg) { \
24 fprintf(stderr, "%s error: %d\n", msg, err); \
29 const char hello[] = "hello, hello!";
30 /* "hello world" would be more standard, but the repeated "hello"
31 * stresses the compression code better, sorry...
34 const char dictionary[] = "hello";
35 uLong dictId; /* Adler32 value of the dictionary */
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[]));
56 /* ===========================================================================
57 * Test compress() and uncompress()
59 void test_compress(compr, comprLen, uncompr, uncomprLen)
60 Byte *compr, *uncompr;
61 uLong comprLen, uncomprLen;
64 uLong len = (uLong)strlen(hello)+1;
66 err = compress(compr, &comprLen, (const Bytef*)hello, len);
67 CHECK_ERR(err, "compress");
69 strcpy((char*)uncompr, "garbage");
71 err = uncompress(uncompr, &uncomprLen, compr, comprLen);
72 CHECK_ERR(err, "uncompress");
74 if (strcmp((char*)uncompr, hello)) {
75 fprintf(stderr, "bad uncompress\n");
78 printf("uncompress(): %s\n", (char *)uncompr);
82 /* ===========================================================================
83 * Test read/write of .gz files
85 void test_gzio(fname, uncompr, uncomprLen)
86 const char *fname; /* compressed file name */
91 fprintf(stderr, "NO_GZCOMPRESS -- gz* functions cannot compress\n");
94 int len = (int)strlen(hello)+1;
98 file = gzopen(fname, "wb");
100 fprintf(stderr, "gzopen error\n");
104 if (gzputs(file, "ello") != 4) {
105 fprintf(stderr, "gzputs err: %s\n", gzerror(file, &err));
108 if (gzprintf(file, ", %s!", "hello") != 8) {
109 fprintf(stderr, "gzprintf err: %s\n", gzerror(file, &err));
112 gzseek(file, 1L, SEEK_CUR); /* add one zero byte */
115 file = gzopen(fname, "rb");
117 fprintf(stderr, "gzopen error\n");
120 strcpy((char*)uncompr, "garbage");
122 if (gzread(file, uncompr, (unsigned)uncomprLen) != len) {
123 fprintf(stderr, "gzread err: %s\n", gzerror(file, &err));
126 if (strcmp((char*)uncompr, hello)) {
127 fprintf(stderr, "bad gzread: %s\n", (char*)uncompr);
130 printf("gzread(): %s\n", (char*)uncompr);
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));
140 if (gzgetc(file) != ' ') {
141 fprintf(stderr, "gzgetc error\n");
145 if (gzungetc(' ', file) != ' ') {
146 fprintf(stderr, "gzungetc error\n");
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));
155 if (strcmp((char*)uncompr, hello + 6)) {
156 fprintf(stderr, "bad gzgets after gzseek\n");
159 printf("gzgets() after gzseek: %s\n", (char*)uncompr);
166 /* ===========================================================================
167 * Test deflate() with small buffers
169 void test_deflate(compr, comprLen)
173 z_stream c_stream; /* compression stream */
175 uLong len = (uLong)strlen(hello)+1;
177 c_stream.zalloc = (alloc_func)0;
178 c_stream.zfree = (free_func)0;
179 c_stream.opaque = (voidpf)0;
181 err = deflateInit(&c_stream, Z_DEFAULT_COMPRESSION);
182 CHECK_ERR(err, "deflateInit");
184 c_stream.next_in = (Bytef*)hello;
185 c_stream.next_out = compr;
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");
192 /* Finish the stream, still forcing small buffers: */
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");
200 err = deflateEnd(&c_stream);
201 CHECK_ERR(err, "deflateEnd");
204 /* ===========================================================================
205 * Test inflate() with small buffers
207 void test_inflate(compr, comprLen, uncompr, uncomprLen)
208 Byte *compr, *uncompr;
209 uLong comprLen, uncomprLen;
212 z_stream d_stream; /* decompression stream */
214 strcpy((char*)uncompr, "garbage");
216 d_stream.zalloc = (alloc_func)0;
217 d_stream.zfree = (free_func)0;
218 d_stream.opaque = (voidpf)0;
220 d_stream.next_in = compr;
221 d_stream.avail_in = 0;
222 d_stream.next_out = uncompr;
224 err = inflateInit(&d_stream);
225 CHECK_ERR(err, "inflateInit");
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");
234 err = inflateEnd(&d_stream);
235 CHECK_ERR(err, "inflateEnd");
237 if (strcmp((char*)uncompr, hello)) {
238 fprintf(stderr, "bad inflate\n");
241 printf("inflate(): %s\n", (char *)uncompr);
245 /* ===========================================================================
246 * Test deflate() with large buffers and dynamic change of compression level
248 void test_large_deflate(compr, comprLen, uncompr, uncomprLen)
249 Byte *compr, *uncompr;
250 uLong comprLen, uncomprLen;
252 z_stream c_stream; /* compression stream */
255 c_stream.zalloc = (alloc_func)0;
256 c_stream.zfree = (free_func)0;
257 c_stream.opaque = (voidpf)0;
259 err = deflateInit(&c_stream, Z_BEST_SPEED);
260 CHECK_ERR(err, "deflateInit");
262 c_stream.next_out = compr;
263 c_stream.avail_out = (uInt)comprLen;
265 /* At this point, uncompr is still mostly zeroes, so it should compress
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");
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");
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");
291 err = deflate(&c_stream, Z_FINISH);
292 if (err != Z_STREAM_END) {
293 fprintf(stderr, "deflate should report Z_STREAM_END\n");
296 err = deflateEnd(&c_stream);
297 CHECK_ERR(err, "deflateEnd");
300 /* ===========================================================================
301 * Test inflate() with large buffers
303 void test_large_inflate(compr, comprLen, uncompr, uncomprLen)
304 Byte *compr, *uncompr;
305 uLong comprLen, uncomprLen;
308 z_stream d_stream; /* decompression stream */
310 strcpy((char*)uncompr, "garbage");
312 d_stream.zalloc = (alloc_func)0;
313 d_stream.zfree = (free_func)0;
314 d_stream.opaque = (voidpf)0;
316 d_stream.next_in = compr;
317 d_stream.avail_in = (uInt)comprLen;
319 err = inflateInit(&d_stream);
320 CHECK_ERR(err, "inflateInit");
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");
330 err = inflateEnd(&d_stream);
331 CHECK_ERR(err, "inflateEnd");
333 if (d_stream.total_out != 2*uncomprLen + comprLen/2) {
334 fprintf(stderr, "bad large inflate: %ld\n", d_stream.total_out);
337 printf("large_inflate(): OK\n");
341 /* ===========================================================================
342 * Test deflate() with full flush
344 void test_flush(compr, comprLen)
348 z_stream c_stream; /* compression stream */
350 uInt len = (uInt)strlen(hello)+1;
352 c_stream.zalloc = (alloc_func)0;
353 c_stream.zfree = (free_func)0;
354 c_stream.opaque = (voidpf)0;
356 err = deflateInit(&c_stream, Z_DEFAULT_COMPRESSION);
357 CHECK_ERR(err, "deflateInit");
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");
366 compr[3]++; /* force an error in first compressed block */
367 c_stream.avail_in = len - 3;
369 err = deflate(&c_stream, Z_FINISH);
370 if (err != Z_STREAM_END) {
371 CHECK_ERR(err, "deflate");
373 err = deflateEnd(&c_stream);
374 CHECK_ERR(err, "deflateEnd");
376 *comprLen = c_stream.total_out;
379 /* ===========================================================================
382 void test_sync(compr, comprLen, uncompr, uncomprLen)
383 Byte *compr, *uncompr;
384 uLong comprLen, uncomprLen;
387 z_stream d_stream; /* decompression stream */
389 strcpy((char*)uncompr, "garbage");
391 d_stream.zalloc = (alloc_func)0;
392 d_stream.zfree = (free_func)0;
393 d_stream.opaque = (voidpf)0;
395 d_stream.next_in = compr;
396 d_stream.avail_in = 2; /* just read the zlib header */
398 err = inflateInit(&d_stream);
399 CHECK_ERR(err, "inflateInit");
401 d_stream.next_out = uncompr;
402 d_stream.avail_out = (uInt)uncomprLen;
404 inflate(&d_stream, Z_NO_FLUSH);
405 CHECK_ERR(err, "inflate");
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");
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 */
417 err = inflateEnd(&d_stream);
418 CHECK_ERR(err, "inflateEnd");
420 printf("after inflateSync(): hel%s\n", (char *)uncompr);
423 /* ===========================================================================
424 * Test deflate() with preset dictionary
426 void test_dict_deflate(compr, comprLen)
430 z_stream c_stream; /* compression stream */
433 c_stream.zalloc = (alloc_func)0;
434 c_stream.zfree = (free_func)0;
435 c_stream.opaque = (voidpf)0;
437 err = deflateInit(&c_stream, Z_BEST_COMPRESSION);
438 CHECK_ERR(err, "deflateInit");
440 err = deflateSetDictionary(&c_stream,
441 (const Bytef*)dictionary, sizeof(dictionary));
442 CHECK_ERR(err, "deflateSetDictionary");
444 dictId = c_stream.adler;
445 c_stream.next_out = compr;
446 c_stream.avail_out = (uInt)comprLen;
448 c_stream.next_in = (Bytef*)hello;
449 c_stream.avail_in = (uInt)strlen(hello)+1;
451 err = deflate(&c_stream, Z_FINISH);
452 if (err != Z_STREAM_END) {
453 fprintf(stderr, "deflate should report Z_STREAM_END\n");
456 err = deflateEnd(&c_stream);
457 CHECK_ERR(err, "deflateEnd");
460 /* ===========================================================================
461 * Test inflate() with a preset dictionary
463 void test_dict_inflate(compr, comprLen, uncompr, uncomprLen)
464 Byte *compr, *uncompr;
465 uLong comprLen, uncomprLen;
468 z_stream d_stream; /* decompression stream */
470 strcpy((char*)uncompr, "garbage");
472 d_stream.zalloc = (alloc_func)0;
473 d_stream.zfree = (free_func)0;
474 d_stream.opaque = (voidpf)0;
476 d_stream.next_in = compr;
477 d_stream.avail_in = (uInt)comprLen;
479 err = inflateInit(&d_stream);
480 CHECK_ERR(err, "inflateInit");
482 d_stream.next_out = uncompr;
483 d_stream.avail_out = (uInt)uncomprLen;
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");
493 err = inflateSetDictionary(&d_stream, (const Bytef*)dictionary,
496 CHECK_ERR(err, "inflate with dict");
499 err = inflateEnd(&d_stream);
500 CHECK_ERR(err, "inflateEnd");
502 if (strcmp((char*)uncompr, hello)) {
503 fprintf(stderr, "bad inflate with dict\n");
506 printf("inflate with dictionary: %s\n", (char *)uncompr);
510 /* ===========================================================================
511 * Usage: example [output.gz [input.gz]]
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;
523 if (zlibVersion()[0] != myVersion[0]) {
524 fprintf(stderr, "incompatible zlib version\n");
527 } else if (strcmp(zlibVersion(), ZLIB_VERSION) != 0) {
528 fprintf(stderr, "warning: different zlib version\n");
531 printf("zlib version %s = 0x%04x, compile flags = 0x%lx\n",
532 ZLIB_VERSION, ZLIB_VERNUM, zlibCompileFlags());
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.
539 if (compr == Z_NULL || uncompr == Z_NULL) {
540 printf("out of memory\n");
543 test_compress(compr, comprLen, uncompr, uncomprLen);
545 test_gzio((argc > 1 ? argv[1] : TESTFILE),
546 uncompr, uncomprLen);
548 test_deflate(compr, comprLen);
549 test_inflate(compr, comprLen, uncompr, uncomprLen);
551 test_large_deflate(compr, comprLen, uncompr, uncomprLen);
552 test_large_inflate(compr, comprLen, uncompr, uncomprLen);
554 test_flush(compr, &comprLen);
555 test_sync(compr, comprLen, uncompr, uncomprLen);
556 comprLen = uncomprLen;
558 test_dict_deflate(compr, comprLen);
559 test_dict_inflate(compr, comprLen, uncompr, uncomprLen);