1
/* example.c -- usage example of the zlib compression library
2
* Copyright (C) 1995-2004 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);