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
6 /* @(#) $Id: example.c,v 1.1.1.2 2002/03/11 21:53:23 tromey Exp $ */
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
);
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