xref: /third_party/zlib/test/example.c (revision 275793ea) 
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
29static 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
34static const char dictionary[] = "hello";
35static uLong dictId;    /* Adler32 value of the dictionary */
36
37#ifdef Z_SOLO
38
39static void *myalloc(void *q, unsigned n, unsigned m)
40{
41    (void)q;
42    return calloc(n, m);
43}
44
45static void myfree(void *q, void *p)
46{
47    (void)q;
48    free(p);
49}
50
51static alloc_func zalloc = myalloc;
52static free_func zfree = myfree;
53
54#else /* !Z_SOLO */
55
56static alloc_func zalloc = (alloc_func)0;
57static free_func zfree = (free_func)0;
58
59/* ===========================================================================
60 * Test compress() and uncompress()
61 */
62static 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 */
87static 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 */
170static 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 */
209static 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 */
252static 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 */
306static 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 */
349static 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 */
385static 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 */
427static 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 */
462static 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
515int 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