1/* example.c -- usage example of the zlib compression library
2 * Copyright (C) 1995-2006, 2011 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
29z_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
34const char dictionary[] = "hello";
35uLong dictId; /* Adler32 value of the dictionary */
36
37void test_deflate       OF((Byte *compr, uLong comprLen));
38void test_inflate       OF((Byte *compr, uLong comprLen,
39                            Byte *uncompr, uLong uncomprLen));
40void test_large_deflate OF((Byte *compr, uLong comprLen,
41                            Byte *uncompr, uLong uncomprLen));
42void test_large_inflate OF((Byte *compr, uLong comprLen,
43                            Byte *uncompr, uLong uncomprLen));
44void test_flush         OF((Byte *compr, uLong *comprLen));
45void test_sync          OF((Byte *compr, uLong comprLen,
46                            Byte *uncompr, uLong uncomprLen));
47void test_dict_deflate  OF((Byte *compr, uLong comprLen));
48void test_dict_inflate  OF((Byte *compr, uLong comprLen,
49                            Byte *uncompr, uLong uncomprLen));
50int  main               OF((int argc, char *argv[]));
51
52
53#ifdef Z_SOLO
54
55void *myalloc OF((void *, unsigned, unsigned));
56void myfree OF((void *, void *));
57
58void *myalloc(q, n, m)
59    void *q;
60    unsigned n, m;
61{
62    q = Z_NULL;
63    return calloc(n, m);
64}
65
66void myfree(void *q, void *p)
67{
68    q = Z_NULL;
69    free(p);
70}
71
72static alloc_func zalloc = myalloc;
73static free_func zfree = myfree;
74
75#else /* !Z_SOLO */
76
77static alloc_func zalloc = (alloc_func)0;
78static free_func zfree = (free_func)0;
79
80void test_compress      OF((Byte *compr, uLong comprLen,
81                            Byte *uncompr, uLong uncomprLen));
82void test_gzio          OF((const char *fname,
83                            Byte *uncompr, uLong uncomprLen));
84
85/* ===========================================================================
86 * Test compress() and uncompress()
87 */
88void test_compress(compr, comprLen, uncompr, uncomprLen)
89    Byte *compr, *uncompr;
90    uLong comprLen, uncomprLen;
91{
92    int err;
93    uLong len = (uLong)strlen(hello)+1;
94
95    err = compress(compr, &comprLen, (const Bytef*)hello, len);
96    CHECK_ERR(err, "compress");
97
98    strcpy((char*)uncompr, "garbage");
99
100    err = uncompress(uncompr, &uncomprLen, compr, comprLen);
101    CHECK_ERR(err, "uncompress");
102
103    if (strcmp((char*)uncompr, hello)) {
104        fprintf(stderr, "bad uncompress\n");
105        exit(1);
106    } else {
107        printf("uncompress(): %s\n", (char *)uncompr);
108    }
109}
110
111/* ===========================================================================
112 * Test read/write of .gz files
113 */
114void test_gzio(fname, uncompr, uncomprLen)
115    const char *fname; /* compressed file name */
116    Byte *uncompr;
117    uLong uncomprLen;
118{
119#ifdef NO_GZCOMPRESS
120    fprintf(stderr, "NO_GZCOMPRESS -- gz* functions cannot compress\n");
121#else
122    int err;
123    int len = (int)strlen(hello)+1;
124    gzFile file;
125    z_off_t pos;
126
127    file = gzopen(fname, "wb");
128    if (file == NULL) {
129        fprintf(stderr, "gzopen error\n");
130        exit(1);
131    }
132    gzputc(file, 'h');
133    if (gzputs(file, "ello") != 4) {
134        fprintf(stderr, "gzputs err: %s\n", gzerror(file, &err));
135        exit(1);
136    }
137    if (gzprintf(file, ", %s!", "hello") != 8) {
138        fprintf(stderr, "gzprintf err: %s\n", gzerror(file, &err));
139        exit(1);
140    }
141    gzseek(file, 1L, SEEK_CUR); /* add one zero byte */
142    gzclose(file);
143
144    file = gzopen(fname, "rb");
145    if (file == NULL) {
146        fprintf(stderr, "gzopen error\n");
147        exit(1);
148    }
149    strcpy((char*)uncompr, "garbage");
150
151    if (gzread(file, uncompr, (unsigned)uncomprLen) != len) {
152        fprintf(stderr, "gzread err: %s\n", gzerror(file, &err));
153        exit(1);
154    }
155    if (strcmp((char*)uncompr, hello)) {
156        fprintf(stderr, "bad gzread: %s\n", (char*)uncompr);
157        exit(1);
158    } else {
159        printf("gzread(): %s\n", (char*)uncompr);
160    }
161
162    pos = gzseek(file, -8L, SEEK_CUR);
163    if (pos != 6 || gztell(file) != pos) {
164        fprintf(stderr, "gzseek error, pos=%ld, gztell=%ld\n",
165                (long)pos, (long)gztell(file));
166        exit(1);
167    }
168
169    if (gzgetc(file) != ' ') {
170        fprintf(stderr, "gzgetc error\n");
171        exit(1);
172    }
173
174    if (gzungetc(' ', file) != ' ') {
175        fprintf(stderr, "gzungetc error\n");
176        exit(1);
177    }
178
179    gzgets(file, (char*)uncompr, (int)uncomprLen);
180    if (strlen((char*)uncompr) != 7) { /* " hello!" */
181        fprintf(stderr, "gzgets err after gzseek: %s\n", gzerror(file, &err));
182        exit(1);
183    }
184    if (strcmp((char*)uncompr, hello + 6)) {
185        fprintf(stderr, "bad gzgets after gzseek\n");
186        exit(1);
187    } else {
188        printf("gzgets() after gzseek: %s\n", (char*)uncompr);
189    }
190
191    gzclose(file);
192#endif
193}
194
195#endif /* Z_SOLO */
196
197/* ===========================================================================
198 * Test deflate() with small buffers
199 */
200void test_deflate(compr, comprLen)
201    Byte *compr;
202    uLong comprLen;
203{
204    z_stream c_stream; /* compression stream */
205    int err;
206    uLong len = (uLong)strlen(hello)+1;
207
208    c_stream.zalloc = zalloc;
209    c_stream.zfree = zfree;
210    c_stream.opaque = (voidpf)0;
211
212    err = deflateInit(&c_stream, Z_DEFAULT_COMPRESSION);
213    CHECK_ERR(err, "deflateInit");
214
215    c_stream.next_in  = (z_const unsigned char *)hello;
216    c_stream.next_out = compr;
217
218    while (c_stream.total_in != len && c_stream.total_out < comprLen) {
219        c_stream.avail_in = c_stream.avail_out = 1; /* force small buffers */
220        err = deflate(&c_stream, Z_NO_FLUSH);
221        CHECK_ERR(err, "deflate");
222    }
223    /* Finish the stream, still forcing small buffers: */
224    for (;;) {
225        c_stream.avail_out = 1;
226        err = deflate(&c_stream, Z_FINISH);
227        if (err == Z_STREAM_END) break;
228        CHECK_ERR(err, "deflate");
229    }
230
231    err = deflateEnd(&c_stream);
232    CHECK_ERR(err, "deflateEnd");
233}
234
235/* ===========================================================================
236 * Test inflate() with small buffers
237 */
238void test_inflate(compr, comprLen, uncompr, uncomprLen)
239    Byte *compr, *uncompr;
240    uLong comprLen, uncomprLen;
241{
242    int err;
243    z_stream d_stream; /* decompression stream */
244
245    strcpy((char*)uncompr, "garbage");
246
247    d_stream.zalloc = zalloc;
248    d_stream.zfree = zfree;
249    d_stream.opaque = (voidpf)0;
250
251    d_stream.next_in  = compr;
252    d_stream.avail_in = 0;
253    d_stream.next_out = uncompr;
254
255    err = inflateInit(&d_stream);
256    CHECK_ERR(err, "inflateInit");
257
258    while (d_stream.total_out < uncomprLen && d_stream.total_in < comprLen) {
259        d_stream.avail_in = d_stream.avail_out = 1; /* force small buffers */
260        err = inflate(&d_stream, Z_NO_FLUSH);
261        if (err == Z_STREAM_END) break;
262        CHECK_ERR(err, "inflate");
263    }
264
265    err = inflateEnd(&d_stream);
266    CHECK_ERR(err, "inflateEnd");
267
268    if (strcmp((char*)uncompr, hello)) {
269        fprintf(stderr, "bad inflate\n");
270        exit(1);
271    } else {
272        printf("inflate(): %s\n", (char *)uncompr);
273    }
274}
275
276/* ===========================================================================
277 * Test deflate() with large buffers and dynamic change of compression level
278 */
279void test_large_deflate(compr, comprLen, uncompr, uncomprLen)
280    Byte *compr, *uncompr;
281    uLong comprLen, uncomprLen;
282{
283    z_stream c_stream; /* compression stream */
284    int err;
285
286    c_stream.zalloc = zalloc;
287    c_stream.zfree = zfree;
288    c_stream.opaque = (voidpf)0;
289
290    err = deflateInit(&c_stream, Z_BEST_SPEED);
291    CHECK_ERR(err, "deflateInit");
292
293    c_stream.next_out = compr;
294    c_stream.avail_out = (uInt)comprLen;
295
296    /* At this point, uncompr is still mostly zeroes, so it should compress
297     * very well:
298     */
299    c_stream.next_in = uncompr;
300    c_stream.avail_in = (uInt)uncomprLen;
301    err = deflate(&c_stream, Z_NO_FLUSH);
302    CHECK_ERR(err, "deflate");
303    if (c_stream.avail_in != 0) {
304        fprintf(stderr, "deflate not greedy\n");
305        exit(1);
306    }
307
308    /* Feed in already compressed data and switch to no compression: */
309    deflateParams(&c_stream, Z_NO_COMPRESSION, Z_DEFAULT_STRATEGY);
310    c_stream.next_in = compr;
311    c_stream.avail_in = (uInt)comprLen/2;
312    err = deflate(&c_stream, Z_NO_FLUSH);
313    CHECK_ERR(err, "deflate");
314
315    /* Switch back to compressing mode: */
316    deflateParams(&c_stream, Z_BEST_COMPRESSION, Z_FILTERED);
317    c_stream.next_in = uncompr;
318    c_stream.avail_in = (uInt)uncomprLen;
319    err = deflate(&c_stream, Z_NO_FLUSH);
320    CHECK_ERR(err, "deflate");
321
322    err = deflate(&c_stream, Z_FINISH);
323    if (err != Z_STREAM_END) {
324        fprintf(stderr, "deflate should report Z_STREAM_END\n");
325        exit(1);
326    }
327    err = deflateEnd(&c_stream);
328    CHECK_ERR(err, "deflateEnd");
329}
330
331/* ===========================================================================
332 * Test inflate() with large buffers
333 */
334void test_large_inflate(compr, comprLen, uncompr, uncomprLen)
335    Byte *compr, *uncompr;
336    uLong comprLen, uncomprLen;
337{
338    int err;
339    z_stream d_stream; /* decompression stream */
340
341    strcpy((char*)uncompr, "garbage");
342
343    d_stream.zalloc = zalloc;
344    d_stream.zfree = zfree;
345    d_stream.opaque = (voidpf)0;
346
347    d_stream.next_in  = compr;
348    d_stream.avail_in = (uInt)comprLen;
349
350    err = inflateInit(&d_stream);
351    CHECK_ERR(err, "inflateInit");
352
353    for (;;) {
354        d_stream.next_out = uncompr;            /* discard the output */
355        d_stream.avail_out = (uInt)uncomprLen;
356        err = inflate(&d_stream, Z_NO_FLUSH);
357        if (err == Z_STREAM_END) break;
358        CHECK_ERR(err, "large inflate");
359    }
360
361    err = inflateEnd(&d_stream);
362    CHECK_ERR(err, "inflateEnd");
363
364    if (d_stream.total_out != 2*uncomprLen + comprLen/2) {
365        fprintf(stderr, "bad large inflate: %ld\n", d_stream.total_out);
366        exit(1);
367    } else {
368        printf("large_inflate(): OK\n");
369    }
370}
371
372/* ===========================================================================
373 * Test deflate() with full flush
374 */
375void test_flush(compr, comprLen)
376    Byte *compr;
377    uLong *comprLen;
378{
379    z_stream c_stream; /* compression stream */
380    int err;
381    uInt len = (uInt)strlen(hello)+1;
382
383    c_stream.zalloc = zalloc;
384    c_stream.zfree = zfree;
385    c_stream.opaque = (voidpf)0;
386
387    err = deflateInit(&c_stream, Z_DEFAULT_COMPRESSION);
388    CHECK_ERR(err, "deflateInit");
389
390    c_stream.next_in  = (z_const unsigned char *)hello;
391    c_stream.next_out = compr;
392    c_stream.avail_in = 3;
393    c_stream.avail_out = (uInt)*comprLen;
394    err = deflate(&c_stream, Z_FULL_FLUSH);
395    CHECK_ERR(err, "deflate");
396
397    compr[3]++; /* force an error in first compressed block */
398    c_stream.avail_in = len - 3;
399
400    err = deflate(&c_stream, Z_FINISH);
401    if (err != Z_STREAM_END) {
402        CHECK_ERR(err, "deflate");
403    }
404    err = deflateEnd(&c_stream);
405    CHECK_ERR(err, "deflateEnd");
406
407    *comprLen = c_stream.total_out;
408}
409
410/* ===========================================================================
411 * Test inflateSync()
412 */
413void test_sync(compr, comprLen, uncompr, uncomprLen)
414    Byte *compr, *uncompr;
415    uLong comprLen, uncomprLen;
416{
417    int err;
418    z_stream d_stream; /* decompression stream */
419
420    strcpy((char*)uncompr, "garbage");
421
422    d_stream.zalloc = zalloc;
423    d_stream.zfree = zfree;
424    d_stream.opaque = (voidpf)0;
425
426    d_stream.next_in  = compr;
427    d_stream.avail_in = 2; /* just read the zlib header */
428
429    err = inflateInit(&d_stream);
430    CHECK_ERR(err, "inflateInit");
431
432    d_stream.next_out = uncompr;
433    d_stream.avail_out = (uInt)uncomprLen;
434
435    inflate(&d_stream, Z_NO_FLUSH);
436    CHECK_ERR(err, "inflate");
437
438    d_stream.avail_in = (uInt)comprLen-2;   /* read all compressed data */
439    err = inflateSync(&d_stream);           /* but skip the damaged part */
440    CHECK_ERR(err, "inflateSync");
441
442    err = inflate(&d_stream, Z_FINISH);
443    if (err != Z_DATA_ERROR) {
444        fprintf(stderr, "inflate should report DATA_ERROR\n");
445        /* Because of incorrect adler32 */
446        exit(1);
447    }
448    err = inflateEnd(&d_stream);
449    CHECK_ERR(err, "inflateEnd");
450
451    printf("after inflateSync(): hel%s\n", (char *)uncompr);
452}
453
454/* ===========================================================================
455 * Test deflate() with preset dictionary
456 */
457void test_dict_deflate(compr, comprLen)
458    Byte *compr;
459    uLong comprLen;
460{
461    z_stream c_stream; /* compression stream */
462    int err;
463
464    c_stream.zalloc = zalloc;
465    c_stream.zfree = zfree;
466    c_stream.opaque = (voidpf)0;
467
468    err = deflateInit(&c_stream, Z_BEST_COMPRESSION);
469    CHECK_ERR(err, "deflateInit");
470
471    err = deflateSetDictionary(&c_stream,
472                (const Bytef*)dictionary, (int)sizeof(dictionary));
473    CHECK_ERR(err, "deflateSetDictionary");
474
475    dictId = c_stream.adler;
476    c_stream.next_out = compr;
477    c_stream.avail_out = (uInt)comprLen;
478
479    c_stream.next_in = (z_const unsigned char *)hello;
480    c_stream.avail_in = (uInt)strlen(hello)+1;
481
482    err = deflate(&c_stream, Z_FINISH);
483    if (err != Z_STREAM_END) {
484        fprintf(stderr, "deflate should report Z_STREAM_END\n");
485        exit(1);
486    }
487    err = deflateEnd(&c_stream);
488    CHECK_ERR(err, "deflateEnd");
489}
490
491/* ===========================================================================
492 * Test inflate() with a preset dictionary
493 */
494void test_dict_inflate(compr, comprLen, uncompr, uncomprLen)
495    Byte *compr, *uncompr;
496    uLong comprLen, uncomprLen;
497{
498    int err;
499    z_stream d_stream; /* decompression stream */
500
501    strcpy((char*)uncompr, "garbage");
502
503    d_stream.zalloc = zalloc;
504    d_stream.zfree = zfree;
505    d_stream.opaque = (voidpf)0;
506
507    d_stream.next_in  = compr;
508    d_stream.avail_in = (uInt)comprLen;
509
510    err = inflateInit(&d_stream);
511    CHECK_ERR(err, "inflateInit");
512
513    d_stream.next_out = uncompr;
514    d_stream.avail_out = (uInt)uncomprLen;
515
516    for (;;) {
517        err = inflate(&d_stream, Z_NO_FLUSH);
518        if (err == Z_STREAM_END) break;
519        if (err == Z_NEED_DICT) {
520            if (d_stream.adler != dictId) {
521                fprintf(stderr, "unexpected dictionary");
522                exit(1);
523            }
524            err = inflateSetDictionary(&d_stream, (const Bytef*)dictionary,
525                                       (int)sizeof(dictionary));
526        }
527        CHECK_ERR(err, "inflate with dict");
528    }
529
530    err = inflateEnd(&d_stream);
531    CHECK_ERR(err, "inflateEnd");
532
533    if (strcmp((char*)uncompr, hello)) {
534        fprintf(stderr, "bad inflate with dict\n");
535        exit(1);
536    } else {
537        printf("inflate with dictionary: %s\n", (char *)uncompr);
538    }
539}
540
541/* ===========================================================================
542 * Usage:  example [output.gz  [input.gz]]
543 */
544
545int main(argc, argv)
546    int argc;
547    char *argv[];
548{
549    Byte *compr, *uncompr;
550    uLong comprLen = 10000*sizeof(int); /* don't overflow on MSDOS */
551    uLong uncomprLen = comprLen;
552    static const char* myVersion = ZLIB_VERSION;
553
554    if (zlibVersion()[0] != myVersion[0]) {
555        fprintf(stderr, "incompatible zlib version\n");
556        exit(1);
557
558    } else if (strcmp(zlibVersion(), ZLIB_VERSION) != 0) {
559        fprintf(stderr, "warning: different zlib version\n");
560    }
561
562    printf("zlib version %s = 0x%04x, compile flags = 0x%lx\n",
563            ZLIB_VERSION, ZLIB_VERNUM, zlibCompileFlags());
564
565    compr    = (Byte*)calloc((uInt)comprLen, 1);
566    uncompr  = (Byte*)calloc((uInt)uncomprLen, 1);
567    /* compr and uncompr are cleared to avoid reading uninitialized
568     * data and to ensure that uncompr compresses well.
569     */
570    if (compr == Z_NULL || uncompr == Z_NULL) {
571        printf("out of memory\n");
572        exit(1);
573    }
574
575#ifdef Z_SOLO
576    argc = strlen(argv[0]);
577#else
578    test_compress(compr, comprLen, uncompr, uncomprLen);
579
580    test_gzio((argc > 1 ? argv[1] : TESTFILE),
581              uncompr, uncomprLen);
582#endif
583
584    test_deflate(compr, comprLen);
585    test_inflate(compr, comprLen, uncompr, uncomprLen);
586
587    test_large_deflate(compr, comprLen, uncompr, uncomprLen);
588    test_large_inflate(compr, comprLen, uncompr, uncomprLen);
589
590    test_flush(compr, &comprLen);
591    test_sync(compr, comprLen, uncompr, uncomprLen);
592    comprLen = uncomprLen;
593
594    test_dict_deflate(compr, comprLen);
595    test_dict_inflate(compr, comprLen, uncompr, uncomprLen);
596
597    free(compr);
598    free(uncompr);
599
600    return 0;
601}
602