example.c
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上传日期:2007-06-06
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文件大小:16k
- /* example.c -- usage example of the zlib compression library
- * Copyright (C) 1995-2002 Jean-loup Gailly.
- * For conditions of distribution and use, see copyright notice in zlib.h
- */
- /* @(#) $Id: example.c,v 1.1.1.1 2002/10/18 01:43:40 ping Exp $ */
- #include <stdio.h>
- #include "zlib.h"
- #ifdef STDC
- # include <string.h>
- # include <stdlib.h>
- #else
- extern void exit OF((int));
- #endif
- #if defined(VMS) || defined(RISCOS)
- # define TESTFILE "foo-gz"
- #else
- # define TESTFILE "foo.gz"
- #endif
- #define CHECK_ERR(err, msg) {
- if (err != Z_OK) {
- fprintf(stderr, "%s error: %dn", msg, err);
- exit(1);
- }
- }
- const char hello[] = "hello, hello!";
- /* "hello world" would be more standard, but the repeated "hello"
- * stresses the compression code better, sorry...
- */
- const char dictionary[] = "hello";
- uLong dictId; /* Adler32 value of the dictionary */
- void test_compress OF((Byte *compr, uLong comprLen,
- Byte *uncompr, uLong uncomprLen));
- void test_gzio OF((const char *out, const char *in,
- Byte *uncompr, int uncomprLen));
- void test_deflate OF((Byte *compr, uLong comprLen));
- void test_inflate OF((Byte *compr, uLong comprLen,
- Byte *uncompr, uLong uncomprLen));
- void test_large_deflate OF((Byte *compr, uLong comprLen,
- Byte *uncompr, uLong uncomprLen));
- void test_large_inflate OF((Byte *compr, uLong comprLen,
- Byte *uncompr, uLong uncomprLen));
- void test_flush OF((Byte *compr, uLong *comprLen));
- void test_sync OF((Byte *compr, uLong comprLen,
- Byte *uncompr, uLong uncomprLen));
- void test_dict_deflate OF((Byte *compr, uLong comprLen));
- void test_dict_inflate OF((Byte *compr, uLong comprLen,
- Byte *uncompr, uLong uncomprLen));
- int main OF((int argc, char *argv[]));
- /* ===========================================================================
- * Test compress() and uncompress()
- */
- void test_compress(compr, comprLen, uncompr, uncomprLen)
- Byte *compr, *uncompr;
- uLong comprLen, uncomprLen;
- {
- int err;
- uLong len = strlen(hello)+1;
- err = compress(compr, &comprLen, (const Bytef*)hello, len);
- CHECK_ERR(err, "compress");
- strcpy((char*)uncompr, "garbage");
- err = uncompress(uncompr, &uncomprLen, compr, comprLen);
- CHECK_ERR(err, "uncompress");
- if (strcmp((char*)uncompr, hello)) {
- fprintf(stderr, "bad uncompressn");
- exit(1);
- } else {
- printf("uncompress(): %sn", (char *)uncompr);
- }
- }
- /* ===========================================================================
- * Test read/write of .gz files
- */
- void test_gzio(out, in, uncompr, uncomprLen)
- const char *out; /* compressed output file */
- const char *in; /* compressed input file */
- Byte *uncompr;
- int uncomprLen;
- {
- int err;
- int len = strlen(hello)+1;
- gzFile file;
- z_off_t pos;
- file = gzopen(out, "wb");
- if (file == NULL) {
- fprintf(stderr, "gzopen errorn");
- exit(1);
- }
- gzputc(file, 'h');
- if (gzputs(file, "ello") != 4) {
- fprintf(stderr, "gzputs err: %sn", gzerror(file, &err));
- exit(1);
- }
- if (gzprintf(file, ", %s!", "hello") != 8) {
- fprintf(stderr, "gzprintf err: %sn", gzerror(file, &err));
- exit(1);
- }
- gzseek(file, 1L, SEEK_CUR); /* add one zero byte */
- gzclose(file);
- file = gzopen(in, "rb");
- if (file == NULL) {
- fprintf(stderr, "gzopen errorn");
- }
- strcpy((char*)uncompr, "garbage");
- uncomprLen = gzread(file, uncompr, (unsigned)uncomprLen);
- if (uncomprLen != len) {
- fprintf(stderr, "gzread err: %sn", gzerror(file, &err));
- exit(1);
- }
- if (strcmp((char*)uncompr, hello)) {
- fprintf(stderr, "bad gzread: %sn", (char*)uncompr);
- exit(1);
- } else {
- printf("gzread(): %sn", (char *)uncompr);
- }
- pos = gzseek(file, -8L, SEEK_CUR);
- if (pos != 6 || gztell(file) != pos) {
- fprintf(stderr, "gzseek error, pos=%ld, gztell=%ldn",
- (long)pos, (long)gztell(file));
- exit(1);
- }
- if (gzgetc(file) != ' ') {
- fprintf(stderr, "gzgetc errorn");
- exit(1);
- }
- gzgets(file, (char*)uncompr, uncomprLen);
- uncomprLen = strlen((char*)uncompr);
- if (uncomprLen != 6) { /* "hello!" */
- fprintf(stderr, "gzgets err after gzseek: %sn", gzerror(file, &err));
- exit(1);
- }
- if (strcmp((char*)uncompr, hello+7)) {
- fprintf(stderr, "bad gzgets after gzseekn");
- exit(1);
- } else {
- printf("gzgets() after gzseek: %sn", (char *)uncompr);
- }
- gzclose(file);
- }
- /* ===========================================================================
- * Test deflate() with small buffers
- */
- void test_deflate(compr, comprLen)
- Byte *compr;
- uLong comprLen;
- {
- z_stream c_stream; /* compression stream */
- int err;
- int len = strlen(hello)+1;
- c_stream.zalloc = (alloc_func)0;
- c_stream.zfree = (free_func)0;
- c_stream.opaque = (voidpf)0;
- err = deflateInit(&c_stream, Z_DEFAULT_COMPRESSION);
- CHECK_ERR(err, "deflateInit");
- c_stream.next_in = (Bytef*)hello;
- c_stream.next_out = compr;
- while (c_stream.total_in != (uLong)len && c_stream.total_out < comprLen) {
- c_stream.avail_in = c_stream.avail_out = 1; /* force small buffers */
- err = deflate(&c_stream, Z_NO_FLUSH);
- CHECK_ERR(err, "deflate");
- }
- /* Finish the stream, still forcing small buffers: */
- for (;;) {
- c_stream.avail_out = 1;
- err = deflate(&c_stream, Z_FINISH);
- if (err == Z_STREAM_END) break;
- CHECK_ERR(err, "deflate");
- }
- err = deflateEnd(&c_stream);
- CHECK_ERR(err, "deflateEnd");
- }
- /* ===========================================================================
- * Test inflate() with small buffers
- */
- void test_inflate(compr, comprLen, uncompr, uncomprLen)
- Byte *compr, *uncompr;
- uLong comprLen, uncomprLen;
- {
- int err;
- z_stream d_stream; /* decompression stream */
- strcpy((char*)uncompr, "garbage");
- d_stream.zalloc = (alloc_func)0;
- d_stream.zfree = (free_func)0;
- d_stream.opaque = (voidpf)0;
- d_stream.next_in = compr;
- d_stream.avail_in = 0;
- d_stream.next_out = uncompr;
- err = inflateInit(&d_stream);
- CHECK_ERR(err, "inflateInit");
- while (d_stream.total_out < uncomprLen && d_stream.total_in < comprLen) {
- d_stream.avail_in = d_stream.avail_out = 1; /* force small buffers */
- err = inflate(&d_stream, Z_NO_FLUSH);
- if (err == Z_STREAM_END) break;
- CHECK_ERR(err, "inflate");
- }
- err = inflateEnd(&d_stream);
- CHECK_ERR(err, "inflateEnd");
- if (strcmp((char*)uncompr, hello)) {
- fprintf(stderr, "bad inflaten");
- exit(1);
- } else {
- printf("inflate(): %sn", (char *)uncompr);
- }
- }
- /* ===========================================================================
- * Test deflate() with large buffers and dynamic change of compression level
- */
- void test_large_deflate(compr, comprLen, uncompr, uncomprLen)
- Byte *compr, *uncompr;
- uLong comprLen, uncomprLen;
- {
- z_stream c_stream; /* compression stream */
- int err;
- c_stream.zalloc = (alloc_func)0;
- c_stream.zfree = (free_func)0;
- c_stream.opaque = (voidpf)0;
- err = deflateInit(&c_stream, Z_BEST_SPEED);
- CHECK_ERR(err, "deflateInit");
- c_stream.next_out = compr;
- c_stream.avail_out = (uInt)comprLen;
- /* At this point, uncompr is still mostly zeroes, so it should compress
- * very well:
- */
- c_stream.next_in = uncompr;
- c_stream.avail_in = (uInt)uncomprLen;
- err = deflate(&c_stream, Z_NO_FLUSH);
- CHECK_ERR(err, "deflate");
- if (c_stream.avail_in != 0) {
- fprintf(stderr, "deflate not greedyn");
- exit(1);
- }
- /* Feed in already compressed data and switch to no compression: */
- deflateParams(&c_stream, Z_NO_COMPRESSION, Z_DEFAULT_STRATEGY);
- c_stream.next_in = compr;
- c_stream.avail_in = (uInt)comprLen/2;
- err = deflate(&c_stream, Z_NO_FLUSH);
- CHECK_ERR(err, "deflate");
- /* Switch back to compressing mode: */
- deflateParams(&c_stream, Z_BEST_COMPRESSION, Z_FILTERED);
- c_stream.next_in = uncompr;
- c_stream.avail_in = (uInt)uncomprLen;
- err = deflate(&c_stream, Z_NO_FLUSH);
- CHECK_ERR(err, "deflate");
- err = deflate(&c_stream, Z_FINISH);
- if (err != Z_STREAM_END) {
- fprintf(stderr, "deflate should report Z_STREAM_ENDn");
- exit(1);
- }
- err = deflateEnd(&c_stream);
- CHECK_ERR(err, "deflateEnd");
- }
- /* ===========================================================================
- * Test inflate() with large buffers
- */
- void test_large_inflate(compr, comprLen, uncompr, uncomprLen)
- Byte *compr, *uncompr;
- uLong comprLen, uncomprLen;
- {
- int err;
- z_stream d_stream; /* decompression stream */
- strcpy((char*)uncompr, "garbage");
- d_stream.zalloc = (alloc_func)0;
- d_stream.zfree = (free_func)0;
- d_stream.opaque = (voidpf)0;
- d_stream.next_in = compr;
- d_stream.avail_in = (uInt)comprLen;
- err = inflateInit(&d_stream);
- CHECK_ERR(err, "inflateInit");
- for (;;) {
- d_stream.next_out = uncompr; /* discard the output */
- d_stream.avail_out = (uInt)uncomprLen;
- err = inflate(&d_stream, Z_NO_FLUSH);
- if (err == Z_STREAM_END) break;
- CHECK_ERR(err, "large inflate");
- }
- err = inflateEnd(&d_stream);
- CHECK_ERR(err, "inflateEnd");
- if (d_stream.total_out != 2*uncomprLen + comprLen/2) {
- fprintf(stderr, "bad large inflate: %ldn", d_stream.total_out);
- exit(1);
- } else {
- printf("large_inflate(): OKn");
- }
- }
- /* ===========================================================================
- * Test deflate() with full flush
- */
- void test_flush(compr, comprLen)
- Byte *compr;
- uLong *comprLen;
- {
- z_stream c_stream; /* compression stream */
- int err;
- int len = strlen(hello)+1;
- c_stream.zalloc = (alloc_func)0;
- c_stream.zfree = (free_func)0;
- c_stream.opaque = (voidpf)0;
- err = deflateInit(&c_stream, Z_DEFAULT_COMPRESSION);
- CHECK_ERR(err, "deflateInit");
- c_stream.next_in = (Bytef*)hello;
- c_stream.next_out = compr;
- c_stream.avail_in = 3;
- c_stream.avail_out = (uInt)*comprLen;
- err = deflate(&c_stream, Z_FULL_FLUSH);
- CHECK_ERR(err, "deflate");
- compr[3]++; /* force an error in first compressed block */
- c_stream.avail_in = len - 3;
- err = deflate(&c_stream, Z_FINISH);
- if (err != Z_STREAM_END) {
- CHECK_ERR(err, "deflate");
- }
- err = deflateEnd(&c_stream);
- CHECK_ERR(err, "deflateEnd");
- *comprLen = c_stream.total_out;
- }
- /* ===========================================================================
- * Test inflateSync()
- */
- void test_sync(compr, comprLen, uncompr, uncomprLen)
- Byte *compr, *uncompr;
- uLong comprLen, uncomprLen;
- {
- int err;
- z_stream d_stream; /* decompression stream */
- strcpy((char*)uncompr, "garbage");
- d_stream.zalloc = (alloc_func)0;
- d_stream.zfree = (free_func)0;
- d_stream.opaque = (voidpf)0;
- d_stream.next_in = compr;
- d_stream.avail_in = 2; /* just read the zlib header */
- err = inflateInit(&d_stream);
- CHECK_ERR(err, "inflateInit");
- d_stream.next_out = uncompr;
- d_stream.avail_out = (uInt)uncomprLen;
- inflate(&d_stream, Z_NO_FLUSH);
- CHECK_ERR(err, "inflate");
- d_stream.avail_in = (uInt)comprLen-2; /* read all compressed data */
- err = inflateSync(&d_stream); /* but skip the damaged part */
- CHECK_ERR(err, "inflateSync");
- err = inflate(&d_stream, Z_FINISH);
- if (err != Z_DATA_ERROR) {
- fprintf(stderr, "inflate should report DATA_ERRORn");
- /* Because of incorrect adler32 */
- exit(1);
- }
- err = inflateEnd(&d_stream);
- CHECK_ERR(err, "inflateEnd");
- printf("after inflateSync(): hel%sn", (char *)uncompr);
- }
- /* ===========================================================================
- * Test deflate() with preset dictionary
- */
- void test_dict_deflate(compr, comprLen)
- Byte *compr;
- uLong comprLen;
- {
- z_stream c_stream; /* compression stream */
- int err;
- c_stream.zalloc = (alloc_func)0;
- c_stream.zfree = (free_func)0;
- c_stream.opaque = (voidpf)0;
- err = deflateInit(&c_stream, Z_BEST_COMPRESSION);
- CHECK_ERR(err, "deflateInit");
- err = deflateSetDictionary(&c_stream,
- (const Bytef*)dictionary, sizeof(dictionary));
- CHECK_ERR(err, "deflateSetDictionary");
- dictId = c_stream.adler;
- c_stream.next_out = compr;
- c_stream.avail_out = (uInt)comprLen;
- c_stream.next_in = (Bytef*)hello;
- c_stream.avail_in = (uInt)strlen(hello)+1;
- err = deflate(&c_stream, Z_FINISH);
- if (err != Z_STREAM_END) {
- fprintf(stderr, "deflate should report Z_STREAM_ENDn");
- exit(1);
- }
- err = deflateEnd(&c_stream);
- CHECK_ERR(err, "deflateEnd");
- }
- /* ===========================================================================
- * Test inflate() with a preset dictionary
- */
- void test_dict_inflate(compr, comprLen, uncompr, uncomprLen)
- Byte *compr, *uncompr;
- uLong comprLen, uncomprLen;
- {
- int err;
- z_stream d_stream; /* decompression stream */
- strcpy((char*)uncompr, "garbage");
- d_stream.zalloc = (alloc_func)0;
- d_stream.zfree = (free_func)0;
- d_stream.opaque = (voidpf)0;
- d_stream.next_in = compr;
- d_stream.avail_in = (uInt)comprLen;
- err = inflateInit(&d_stream);
- CHECK_ERR(err, "inflateInit");
- d_stream.next_out = uncompr;
- d_stream.avail_out = (uInt)uncomprLen;
- for (;;) {
- err = inflate(&d_stream, Z_NO_FLUSH);
- if (err == Z_STREAM_END) break;
- if (err == Z_NEED_DICT) {
- if (d_stream.adler != dictId) {
- fprintf(stderr, "unexpected dictionary");
- exit(1);
- }
- err = inflateSetDictionary(&d_stream, (const Bytef*)dictionary,
- sizeof(dictionary));
- }
- CHECK_ERR(err, "inflate with dict");
- }
- err = inflateEnd(&d_stream);
- CHECK_ERR(err, "inflateEnd");
- if (strcmp((char*)uncompr, hello)) {
- fprintf(stderr, "bad inflate with dictn");
- exit(1);
- } else {
- printf("inflate with dictionary: %sn", (char *)uncompr);
- }
- }
- /* ===========================================================================
- * Usage: example [output.gz [input.gz]]
- */
- int main(argc, argv)
- int argc;
- char *argv[];
- {
- Byte *compr, *uncompr;
- uLong comprLen = 10000*sizeof(int); /* don't overflow on MSDOS */
- uLong uncomprLen = comprLen;
- static const char* myVersion = ZLIB_VERSION;
- if (zlibVersion()[0] != myVersion[0]) {
- fprintf(stderr, "incompatible zlib versionn");
- exit(1);
- } else if (strcmp(zlibVersion(), ZLIB_VERSION) != 0) {
- fprintf(stderr, "warning: different zlib versionn");
- }
- compr = (Byte*)calloc((uInt)comprLen, 1);
- uncompr = (Byte*)calloc((uInt)uncomprLen, 1);
- /* compr and uncompr are cleared to avoid reading uninitialized
- * data and to ensure that uncompr compresses well.
- */
- if (compr == Z_NULL || uncompr == Z_NULL) {
- printf("out of memoryn");
- exit(1);
- }
- test_compress(compr, comprLen, uncompr, uncomprLen);
- test_gzio((argc > 1 ? argv[1] : TESTFILE),
- (argc > 2 ? argv[2] : TESTFILE),
- uncompr, (int)uncomprLen);
- test_deflate(compr, comprLen);
- test_inflate(compr, comprLen, uncompr, uncomprLen);
- test_large_deflate(compr, comprLen, uncompr, uncomprLen);
- test_large_inflate(compr, comprLen, uncompr, uncomprLen);
- test_flush(compr, &comprLen);
- test_sync(compr, comprLen, uncompr, uncomprLen);
- comprLen = uncomprLen;
- test_dict_deflate(compr, comprLen);
- test_dict_inflate(compr, comprLen, uncompr, uncomprLen);
- exit(0);
- return 0; /* to avoid warning */
- }