289 lines
7.0 KiB
C
289 lines
7.0 KiB
C
/* example.c -- usage example of the zlib compression library
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* Copyright (C) 1995 Jean-loup Gailly.
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* For conditions of distribution and use, see copyright notice in zlib.h
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*/
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/* $Id: example.c,v 1.7 1995/05/01 16:57:22 jloup Exp $ */
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#include <stdio.h>
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#include "zlib.h"
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#ifdef STDC
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# include <string.h>
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#endif
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extern void exit __P((int));
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#define BUFLEN 4096
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#define local static
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/* For MSDOS and other systems with limitation on stack size. For Unix,
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#define local
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works also.
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*/
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#define CHECK_ERR(err, msg) { \
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if (err != Z_OK) { \
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fprintf(stderr, "%s error: %d\n", msg, err); \
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exit(1); \
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} \
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}
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char *hello = "hello world";
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void test_compress __P((void));
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void test_gzio __P((char *out, char *in));
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void test_deflate __P((Byte compr[]));
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void test_inflate __P((Byte compr[]));
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void main __P((int argc, char *argv[]));
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/* ===========================================================================
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* Test compress() and uncompress()
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*/
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void test_compress()
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{
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local Byte compr[BUFLEN];
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uLong comprLen = sizeof(compr);
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local Byte uncompr[BUFLEN];
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uLong uncomprLen = sizeof(uncompr);
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int err;
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uLong len = strlen(hello)+1;
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err = compress(compr, &comprLen, (Byte*)hello, len);
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CHECK_ERR(err, "compress");
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strcpy((char*)uncompr, "garbage");
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err = uncompress(uncompr, &uncomprLen, compr, comprLen);
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CHECK_ERR(err, "uncompress");
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if (strcmp((char*)uncompr, hello)) {
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fprintf(stderr, "bad uncompress\n");
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} else {
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printf("uncompress(): %s\n", uncompr);
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}
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}
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/* ===========================================================================
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* Test read/write of .gz files
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*/
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void test_gzio(out, in)
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char *out; /* output file */
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char *in; /* input file */
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{
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local Byte uncompr[BUFLEN];
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int uncomprLen = sizeof(uncompr);
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int err;
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int len = strlen(hello)+1;
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gzFile file;
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file = gzopen(out, "wb");
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if (file == NULL) {
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fprintf(stderr, "gzopen error\n");
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exit(1);
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}
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if (gzwrite(file, hello, len) != len) {
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fprintf(stderr, "gzwrite err: %s\n", gzerror(file, &err));
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}
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gzclose(file);
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file = gzopen(in, "rb");
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if (file == NULL) {
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fprintf(stderr, "gzopen error\n");
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}
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strcpy((char*)uncompr, "garbage");
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uncomprLen = gzread(file, uncompr, uncomprLen);
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if (uncomprLen != len) {
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fprintf(stderr, "gzread err: %s\n", gzerror(file, &err));
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}
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gzclose(file);
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if (strcmp((char*)uncompr, hello)) {
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fprintf(stderr, "bad gzread\n");
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} else {
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printf("gzread(): %s\n", uncompr);
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}
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}
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/* ===========================================================================
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* Test deflate() with small buffers
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*/
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void test_deflate(compr)
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Byte compr[];
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{
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z_stream c_stream; /* compression stream */
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int err;
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int len = strlen(hello)+1;
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c_stream.zalloc = (alloc_func)0;
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c_stream.zfree = (free_func)0;
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err = deflateInit(&c_stream, Z_DEFAULT_COMPRESSION);
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CHECK_ERR(err, "deflateInit");
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c_stream.next_in = (Byte*)hello;
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c_stream.next_out = compr;
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while (c_stream.total_in != (uLong)len) {
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c_stream.avail_in = c_stream.avail_out = 1; /* force small buffers */
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err = deflate(&c_stream, Z_NO_FLUSH);
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CHECK_ERR(err, "deflate");
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}
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/* Finish the stream, still forcing small buffers: */
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for (;;) {
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c_stream.avail_out = 1;
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err = deflate(&c_stream, Z_FINISH);
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if (err == Z_STREAM_END) break;
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CHECK_ERR(err, "deflate");
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}
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err = deflateEnd(&c_stream);
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CHECK_ERR(err, "deflateEnd");
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}
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/* ===========================================================================
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* Test inflate() with small buffers
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*/
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void test_inflate(compr)
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Byte compr[];
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{
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local Byte uncompr[BUFLEN];
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int err;
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z_stream d_stream; /* decompression stream */
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strcpy((char*)uncompr, "garbage");
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d_stream.zalloc = (alloc_func)0;
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d_stream.zfree = (free_func)0;
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err = inflateInit(&d_stream);
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CHECK_ERR(err, "inflateInit");
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d_stream.next_in = compr;
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d_stream.next_out = uncompr;
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for (;;) {
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d_stream.avail_in = d_stream.avail_out = 1; /* force small buffers */
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err = inflate(&d_stream, Z_NO_FLUSH);
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if (err == Z_STREAM_END) break;
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CHECK_ERR(err, "inflate");
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}
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err = inflateEnd(&d_stream);
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CHECK_ERR(err, "inflateEnd");
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if (strcmp((char*)uncompr, hello)) {
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fprintf(stderr, "bad inflate\n");
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} else {
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printf("inflate(): %s\n", uncompr);
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}
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}
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/* ===========================================================================
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* Test deflate() with full flush
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*/
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void test_flush(compr)
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Byte compr[];
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{
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z_stream c_stream; /* compression stream */
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int err;
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int len = strlen(hello)+1;
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c_stream.zalloc = (alloc_func)0;
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c_stream.zfree = (free_func)0;
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err = deflateInit(&c_stream, Z_DEFAULT_COMPRESSION);
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CHECK_ERR(err, "deflateInit");
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c_stream.next_in = (Byte*)hello;
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c_stream.next_out = compr;
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c_stream.avail_in = 3;
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c_stream.avail_out = BUFLEN;
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err = deflate(&c_stream, Z_FULL_FLUSH);
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CHECK_ERR(err, "deflate");
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compr[3]++; /* force an error in first compressed block */
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c_stream.avail_in = len - 3;
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err = deflate(&c_stream, Z_FINISH);
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if (err != Z_STREAM_END) {
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CHECK_ERR(err, "deflate");
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}
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err = deflateEnd(&c_stream);
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CHECK_ERR(err, "deflateEnd");
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}
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/* ===========================================================================
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* Test inflateSync()
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*/
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void test_sync(compr)
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Byte compr[];
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{
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local Byte uncompr[BUFLEN];
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int err;
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z_stream d_stream; /* decompression stream */
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strcpy((char*)uncompr, "garbage");
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d_stream.zalloc = (alloc_func)0;
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d_stream.zfree = (free_func)0;
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err = inflateInit(&d_stream);
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CHECK_ERR(err, "inflateInit");
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d_stream.next_in = compr;
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d_stream.next_out = uncompr;
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d_stream.avail_in = 2; /* just read the zlib header */
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d_stream.avail_out = sizeof(uncompr);
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inflate(&d_stream, Z_NO_FLUSH);
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CHECK_ERR(err, "inflate");
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d_stream.avail_in = BUFLEN-2; /* let inflate read all compressed data */
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err = inflateSync(&d_stream); /* skip the damaged part */
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CHECK_ERR(err, "inflateSync");
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err = inflate(&d_stream, Z_FINISH);
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if (err != Z_DATA_ERROR) {
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fprintf(stderr, "inflate should report DATA_ERROR\n");
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/* Because of incorrect adler32 */
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}
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err = inflateEnd(&d_stream);
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CHECK_ERR(err, "inflateEnd");
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printf("after inflateSync(): %s\n", uncompr);
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}
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/* ===========================================================================
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* Usage: example [output.gz [input.gz]]
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*/
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void main(argc, argv)
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int argc;
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char *argv[];
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{
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local Byte compr[BUFLEN];
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if (zlib_version[0] != ZLIB_VERSION[0]) {
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fprintf(stderr, "incompatible zlib version\n");
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exit(1);
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} else if (strcmp(zlib_version, ZLIB_VERSION) != 0) {
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fprintf(stderr, "warning: different zlib version\n");
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}
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test_compress();
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test_gzio((argc > 1 ? argv[1] : "foo.gz"),
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(argc > 2 ? argv[2] : "foo.gz"));
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test_deflate(compr);
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test_inflate(compr);
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test_flush(compr);
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test_sync(compr);
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exit(0);
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}
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