504 lines
14 KiB
C
504 lines
14 KiB
C
/* example.c -- usage example of the zlib compression library
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* Copyright (C) 1995-1996 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 1.16 1996/05/23 17:11:28 me 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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# include <stdlib.h>
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#else
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extern void exit OF((int));
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#endif
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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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const char hello[] = "hello, hello!";
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/* "hello world" would be more standard, but the repeated "hello"
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* stresses the compression code better, sorry...
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*/
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const char dictionary[] = "hello";
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uLong dictId; /* Adler32 value of the dictionary */
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void test_compress OF((Byte *compr, uLong comprLen,
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Byte *uncompr, uLong uncomprLen));
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void test_gzio OF((const char *out, const char *in,
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Byte *uncompr, int uncomprLen));
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void test_deflate OF((Byte *compr, uLong comprLen));
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void test_inflate OF((Byte *compr, uLong comprLen,
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Byte *uncompr, uLong uncomprLen));
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void test_large_deflate OF((Byte *compr, uLong comprLen,
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Byte *uncompr, uLong uncomprLen));
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void test_large_inflate OF((Byte *compr, uLong comprLen,
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Byte *uncompr, uLong uncomprLen));
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void test_flush OF((Byte *compr, uLong comprLen));
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void test_sync OF((Byte *compr, uLong comprLen,
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Byte *uncompr, uLong uncomprLen));
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void test_dict_deflate OF((Byte *compr, uLong comprLen));
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void test_dict_inflate OF((Byte *compr, uLong comprLen,
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Byte *uncompr, uLong uncomprLen));
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int main OF((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(compr, comprLen, uncompr, uncomprLen)
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Byte *compr, *uncompr;
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uLong comprLen, uncomprLen;
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{
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int err;
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uLong len = strlen(hello)+1;
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err = compress(compr, &comprLen, (const Bytef*)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, uncompr, uncomprLen)
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const char *out; /* output file */
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const char *in; /* input file */
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Byte *uncompr;
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int uncomprLen;
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{
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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, (const voidp)hello, (unsigned)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, (unsigned)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, comprLen)
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Byte *compr;
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uLong comprLen;
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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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c_stream.opaque = (voidpf)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 = (Bytef*)hello;
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c_stream.next_out = compr;
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while (c_stream.total_in != (uLong)len && c_stream.total_out < comprLen) {
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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, comprLen, uncompr, uncomprLen)
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Byte *compr, *uncompr;
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uLong comprLen, uncomprLen;
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{
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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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d_stream.opaque = (voidpf)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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while (d_stream.total_out < uncomprLen && d_stream.total_in < comprLen) {
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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 large buffers and dynamic change of compression level
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*/
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void test_large_deflate(compr, comprLen, uncompr, uncomprLen)
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Byte *compr, *uncompr;
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uLong comprLen, uncomprLen;
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{
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z_stream c_stream; /* compression stream */
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int err;
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c_stream.zalloc = (alloc_func)0;
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c_stream.zfree = (free_func)0;
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c_stream.opaque = (voidpf)0;
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err = deflateInit(&c_stream, Z_BEST_SPEED);
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CHECK_ERR(err, "deflateInit");
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c_stream.next_out = compr;
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c_stream.avail_out = (uInt)comprLen;
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/* At this point, uncompr is still mostly zeroes, so it should compress
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* very well:
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*/
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c_stream.next_in = uncompr;
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c_stream.avail_in = (uInt)uncomprLen;
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err = deflate(&c_stream, Z_NO_FLUSH);
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CHECK_ERR(err, "deflate");
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if (c_stream.avail_in != 0) {
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fprintf(stderr, "deflate not greedy\n");
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}
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/* Feed in already compressed data and switch to no compression: */
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deflateParams(&c_stream, Z_NO_COMPRESSION, Z_DEFAULT_STRATEGY);
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c_stream.next_in = compr;
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c_stream.avail_in = (uInt)comprLen/2;
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err = deflate(&c_stream, Z_NO_FLUSH);
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CHECK_ERR(err, "deflate");
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/* Switch back to compressing mode: */
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deflateParams(&c_stream, Z_BEST_COMPRESSION, Z_FILTERED);
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c_stream.next_in = uncompr;
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c_stream.avail_in = (uInt)uncomprLen;
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err = deflate(&c_stream, Z_NO_FLUSH);
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CHECK_ERR(err, "deflate");
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err = deflate(&c_stream, Z_FINISH);
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if (err != Z_STREAM_END) {
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fprintf(stderr, "deflate should report Z_STREAM_END\n");
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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 large buffers
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*/
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void test_large_inflate(compr, comprLen, uncompr, uncomprLen)
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Byte *compr, *uncompr;
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uLong comprLen, uncomprLen;
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{
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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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d_stream.opaque = (voidpf)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.avail_in = (uInt)comprLen;
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for (;;) {
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d_stream.next_out = uncompr; /* discard the output */
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d_stream.avail_out = (uInt)uncomprLen;
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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, "large 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 (d_stream.total_out != 2*uncomprLen + comprLen/2) {
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fprintf(stderr, "bad large inflate: %ld\n", d_stream.total_out);
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} else {
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printf("large_inflate(): OK\n");
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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, comprLen)
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Byte *compr;
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uLong comprLen;
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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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c_stream.opaque = (voidpf)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 = (Bytef*)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 = (uInt)comprLen;
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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, comprLen, uncompr, uncomprLen)
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Byte *compr, *uncompr;
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uLong comprLen, uncomprLen;
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{
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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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d_stream.opaque = (voidpf)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 = (uInt)uncomprLen;
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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 = (uInt)comprLen-2; /* read all compressed data */
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err = inflateSync(&d_stream); /* but 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(): hel%s\n", uncompr);
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}
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/* ===========================================================================
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* Test deflate() with preset dictionary
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*/
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void test_dict_deflate(compr, comprLen)
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Byte *compr;
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uLong comprLen;
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{
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z_stream c_stream; /* compression stream */
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int err;
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c_stream.zalloc = (alloc_func)0;
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c_stream.zfree = (free_func)0;
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c_stream.opaque = (voidpf)0;
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err = deflateInit(&c_stream, Z_BEST_COMPRESSION);
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CHECK_ERR(err, "deflateInit");
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err = deflateSetDictionary(&c_stream,
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(const Bytef*)dictionary, sizeof(dictionary));
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CHECK_ERR(err, "deflateSetDictionary");
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dictId = c_stream.adler;
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c_stream.next_out = compr;
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c_stream.avail_out = (uInt)comprLen;
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c_stream.next_in = (Bytef*)hello;
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c_stream.avail_in = (uInt)strlen(hello)+1;
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err = deflate(&c_stream, Z_FINISH);
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if (err != Z_STREAM_END) {
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fprintf(stderr, "deflate should report Z_STREAM_END\n");
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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 a preset dictionary
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*/
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void test_dict_inflate(compr, comprLen, uncompr, uncomprLen)
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Byte *compr, *uncompr;
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uLong comprLen, uncomprLen;
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{
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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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d_stream.opaque = (voidpf)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.avail_in = (uInt)comprLen;
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d_stream.next_out = uncompr;
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d_stream.avail_out = (uInt)uncomprLen;
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for (;;) {
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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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if (err == Z_NEED_DICT) {
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if (d_stream.adler != dictId) {
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fprintf(stderr, "unexpected dictionary");
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exit(1);
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}
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err = inflateSetDictionary(&d_stream, (const Bytef*)dictionary,
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sizeof(dictionary));
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}
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CHECK_ERR(err, "inflate with dict");
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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 with dict\n");
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} else {
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printf("inflate with dictionary: %s\n", uncompr);
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}
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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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int main(argc, argv)
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int argc;
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char *argv[];
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{
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Byte *compr, *uncompr;
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uLong comprLen = 10000*sizeof(int); /* don't overflow on MSDOS */
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uLong uncomprLen = comprLen;
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if (zlibVersion()[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(zlibVersion(), ZLIB_VERSION) != 0) {
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fprintf(stderr, "warning: different zlib version\n");
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}
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compr = (Byte*)calloc((uInt)comprLen, 1);
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uncompr = (Byte*)calloc((uInt)uncomprLen, 1);
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/* compr and uncompr are cleared to avoid reading uninitialized
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* data and to ensure that uncompr compresses well.
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*/
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if (compr == Z_NULL || uncompr == Z_NULL) {
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printf("out of memory\n");
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exit(1);
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}
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test_compress(compr, comprLen, uncompr, uncomprLen);
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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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uncompr, (int)uncomprLen);
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test_deflate(compr, comprLen);
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test_inflate(compr, comprLen, uncompr, uncomprLen);
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test_large_deflate(compr, comprLen, uncompr, uncomprLen);
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test_large_inflate(compr, comprLen, uncompr, uncomprLen);
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test_flush(compr, comprLen);
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test_sync(compr, comprLen, uncompr, uncomprLen);
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test_dict_deflate(compr, comprLen);
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test_dict_inflate(compr, comprLen, uncompr, uncomprLen);
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exit(0);
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return 0; /* to avoid warning */
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|
}
|