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/* example.c -- usage example of the zlib compression library
* Copyright (C) 1995 Jean-loup Gailly.
* For conditions of distribution and use, see copyright notice in zlib.h
*/
/* $Id: example.c,v 1.4 1995/04/14 13:32:49 jloup Exp $ */
#include <stdio.h>
#include "zlib.h"
#define BUFLEN 4096
#define local static
/* For MSDOS and other systems with limitation on stack size. For Unix,
#define local
works also.
*/
#define CHECK_ERR(err, msg) { \
if (err != Z_OK) { \
fprintf(stderr, "%s error: %d\n", msg, err); \
exit(1); \
} \
}
char *hello = "hello world";
/* ===========================================================================
* Test compress() and uncompress()
*/
void test_compress()
{
local Byte compr[BUFLEN];
uLong comprLen = sizeof(compr);
local Byte uncompr[BUFLEN];
uLong uncomprLen = sizeof(uncompr);
int err;
uLong len = strlen(hello)+1;
err = compress(compr, &comprLen, hello, len);
CHECK_ERR(err, "compress");
strcpy(uncompr, "garbage");
err = uncompress(uncompr, &uncomprLen, compr, comprLen);
CHECK_ERR(err, "uncompress");
if (strcmp(uncompr, hello)) {
fprintf(stderr, "bad uncompress\n");
} else {
printf("uncompress(): %s\n", uncompr);
}
}
/* ===========================================================================
* Test read/write of .gz files
*/
void test_gzio(out, in)
char *out; /* output file */
char *in; /* input file */
{
local Byte uncompr[BUFLEN];
uLong uncomprLen = sizeof(uncompr);
int err;
int len = strlen(hello)+1;
gzFile file;
file = gzopen(out, "wb");
if (file == NULL) {
fprintf(stderr, "gzopen error\n");
exit(1);
}
if (gzwrite(file, hello, len) != len) {
fprintf(stderr, "gzwrite err: %s\n", gzerror(file, &err));
}
gzclose(file);
file = gzopen(in, "rb");
if (file == NULL) {
fprintf(stderr, "gzopen error\n");
}
strcpy(uncompr, "garbage");
uncomprLen = gzread(file, uncompr, uncomprLen);
if (uncomprLen != len) {
fprintf(stderr, "gzread err: %s\n", gzerror(file, &err));
}
gzclose(file);
if (strcmp(uncompr, hello)) {
fprintf(stderr, "bad gzread\n");
} else {
printf("gzread(): %s\n", uncompr);
}
}
/* ===========================================================================
* Test deflate() with small buffers, return the compressed length.
*/
uLong test_deflate(compr)
Byte compr[];
{
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;
err = deflateInit(&c_stream, Z_DEFAULT_COMPRESSION);
CHECK_ERR(err, "deflateInit");
c_stream.next_in = (Byte*)hello;
c_stream.next_out = compr;
while (c_stream.total_in != len) {
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: */
do {
c_stream.avail_out = 1;
err = deflate(&c_stream, Z_FINISH);
CHECK_ERR(err, "deflate");
} while (c_stream.avail_out == 0);
err = deflateEnd(&c_stream);
CHECK_ERR(err, "deflateEnd");
return c_stream.total_out;
}
/* ===========================================================================
* Test inflate() with small buffers
*/
void test_inflate(compr)
Byte compr[];
{
local Byte uncompr[BUFLEN];
int err;
z_stream d_stream; /* decompression stream */
strcpy(uncompr, "garbage");
d_stream.zalloc = (alloc_func)0;
d_stream.zfree = (free_func)0;
err = inflateInit(&d_stream);
CHECK_ERR(err, "inflateInit");
d_stream.next_in = compr;
d_stream.next_out = uncompr;
for (;;) {
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(uncompr, hello)) {
fprintf(stderr, "bad inflate\n");
} else {
printf("inflate(): %s\n", uncompr);
}
}
/* ===========================================================================
* Usage: example [output.gz [input.gz]]
*/
void main(argc, argv)
int argc;
char *argv[];
{
local Byte compr[BUFLEN];
uLong comprLen;
if (zlib_version[0] != ZLIB_VERSION[0]) {
fprintf(stderr, "incompatible zlib version\n");
exit(1);
} else if (strcmp(zlib_version, ZLIB_VERSION) != 0) {
fprintf(stderr, "warning: different zlib version\n");
}
test_compress();
test_gzio((argc > 1 ? argv[1] : "foo.gz"),
(argc > 2 ? argv[2] : "foo.gz"));
comprLen = test_deflate(compr);
test_inflate(compr);
exit(0);
}
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