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/*
* tgunzip - gzip decompressor example
*
* Copyright (c) 2003 by Joergen Ibsen / Jibz
* All Rights Reserved
*
* http://www.ibsensoftware.com/
*
* Copyright (c) 2014-2016 by Paul Sokolovsky
*
* This software is provided 'as-is', without any express
* or implied warranty. In no event will the authors be
* held liable for any damages arising from the use of
* this software.
*
* Permission is granted to anyone to use this software
* for any purpose, including commercial applications,
* and to alter it and redistribute it freely, subject to
* the following restrictions:
*
* 1. The origin of this software must not be
* misrepresented; you must not claim that you
* wrote the original software. If you use this
* software in a product, an acknowledgment in
* the product documentation would be appreciated
* but is not required.
*
* 2. Altered source versions must be plainly marked
* as such, and must not be misrepresented as
* being the original software.
*
* 3. This notice may not be removed or altered from
* any source distribution.
*/
#include <stdlib.h>
#include <stdio.h>
#include "uzlib.h"
/* produce decompressed output in chunks of this size */
/* defauly is to decompress byte by byte; can be any other length */
#define OUT_CHUNK_SIZE 1
void exit_error(const char *what)
{
printf("ERROR: %s\n", what);
exit(1);
}
int main(int argc, char *argv[])
{
FILE *fin, *fout;
unsigned int len, dlen, outlen;
const unsigned char *source;
unsigned char *dest;
int res;
printf("tgunzip - example from the tiny inflate library (www.ibsensoftware.com)\n\n");
if (argc < 3)
{
printf(
"Syntax: tgunzip <source> <destination>\n\n"
"Both input and output are kept in memory, so do not use this on huge files.\n");
return 1;
}
uzlib_init();
/* -- open files -- */
if ((fin = fopen(argv[1], "rb")) == NULL) exit_error("source file");
if ((fout = fopen(argv[2], "wb")) == NULL) exit_error("destination file");
/* -- read source -- */
fseek(fin, 0, SEEK_END);
len = ftell(fin);
fseek(fin, 0, SEEK_SET);
source = (unsigned char *)malloc(len);
if (source == NULL) exit_error("memory");
if (fread((unsigned char*)source, 1, len, fin) != len) exit_error("read");
fclose(fin);
if (len < 4) exit_error("file too small");
/* -- get decompressed length -- */
dlen = source[len - 1];
dlen = 256*dlen + source[len - 2];
dlen = 256*dlen + source[len - 3];
dlen = 256*dlen + source[len - 4];
outlen = dlen;
/* there can be mismatch between length in the trailer and actual
data stream; to avoid buffer overruns on overlong streams, reserve
one extra byte */
dlen++;
dest = (unsigned char *)malloc(dlen);
if (dest == NULL) exit_error("memory");
/* -- decompress data -- */
struct uzlib_uncomp d;
// uzlib_uncompress_init(&d, malloc(32768), 32768);
uzlib_uncompress_init(&d, NULL, 0);
/* all 3 fields below must be initialized by user */
d.source = source;
d.source_limit = source + len - 4;
d.source_read_cb = NULL;
res = uzlib_gzip_parse_header(&d);
if (res != TINF_OK) {
printf("Error parsing header: %d\n", res);
exit(1);
}
d.dest_start = d.dest = dest;
while (dlen) {
unsigned int chunk_len = dlen < OUT_CHUNK_SIZE ? dlen : OUT_CHUNK_SIZE;
d.dest_limit = d.dest + chunk_len;
res = uzlib_uncompress_chksum(&d);
dlen -= chunk_len;
if (res != TINF_OK) {
break;
}
}
if (res != TINF_DONE) {
printf("Error during decompression: %d\n", res);
exit(-res);
}
printf("decompressed %lu bytes\n", d.dest - dest);
#if 0
if (d.dest - dest != gz.dlen) {
printf("Invalid decompressed length: %lu vs %u\n", d.dest - dest, gz.dlen);
}
if (tinf_crc32(dest, gz.dlen) != gz.crc32) {
printf("Invalid decompressed crc32\n");
}
#endif
/* -- write output -- */
fwrite(dest, 1, outlen, fout);
fclose(fout);
return 0;
}
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