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/* unzip.c -- decompress files in gzip or pkzip format.
* Copyright (C) 1992-1993 Jean-loup Gailly
* This is free software; you can redistribute it and/or modify it under the
* terms of the GNU General Public License, see the file COPYING.
*
* The code in this file is derived from the file funzip.c written
* and put in the public domain by Mark Adler.
*/
/*
This version can extract files in gzip format.
Only the first entry is extracted, and it has to be
either deflated or stored.
*/
#ifdef RCSID
static char rcsid[] = "$Id: unzip.c,v 1.1 2002/08/18 00:59:21 hpa Exp $";
#endif
#include "tailor.h"
#include "gzip.h"
/* ===========================================================================
* Unzip in to out. This routine works on gzip files only.
*
* IN assertions: the buffer inbuf contains already the beginning of
* the compressed data, from offsets inptr to insize-1 included.
* The magic header has already been checked. The output buffer is cleared.
*/
int unzip(int in, int out)
{
ulg orig_crc = 0; /* original crc */
ulg orig_len = 0; /* original uncompressed length */
int n;
uch buf[8]; /* extended local header */
ifd = in;
ofd = out;
updcrc(NULL, 0); /* initialize crc */
/* Decompress */
if (method == DEFLATED) {
int res = inflate();
if (res == 3) {
error("out of memory");
} else if (res != 0) {
error("invalid compressed data--format violated");
}
} else {
error("internal error, invalid method");
}
/* Get the crc and original length */
/* crc32 (see algorithm.doc)
* uncompressed input size modulo 2^32
*/
for (n = 0; n < 8; n++) {
buf[n] = (uch)get_byte(); /* may cause an error if EOF */
}
orig_crc = LG(buf);
orig_len = LG(buf + 4);
/* Validate decompression */
if (orig_crc != updcrc(outbuf, 0)) {
error("invalid compressed data--crc error");
}
if (orig_len != (ulg)bytes_out) {
error("invalid compressed data--length error");
}
return OK;
}
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