67 lines
1.7 KiB
C
67 lines
1.7 KiB
C
/*
|
|
* tinfzlib - tiny zlib decompressor
|
|
*
|
|
* 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 "tinf.h"
|
|
|
|
int uzlib_zlib_parse_header(TINF_DATA *d)
|
|
{
|
|
unsigned char cmf, flg;
|
|
|
|
/* -- get header bytes -- */
|
|
|
|
cmf = uzlib_get_byte(d);
|
|
flg = uzlib_get_byte(d);
|
|
|
|
/* -- check format -- */
|
|
|
|
/* check checksum */
|
|
if ((256*cmf + flg) % 31) return TINF_DATA_ERROR;
|
|
|
|
/* check method is deflate */
|
|
if ((cmf & 0x0f) != 8) return TINF_DATA_ERROR;
|
|
|
|
/* check window size is valid */
|
|
if ((cmf >> 4) > 7) return TINF_DATA_ERROR;
|
|
|
|
/* check there is no preset dictionary */
|
|
if (flg & 0x20) return TINF_DATA_ERROR;
|
|
|
|
/* initialize for adler32 checksum */
|
|
d->checksum_type = TINF_CHKSUM_ADLER;
|
|
d->checksum = 1;
|
|
|
|
return cmf >> 4;
|
|
}
|