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/*
* uzlib - tiny deflate/inflate library (deflate, gzip, zlib)
*
* Copyright (c) 2003 by Joergen Ibsen / Jibz
* All Rights Reserved
*
* http://www.ibsensoftware.com/
*
* Copyright (c) 2014-2018 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;
}
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