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/*
* CRC32 checksum
*
* Copyright (c) 1998-2003 by Joergen Ibsen / Jibz
* All Rights Reserved
*
* http://www.ibsensoftware.com/
*
* 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.
*/
/*
* CRC32 algorithm taken from the zlib source, which is
* Copyright (C) 1995-1998 Jean-loup Gailly and Mark Adler
*/
#include "uzlib.h"
static const unsigned int tinf_crc32tab[16] = {
0x00000000, 0x1db71064, 0x3b6e20c8, 0x26d930ac, 0x76dc4190,
0x6b6b51f4, 0x4db26158, 0x5005713c, 0xedb88320, 0xf00f9344,
0xd6d6a3e8, 0xcb61b38c, 0x9b64c2b0, 0x86d3d2d4, 0xa00ae278,
0xbdbdf21c
};
/* crc is previous value for incremental computation, 0xffffffff initially */
uint32_t uzlib_crc32(const void *data, unsigned int length, uint32_t crc)
{
const unsigned char *buf = (const unsigned char *)data;
unsigned int i;
for (i = 0; i < length; ++i)
{
crc ^= buf[i];
crc = tinf_crc32tab[crc & 0x0f] ^ (crc >> 4);
crc = tinf_crc32tab[crc & 0x0f] ^ (crc >> 4);
}
// return value suitable for passing in next time, for final value invert it
return crc/* ^ 0xffffffff*/;
}
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