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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 <stdint.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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