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1 | /****************************************************************************** |
2 | * Arachnoid Graphics Plugin for Mupen64Plus |
3 | * http://bitbucket.org/wahrhaft/mupen64plus-video-arachnoid/ |
4 | * |
5 | * Copyright (C) 2007 Kristofer Karlsson, Rickard Niklasson |
6 | * |
7 | * This program is free software; you can redistribute it and/or |
8 | * modify it under the terms of the GNU General Public License |
9 | * as published by the Free Software Foundation; either version 2 |
10 | * of the License, or (at your option) any later version. |
11 | * |
12 | * This program is distributed in the hope that it will be useful, |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
15 | * GNU General Public License for more details. |
16 | * |
17 | * You should have received a copy of the GNU General Public License |
18 | * along with this program; if not, write to the Free Software |
19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. |
20 | *****************************************************************************/ |
21 | |
22 | #ifndef CYCLIC_REDUNDANCY_CHECK_CALCULATOR_H_ |
23 | #define CYCLIC_REDUNDANCY_CHECK_CALCULATOR_H_ |
24 | |
25 | //***************************************************************************** |
26 | //! Cyclic Redundancy Check Calculator |
27 | //! CRC is a type of hash function which is used to produce a small, |
28 | //! fixed-size checksum of a larger block of data. |
29 | //! |
30 | //! Often used in networks for reducing errors caused by noise. |
31 | //! |
32 | //! http://en.wikipedia.org/wiki/CRC32 |
33 | //! http://en.wikipedia.org/wiki/Hash_function |
34 | //! http://en.wikipedia.org/wiki/Hash_table |
35 | //! http://www.gamedev.net/reference/articles/article1941.asp |
36 | //! http://www.codeproject.com/cpp/crc32_large.asp |
37 | //***************************************************************************** |
38 | class CRCCalculator |
39 | { |
40 | public: |
41 | |
42 | //Constructor |
43 | CRCCalculator(); |
44 | |
45 | //Functions for calculating crc values |
46 | unsigned int calcCRC(unsigned int crc, void *buffer, unsigned int count); |
47 | unsigned int calcPaletteCRC(unsigned int crc, void *buffer, unsigned int count); |
48 | |
49 | private: |
50 | |
51 | //Help function used to build hash table |
52 | unsigned int _reflect(unsigned int ref, char ch); |
53 | |
54 | private: |
55 | |
56 | static unsigned int m_crcTable[256]; //!< Hash table that associates keys with values |
57 | }; |
58 | |
59 | #endif |