| 1 | /* |
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| 2 | * ORXONOX - the hottest 3D action shooter ever to exist |
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| 3 | * > www.orxonox.net < |
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| 4 | * |
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| 5 | * |
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| 6 | * License notice: |
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| 7 | * |
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| 8 | * This program is free software; you can redistribute it and/or |
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| 9 | * modify it under the terms of the GNU General Public License |
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| 10 | * as published by the Free Software Foundation; either version 2 |
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| 11 | * of the License, or (at your option) any later version. |
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| 12 | * |
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| 13 | * This program is distributed in the hope that it will be useful, |
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| 14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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| 16 | * GNU General Public License for more details. |
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| 17 | * |
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| 18 | * You should have received a copy of the GNU General Public License |
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| 19 | * along with this program; if not, write to the Free Software |
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| 20 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. |
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| 21 | * |
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| 22 | * Author: |
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| 23 | * ... |
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| 24 | * Co-authors: |
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| 25 | * ... |
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| 26 | * |
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| 27 | */ |
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| 28 | |
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| 29 | #include "CRC32.h" |
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| 30 | |
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| 31 | namespace orxonox |
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| 32 | { |
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| 33 | void calcCRCBit(uint32_t &crc32, int bit) |
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| 34 | { |
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| 35 | int hbit = (crc32 & 0x80000000) ? 1 : 0; |
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| 36 | if (hbit != bit) |
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| 37 | crc32 = (crc32 << 1) ^ UTIL_CRC32POLY; |
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| 38 | else |
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| 39 | crc32 = crc32 << 1; |
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| 40 | } |
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| 41 | |
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| 42 | uint32_t calcCRC(unsigned char *data, unsigned int dataLength) |
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| 43 | { |
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| 44 | uint32_t crc32 = 0; |
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| 45 | for(unsigned int i = 0; i < dataLength; i++) |
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| 46 | { |
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| 47 | calcCRCBit(crc32, (data[i] & 0x1) >> 0); // 1st bit |
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| 48 | calcCRCBit(crc32, (data[i] & 0x2) >> 1); // 2nd bit |
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| 49 | calcCRCBit(crc32, (data[i] & 0x3) >> 2); // 3rd bit |
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| 50 | calcCRCBit(crc32, (data[i] & 0x4) >> 3); // 4th bit |
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| 51 | calcCRCBit(crc32, (data[i] & 0x5) >> 4); // 5th bit |
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| 52 | calcCRCBit(crc32, (data[i] & 0x6) >> 5); // 6th bit |
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| 53 | calcCRCBit(crc32, (data[i] & 0x7) >> 6); // 7th bit |
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| 54 | calcCRCBit(crc32, (data[i] & 0x8) >> 7); // 8th bit |
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| 55 | } |
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| 56 | return crc32; |
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| 57 | } |
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| 58 | } |
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| 59 | |
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