36 lines
1.2 KiB
C
36 lines
1.2 KiB
C
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/*
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* This file is part of OP25
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*
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* This is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 3, or (at your option)
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* any later version.
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*
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* This software is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this software; see the file COPYING. If not, write to
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* the Free Software Foundation, Inc., 51 Franklin Street,
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* Boston, MA 02110-1301, USA.
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*/
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#ifndef INCLUDED_CRC16_H
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#define INCLUDED_CRC16_H
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static inline uint16_t crc16(const uint8_t buf[], int len) {
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uint32_t poly = (1<<12) + (1<<5) + (1<<0);
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uint32_t crc = 0;
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for(int i=0; i<len; i++) {
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uint8_t bit = buf[i] & 1;
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crc = ((crc << 1) | bit) & 0x1ffff;
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if (crc & 0x10000)
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crc = (crc & 0xffff) ^ poly;
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}
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crc = crc ^ 0xffff;
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return crc & 0xffff;
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}
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#endif /* INCLUDED_CRC16_H */
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