Janosch
71 lines
1.8 KiB
C
71 lines
1.8 KiB
C
/*
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* This file is part of the stm32-sine project.
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*
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* Copyright (C) 2021 David J. Fiddes <D.J@fiddes.net>
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*
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* This program 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 of the License, or
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* (at your option) any later version.
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*
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* This program 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 program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef __CRC8_H_
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#define __CRC8_H_
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#include <stdint.h>
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/*
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* Precalculated look up table for CRC calculation
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*/
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extern const uint8_t crc_table[256];
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/**
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* \brief Calculate 8-bit CRC
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*
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*
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* Calculate an 8-bit CRC of a block of data. The algorithm used depends on
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* library configuration.
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*
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* \param[in] p pointer to the data to take we wish to compute the CRC of
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* \param[in] len length of the data
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* \param[in] crc Initial value for the CRC algorithm (or CRC of previous data)
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*
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* \return Calculated CRC value
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*/
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inline uint8_t crc8(uint8_t* p, uint8_t len, uint8_t crc)
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{
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while (len--)
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{
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crc = crc_table[crc ^ *p++];
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}
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return crc;
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}
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/**
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* \brief Calculate 8-bit CRC of a byte
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*
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* Calculate an 8-bit CRC of a single byte. The algorithm used depends on
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* library configuration.
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*
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* \param[in] input data byte to compute the CRC of
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* \param[in] crc Initial value for the CRC algorithm (or CRC of previous data)
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*
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* \return Calculated CRC value
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*/
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inline uint8_t crc8(uint8_t input, uint8_t crc)
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{
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crc = crc_table[crc ^ input];
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return crc;
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}
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#endif /* __CRC8_H_ */
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