55 lines
1.3 KiB
C++
55 lines
1.3 KiB
C++
/*
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* This file is part of the "bluetoothheater" distribution
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* (https://gitlab.com/mrjones.id.au/bluetoothheater)
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*
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* Copyright (C) 2018 Ray Jones <ray@mrjones.id.au>
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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 <https://www.gnu.org/licenses/>.
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*
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*/
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#include "MODBUS-CRC16.h"
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CModBusCRC16::CModBusCRC16()
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{
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_CRC = 0xffff;
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}
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void
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CModBusCRC16::reset()
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{
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_CRC = 0xffff;
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}
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uint16_t
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CModBusCRC16::process(int len, const uint8_t* pData)
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{
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// calculate a CRC-16/MODBUS checksum using the bytes of the data array
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// carries on from prior developed CRC value, or 0xffff if first pass
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while (len--)
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{
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uint8_t nTemp = *pData++ ^ _CRC;
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_CRC >>= 8;
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_CRC ^= _CRCTable[nTemp];
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}
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return _CRC;
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}
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uint16_t
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CModBusCRC16::get() const
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{
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return _CRC;
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} |