mirror of
https://github.com/RobTillaart/Arduino.git
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106 lines
1.8 KiB
C++
106 lines
1.8 KiB
C++
//
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// FILE: CRC64.cpp
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// AUTHOR: Rob Tillaart
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// PURPOSE: Arduino class for CRC64;
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// URL: https://github.com/RobTillaart/CRC
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#include "CRC64.h"
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CRC64::CRC64()
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{
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reset();
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}
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void CRC64::reset()
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{
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_polynome = CRC64_DEFAULT_POLYNOME;
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_startMask = 0;
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_endMask = 0;
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_crc = 0;
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_reverseIn = false;
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_reverseOut = false;
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_started = false;
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_count = 0;
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}
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void CRC64::restart()
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{
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_started = true;
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_crc = _startMask;
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_count = 0;
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}
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void CRC64::add(uint8_t value)
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{
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_count++;
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_update(value);
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}
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void CRC64::add(uint8_t * array, uint32_t length)
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{
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_count += length;
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while (length--)
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{
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yield();
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_update(*array++);
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}
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}
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uint64_t CRC64::getCRC()
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{
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uint64_t rv = _crc;
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if (_reverseOut) rv = _reverse(rv);
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rv ^=_endMask;
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return rv;
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}
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void CRC64::_update(uint8_t value)
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{
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if (!_started) restart();
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if (_reverseIn) value = _reverse8(value);
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_crc ^= ((uint64_t)value) << 56;;
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for (uint8_t i = 8; i; i--)
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{
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if (_crc & (1ULL << 63))
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{
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_crc <<= 1;
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_crc ^= _polynome;
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}
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else
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{
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_crc <<= 1;
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}
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}
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}
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uint64_t CRC64::_reverse(uint64_t in)
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{
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uint64_t x = in;
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x = (((x & 0xAAAAAAAAAAAAAAAA) >> 1) | ((x & 0x5555555555555555) << 1));
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x = (((x & 0xCCCCCCCCCCCCCCCC) >> 2) | ((x & 0x3333333333333333) << 2));
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x = (((x & 0xF0F0F0F0F0F0F0F0) >> 4) | ((x & 0x0F0F0F0F0F0F0F0F) << 4));
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x = (((x & 0xFF00FF00FF00FF00) >> 8) | ((x & 0x00FF00FF00FF00FF) << 8));
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x = (((x & 0xFFFF0000FFFF0000) >> 16) | ((x & 0x0000FFFF0000FFFF) << 16));
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x = (x >> 32) | (x << 32);
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return x;
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}
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uint8_t CRC64::_reverse8(uint8_t in)
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{
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uint8_t x = in;
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x = (((x & 0xAA) >> 1) | ((x & 0x55) << 1));
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x = (((x & 0xCC) >> 2) | ((x & 0x33) << 2));
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x = ((x >> 4) | (x << 4));
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return x;
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}
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// -- END OF FILE --
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