GY-63_MS5611/libraries/CRC/CRC16.cpp

109 lines
1.6 KiB
C++
Raw Normal View History

2021-01-29 06:31:58 -05:00
//
// FILE: CRC16.cpp
// AUTHOR: Rob Tillaart
// PURPOSE: Arduino class for CRC16
// URL: https://github.com/RobTillaart/CRC
#include "CRC16.h"
CRC16::CRC16()
{
reset();
}
void CRC16::reset()
{
_polynome = CRC16_DEFAULT_POLYNOME;
_startMask = 0;
_endMask = 0;
_crc = 0;
_reverseIn = false;
_reverseOut = false;
_started = false;
_count = 0;
}
void CRC16::restart()
{
_started = true;
_crc = _startMask;
_count = 0;
}
void CRC16::add(uint8_t value)
{
_count++;
_update(value);
}
void CRC16::add(uint8_t * array, uint32_t length)
{
_count += length;
while (length--)
{
yield();
uint8_t data = *array++;
_update(data);
}
}
uint16_t CRC16::getCRC()
{
uint16_t rv = _crc;
if (_reverseOut) rv = _reverse(rv);
rv ^= _endMask;
return rv;
}
void CRC16::_update(uint8_t value)
{
if (!_started) restart();
2021-04-07 07:31:22 -04:00
if (_reverseIn) value = _reverse8(value);
2021-01-29 06:31:58 -05:00
_crc ^= ((uint16_t)value) << 8;;
for (uint8_t i = 8; i; i--)
{
if (_crc & (1UL << 15))
{
_crc <<= 1;
_crc ^= _polynome;
}
else
{
_crc <<= 1;
}
}
}
uint16_t CRC16::_reverse(uint16_t in)
{
uint16_t x = in;
x = (((x & 0XAAAA) >> 1) | ((x & 0X5555) << 1));
x = (((x & 0xCCCC) >> 2) | ((x & 0X3333) << 2));
x = (((x & 0xF0F0) >> 4) | ((x & 0X0F0F) << 4));
x = (( x >> 8) | (x << 8));
return x;
}
2021-12-14 14:22:40 -05:00
2021-04-07 07:31:22 -04:00
uint8_t CRC16::_reverse8(uint8_t in)
{
uint8_t x = in;
x = (((x & 0xAA) >> 1) | ((x & 0x55) << 1));
x = (((x & 0xCC) >> 2) | ((x & 0x33) << 2));
x = ((x >> 4) | (x << 4));
return x;
}
2021-12-14 14:22:40 -05:00
// -- END OF FILE --