File content as of revision 86:2ce08ca58b9e:

#include "crc.h"


uint8_t OneWire::crc::calculateCrc8(uint8_t crc8, uint8_t data)
{
    // See Application Note 27
    crc8 = crc8 ^ data;
    for (int i = 0; i < 8; i++)
    {
        if (crc8 & 1)
        {
            crc8 = (crc8 >> 1) ^ 0x8c;
        }
        else
        {
            crc8 = (crc8 >> 1);
        }
    }
 
    return crc8;
}
 
uint8_t OneWire::crc::calculateCrc8(const uint8_t * data, size_t dataLen, uint8_t crc)
{
    for (size_t i = 0; i < dataLen; i++)
    {
        crc = calculateCrc8(crc, data[i]);
    }
    return crc;
}
 
uint16_t OneWire::crc::calculateCrc16(uint16_t crc16, uint16_t data)
{
    const uint16_t oddparity[] = { 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0 };

    data = (data ^ (crc16 & 0xff)) & 0xff;
    crc16 >>= 8;

    if (oddparity[data & 0xf] ^ oddparity[data >> 4])
    {
        crc16 ^= 0xc001;
    }

    data <<= 6;
    crc16 ^= data;
    data <<= 1;
    crc16 ^= data;

    return crc16;
}

uint16_t OneWire::crc::calculateCrc16(const uint8_t * data, size_t dataOffset, size_t dataLen, uint16_t crc)
{
    for (size_t i = dataOffset; i < (dataLen + dataOffset); i++)
    {
        crc = calculateCrc16(crc, data[i]);
    }
    return crc;
}