tinysbus/tinysbus/crc.py

import struct

def calculate_crc(message):
    """
    Calculate the CRC on all bytes of the message
    :return: The CRC value as a single int-16
    """
    crc = 0x0000
    for char in message:
        crc =  CRC16TABLE[((crc >> 8) ^ char) & 0xFF] ^ (crc << 8) & 0xFFFF
    return struct.pack('>H', crc)

CRC16TABLE = [0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50A5,
              0x60C6, 0x70E7, 0x8108, 0x9129, 0xA14A, 0xB16B,
              0xC18C, 0xD1AD, 0xE1CE, 0xF1EF, 0x1231, 0x0210,
              0x3273, 0x2252, 0x52B5, 0x4294, 0x72F7, 0x62D6,
              0x9339, 0x8318, 0xB37B, 0xA35A, 0xD3BD, 0xC39C,
              0xF3FF, 0xE3DE, 0x2462, 0x3443, 0x0420, 0x1401,
              0x64E6, 0x74C7, 0x44A4, 0x5485, 0xA56A, 0xB54B,
              0x8528, 0x9509, 0xE5EE, 0xF5CF, 0xC5AC, 0xD58D,
              0x3653, 0x2672, 0x1611, 0x0630, 0x76D7, 0x66F6,
              0x5695, 0x46B4, 0xB75B, 0xA77A, 0x9719, 0x8738,
              0xF7DF, 0xE7FE, 0xD79D, 0xC7BC, 0x48C4, 0x58E5,
              0x6886, 0x78A7, 0x0840, 0x1861, 0x2802, 0x3823,
              0xC9CC, 0xD9ED, 0xE98E, 0xF9AF, 0x8948, 0x9969,
              0xA90A, 0xB92B, 0x5AF5, 0x4AD4, 0x7AB7, 0x6A96,
              0x1A71, 0x0A50, 0x3A33, 0x2A12, 0xDBFD, 0xCBDC,
              0xFBBF, 0xEB9E, 0x9B79, 0x8B58, 0xBB3B, 0xAB1A,
              0x6CA6, 0x7C87, 0x4CE4, 0x5CC5, 0x2C22, 0x3C03,
              0x0C60, 0x1C41, 0xEDAE, 0xFD8F, 0xCDEC, 0xDDCD,
              0xAD2A, 0xBD0B, 0x8D68, 0x9D49, 0x7E97, 0x6EB6,
              0x5ED5, 0x4EF4, 0x3E13, 0x2E32, 0x1E51, 0x0E70,
              0xFF9F, 0xEFBE, 0xDFDD, 0xCFFC, 0xBF1B, 0xAF3A,
              0x9F59, 0x8F78, 0x9188, 0x81A9, 0xB1CA, 0xA1EB,
              0xD10C, 0xC12D, 0xF14E, 0xE16F, 0x1080, 0x00A1,
              0x30C2, 0x20E3, 0x5004, 0x4025, 0x7046, 0x6067,
              0x83B9, 0x9398, 0xA3FB, 0xB3DA, 0xC33D, 0xD31C,
              0xE37F, 0xF35E, 0x02B1, 0x1290, 0x22F3, 0x32D2,
              0x4235, 0x5214, 0x6277, 0x7256, 0xB5EA, 0xA5CB,
              0x95A8, 0x8589, 0xF56E, 0xE54F, 0xD52C, 0xC50D,
              0x34E2, 0x24C3, 0x14A0, 0x0481, 0x7466, 0x6447,
              0x5424, 0x4405, 0xA7DB, 0xB7FA, 0x8799, 0x97B8,
              0xE75F, 0xF77E, 0xC71D, 0xD73C, 0x26D3, 0x36F2,
              0x0691, 0x16B0, 0x6657, 0x7676, 0x4615, 0x5634,
              0xD94C, 0xC96D, 0xF90E, 0xE92F, 0x99C8, 0x89E9,
              0xB98A, 0xA9AB, 0x5844, 0x4865, 0x7806, 0x6827,
              0x18C0, 0x08E1, 0x3882, 0x28A3, 0xCB7D, 0xDB5C,
              0xEB3F, 0xFB1E, 0x8BF9, 0x9BD8, 0xABBB, 0xBB9A,
              0x4A75, 0x5A54, 0x6A37, 0x7A16, 0x0AF1, 0x1AD0,
              0x2AB3, 0x3A92, 0xFD2E, 0xED0F, 0xDD6C, 0xCD4D,
              0xBDAA, 0xAD8B, 0x9DE8, 0x8DC9, 0x7C26, 0x6C07,
              0x5C64, 0x4C45, 0x3CA2, 0x2C83, 0x1CE0, 0x0CC1,
              0xEF1F, 0xFF3E, 0xCF5D, 0xDF7C, 0xAF9B, 0xBFBA,
              0x8FD9, 0x9FF8, 0x6E17, 0x7E36, 0x4E55, 0x5E74,
              0x2E93, 0x3EB2, 0x0ED1, 0x1EF0]