Lua CRC16-ccitt example - Printable Version

Code:
data = ('njhyTFGV')

init = 0xffff

crc = init

function crc16_ccitt(crc, data)

  msb = bit.rshift(crc , 8)

  lsb = bit.band(crc , 255)

  --log(msb, lsb)

  for i = 1, #data do

    strb = string.byte(data, i, i)

    x = bit.bxor(strb, msb)

    --log(strb,msb, x)

    x = bit.bxor(x,  bit.rshift(x,4))

    --log(x)

    msb = bit.band(bit.bxor(lsb , bit.rshift(x , 3) , bit.lshift(x , 4)) , 255)

    lsb = bit.band(bit.bxor(x , bit.lshift(x , 5)) , 255)

    log(msb, lsb, x)

    end

  res = lsb + bit.lshift(msb, 8)

  return res , string.format('%x', res)

end

  

log(crc16_ccitt(crc, data))