tbfh.py 文件源码

def _checksum (self, buffer):
        '''
        Calculate the TBF header checksum.
        '''
        # Add 0s to the end to make sure that we are multiple of 4.
        padding = len(buffer) % 4
        if padding != 0:
            padding = 4 - padding
            buffer += bytes([0]*padding)

        # Loop throw
        checksum = 0
        for i in range(0, len(buffer), 4):
            checksum ^= struct.unpack('<I', buffer[i:i+4])[0]

        return checksum