format_nmea.py 文件源码

def checksum(self, samples):
        if samples is None:
            return None

        completed = []
        for sentence in samples:
            assert sentence[0] == "$"
            cksum = reduce(xor, (ord(s) for s in sentence[1:]))
            completed.append("%s*%02X" % (sentence, cksum))

        if len(completed) == 0:
            return None

        # NMEA0183 uses \r\n as line separator even on Unix systems.
        s = ""
        for line in completed:
            s = s + line + "\r\n"
        return s