nmea.py 文件源码

def lineReceived(self, line):
        if not line.startswith('$'):
            if self.ignore_invalid_sentence:
                return
            raise InvalidSentence("%r does not begin with $" % (line,))
        # message is everything between $ and *, checksum is xor of all ASCII values of the message
        strmessage, checksum = line[1:].strip().split('*')
        message = strmessage.split(',')
        sentencetype, message = message[0], message[1:]
        dispatch = self.dispatch.get(sentencetype, None)
        if (not dispatch) and (not self.ignore_unknown_sentencetypes):
            raise InvalidSentence("sentencetype %r" % (sentencetype,))
        if not self.ignore_checksum_mismatch:
            checksum, calculated_checksum = int(checksum, 16), reduce(operator.xor, map(ord, strmessage))
            if checksum != calculated_checksum:
                raise InvalidChecksum("Given 0x%02X != 0x%02X" % (checksum, calculated_checksum))
        handler = getattr(self, "handle_%s" % dispatch, None)
        decoder = getattr(self, "decode_%s" % dispatch, None)
        if not (dispatch and handler and decoder):
            # missing dispatch, handler, or decoder
            return
        # return handler(*decoder(*message))
        try:
            decoded = decoder(*message)
        except Exception, e:
            raise InvalidSentence("%r is not a valid %s (%s) sentence" % (line, sentencetype, dispatch))
        return handler(*decoded)