def from_raw_data(cls, data):
"""
@param data: Bla
@type data: bytes
"""
if not data:
raise EmptyMessageError()
transmitted_crc = data[-1]
computed_crc = crc8.calc(data[0:-1])
if transmitted_crc != computed_crc:
raise MessageCRCError(transmitted_crc=transmitted_crc, computed_crc=computed_crc)
msg_type = int.from_bytes(data[0:3], byteorder='big')
if msg_type == MessageTypes.MSG_PONG:
msg = PongMessage.from_raw_data(data[3:-1])
elif msg_type == MessageTypes.MSG_CONFIRMATION:
msg = ConfirmationMessage.from_raw_data(data[3:-1])
elif msg_type == MessageTypes.MSG_CUR_PARAMETER:
msg = CurParameterMessage.from_raw_data(data[3:-1])
else:
raise UnknownMessageType()
return msg
def encode_for_writing_without_msg_num(self):
val = b''
msg_type = self.message_type().to_bytes(3, byteorder='big')
data = self.prepare_data()
crc = crc8.calc(msg_type+data).to_bytes(1, byteorder='big')
val += STX+STX+self.escape_bytes(msg_type)+self.escape_bytes(data)+self.escape_bytes(crc)+ETB
return val
def encode_for_writing(self):
val = b''
msg_num = (self.message_number() if self.message_number() is not None else 0).to_bytes(3, byteorder='big')
msg_type = self.message_type().to_bytes(3, byteorder='big')
data = self.prepare_data()
crc = crc8.calc(msg_num+msg_type+data).to_bytes(1, byteorder='big')
val += STX+STX+self.escape_bytes(msg_num)+self.escape_bytes(msg_type)+self.escape_bytes(data)+self.escape_bytes(crc)+ETB
return val
