def loop()

in scripts/mcast.py [0:0]

• 45 lines of code
• 12 McCabe index (conditional complexity)

    def loop(self, interval=1):
        packets = dict()

        try:
            while True:
                (segment, (ip4_addr, port)) = self.sock.recvfrom(1024)

                if not segment:
                    logging.info("Exiting as received an empty packet...")
                    sys.exit(0)

                tup = segment.split()
                if len(tup) < 3:
                    logging.info("Exiting as received an empty data packet...")
                    sys.exit(0)

                # @see DATA_FMT
                (id, time_sent, data) = tup
                try:
                    id = int(id)
                    time_sent = float(time_sent)
                except ValueError:
                    logging.warn("Unexpected formatted data was received. Skip it.")
                    continue

                last_ids = packets.get((ip4_addr, port), [])
                if last_ids:
                    last_id = last_ids[-1]
                else:
                    last_id = 0
                    packets[(ip4_addr, port)] = []

                delta = time.time() - time_sent
                from_s = "from %s:%d" % (ip4_addr, port)

                logging.info("Received '%s' (#%d) %s, time=%f" % (data, id, from_s, delta))

                if id < last_id:
                    logging.debug("Inversion! #%d %s is younger than last one (#%d)." % (id, from_s, last_id))
                elif id == last_id:
                    logging.debug("DUP segment! #%d %s" % (id, from_s))
                else:
                    if id > (last_id + 1):
                        last_received = packets[(ip4_addr, port)]
                        losts = ["#%d" % i for i in range(last_id + 1, id) if i not in last_received]
                        losts_s = ", ".join(losts)
                        logging.debug("LOST segments! %s %s" % (losts_s, from_s))

                packets[(ip4_addr, port)].append(id)

                # TODO: Send back to client.
                #ssize = self.sock.sendto(segment, (ip4_addr, port))
                #if ssize < len(segment):
                #    logging.warn("Failed to send back to the client: %s (port: %d)" % (ip4_addr, port))

                time.sleep(interval)

        except (KeyboardInterrupt, SystemExit):
            logging.info("Exiting...")
            self.dump_stat(packets)
        except:
            traceback.print_exc()