Sender.py

__author__ = 'Roshan'
import socket


import  makePacket

PKT_SIZE = 100
BUFSIZ = 256

class Sender:

    def __init__(self, ip, port, window_size=5):
        self.address = (ip, port)
        self.sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        self.window_size = window_size
        # self.sock.bind(self.address)

    def set_my_address(self, ip, port):
        self.sock.bind((ip, port))

    def set_window_size(self, size):
        self.window_size = size

    def send(self, data):
        ## todo: only send a window at a time
        self._send(data)
        # data, addr = self.sock.recvfrom(1024)


    def _send(self, data):

        data = [ i for i in zip(self._get_sequence_number(), self._data_chunk(data))]

        print()
        print("Sending # {} of packets".format(len(data)))

        index = 0
        while index <= len(data):

            # print()

            current_frame_set = data[index: index+self.window_size]

            # print("pkt sending:", end=" ")
            for data_chunk in current_frame_set:
                pkt = makePacket.Packet(data_chunk[1], data_chunk[0])
                serial_pkt = pkt.serialize()
                # print("PKT:", pkt.sequence_no, end=" ")
                # print(pkt.sequence_no, end=" ")
                i = self.sock.sendto(serial_pkt, self.address)
                # print("PKT:", pkt.sequence_no, "sent", i, "bytes")

            # print()

            ack = self._receive_ack()
            ack = ack.decode()

            if ack[-3:] == "END":
                # print("End of transition; Exiting....")
                # print()
                break
            if ack[-3:] == "ALL":
                # print("Need to send them all again!!!")
                continue

            if ack[:2] == "RR":
                index += self.window_size
            else: #rejected
                next_seq_number = int(ack[-1])
                # print("next_seq_number: ", next_seq_number)
                add_to_index = 0
                for pkt in current_frame_set:
                    # print("pkt.sequence_no", pkt[0])
                    if pkt[0] == next_seq_number:
                        break

                    add_to_index += 1

                # print("add to index ", add_to_index)

                index += add_to_index

            # print("INDEX", index)



    def _data_chunk(self, data):
        for i in range(0, len(data), makePacket.PACKET_SIZE):
            yield data[i:i+makePacket.PACKET_SIZE]

    @staticmethod
    def _get_sequence_number():
        seq = 0
        while True:
            yield seq

            seq += 1
            if seq >= makePacket.MAX_SEQUENCE_NUMBER:
                seq = 0


    def _receive_ack(self):
        data, addr = self.sock.recvfrom(BUFSIZ)
        # print("_received_ack:", data.decode())
        return data

    def close(self):
        self.sock.close()