content: /*
   * Copyright (C) 2016 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package com.google.android.exoplayer2.upstream;
  
  import android.net.Uri;
  import com.google.android.exoplayer2.C;
  import java.io.IOException;
  import java.net.DatagramPacket;
  import java.net.DatagramSocket;
  import java.net.InetAddress;
  import java.net.InetSocketAddress;
  import java.net.MulticastSocket;
  import java.net.SocketException;
  
  /**
   * A UDP {@link DataSource}.
   */
  public final class UdpDataSource implements DataSource {
  
    /**
     * Thrown when an error is encountered when trying to read from a {@link UdpDataSource}.
     */
    public static final class UdpDataSourceException extends IOException {
  
      public UdpDataSourceException(IOException cause) {
        super(cause);
      }
  
    }
  
    /**
     * The default maximum datagram packet size, in bytes.
     */
    public static final int DEFAULT_MAX_PACKET_SIZE = 2000;
  
    /**
     * The default socket timeout, in milliseconds.
     */
    public static final int DEAFULT_SOCKET_TIMEOUT_MILLIS = 8 * 1000;
  
    private final TransferListener<? super UdpDataSource> listener;
    private final int socketTimeoutMillis;
    private final byte[] packetBuffer;
    private final DatagramPacket packet;
  
    private Uri uri;
    private DatagramSocket socket;
    private MulticastSocket multicastSocket;
    private InetAddress address;
    private InetSocketAddress socketAddress;
    private boolean opened;
  
    private int packetRemaining;
  
    /**
     * @param listener An optional listener.
     */
    public UdpDataSource(TransferListener<? super UdpDataSource> listener) {
      this(listener, DEFAULT_MAX_PACKET_SIZE);
    }
  
    /**
     * @param listener An optional listener.
     * @param maxPacketSize The maximum datagram packet size, in bytes.
     */
    public UdpDataSource(TransferListener<? super UdpDataSource> listener, int maxPacketSize) {
      this(listener, maxPacketSize, DEAFULT_SOCKET_TIMEOUT_MILLIS);
    }
  
    /**
     * @param listener An optional listener.
     * @param maxPacketSize The maximum datagram packet size, in bytes.
     * @param socketTimeoutMillis The socket timeout in milliseconds. A timeout of zero is interpreted
     *     as an infinite timeout.
     */
    public UdpDataSource(TransferListener<? super UdpDataSource> listener, int maxPacketSize,
        int socketTimeoutMillis) {
      this.listener = listener;
      this.socketTimeoutMillis = socketTimeoutMillis;
      packetBuffer = new byte[maxPacketSize];
      packet = new DatagramPacket(packetBuffer, 0, maxPacketSize);
    }
  
    @Override
    public long open(DataSpec dataSpec) throws UdpDataSourceException {
      uri = dataSpec.uri;
      String host = uri.getHost();
      int port = uri.getPort();
  
      try {
        address = InetAddress.getByName(host);
        socketAddress = new InetSocketAddress(address, port);
        if (address.isMulticastAddress()) {
          multicastSocket = new MulticastSocket(socketAddress);
          multicastSocket.joinGroup(address);
          socket = multicastSocket;
        } else {
          socket = new DatagramSocket(socketAddress);
        }
      } catch (IOException e) {
        throw new UdpDataSourceException(e);
      }
  
      try {
        socket.setSoTimeout(socketTimeoutMillis);
      } catch (SocketException e) {
        throw new UdpDataSourceException(e);
      }
  
      opened = true;
      if (listener != null) {
        listener.onTransferStart(this, dataSpec);
      }
      return C.LENGTH_UNSET;
    }
  
    @Override
    public int read(byte[] buffer, int offset, int readLength) throws UdpDataSourceException {
      if (readLength == 0) {
        return 0;
      }
  
      if (packetRemaining == 0) {
        // We've read all of the data from the current packet. Get another.
        try {
          socket.receive(packet);
        } catch (IOException e) {
          throw new UdpDataSourceException(e);
        }
        packetRemaining = packet.getLength();
        if (listener != null) {
          listener.onBytesTransferred(this, packetRemaining);
        }
      }
  
      int packetOffset = packet.getLength() - packetRemaining;
      int bytesToRead = Math.min(packetRemaining, readLength);
      System.arraycopy(packetBuffer, packetOffset, buffer, offset, bytesToRead);
      packetRemaining -= bytesToRead;
      return bytesToRead;
    }
  
    @Override
    public Uri getUri() {
      return uri;
    }
  
    @Override
    public void close() {
      uri = null;
      if (multicastSocket != null) {
        try {
          multicastSocket.leaveGroup(address);
        } catch (IOException e) {
          // Do nothing.
        }
        multicastSocket = null;
      }
      if (socket != null) {
        socket.close();
        socket = null;
      }
      address = null;
      socketAddress = null;
      packetRemaining = 0;
      if (opened) {
        opened = false;
        if (listener != null) {
          listener.onTransferEnd(this);
        }
      }
    }
  
  }
  