text: /**********
  This library is free software; you can redistribute it and/or modify it under
  the terms of the GNU Lesser General Public License as published by the
  Free Software Foundation; either version 2.1 of the License, or (at your
  option) any later version. (See <http://www.gnu.org/copyleft/lesser.html>.)
  
  This library is distributed in the hope that it will be useful, but WITHOUT
  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for
  more details.
  
  You should have received a copy of the GNU Lesser General Public License
  along with this library; if not, write to the Free Software Foundation, Inc.,
  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA
  **********/
  // "liveMedia"
  // Copyright (c) 1996-2013 Live Networks, Inc.  All rights reserved.
  // A simple UDP source, where every UDP payload is a complete frame
  // Implementation
  
  #include "BasicUDPSource.hh"
  #include <GroupsockHelper.hh>
  
  BasicUDPSource* BasicUDPSource::createNew(UsageEnvironment& env,
  					Groupsock* inputGS) {
    return new BasicUDPSource(env, inputGS);
  }
  
  BasicUDPSource::BasicUDPSource(UsageEnvironment& env, Groupsock* inputGS)
    : FramedSource(env), fInputGS(inputGS), fHaveStartedReading(False) {
    // Try to use a large receive buffer (in the OS):
    increaseReceiveBufferTo(env, inputGS->socketNum(), 50*1024);
  
    // Make the socket non-blocking, even though it will be read from only asynchronously, when packets arrive.
    // The reason for this is that, in some OSs, reads on a blocking socket can (allegedly) sometimes block,
    // even if the socket was previously reported (e.g., by "select()") as having data available.
    // (This can supposedly happen if the UDP checksum fails, for example.)
    makeSocketNonBlocking(fInputGS->socketNum());
  }
  
  BasicUDPSource::~BasicUDPSource(){
    envir().taskScheduler().turnOffBackgroundReadHandling(fInputGS->socketNum());
  }
  
  void BasicUDPSource::doGetNextFrame() {
    if (!fHaveStartedReading) {
      // Await incoming packets:
      envir().taskScheduler().turnOnBackgroundReadHandling(fInputGS->socketNum(),
  	 (TaskScheduler::BackgroundHandlerProc*)&incomingPacketHandler, this);
      fHaveStartedReading = True;
    }
  }
  
  void BasicUDPSource::doStopGettingFrames() {
    envir().taskScheduler().turnOffBackgroundReadHandling(fInputGS->socketNum());
    fHaveStartedReading = False;
  }
  
  
  void BasicUDPSource::incomingPacketHandler(BasicUDPSource* source, int /*mask*/){
    source->incomingPacketHandler1();
  }
  
  void BasicUDPSource::incomingPacketHandler1() {
    if (!isCurrentlyAwaitingData()) return; // we're not ready for the data yet
  
    // Read the packet into our desired destination:
    struct sockaddr_in fromAddress;
    if (!fInputGS->handleRead(fTo, fMaxSize, fFrameSize, fromAddress)) return;
  
    // Tell our client that we have new data:
    afterGetting(this); // we're preceded by a net read; no infinite recursion
  }
  