ReorderingPacketBuffer Class Reference

Collaboration diagram for ReorderingPacketBuffer:

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Public Member Functions

 ReorderingPacketBuffer (BufferedPacketFactory *packetFactory)
virtual ~ReorderingPacketBuffer ()
void reset ()
BufferedPacket * getFreePacket (MultiFramedRTPSource *ourSource)
Boolean storePacket (BufferedPacket *bPacket)
BufferedPacket * getNextCompletedPacket (Boolean &packetLossPreceded)
void releaseUsedPacket (BufferedPacket *packet)
void freePacket (BufferedPacket *packet)
Boolean isEmpty () const
void setThresholdTime (unsigned uSeconds)
void resetHaveSeenFirstPacket ()

Private Attributes

BufferedPacketFactory * fPacketFactory
unsigned fThresholdTime
Boolean fHaveSeenFirstPacket
unsigned short fNextExpectedSeqNo
BufferedPacket * fHeadPacket
BufferedPacket * fTailPacket
BufferedPacket * fSavedPacket
Boolean fSavedPacketFree

Detailed Description

Definition at line 28 of file MultiFramedRTPSource.cpp.

Constructor & Destructor Documentation

ReorderingPacketBuffer::ReorderingPacketBuffer ( BufferedPacketFactory *  packetFactory  ) 

Definition at line 470 of file MultiFramedRTPSource.cpp.

References NULL.

00471   : fThresholdTime(100000) /* default reordering threshold: 100 ms */,
00472     fHaveSeenFirstPacket(False), fHeadPacket(NULL), fTailPacket(NULL), fSavedPacket(NULL), fSavedPacketFree(True) {
00473   fPacketFactory = (packetFactory == NULL)
00474     ? (new BufferedPacketFactory)
00475     : packetFactory;
00476 }

ReorderingPacketBuffer::~ReorderingPacketBuffer (  )  [virtual]

Definition at line 478 of file MultiFramedRTPSource.cpp.

References fPacketFactory, and reset().

00478                                                 {
00479   reset();
00480   delete fPacketFactory;
00481 }

Member Function Documentation

void ReorderingPacketBuffer::reset (  ) 

Definition at line 483 of file MultiFramedRTPSource.cpp.

References fHeadPacket, fSavedPacket, fSavedPacketFree, fTailPacket, NULL, and resetHaveSeenFirstPacket().

Referenced by MultiFramedRTPSource::doStopGettingFrames(), and ~ReorderingPacketBuffer().

00483                                    {
00484   if (fSavedPacketFree) delete fSavedPacket; // because fSavedPacket is not in the list
00485   delete fHeadPacket; // will also delete fSavedPacket if it's in the list
00486   resetHaveSeenFirstPacket();
00487   fHeadPacket = fTailPacket = fSavedPacket = NULL;
00488 }

BufferedPacket * ReorderingPacketBuffer::getFreePacket ( MultiFramedRTPSource *  ourSource  ) 

Definition at line 490 of file MultiFramedRTPSource.cpp.

References BufferedPacketFactory::createNewPacket(), False, fPacketFactory, fSavedPacket, fSavedPacketFree, NULL, and True.

Referenced by MultiFramedRTPSource::networkReadHandler1().

00490                                                                                      {
00491   if (fSavedPacket == NULL) { // we're being called for the first time
00492     fSavedPacket = fPacketFactory->createNewPacket(ourSource);
00493     fSavedPacketFree = True;
00494   }
00495 
00496   if (fSavedPacketFree == True) {
00497     fSavedPacketFree = False;
00498     return fSavedPacket;
00499   } else {
00500     return fPacketFactory->createNewPacket(ourSource);
00501   }
00502 }

Boolean ReorderingPacketBuffer::storePacket ( BufferedPacket *  bPacket  ) 

Definition at line 504 of file MultiFramedRTPSource.cpp.

References False, fHaveSeenFirstPacket, fHeadPacket, fNextExpectedSeqNo, fTailPacket, BufferedPacket::isFirstPacket(), BufferedPacket::nextPacket(), NULL, BufferedPacket::rtpSeqNo(), seqNumLT(), and True.

Referenced by MultiFramedRTPSource::networkReadHandler1().

00504                                                                    {
00505   unsigned short rtpSeqNo = bPacket->rtpSeqNo();
00506 
00507   if (!fHaveSeenFirstPacket) {
00508     fNextExpectedSeqNo = rtpSeqNo; // initialization
00509     bPacket->isFirstPacket() = True;
00510     fHaveSeenFirstPacket = True;
00511   }
00512 
00513   // Ignore this packet if its sequence number is less than the one
00514   // that we're looking for (in this case, it's been excessively delayed).
00515   if (seqNumLT(rtpSeqNo, fNextExpectedSeqNo)) return False;
00516 
00517   if (fTailPacket == NULL) {
00518     // Common case: There are no packets in the queue; this will be the first one:
00519     bPacket->nextPacket() = NULL;
00520     fHeadPacket = fTailPacket = bPacket;
00521     return True;
00522   }
00523 
00524   if (seqNumLT(fTailPacket->rtpSeqNo(), rtpSeqNo)) {
00525     // The next-most common case: There are packets already in the queue; this packet arrived in order => put it at the tail:
00526     bPacket->nextPacket() = NULL;
00527     fTailPacket->nextPacket() = bPacket;
00528     fTailPacket = bPacket;
00529     return True;
00530   } 
00531 
00532   if (rtpSeqNo == fTailPacket->rtpSeqNo()) {
00533     // This is a duplicate packet - ignore it
00534     return False;
00535   }
00536 
00537   // Rare case: This packet is out-of-order.  Run through the list (from the head), to figure out where it belongs:
00538   BufferedPacket* beforePtr = NULL;
00539   BufferedPacket* afterPtr = fHeadPacket;
00540   while (afterPtr != NULL) {
00541     if (seqNumLT(rtpSeqNo, afterPtr->rtpSeqNo())) break; // it comes here
00542     if (rtpSeqNo == afterPtr->rtpSeqNo()) {
00543       // This is a duplicate packet - ignore it
00544       return False;
00545     }
00546 
00547     beforePtr = afterPtr;
00548     afterPtr = afterPtr->nextPacket();
00549   }
00550 
00551   // Link our new packet between "beforePtr" and "afterPtr":
00552   bPacket->nextPacket() = afterPtr;
00553   if (beforePtr == NULL) {
00554     fHeadPacket = bPacket;
00555   } else {
00556     beforePtr->nextPacket() = bPacket;
00557   }
00558 
00559   return True;
00560 }

BufferedPacket * ReorderingPacketBuffer::getNextCompletedPacket ( Boolean &  packetLossPreceded  ) 

Definition at line 577 of file MultiFramedRTPSource.cpp.

References fHeadPacket, fNextExpectedSeqNo, fThresholdTime, BufferedPacket::isFirstPacket(), NULL, BufferedPacket::rtpSeqNo(), BufferedPacket::timeReceived(), and True.

Referenced by MultiFramedRTPSource::doGetNextFrame1().

00577                                                     {
00578   if (fHeadPacket == NULL) return NULL;
00579 
00580   // Check whether the next packet we want is already at the head
00581   // of the queue:
00582   // ASSERT: fHeadPacket->rtpSeqNo() >= fNextExpectedSeqNo
00583   if (fHeadPacket->rtpSeqNo() == fNextExpectedSeqNo) {
00584     packetLossPreceded = fHeadPacket->isFirstPacket();
00585         // (The very first packet is treated as if there was packet loss beforehand.)
00586     return fHeadPacket;
00587   }
00588 
00589   // We're still waiting for our desired packet to arrive.  However, if
00590   // our time threshold has been exceeded, then forget it, and return
00591   // the head packet instead:
00592   Boolean timeThresholdHasBeenExceeded;
00593   if (fThresholdTime == 0) {
00594     timeThresholdHasBeenExceeded = True; // optimization
00595   } else {
00596     struct timeval timeNow;
00597     gettimeofday(&timeNow, NULL);
00598     unsigned uSecondsSinceReceived
00599       = (timeNow.tv_sec - fHeadPacket->timeReceived().tv_sec)*1000000
00600       + (timeNow.tv_usec - fHeadPacket->timeReceived().tv_usec);
00601     timeThresholdHasBeenExceeded = uSecondsSinceReceived > fThresholdTime;
00602   }
00603   if (timeThresholdHasBeenExceeded) {
00604     fNextExpectedSeqNo = fHeadPacket->rtpSeqNo();
00605         // we've given up on earlier packets now
00606     packetLossPreceded = True;
00607     return fHeadPacket;
00608   }
00609 
00610   // Otherwise, keep waiting for our desired packet to arrive:
00611   return NULL;
00612 }

void ReorderingPacketBuffer::releaseUsedPacket ( BufferedPacket *  packet  ) 

Definition at line 562 of file MultiFramedRTPSource.cpp.

References fHeadPacket, fNextExpectedSeqNo, freePacket(), fTailPacket, BufferedPacket::nextPacket(), and NULL.

Referenced by MultiFramedRTPSource::doGetNextFrame1().

00562                                                                      {
00563   // ASSERT: packet == fHeadPacket
00564   // ASSERT: fNextExpectedSeqNo == packet->rtpSeqNo()
00565   ++fNextExpectedSeqNo; // because we're finished with this packet now
00566 
00567   fHeadPacket = fHeadPacket->nextPacket();
00568   if (!fHeadPacket) { 
00569     fTailPacket = NULL;
00570   }
00571   packet->nextPacket() = NULL;
00572 
00573   freePacket(packet);
00574 }

void ReorderingPacketBuffer::freePacket ( BufferedPacket *  packet  )  [inline]

Definition at line 38 of file MultiFramedRTPSource.cpp.

References fSavedPacket, fSavedPacketFree, and True.

Referenced by MultiFramedRTPSource::networkReadHandler1(), and releaseUsedPacket().

00038                                           {
00039     if (packet != fSavedPacket) {
00040       delete packet;
00041     } else {
00042       fSavedPacketFree = True;
00043     }
00044   }

Boolean ReorderingPacketBuffer::isEmpty (  )  const [inline]

Definition at line 45 of file MultiFramedRTPSource.cpp.

References fHeadPacket, and NULL.

Referenced by MultiFramedRTPSource::doGetNextFrame1().

00045 { return fHeadPacket == NULL; }

void ReorderingPacketBuffer::setThresholdTime ( unsigned  uSeconds  )  [inline]

Definition at line 47 of file MultiFramedRTPSource.cpp.

References fThresholdTime.

Referenced by MultiFramedRTPSource::setPacketReorderingThresholdTime().

00047 { fThresholdTime = uSeconds; }

void ReorderingPacketBuffer::resetHaveSeenFirstPacket (  )  [inline]

Definition at line 48 of file MultiFramedRTPSource.cpp.

References False, and fHaveSeenFirstPacket.

Referenced by MultiFramedRTPSource::networkReadHandler1(), and reset().

00048 { fHaveSeenFirstPacket = False; }

Field Documentation

BufferedPacketFactory* ReorderingPacketBuffer::fPacketFactory [private]

Definition at line 51 of file MultiFramedRTPSource.cpp.

Referenced by getFreePacket(), and ~ReorderingPacketBuffer().

unsigned ReorderingPacketBuffer::fThresholdTime [private]

Definition at line 52 of file MultiFramedRTPSource.cpp.

Referenced by getNextCompletedPacket(), and setThresholdTime().

Boolean ReorderingPacketBuffer::fHaveSeenFirstPacket [private]

Definition at line 53 of file MultiFramedRTPSource.cpp.

Referenced by resetHaveSeenFirstPacket(), and storePacket().

unsigned short ReorderingPacketBuffer::fNextExpectedSeqNo [private]

Definition at line 54 of file MultiFramedRTPSource.cpp.

Referenced by getNextCompletedPacket(), releaseUsedPacket(), and storePacket().

BufferedPacket* ReorderingPacketBuffer::fHeadPacket [private]

Definition at line 55 of file MultiFramedRTPSource.cpp.

Referenced by getNextCompletedPacket(), isEmpty(), releaseUsedPacket(), reset(), and storePacket().

BufferedPacket* ReorderingPacketBuffer::fTailPacket [private]

Definition at line 56 of file MultiFramedRTPSource.cpp.

Referenced by releaseUsedPacket(), reset(), and storePacket().

BufferedPacket* ReorderingPacketBuffer::fSavedPacket [private]

Definition at line 57 of file MultiFramedRTPSource.cpp.

Referenced by freePacket(), getFreePacket(), and reset().

Boolean ReorderingPacketBuffer::fSavedPacketFree [private]

Definition at line 59 of file MultiFramedRTPSource.cpp.

Referenced by freePacket(), getFreePacket(), and reset().

The documentation for this class was generated from the following file:
Generated on Mon Apr 29 13:32:28 2013 for live by  doxygen 1.5.2