/// <summary>
/// Broadcasts a single chunk and stores it in the frame buffer.
/// </summary>
/// <param name="chunk">The chunk to send</param>
private void RtpSend(Chunk chunk, MessagePriority priority)
{
using(Synchronizer.Lock(this)) {
using(MemoryStream stream = new MemoryStream((int) (this.m_Encoder.MaximumChunkSize * 2))) {
// Store the sequence number of non-real-time chunks so they can be NACKed.
// Use "++this.m_FrameSequence" so that non-real-time chunks always have a
// FrameSequence that is greater than 0.
if (priority != MessagePriority.RealTime)
chunk.FrameSequence = ++this.m_FrameSequence;
// If the chunk is not real time (or it is being resent a second time),
// store the chunk in the buffer so a NACK request can resend it.
if (chunk.FrameSequence > ulong.MinValue)
this.m_FrameBuffer.Insert(chunk);
// Buffering the chunk probably evicted other chunks from the buffer,
// so get the oldest frame in the buffer so receivers don't waste time
// sending NACKs for chunks that are no longer available.
chunk.OldestRecoverableFrame = this.m_FrameBuffer.OldestRecoverableFrame;
chunk.OldestRecoverableMessage = this.m_FrameBuffer.OldestRecoverableMessage;
// Serialize the chunk (which itself contains a serialized message).
// TODO: see whether the wire protocol can be made more efficient.
stream.Position = 0;
this.m_Encoder.EncodeChunk(stream, chunk);
// Prepare the frame to be sent over RTP.
BufferChunk buffer = new BufferChunk(stream.GetBuffer(), 0, (int) stream.Length);
// Send it (or drop some percentage of packets if the debug option is enabled).
if(DEBUG_DROP_RANDOM_FRAMES <= 0 || new Random().Next(100) >= DEBUG_DROP_RANDOM_FRAMES) {
Debug.WriteLine(string.Format("Sending frame #{0} ({1} bytes, message #{2}, chunk #{3} of {4}, depending on #{5}, priority {6})",
chunk.FrameSequence,
chunk.Data.Length,
chunk.MessageSequence,
chunk.ChunkSequenceInMessage + 1,
chunk.NumberOfChunksInMessage,
chunk.MessageDependency,
priority),
this.GetType().ToString());
try {
this.m_RtpSender.Send( buffer );
} catch( Exception ) {
this.Reset();
}
}
else {
Debug.WriteLine(string.Format("DEBUG: Dropping frame #{0} ({1} bytes, message #{2}, chunk #{3} of {4}, depending on #{5}, priority {6})",
chunk.FrameSequence,
chunk.Data.Length,
chunk.MessageSequence,
chunk.ChunkSequenceInMessage + 1,
chunk.NumberOfChunksInMessage,
chunk.MessageDependency,
priority),
this.GetType().ToString());
}
}
}
}
/// <summary>
/// Writes a chunk to a data stream.
/// </summary>
public void EncodeChunk(Stream stream, Chunk chunk)
{
// FIXME: More efficient encoding of chunks might be possible here.
// Custom encoding would require a Decode method to be used by RTPMessageReceiver.
this.m_Formatter.Serialize(stream, chunk);
}
/// <summary>
/// Serializes the given message and constructs a number of
/// chunks containing the serialized data.
/// </summary>
/// <param name="message">The message to serialize.</param>
/// <param name="messageSequence">
/// A reference to a counter which will be incremented.
/// This becomes the value of each chunk's
/// <see cref="Chunk.MessageSequence"/> field.
/// </param>
/// <returns>
/// A non-empty array containing the created chunks.
/// </returns>
public Chunk[] MakeChunks(Message message, ref ulong messageSequence)
{
++messageSequence;
ulong currentChunkSequence = 0;
ulong maxSize = this.m_MaximumChunkSize;
using(MemoryStream stream = new MemoryStream()) {
// Serialize the message.
this.m_Formatter.Serialize(stream, message);
// Calculate the number of chunks needed to span the message and allocate an array to hold them.
ulong length = ((ulong) stream.Length);
ulong count = (length / maxSize) + (length % maxSize == 0ul ? 0ul : 1ul);
Chunk[] chunks = new Chunk[count];
stream.Position = 0;
int index = 0;
for(ulong amountLeft; (amountLeft = length - ((ulong) stream.Position)) > 0; index++) {
// Read the deserialized data into a small array.
byte[] chunk = new byte[amountLeft < maxSize ? amountLeft : maxSize];
int read = stream.Read(chunk, 0, chunk.Length);
if(read != chunk.Length)
throw new ApplicationException("Couldn't read enough data from MemoryStream.");
// Create a chunk, updating the sequence numbers.
chunks[index] = new Chunk(chunk, messageSequence, currentChunkSequence++, count);
}
return chunks;
}
}
/// <summary>
/// Updates <see cref="m_Buffer"/> with the specified chunk at the specified index,
/// and also keeps the <see cref="OldestMessageSequence"/> value up-to-date.
/// </summary>
/// <param name="index">The index at which to place the chunk.</param>
/// <param name="chunk">
/// The chunk to insert, or <c>null</c> if the chunk is being removed from the buffer.
/// </param>
private void Set(ulong index, Chunk chunk)
{
ulong count;
ulong message;
// First decrement the count for the OLD chunk's message sequence number.
Chunk old = this.m_Buffer[index];
if (old != null) {
message = old.MessageSequence;
if (message > ulong.MinValue)
if (this.m_MessageSequences.TryGetValue(message, out count) && count > 0)
if (count <= 1)
this.m_MessageSequences.Remove(message);
else
this.m_MessageSequences[message] = count - 1;
else throw new ApplicationException("Unmatched insertions and removals into the FrameBuffer.");
}
// Now insert the chunk in the buffer.
this.m_Buffer[index] = chunk;
// Finally increment the count for the NEW chunk's message sequence number.
if (chunk != null) {
message = chunk.MessageSequence;
if (message > ulong.MinValue)
if (this.m_MessageSequences.TryGetValue(message, out count))
this.m_MessageSequences[message] = count + 1;
else this.m_MessageSequences[message] = 1;
}
}
/// <summary>
/// If connected, send a message, otherwise do nothing.
/// </summary>
/// <param name="chunk"></param>
/// <param name="group"></param>
public void Send(Chunk chunk, Group group, MessageTags tags)
{
AsyncCallback ac = new AsyncCallback(SendCallback);
using (MemoryStream stream = new MemoryStream((int)(this.m_Encoder.MaximumChunkSize * 2))) {
stream.Position = 0;
this.m_Encoder.EncodeChunk(stream, chunk);
Trace.WriteLine(string.Format("TCPClient sending message #{0}, chunk #{1} of {2}, {3} bytes.",
chunk.MessageSequence,
chunk.ChunkSequenceInMessage + 1,
chunk.NumberOfChunksInMessage,
chunk.Data.Length),
this.GetType().ToString());
byte[] buffer = stream.GetBuffer();
int length = (int)stream.Length;
if ((m_Socket.Connected) && (m_Connected))
while (true) {
try {
m_Socket.BeginSend(buffer, 0, length, SocketFlags.None, ac, new SendState(m_Socket, length)); //BeginSend since it won't block.
break;
}
catch (SocketException se) {
if (se.ErrorCode == 10055) {
Trace.WriteLine("Client Send queue is full. Sleeping 50 mS", this.GetType().ToString());
Thread.Sleep(50);
}
else {
Trace.WriteLine("SendThread socket exception: " + se.ToString() + " Error code: " + se.ErrorCode.ToString(), this.GetType().ToString());
break;
}
}
catch (ObjectDisposedException ode) {
Trace.WriteLine("SendThread ObjectDisposedException: " + ode.Message, this.GetType().ToString());
break;
}
catch (Exception e) {
Trace.WriteLine("SendThread Exception: " + e.ToString(), this.GetType().ToString());
break;
}
}
else {
Trace.WriteLine("SendThread found a socket disconnected. Send request ignored.", this.GetType().ToString());
}
}
}
/// <summary>
/// Broadcasts a single chunk and stores it in the frame buffer.
/// </summary>
/// <param name="chunk">The chunk to send</param>
private void CapabilitySend(Chunk chunk, MessagePriority priority)
{
using(Synchronizer.Lock(this)) {
// Store the sequence number of non-real-time chunks so they can be NACKed.
// Use "++this.m_FrameSequence" so that non-real-time chunks always have a
// FrameSequence that is greater than 0.
if (priority != MessagePriority.RealTime)
chunk.FrameSequence = ++this.m_FrameSequence;
// If the chunk is not real time (or it is being resent a second time),
// store the chunk in the buffer so a NACK request can resend it.
if (chunk.FrameSequence > ulong.MinValue)
this.m_FrameBuffer.Insert(chunk);
// Buffering the chunk probably evicted other chunks from the buffer,
// so get the oldest frame in the buffer so receivers don't waste time
// sending NACKs for chunks that are no longer available.
chunk.OldestRecoverableFrame = this.m_FrameBuffer.OldestRecoverableFrame;
chunk.OldestRecoverableMessage = this.m_FrameBuffer.OldestRecoverableMessage;
Debug.WriteLine(string.Format("Sending frame #{0} ({1} bytes, message #{2}, chunk #{3} of {4}, depending on #{5}, priority {6})",
chunk.FrameSequence,
chunk.Data.Length,
chunk.MessageSequence,
chunk.ChunkSequenceInMessage + 1,
chunk.NumberOfChunksInMessage,
chunk.MessageDependency,
priority),
this.GetType().ToString());
SendObject(new CapabilityMessageWrapper(chunk, m_LocalId, Guid.Empty, m_Capability.IsSender));
}
}
/// <summary>
/// Finds and removes the chunk with the given
/// <see cref="Chunk.FrameSequence">frame sequence number</see> from the buffer.
/// <remarks>
/// Note that this does NOT update <see cref="OldestRecoverableFrame"/>
/// or <see cref="OldestRecoverableMessage"/>. It is expected that the
/// chunk will be reinserted into the buffer in the future.
/// </remarks>
/// </summary>
/// <param name="frameSequence">
/// The <see cref="Chunk.FrameSequence">frame sequence number</see> to extract
/// from the buffer.
/// </param>
/// <param name="chunk">The chunk extracted from the buffer, if available.</param>
/// <returns>
/// <c>true</c> if the given <paramref name="frameSequence"/> was in the range
/// <see cref="OldestRecoverableFrame"/> to <see cref="NewestRecoverableFrame"/>;
/// <c>false</c> otherwise. (A <c>true</c> return value does not imply that
/// <paramref name="chunk"/> was set to non-null, since the chunk with the given
/// <paramref name="frameSequence"/> might have been previously been removed from
/// the buffer by <see cref="Take"/>, or might never have been inserted in the
/// first place.)
/// </returns>
public bool Take(ulong frameSequence, out Chunk chunk)
{
if (this.m_Oldest <= frameSequence && frameSequence <= this.m_Newest) {
ulong index = frameSequence % this.m_BufferSize;
// FIXME: This shouldn't update OldestMessageSequence.
// But if we don't, then Insert() will cause the count to get unbalanced.
chunk = this.m_Buffer[index];
this.Set(index, null);
Debug.Assert(chunk == null || chunk.FrameSequence == frameSequence,
"FrameBuffer table entry has mismatched frame sequence number.");
return true;
} else {
chunk = null;
return false;
}
}
/// <summary>
/// Attempts to assemble a chunk from a chunked messages,
/// and sends a NACK when dropped chunks are detected.
/// </summary>
/// <param name="chunk">The received chunk to process</param>
/// <returns>If the chunk was the last remaining chunk needed to complete a message,
/// returns the deserialized message; otherwise, <code>null</code></returns>
public IEnumerable<object> Add(Chunk chunk)
{
if (chunk.FrameSequence > 0) {
// Check if we have seen this packet before. If so, do nothing.
if (DisjointSet.Contains(ref this.m_ReceivedFrameSequences, chunk.FrameSequence))
yield break;
DisjointSet.Add(ref this.m_ReceivedFrameSequences, chunk.FrameSequence);
// Save space in the ReceivedSequenceNumbers queue by adding all chunks
// that we can't expect to receive anymore.
if (chunk.OldestRecoverableFrame > ulong.MinValue)
DisjointSet.Add(ref this.m_ReceivedFrameSequences, new Range(ulong.MinValue, chunk.OldestRecoverableFrame - 1));
// Check the frame sequence number to see if any frames were skipped.
// If so, then it is likely that the frame has been dropped, so it is
// necessary to send a NACK.
if (chunk.FrameSequence > this.m_GreatestFrameSequence + 1ul) {
//Debug.WriteLine(string.Format("Frames #{0}-{1} were dropped ({2} total)! Requesting replacements (oldest recoverable is #{3})...",
// this.m_GreatestFrameSequence + 1ul, chunk.FrameSequence - 1ul, chunk.FrameSequence - this.m_GreatestFrameSequence - 1,
// chunk.OldestRecoverableFrame), this.GetType().ToString());
if (this.Nack != null) {
// Send a NACK which requests rebroadcast of all the skipped frames.
Range range = new Range(
Math.Max(this.m_GreatestFrameSequence + 1ul, chunk.OldestRecoverableFrame),
chunk.FrameSequence - 1ul);
this.Nack(range);
}
}
// Otherwise, don't do anything special. These two branches are for debugging.
else if (chunk.FrameSequence == this.m_GreatestFrameSequence) {
// Duplicate chunk received, or else the first chunk ever received.
} else if (chunk.FrameSequence < this.m_GreatestFrameSequence && chunk.FrameSequence > ulong.MinValue) {
Debug.WriteLine(string.Format("%%% Frame #{0} (message #{1}, chunk #{2} of {3}, {4} bytes) received out of order (off by {5})",
chunk.FrameSequence,
chunk.MessageSequence,
chunk.ChunkSequenceInMessage + 1,
chunk.NumberOfChunksInMessage,
chunk.Data.Length,
this.m_GreatestFrameSequence - chunk.FrameSequence),
this.GetType().ToString());
}
// Assuming the chunk has not been duplicated or received out of order,
// update our variable containing the highest sequence number seen
// so far so we know which future frames have been dropped.
if (chunk.FrameSequence > this.m_GreatestFrameSequence)
this.m_GreatestFrameSequence = chunk.FrameSequence;
}
// If the message depends on a message that has not yet been received,
// add it to the queue of chunks waiting for that message.
// Then, STOP PROCESSING the message.
// Assemble(chunk) will get called by FlushWaitingChunks after
// the dependencies are satisfied.
if (chunk.MessageDependency > ulong.MinValue && !DisjointSet.Contains(ref this.m_ReceivedMessages, chunk.MessageDependency)) {
List<Chunk> waiters;
if (!this.m_ChunksWaitingForDependencies.TryGetValue(chunk.MessageDependency, out waiters))
this.m_ChunksWaitingForDependencies[chunk.MessageDependency] = waiters = new List<Chunk>();
Debug.WriteLine(string.Format("@@@ Unsatisfied dependency: message #{0} (chunk #{1} of {2}) depends on #{3}; {4} chunks are already waiting.",
chunk.MessageSequence,
chunk.ChunkSequenceInMessage + 1,
chunk.NumberOfChunksInMessage,
chunk.MessageDependency, waiters.Count));
waiters.Add(chunk);
yield break;
}
// Flush any dependencies of messages we can no longer expect to recover.
// Do this by finding the difference between the range of all unrecoverable
// message sequence numbers and the sequence numbers that have been received.
// FlushWaitingChunks is called on each of the unsatisfiable sequence numbers.
if (chunk.OldestRecoverableMessage > ulong.MinValue) {
Range unrecoverable = new Range(ulong.MinValue, chunk.OldestRecoverableMessage - 1);
DisjointSet unsatisfiable = unrecoverable;
DisjointSet.Remove(ref unsatisfiable, this.m_ReceivedMessages);
if(unsatisfiable != null)
foreach (ulong unsatisfied in unsatisfiable)
this.FlushWaitingChunks(unsatisfied);
DisjointSet.Add(ref this.m_ReceivedMessages, unrecoverable);
}
// If the dependency is already satisfied (or not specified),
// attempt to assemble the chunk into a completed message.
foreach (object message in this.Assemble(chunk))
yield return message;
}
public ChunksAndPriority(Chunk[] chunks, MessageTags tags)
{
this.Chunks = chunks;
this.Tags = tags;
}
/// <summary>
/// Adds a chunk to the message.
/// The chunk must be part of the message;
/// that is, <see cref="IsInRange">IsInRange(<paramref name="chunk"/>)</see>
/// must return <c>true</c>.
/// </summary>
/// <param name="chunk">
/// The chunk to add to the message.
/// </param>
public void Add(Chunk chunk)
{
ulong index = chunk.ChunkSequenceInMessage;
ulong chunks = ((ulong)this.m_Data.LongLength);
if (index < 0 || index >= chunks)
throw new ArgumentException("Chunk is not part of the message being assembled by this MessageAssembler.", "chunk");
// If the chunk is not a duplicate, insert its contents into the data array.
// (The chunked message cannot be deserialized until all chunks have been received.)
if (this.m_Data[index] == null) {
Debug.Assert(this.m_Remaining >= 1);
// This chunk has not been received before.
this.m_Data[index] = chunk.Data;
this.m_Remaining--;
Debug.WriteLine(string.Format("Received message #{0}, chunk #{0} of {1} ({2} bytes); {3} chunks remaining.",
chunk.MessageSequence,
chunk.ChunkSequenceInMessage + 1,
chunk.NumberOfChunksInMessage,
chunk.Data.LongLength,
this.m_Remaining),
this.GetType().ToString());
}
}
/// <summary>
/// Gets whether the given chunk is part of the message
/// being assembled by this <see cref="MessageAssembler"/>.
/// </summary>
/// <param name="chunk">
/// The chunk to test.
/// </param>
/// <returns>
/// Whether the chunk's sequence number is in range.
/// </returns>
public bool IsInRange(Chunk chunk)
{
return chunk.MessageSequence == this.m_MessageSequence;
}
/// <summary>
/// Attempts to assemble the chunk into a completed message.
/// If this is the last chunk of a message, the completed message
/// is returned, and any unsatisfied dependencies that are now
/// satisfied by the completed message are recursively assembled.
/// All such assembled message are also returned via the enumeration.
/// </summary>
/// <remarks>
/// This method is called by <see cref="Add"/> and <see cref="FlushWaitingChunks"/>,
/// after all chunk dependencies are satisfied.
/// </remarks>
/// <param name="chunk">The chunk to assemble.</param>
/// <returns>
/// The enumeration of decoded messages.
/// The enumeration may be empty or may
/// have arbitrarily many members if dependencies were
/// (recursively) satisfied by this chunk.
/// </returns>
protected IEnumerable<object> Assemble(Chunk chunk)
{
// Process single-chunk messages immediately.
if (chunk.NumberOfChunksInMessage <= 1) {
// Don't create a MessageAssembler for singleton chunks.
// Instead, just return the message immediately.
using (MemoryStream ms = new MemoryStream(chunk.Data)) {
yield return this.m_Formatter.Deserialize(ms);
// The message has been completed, so flush any chunks which were waiting for it.
foreach (object dependent in this.FlushWaitingChunks(chunk.MessageSequence))
yield return dependent;
yield break;
}
}
// For multi-chunk messages, we first attempt to find an existing MessageAssembler
// instance for the message to which the chunk belongs (based on the range of chunk
// sequence numbers the message spans).
MessageAssembler assembler = this.NewestMessageAssember, previous = null;
object message;
for (; ; ) {
bool done, remove, complete;
// If there does not exist any assembler for which IsInRange(chunk) returned true,
// create one to hold the chunk.
if (assembler == null) {
Debug.WriteLine(string.Format("Creating a new MessageAssembler to manage multipart message (message #{0}, chunks #{1}-{2})",
chunk.MessageSequence,
chunk.ChunkSequenceInMessage + 1,
chunk.NumberOfChunksInMessage),
this.GetType().ToString());
assembler = new MessageAssembler(chunk.MessageSequence,
chunk.NumberOfChunksInMessage, this.m_Formatter);
// Insert the assembler as the first entry in our linked list,
// since it is most likely to be used by subsequent chunks.
assembler.NextOldestAssembler = this.NewestMessageAssember;
this.NewestMessageAssember = assembler;
}
// See if the chunk belongs to the current assembler.
if (assembler.MessageSequence == chunk.MessageSequence) {
// If so, add the chunk to it, and we can stop searching.
assembler.Add(chunk);
done = true;
// If the message has been fully assembled, process it
// and remove the no-longer-needed assembler.
complete = assembler.IsComplete;
if (complete) {
message = assembler.DeserializeMessage();
remove = true;
} else {
message = null;
remove = false;
}
}
else if (assembler.MessageSequence < chunk.OldestRecoverableMessage) {
// For each message assembler that is waiting for more chunks (and to which the current
// chunk does not belong), make sure it will be possible to complete the message in
// the future. If the sender reports that its OldestRecoverableFrame is greater than
// the sequence number of any frame yet needed to complete the message, then no
// NACK we send can ever satisfy our needs, so we discard the message completely
// (removing the assembler from the linked list).
Debug.WriteLine(string.Format("### Giving up on message #{0} (chunks #{0}-{1}): the oldest available chunk is {2}!",
chunk.MessageSequence,
chunk.ChunkSequenceInMessage + 1,
chunk.NumberOfChunksInMessage,
chunk.OldestRecoverableMessage), this.GetType().ToString());
remove = true;
message = null;
done = false;
complete = false;
}
else {
remove = false;
message = null;
done = false;
complete = false;
}
// If the assembler is no longer useful, remove it from the linked list.
// (There are a couple of conditions, above, under which this might happen.)
if (remove) {
if (previous == null) {
this.NewestMessageAssember = assembler.NextOldestAssembler;
} else {
previous.NextOldestAssembler = assembler.NextOldestAssembler;
}
}
// If an assembler was found which accepted the chunk, we're done.
// (There are a couple of conditions, above, under which this might happen.)
if (done) {
if (complete) {
yield return message;
// The message has been completed, so flush any chunks which were waiting for it.
foreach (object dependent in this.FlushWaitingChunks(chunk.MessageSequence))
yield return dependent;
}
yield break;
} else {
// Get the next assembler. Do not break from the loop if there
// is no "next" assembler, since one will be created.
previous = assembler;
assembler = assembler.NextOldestAssembler;
}
}
}
/// <summary>
/// Writes a chunk to a data stream.
/// </summary>
public void EncodeChunk(Stream stream, Chunk chunk)
{
// FIXME: More efficient encoding of chunks might be possible here.
// Custom encoding would require a Decode method to be used by RTPMessageReceiver.
#if GENERIC_SERIALIZATION
chunk.Serialize().WriteToStream( stream );
#else
this.m_Formatter.Serialize( stream, chunk );
#endif
}
/// <summary>
/// Serialize the chunk then enqueue a send operation for each client socket for which there is a
/// participant membership in the receivers group.
/// </summary>
/// <param name="chunk"></param>
/// <param name="receivers"></param>
public void Send(Chunk chunk, Group receivers, MessageTags tags)
{
using (MemoryStream stream = new MemoryStream((int)(this.m_Encoder.MaximumChunkSize * 2))) {
stream.Position = 0;
this.m_Encoder.EncodeChunk(stream, chunk);
byte[] buffer = stream.GetBuffer();
int length = (int)stream.Length;
//Unicast to multicast bridge
#if RTP_BUILD
if ((this.m_U2MBridge != null) && !(receivers is SingletonGroup)) {
this.m_U2MBridge.Send(buffer,length,tags);
}
#endif
lock (m_AllClients) {
foreach (ClientData client in m_AllClients.Values) {
if (client.Participant != null) {
if (!client.Participant.Groups.Contains(receivers)) {
if (receivers == Group.AllParticipant) {
//Should never happen
Trace.WriteLine("!!!Participant has lost membership in 'All Participants' (sending anyway). Client= " + client.Id.ToString(), this.GetType().ToString());
if (client.Socket != null)
Trace.WriteLine(" Socket endpoint=" + client.Socket.RemoteEndPoint.ToString());
}
else {
//Ignoring participant (no group match)
if (receivers is SingletonGroup) {
//Trace.WriteLine("Ignoring participant; no group match for singleton group; participant= " + client.Id.ToString(), this.GetType().ToString());
}
else
Trace.WriteLine("Ignoring participant; no group match for group: " + receivers.FriendlyName + "; participant= " + client.Id.ToString(), this.GetType().ToString());
continue;
}
}
}
else {
//This probably shouldn't ever happen
Trace.WriteLine("Failed to find a participant for a connected socket.", this.GetType().ToString());
continue;
}
m_ServerSender.Send(buffer, length, client, tags, chunk.MessageSequence, chunk.ChunkSequenceInMessage,false);
}
}
}
}
public void Send(Chunk chunk)
{
using(MemoryStream ms = new MemoryStream()) {
this.m_bf.Serialize(ms, chunk);
this.m_Sender.Send(new BufferChunk(ms.GetBuffer(), 0, (int) ms.Length));
}
}
/// <summary>
/// Inserts the given chunk into the buffer.
/// </summary>
/// <remarks>
/// <para>
/// If the chunk's <see cref="Chunk.FrameSequence">frame sequence number</see> is
/// higher than any previously inserted chunk, then <see cref="NewestRecoverableFrame"/>
/// and <see cref="OldestRecoverableFrame"/> are updated to reflect the size of the buffer.
/// Any chunks whose frame sequence numbers fall outside of that range are removed, and
/// will no longer be recoverable under any circumnstances.
/// </para>
/// <para>
/// On the other hand, if the chunk is older than <see cref="NewestRecoverableFrame"/>,
/// then it is simply inserted into the buffer, unless it is also older than
/// <see cref="OldestRecoverableFrame"/>, in which case it is discarded.
/// </para>
/// </remarks>
/// <param name="value">The chunk to insert.</param>
public void Insert(Chunk value)
{
if (value == null)
throw new ArgumentNullException("value", "The data inserted into the buffer cannot be null.");
// Compute the index into the buffer table where the new data will go.
ulong index = value.FrameSequence % this.m_BufferSize;
// If the chunk is not inserted in ascending order, then all we have to
// do is insert it into the same index in the table as Take() would access.
if (this.m_Newest >= value.FrameSequence && value.FrameSequence != 0) {
if (this.m_Oldest <= value.FrameSequence && value.FrameSequence <= this.m_Newest)
this.Set(index, value);
return;
}
// Store the new chunk in the buffer.
this.Set(index, value);
// We must special-case the first time a chunk is buffered.
if (this.m_First == ulong.MaxValue) {
this.m_Oldest = this.m_First = this.m_Newest = value.FrameSequence;
} else {
// If the frame sequences are not sequential, we need to clean up invalid entries
// that were not already overwritten. We use "++expired" to skip the most recent
// valid entry. The "failsafe" ensures that no more than m_BufferSize iterations
// are made (more wouldn't hurt but would be wasteful). The index is hashed into
// the table each time in case it wraps around to the beginning.
for (ulong failsafe = 0, expired = this.m_Newest; ++expired < value.FrameSequence && failsafe++ < this.m_BufferSize; )
this.Set(expired % this.m_BufferSize, null);
// Regardless, we need to set the new m_Newest.
Debug.Assert(value.FrameSequence > this.m_Newest);
this.m_Newest = value.FrameSequence;
// We need to find the new oldest entry. Until the first m_BufferSize entries
// are added, the first entry cannot have been overwritten and it is the oldest.
Debug.Assert(value.FrameSequence > this.m_First);
if (value.FrameSequence - this.m_First < this.m_BufferSize) {
this.m_Oldest = this.m_First;
}
// Otherwise the oldest entry must increase. If sequence numbers were skipped,
// it may increase by more than one if additional entries are null.
// The loop must terminate because the new, non-null entry was set above.
else
while (this.m_Buffer[++this.m_Oldest % this.m_BufferSize] == null) ;
}
}
public void Send(Chunk chunk)
{
this.Post(this.m_SendChunkDelegate, new object[] { chunk });
}
public NetworkChunkEvent(Chunk chunk, long timeIndex, string source)
: base(timeIndex, source)
{
this.chunk = chunk;
}
