space-pew/Lidgren.Network/NetPeer.Fragmentation.cs

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C#
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2015-12-04 10:23:49 +01:00
using System;
using System.Threading;
using System.Collections.Generic;
namespace Lidgren.Network
{
internal class ReceivedFragmentGroup
{
//public float LastReceived;
public byte[] Data;
public NetBitVector ReceivedChunks;
}
public partial class NetPeer
{
private int m_lastUsedFragmentGroup;
private Dictionary<NetConnection, Dictionary<int, ReceivedFragmentGroup>> m_receivedFragmentGroups;
// on user thread
private NetSendResult SendFragmentedMessage(NetOutgoingMessage msg, IList<NetConnection> recipients, NetDeliveryMethod method, int sequenceChannel)
{
// Note: this group id is PER SENDING/NetPeer; ie. same id is sent to all recipients;
// this should be ok however; as long as recipients differentiate between same id but different sender
int group = Interlocked.Increment(ref m_lastUsedFragmentGroup);
if (group >= NetConstants.MaxFragmentationGroups)
{
// @TODO: not thread safe; but in practice probably not an issue
m_lastUsedFragmentGroup = 1;
group = 1;
}
msg.m_fragmentGroup = group;
// do not send msg; but set fragmentgroup in case user tries to recycle it immediately
// create fragmentation specifics
int totalBytes = msg.LengthBytes;
// determine minimum mtu for all recipients
int mtu = GetMTU(recipients);
int bytesPerChunk = NetFragmentationHelper.GetBestChunkSize(group, totalBytes, mtu);
int numChunks = totalBytes / bytesPerChunk;
if (numChunks * bytesPerChunk < totalBytes)
numChunks++;
NetSendResult retval = NetSendResult.Sent;
int bitsPerChunk = bytesPerChunk * 8;
int bitsLeft = msg.LengthBits;
for (int i = 0; i < numChunks; i++)
{
NetOutgoingMessage chunk = CreateMessage(0);
chunk.m_bitLength = (bitsLeft > bitsPerChunk ? bitsPerChunk : bitsLeft);
chunk.m_data = msg.m_data;
chunk.m_fragmentGroup = group;
chunk.m_fragmentGroupTotalBits = totalBytes * 8;
chunk.m_fragmentChunkByteSize = bytesPerChunk;
chunk.m_fragmentChunkNumber = i;
NetException.Assert(chunk.m_bitLength != 0);
NetException.Assert(chunk.GetEncodedSize() < mtu);
Interlocked.Add(ref chunk.m_recyclingCount, recipients.Count);
foreach (NetConnection recipient in recipients)
{
var res = recipient.EnqueueMessage(chunk, method, sequenceChannel);
if ((int)res > (int)retval)
retval = res; // return "worst" result
}
bitsLeft -= bitsPerChunk;
}
return retval;
}
private void HandleReleasedFragment(NetIncomingMessage im)
{
VerifyNetworkThread();
//
// read fragmentation header and combine fragments
//
int group;
int totalBits;
int chunkByteSize;
int chunkNumber;
int ptr = NetFragmentationHelper.ReadHeader(
im.m_data, 0,
out group,
out totalBits,
out chunkByteSize,
out chunkNumber
);
NetException.Assert(im.LengthBytes > ptr);
NetException.Assert(group > 0);
NetException.Assert(totalBits > 0);
NetException.Assert(chunkByteSize > 0);
int totalBytes = NetUtility.BytesToHoldBits((int)totalBits);
int totalNumChunks = totalBytes / chunkByteSize;
if (totalNumChunks * chunkByteSize < totalBytes)
totalNumChunks++;
NetException.Assert(chunkNumber < totalNumChunks);
if (chunkNumber >= totalNumChunks)
{
LogWarning("Index out of bounds for chunk " + chunkNumber + " (total chunks " + totalNumChunks + ")");
return;
}
Dictionary<int, ReceivedFragmentGroup> groups;
if (!m_receivedFragmentGroups.TryGetValue(im.SenderConnection, out groups))
{
groups = new Dictionary<int, ReceivedFragmentGroup>();
m_receivedFragmentGroups[im.SenderConnection] = groups;
}
ReceivedFragmentGroup info;
if (!groups.TryGetValue(group, out info))
{
info = new ReceivedFragmentGroup();
info.Data = new byte[totalBytes];
info.ReceivedChunks = new NetBitVector(totalNumChunks);
groups[group] = info;
}
info.ReceivedChunks[chunkNumber] = true;
//info.LastReceived = (float)NetTime.Now;
// copy to data
int offset = (chunkNumber * chunkByteSize);
Buffer.BlockCopy(im.m_data, ptr, info.Data, offset, im.LengthBytes - ptr);
int cnt = info.ReceivedChunks.Count();
//LogVerbose("Found fragment #" + chunkNumber + " in group " + group + " offset " + offset + " of total bits " + totalBits + " (total chunks done " + cnt + ")");
LogVerbose("Received fragment " + chunkNumber + " of " + totalNumChunks + " (" + cnt + " chunks received)");
if (info.ReceivedChunks.Count() == totalNumChunks)
{
// Done! Transform this incoming message
im.m_data = info.Data;
im.m_bitLength = (int)totalBits;
im.m_isFragment = false;
LogVerbose("Fragment group #" + group + " fully received in " + totalNumChunks + " chunks (" + totalBits + " bits)");
groups.Remove(group);
ReleaseMessage(im);
}
else
{
// data has been copied; recycle this incoming message
Recycle(im);
}
return;
}
}
}