Changed lobby & chatMsg IDs to from uint to ushort, added a utility class that handles the wrap around of IDs

Subsurface/Barotrauma.csproj

@@ -163,6 +163,7 @@
     <Compile Include="Source\Networking\NetEntityEvent\NetEntityEventManager.cs" />
     <Compile Include="Source\Networking\NetEntityEvent\ServerEntityEventManager.cs" />
     <Compile Include="Source\Networking\NetStats.cs" />
+    <Compile Include="Source\Networking\NetIdUtils.cs" />
     <Compile Include="Source\Networking\RespawnManager.cs" />
     <Compile Include="Source\Networking\ServerLog.cs" />
     <Compile Include="Source\Networking\WhiteList.cs" />

Subsurface/Source/Networking/ChatMessage.cs

@@ -47,9 +47,9 @@ namespace Barotrauma.Networking
             private set;
         }
 
-        public static UInt32 LastID = 0;
+        public static UInt16 LastID = 0;
 
-        public UInt32 NetStateID
+        public UInt16 NetStateID
         {
             get;
             set;
@@ -138,9 +138,9 @@ namespace Barotrauma.Networking
 
         static public void ServerRead(NetIncomingMessage msg, Client c)
         {
-            UInt32 ID = msg.ReadUInt32();
+            UInt16 ID = msg.ReadUInt16();
             string txt = msg.ReadString();
-            if (c.lastSentChatMsgID < ID)
+            if (NetIdUtils.IdMoreRecent(ID, c.lastSentChatMsgID))
             {
                 //this chat message is new to the server
                 GameMain.Server.SendChatMessage(txt, null, c);
@@ -169,7 +169,7 @@ namespace Barotrauma.Networking
 
         static public void ClientRead(NetIncomingMessage msg)
         {
-            UInt32 ID = msg.ReadUInt32();
+            UInt16 ID = msg.ReadUInt16();
             ChatMessageType type = (ChatMessageType)msg.ReadByte();           
             string txt = msg.ReadString();
 
@@ -189,7 +189,7 @@ namespace Barotrauma.Networking
                 senderName = msg.ReadString();
             }
 
-            if (ID > LastID)
+            if (NetIdUtils.IdMoreRecent(ID, LastID))
             {
                 GameMain.Client.AddChatMessage(txt, type, senderName, senderCharacter);
                 LastID = ID;

Subsurface/Source/Networking/Client.cs

@@ -30,11 +30,11 @@ namespace Barotrauma.Networking
         public NetConnection Connection { get; set; }
         public string version;
         public bool inGame;
-        public UInt32 lastRecvGeneralUpdate = 0;
+        public UInt16 lastRecvGeneralUpdate = 0;
 
         public bool hasLobbyData = false;
-        public UInt32 lastSentChatMsgID = 0; //last msg this client said
+        public UInt16 lastSentChatMsgID = 0; //last msg this client said
-        public UInt32 lastRecvChatMsgID = 0; //last msg this client knows about
+        public UInt16 lastRecvChatMsgID = 0; //last msg this client knows about
 
         public UInt32 lastSentEntityEventID = 0;
         public UInt32 lastRecvEntityEventID = 0;
@@ -42,7 +42,7 @@ namespace Barotrauma.Networking
         public UInt32 lastRecvEntitySpawnID = 0;
 
         public List<ChatMessage> chatMsgQueue = new List<ChatMessage>();
-        public UInt32 lastChatMsgQueueID;
+        public UInt16 lastChatMsgQueueID;
         public float ChatSpamSpeed;
         public float ChatSpamTimer;
         public int ChatSpamCount;

Subsurface/Source/Networking/GameClient.cs

@@ -35,8 +35,8 @@ namespace Barotrauma.Networking
         private int nonce;
         private string saltedPw;
 
-        private UInt32 lastSentChatMsgID = 0; //last message this client has successfully sent
+        private UInt16 lastSentChatMsgID = 0; //last message this client has successfully sent
-        private UInt32 lastQueueChatMsgID = 0; //last message added to the queue
+        private UInt16 lastQueueChatMsgID = 0; //last message added to the queue
         private List<ChatMessage> chatMsgQueue = new List<ChatMessage>();
 
         public UInt32 LastSentEntityEventID;
@@ -729,13 +729,13 @@ namespace Barotrauma.Networking
 
                         if (lobbyUpdated)
                         {
-                            UInt32 updateID     = inc.ReadUInt32();
+                            UInt16 updateID     = inc.ReadUInt16();
                             string serverName   = inc.ReadString();
                             string serverText   = inc.ReadString();
  
                             if (inc.ReadBoolean())
                             {
-                                ReadInitialUpdate(inc, updateID <= GameMain.NetLobbyScreen.LastUpdateID);
+                                ReadInitialUpdate(inc, !NetIdUtils.IdMoreRecent(updateID,GameMain.NetLobbyScreen.LastUpdateID));
                             }
 
                             string selectSubName        = inc.ReadString();
@@ -768,7 +768,7 @@ namespace Barotrauma.Networking
                             }
 
                             //ignore the message if we already a more up-to-date one
-                            if (updateID > GameMain.NetLobbyScreen.LastUpdateID)
+                            if (NetIdUtils.IdMoreRecent(updateID, GameMain.NetLobbyScreen.LastUpdateID))
                             {
                                 GameMain.NetLobbyScreen.LastUpdateID = updateID;
 
@@ -811,7 +811,7 @@ namespace Barotrauma.Networking
                                 Voting.AllowModeVoting = allowModeVoting;
                             }
                         }
-                        lastSentChatMsgID = inc.ReadUInt32();
+                        lastSentChatMsgID = inc.ReadUInt16();
                         break;
                     case ServerNetObject.CHAT_MESSAGE:
                         ChatMessage.ClientRead(inc);
@@ -833,7 +833,7 @@ namespace Barotrauma.Networking
                 switch (objHeader)
                 {
                     case ServerNetObject.SYNC_IDS:
-                        lastSentChatMsgID = inc.ReadUInt32();
+                        lastSentChatMsgID = inc.ReadUInt16();
                         LastSentEntityEventID = inc.ReadUInt32();
                         break;
                     case ServerNetObject.ENTITY_POSITION:
@@ -878,11 +878,8 @@ namespace Barotrauma.Networking
             outmsg.Write((byte)ClientNetObject.SYNC_IDS);
             outmsg.Write(GameMain.NetLobbyScreen.LastUpdateID);
             outmsg.Write(ChatMessage.LastID);
-            ChatMessage removeMsg;
+
-            while ((removeMsg=chatMsgQueue.Find(cMsg => cMsg.NetStateID <= lastSentChatMsgID)) != null)
+            chatMsgQueue.RemoveAll(cMsg => !NetIdUtils.IdMoreRecent(cMsg.NetStateID, lastSentChatMsgID));
-            {
-                chatMsgQueue.Remove(removeMsg);
-            }
 
             foreach (ChatMessage cMsg in chatMsgQueue)
             {
@@ -903,11 +900,7 @@ namespace Barotrauma.Networking
             outmsg.Write(Entity.Spawner.NetStateID);
             outmsg.Write(entityEventManager.LastReceivedID);
 
-            ChatMessage removeMsg;
+            chatMsgQueue.RemoveAll(cMsg => !NetIdUtils.IdMoreRecent(cMsg.NetStateID, lastSentChatMsgID));
-            while ((removeMsg = chatMsgQueue.Find(cMsg => cMsg.NetStateID <= lastSentChatMsgID)) != null)
-            {
-                chatMsgQueue.Remove(removeMsg);
-            }
 
             foreach (ChatMessage cMsg in chatMsgQueue)
             {

Subsurface/Source/Networking/GameServer.cs

@@ -78,6 +78,8 @@ namespace Barotrauma.Networking
             config.SimulatedMinimumLatency = 0.1f;
 
             config.ConnectionTimeout = 60.0f;
+
+            NetIdUtils.Test();
 #endif 
             config.Port = port;
             Port = port;
@@ -622,8 +624,8 @@ namespace Barotrauma.Networking
                 {
                     case ClientNetObject.SYNC_IDS:
                         //TODO: might want to use a clever class for this
-                        c.lastRecvGeneralUpdate = Math.Min(Math.Max(c.lastRecvGeneralUpdate, inc.ReadUInt32()), GameMain.NetLobbyScreen.LastUpdateID);
+                        c.lastRecvGeneralUpdate = NetIdUtils.Clamp(inc.ReadUInt16(), c.lastRecvGeneralUpdate, GameMain.NetLobbyScreen.LastUpdateID);
-                        c.lastRecvChatMsgID     = Math.Min(Math.Max(c.lastRecvChatMsgID, inc.ReadUInt32()), c.lastChatMsgQueueID);
+                        c.lastRecvChatMsgID     = NetIdUtils.Clamp(inc.ReadUInt16(), c.lastRecvChatMsgID, c.lastChatMsgQueueID);
                         break;
                     case ClientNetObject.CHAT_MESSAGE:
                         ChatMessage.ServerRead(inc, c);
@@ -657,7 +659,7 @@ namespace Barotrauma.Networking
                     case ClientNetObject.SYNC_IDS:
                         //TODO: might want to use a clever class for this
                         
-                        UInt32 lastRecvChatMsgID        = inc.ReadUInt32();
+                        UInt16 lastRecvChatMsgID        = inc.ReadUInt16();
                         UInt32 lastRecvEntitySpawnID    = inc.ReadUInt32();
                         UInt32 lastRecvEntityEventID    = inc.ReadUInt32();
 
@@ -734,7 +736,7 @@ namespace Barotrauma.Networking
             outmsg.Write(c.lastSentChatMsgID); //send this to client so they know which chat messages weren't received by the server
             outmsg.Write(c.lastSentEntityEventID);
 
-            c.chatMsgQueue.RemoveAll(cMsg => cMsg.NetStateID <= c.lastRecvChatMsgID);
+            c.chatMsgQueue.RemoveAll(cMsg => !NetIdUtils.IdMoreRecent(cMsg.NetStateID, c.lastRecvChatMsgID));
             foreach (ChatMessage cMsg in c.chatMsgQueue)
             {
                 cMsg.ServerWrite(outmsg, c);
@@ -798,7 +800,7 @@ namespace Barotrauma.Networking
 
             outmsg.Write((byte)ServerNetObject.SYNC_IDS);
 
-            if (c.lastRecvGeneralUpdate<GameMain.NetLobbyScreen.LastUpdateID)
+            if (NetIdUtils.IdMoreRecent(GameMain.NetLobbyScreen.LastUpdateID, c.lastRecvGeneralUpdate))
             {
                 outmsg.Write(true);
                 outmsg.WritePadBits();
@@ -849,7 +851,7 @@ namespace Barotrauma.Networking
 
             outmsg.Write(c.lastSentChatMsgID); //send this to client so they know which chat messages weren't received by the server
 
-            c.chatMsgQueue.RemoveAll(cMsg => cMsg.NetStateID <= c.lastRecvChatMsgID);
+            c.chatMsgQueue.RemoveAll(cMsg => !NetIdUtils.IdMoreRecent(cMsg.NetStateID, c.lastRecvChatMsgID));
             foreach (ChatMessage cMsg in c.chatMsgQueue)
             {
                 cMsg.ServerWrite(outmsg, c);
@@ -1482,8 +1484,8 @@ namespace Barotrauma.Networking
                     senderCharacter);
                 
                 chatMsg.NetStateID = client.chatMsgQueue.Count > 0 ?
-                    client.chatMsgQueue.Last().NetStateID + 1 : 
+                    (ushort)(client.chatMsgQueue.Last().NetStateID + 1) :
-                    client.lastRecvChatMsgID+1;
+                    (ushort)(client.lastRecvChatMsgID + 1);
 
                 client.chatMsgQueue.Add(chatMsg);
                 client.lastChatMsgQueueID = chatMsg.NetStateID;

Subsurface/Source/Networking/NetIdUtils.cs

@@ -0,0 +1,57 @@
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Barotrauma.Networking
+{
+    static class NetIdUtils
+    {
+        /// <summary>
+        /// Is newID more recent than oldID
+        /// </summary>
+        public static bool IdMoreRecent(ushort newID, ushort oldID)
+        {
+            uint id1 = newID;
+            uint id2 = oldID;
+
+            return
+                (id1 > id2) && (id1 - id2 <= ushort.MaxValue / 2)
+                   ||
+                (id2 > id1) && (id2 - id1 > ushort.MaxValue / 2);
+        }
+
+        public static ushort Clamp(ushort id, ushort min, ushort max)
+        {
+            if (IdMoreRecent(min, max))
+            {
+                throw new ArgumentException("Min cannot be larger than max");
+            }
+
+            if (!IdMoreRecent(id, min))
+            {
+                return min;
+            }
+            else if (IdMoreRecent(id, max))
+            {
+                return max;
+            }
+
+            return id;
+        }
+
+#if DEBUG
+        public static void Test()
+        {
+            Debug.Assert(NetIdUtils.IdMoreRecent((ushort)2, (ushort)1));
+            Debug.Assert(NetIdUtils.IdMoreRecent((ushort)2, (ushort)(ushort.MaxValue - 5)));
+            Debug.Assert(!NetIdUtils.IdMoreRecent((ushort)ushort.MaxValue, (ushort)5));
+
+            Debug.Assert(Clamp((ushort)5, (ushort)1, (ushort)10) == 5);
+            Debug.Assert(Clamp((ushort)(ushort.MaxValue - 5), (ushort)(ushort.MaxValue - 2), (ushort)3) == (ushort)(ushort.MaxValue - 2));
+        }
+#endif
+    }
+}

Subsurface/Source/Screens/NetLobbyScreen.cs

@@ -52,9 +52,8 @@ namespace Barotrauma
         public bool IsServer;
         public string ServerName;
 
-        const float NetworkUpdateInterval = 1.0f;
+        private UInt16 lastUpdateID;
-        private UInt32 lastUpdateID;
+        public UInt16 LastUpdateID
-        public UInt32 LastUpdateID
         {
             get { if (GameMain.Server != null && lastUpdateID < 1) lastUpdateID++; return lastUpdateID; }
             set { if (GameMain.Server != null) return; lastUpdateID = value; }