10 files changed, 242 insertions, 120 deletions

diff --git a/OpenSim/Framework/AgentCircuitData.cs b/OpenSim/Framework/AgentCircuitData.cs
index 3dbc215..dbd47d3 100644
--- a/OpenSim/Framework/AgentCircuitData.cs
+++ b/OpenSim/Framework/AgentCircuitData.cs
@@ -152,27 +152,6 @@ namespace OpenSim.Framework
         }
 
         /// <summary>
-        /// Create AgentCircuitData from a Serializable AgentCircuitData
-        /// </summary>
-        /// <param name="cAgent"></param>
-        public AgentCircuitData(sAgentCircuitData cAgent)
-        {
-            AgentID = new UUID(cAgent.AgentID);
-            SessionID = new UUID(cAgent.SessionID);
-            SecureSessionID = new UUID(cAgent.SecureSessionID);
-            startpos = new Vector3(cAgent.startposx, cAgent.startposy, cAgent.startposz);
-            firstname = cAgent.firstname;
-            lastname = cAgent.lastname;
-            circuitcode = cAgent.circuitcode;
-            child = cAgent.child;
-            InventoryFolder = new UUID(cAgent.InventoryFolder);
-            BaseFolder = new UUID(cAgent.BaseFolder);
-            CapsPath = cAgent.CapsPath;
-            ChildrenCapSeeds = cAgent.ChildrenCapSeeds;
-            Viewer = cAgent.Viewer;
-        }
-
-        /// <summary>
         /// Pack AgentCircuitData into an OSDMap for transmission over LLSD XML or LLSD json
         /// </summary>
         /// <returns>map of the agent circuit data</returns>
@@ -369,52 +348,4 @@ namespace OpenSim.Framework
     }
 
 
-    /// <summary>
-    /// Serializable Agent Circuit Data
-    /// </summary>
-    [Serializable]
-    public class sAgentCircuitData
-    {
-        public Guid AgentID;
-        public Guid BaseFolder;
-        public string CapsPath = String.Empty;
-        public Dictionary<ulong, string> ChildrenCapSeeds;
-        public bool child;
-        public uint circuitcode;
-        public string firstname;
-        public Guid InventoryFolder;
-        public string lastname;
-        public Guid SecureSessionID;
-        public Guid SessionID;
-        public float startposx;
-        public float startposy;
-        public float startposz;
-        public string Viewer;
-        public string Channel;
-        public string Mac;
-        public string Id0;
-
-        public sAgentCircuitData()
-        {
-        }
-
-        public sAgentCircuitData(AgentCircuitData cAgent)
-        {
-            AgentID = cAgent.AgentID.Guid;
-            SessionID = cAgent.SessionID.Guid;
-            SecureSessionID = cAgent.SecureSessionID.Guid;
-            startposx = cAgent.startpos.X;
-            startposy = cAgent.startpos.Y;
-            startposz = cAgent.startpos.Z;
-            firstname = cAgent.firstname;
-            lastname = cAgent.lastname;
-            circuitcode = cAgent.circuitcode;
-            child = cAgent.child;
-            InventoryFolder = cAgent.InventoryFolder.Guid;
-            BaseFolder = cAgent.BaseFolder.Guid;
-            CapsPath = cAgent.CapsPath;
-            ChildrenCapSeeds = cAgent.ChildrenCapSeeds;
-            Viewer = cAgent.Viewer;
-        }
-    }
 }
diff --git a/OpenSim/Framework/ChildAgentDataUpdate.cs b/OpenSim/Framework/ChildAgentDataUpdate.cs
index ce0b2fb..a626b82 100644
--- a/OpenSim/Framework/ChildAgentDataUpdate.cs
+++ b/OpenSim/Framework/ChildAgentDataUpdate.cs
@@ -62,7 +62,7 @@ namespace OpenSim.Framework
         UUID AgentID { get; set; }
 
         OSDMap Pack();
-        void Unpack(OSDMap map);
+        void Unpack(OSDMap map, IScene scene);
     }
 
     /// <summary>
@@ -122,7 +122,7 @@ namespace OpenSim.Framework
             return args;
         }
 
-        public void Unpack(OSDMap args)
+        public void Unpack(OSDMap args, IScene scene)
         {
             if (args.ContainsKey("region_handle"))
                 UInt64.TryParse(args["region_handle"].AsString(), out RegionHandle);
@@ -329,6 +329,10 @@ namespace OpenSim.Framework
 
         public string CallbackURI;
 
+        // These two must have the same Count
+        public List<ISceneObject> AttachmentObjects;
+        public List<string> AttachmentObjectStates;
+
         public virtual OSDMap Pack()
         {
             m_log.InfoFormat("[CHILDAGENTDATAUPDATE] Pack data");
@@ -441,7 +445,30 @@ namespace OpenSim.Framework
             if ((CallbackURI != null) && (!CallbackURI.Equals("")))
                 args["callback_uri"] = OSD.FromString(CallbackURI);
 
+            // Attachment objects for fatpack messages
+            if (AttachmentObjects != null)
+            {
+                int i = 0;
+                OSDArray attObjs = new OSDArray(AttachmentObjects.Count);
+                foreach (ISceneObject so in AttachmentObjects)
+                {
+                    OSDMap info = new OSDMap(4);
+                    info["sog"] = OSD.FromString(so.ToXml2());
+                    info["extra"] = OSD.FromString(so.ExtraToXmlString());
+                    info["modified"] = OSD.FromBoolean(so.HasGroupChanged);
+                    try
+                    {
+                        info["state"] = OSD.FromString(AttachmentObjectStates[i++]);
+                    }
+                    catch (IndexOutOfRangeException e)
+                    {
+                        m_log.WarnFormat("[CHILD AGENT DATA]: scrtips list is shorter than object list.");
+                    }
 
+                    attObjs.Add(info);
+                }
+                args["attach_objects"] = attObjs;
+            }
             return args;
         }
 
@@ -450,7 +477,7 @@ namespace OpenSim.Framework
         /// Avoiding reflection makes it painful to write, but that's the price!
         /// </summary>
         /// <param name="hash"></param>
-        public virtual void Unpack(OSDMap args)
+        public virtual void Unpack(OSDMap args, IScene scene)
         {
             m_log.InfoFormat("[CHILDAGENTDATAUPDATE] Unpack data");
 
@@ -628,6 +655,26 @@ namespace OpenSim.Framework
 
             if (args["callback_uri"] != null)
                 CallbackURI = args["callback_uri"].AsString();
+
+            // Attachment objects
+            if (args["attach_objects"] != null && args["attach_objects"].Type == OSDType.Array)
+            {
+                OSDArray attObjs = (OSDArray)(args["attach_objects"]);
+                AttachmentObjects = new List<ISceneObject>();
+                AttachmentObjectStates = new List<string>();
+                foreach (OSD o in attObjs)
+                {
+                    if (o.Type == OSDType.Map)
+                    {
+                        OSDMap info = (OSDMap)o;
+                        ISceneObject so = scene.DeserializeObject(info["sog"].AsString());
+                        so.ExtraFromXmlString(info["extra"].AsString());
+                        so.HasGroupChanged = info["modified"].AsBoolean();
+                        AttachmentObjects.Add(so);
+                        AttachmentObjectStates.Add(info["state"].AsString());
+                    }
+                }
+            }
         }
 
         public AgentData()
@@ -655,9 +702,9 @@ namespace OpenSim.Framework
             return base.Pack();
         }
 
-        public override void Unpack(OSDMap map)
+        public override void Unpack(OSDMap map, IScene scene)
         {
-            base.Unpack(map);
+            base.Unpack(map, scene);
         }
     }
 }
diff --git a/OpenSim/Framework/ClientInfo.cs b/OpenSim/Framework/ClientInfo.cs
index fbd18b5..62acb70 100644
--- a/OpenSim/Framework/ClientInfo.cs
+++ b/OpenSim/Framework/ClientInfo.cs
@@ -31,10 +31,9 @@ using System.Net;
 
 namespace OpenSim.Framework
 {
-    [Serializable]
     public class ClientInfo
     {
-        public sAgentCircuitData agentcircuit;
+        public AgentCircuitData agentcircuit;
 
         public Dictionary<uint, byte[]> needAck;
 
diff --git a/OpenSim/Framework/Console/CommandConsole.cs b/OpenSim/Framework/Console/CommandConsole.cs
index 52bcd55..be36cf2 100644
--- a/OpenSim/Framework/Console/CommandConsole.cs
+++ b/OpenSim/Framework/Console/CommandConsole.cs
@@ -592,9 +592,7 @@ namespace OpenSim.Framework.Console
             string line = ReadLine(m_defaultPrompt + "# ", true, true);
 
             if (line != String.Empty)
-            {
-                m_log.Info("[CONSOLE] Invalid command");
-            }
+                Output("Invalid command");
         }
 
         public void RunCommand(string cmd)
diff --git a/OpenSim/Framework/IClientAPI.cs b/OpenSim/Framework/IClientAPI.cs
index f573c32..069987b 100644
--- a/OpenSim/Framework/IClientAPI.cs
+++ b/OpenSim/Framework/IClientAPI.cs
@@ -572,34 +572,69 @@ namespace OpenSim.Framework
 
     public class IEntityUpdate
     {
-        public ISceneEntity Entity;
-        public uint Flags;
+        private ISceneEntity m_entity;
+        private uint m_flags;
+        private int m_updateTime;
+
+        public ISceneEntity Entity
+        {
+            get { return m_entity; }
+        }
+
+        public uint Flags
+        {
+            get { return m_flags; }
+        }
+
+        public int UpdateTime
+        {
+            get { return m_updateTime; }
+        }
 
         public virtual void Update(IEntityUpdate update)
         {
-            this.Flags |= update.Flags;
+            m_flags |= update.Flags;
+
+            // Use the older of the updates as the updateTime
+            if (Util.EnvironmentTickCountCompare(UpdateTime, update.UpdateTime) > 0)
+                m_updateTime = update.UpdateTime;
         }
 
         public IEntityUpdate(ISceneEntity entity, uint flags)
         {
-            Entity = entity;
-            Flags = flags;
+            m_entity = entity;
+            m_flags = flags;
+            m_updateTime = Util.EnvironmentTickCount();
+        }
+
+        public IEntityUpdate(ISceneEntity entity, uint flags, Int32 updateTime)
+        {
+            m_entity = entity;
+            m_flags = flags;
+            m_updateTime = updateTime;
         }
     }
-    
 
     public class EntityUpdate : IEntityUpdate
     {
-        // public ISceneEntity Entity;
-        // public PrimUpdateFlags Flags;
-        public float TimeDilation;
+        private float m_timeDilation;
+
+        public float TimeDilation
+        {
+            get { return m_timeDilation; }
+        }
 
         public EntityUpdate(ISceneEntity entity, PrimUpdateFlags flags, float timedilation)
-            : base(entity,(uint)flags)
+            : base(entity, (uint)flags)
         {
-            //Entity = entity;
             // Flags = flags;
-            TimeDilation = timedilation;
+            m_timeDilation = timedilation;
+        }
+
+        public EntityUpdate(ISceneEntity entity, PrimUpdateFlags flags, float timedilation, Int32 updateTime)
+            : base(entity,(uint)flags,updateTime)
+        {
+            m_timeDilation = timedilation;
         }
     }
 
diff --git a/OpenSim/Region/ClientStack/LindenUDP/PriorityQueue.cs b/OpenSim/Framework/PriorityQueue.cs
index b62ec07..3e6fdaa 100644
--- a/OpenSim/Region/ClientStack/LindenUDP/PriorityQueue.cs
+++ b/OpenSim/Framework/PriorityQueue.cs
@@ -34,50 +34,81 @@ using OpenSim.Framework;
 using OpenSim.Framework.Client;
 using log4net;
 
-namespace OpenSim.Region.ClientStack.LindenUDP
+namespace OpenSim.Framework
 {
     public class PriorityQueue
     {
         private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
 
-        internal delegate bool UpdatePriorityHandler(ref uint priority, ISceneEntity entity);
+        public delegate bool UpdatePriorityHandler(ref uint priority, ISceneEntity entity);
 
-        // Heap[0] for self updates
-        // Heap[1..12] for entity updates
+        /// <summary>
+        /// Total number of queues (priorities) available
+        /// </summary>
+        public const uint NumberOfQueues = 12;
 
-        internal const uint m_numberOfQueues = 12;
+        /// <summary>
+        /// Number of queuest (priorities) that are processed immediately
+        /// </summary.
+        public const uint NumberOfImmediateQueues = 2;
 
-        private MinHeap<MinHeapItem>[] m_heaps = new MinHeap<MinHeapItem>[m_numberOfQueues];
+        private MinHeap<MinHeapItem>[] m_heaps = new MinHeap<MinHeapItem>[NumberOfQueues];
         private Dictionary<uint, LookupItem> m_lookupTable;
+
+        // internal state used to ensure the deqeues are spread across the priority
+        // queues "fairly". queuecounts is the amount to pull from each queue in 
+        // each pass. weighted towards the higher priority queues
         private uint m_nextQueue = 0;
+        private uint m_countFromQueue = 0;
+        private uint[] m_queueCounts = { 8, 4, 4, 2, 2, 2, 2, 1, 1, 1, 1, 1 };
+
+        // next request is a counter of the number of updates queued, it provides
+        // a total ordering on the updates coming through the queue and is more
+        // lightweight (and more discriminating) than tick count
         private UInt64 m_nextRequest = 0;
 
+        /// <summary>
+        /// Lock for enqueue and dequeue operations on the priority queue
+        /// </summary>
         private object m_syncRoot = new object();
         public object SyncRoot {
             get { return this.m_syncRoot; }
         }
 
-        internal PriorityQueue() : this(MinHeap<MinHeapItem>.DEFAULT_CAPACITY) { }
+#region constructor
+        public PriorityQueue() : this(MinHeap<MinHeapItem>.DEFAULT_CAPACITY) { }
 
-        internal PriorityQueue(int capacity)
+        public PriorityQueue(int capacity)
         {
             m_lookupTable = new Dictionary<uint, LookupItem>(capacity);
 
             for (int i = 0; i < m_heaps.Length; ++i)
                 m_heaps[i] = new MinHeap<MinHeapItem>(capacity);
+
+            m_nextQueue = NumberOfImmediateQueues;
+            m_countFromQueue = m_queueCounts[m_nextQueue];
         }
+#endregion Constructor
 
-        internal int Count
+#region PublicMethods
+        /// <summary>
+        /// Return the number of items in the queues
+        /// </summary>
+        public int Count
         {
             get
             {
                 int count = 0;
                 for (int i = 0; i < m_heaps.Length; ++i)
                     count += m_heaps[i].Count;
+                
                 return count;
             }
         }
 
+        /// <summary>
+        /// Enqueue an item into the specified priority queue
+        /// </summary>
         public bool Enqueue(uint pqueue, IEntityUpdate value)
         {
             LookupItem lookup;
@@ -91,7 +122,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
                 lookup.Heap.Remove(lookup.Handle);
             }
 
-            pqueue = Util.Clamp<uint>(pqueue, 0, m_numberOfQueues - 1);
+            pqueue = Util.Clamp<uint>(pqueue, 0, NumberOfQueues - 1);
             lookup.Heap = m_heaps[pqueue];
             lookup.Heap.Add(new MinHeapItem(pqueue, entry, value), ref lookup.Handle);
             m_lookupTable[localid] = lookup;
@@ -99,20 +130,62 @@ namespace OpenSim.Region.ClientStack.LindenUDP
             return true;
         }
 
-        internal bool TryDequeue(out IEntityUpdate value, out Int32 timeinqueue)
+        /// <summary>
+        /// Remove an item from one of the queues. Specifically, it removes the
+        /// oldest item from the next queue in order to provide fair access to
+        /// all of the queues
+        /// </summary>
+        public bool TryDequeue(out IEntityUpdate value, out Int32 timeinqueue)
         {
-            for (int i = 0; i < m_numberOfQueues; ++i)
+            // If there is anything in priority queue 0, return it first no
+            // matter what else. Breaks fairness. But very useful.
+            for (int iq = 0; iq < NumberOfImmediateQueues; iq++)
             {
-                // To get the fair queing, we cycle through each of the
-                // queues when finding an element to dequeue, this code
-                // assumes that the distribution of updates in the queues
-                // is polynomial, probably quadractic (eg distance of PI * R^2)
-                uint h = (uint)((m_nextQueue + i) % m_numberOfQueues);
-                if (m_heaps[h].Count > 0)
+                if (m_heaps[iq].Count > 0)
                 {
-                    m_nextQueue = (uint)((h + 1) % m_numberOfQueues);
+                    MinHeapItem item = m_heaps[iq].RemoveMin();
+                    m_lookupTable.Remove(item.Value.Entity.LocalId);
+                    timeinqueue = Util.EnvironmentTickCountSubtract(item.EntryTime);
+                    value = item.Value;
 
-                    MinHeapItem item = m_heaps[h].RemoveMin();
+                    return true;
+                }
+            }
+            
+            // To get the fair queing, we cycle through each of the
+            // queues when finding an element to dequeue. 
+            // We pull (NumberOfQueues - QueueIndex) items from each queue in order
+            // to give lower numbered queues a higher priority and higher percentage
+            // of the bandwidth. 
+            
+            // Check for more items to be pulled from the current queue
+            if (m_heaps[m_nextQueue].Count > 0 && m_countFromQueue > 0)
+            {
+                m_countFromQueue--;
+                
+                MinHeapItem item = m_heaps[m_nextQueue].RemoveMin();
+                m_lookupTable.Remove(item.Value.Entity.LocalId);
+                timeinqueue = Util.EnvironmentTickCountSubtract(item.EntryTime);
+                value = item.Value;
+                
+                return true;
+            }
+            
+            // Find the next non-immediate queue with updates in it
+            for (int i = 0; i < NumberOfQueues; ++i)
+            {
+                m_nextQueue = (uint)((m_nextQueue + 1) % NumberOfQueues);
+                m_countFromQueue = m_queueCounts[m_nextQueue];
+
+                // if this is one of the immediate queues, just skip it
+                if (m_nextQueue < NumberOfImmediateQueues)
+                    continue;
+                
+                if (m_heaps[m_nextQueue].Count > 0)
+                {
+                    m_countFromQueue--;
+
+                    MinHeapItem item = m_heaps[m_nextQueue].RemoveMin();
                     m_lookupTable.Remove(item.Value.Entity.LocalId);
                     timeinqueue = Util.EnvironmentTickCountSubtract(item.EntryTime);
                     value = item.Value;
@@ -126,7 +199,11 @@ namespace OpenSim.Region.ClientStack.LindenUDP
             return false;
         }
 
-        internal void Reprioritize(UpdatePriorityHandler handler)
+        /// <summary>
+        /// Reapply the prioritization function to each of the updates currently
+        /// stored in the priority queues. 
+        /// </summary
+        public void Reprioritize(UpdatePriorityHandler handler)
         {
             MinHeapItem item;
             foreach (LookupItem lookup in new List<LookupItem>(this.m_lookupTable.Values))
@@ -140,7 +217,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
                     {
                         // unless the priority queue has changed, there is no need to modify
                         // the entry
-                        pqueue = Util.Clamp<uint>(pqueue, 0, m_numberOfQueues - 1);
+                        pqueue = Util.Clamp<uint>(pqueue, 0, NumberOfQueues - 1);
                         if (pqueue != item.PriorityQueue)
                         {
                             lookup.Heap.Remove(lookup.Handle);
@@ -161,17 +238,18 @@ namespace OpenSim.Region.ClientStack.LindenUDP
             }
         }
 
+        /// <summary>
+        /// </summary>
         public override string ToString()
         {
             string s = "";
-            for (int i = 0; i < m_numberOfQueues; i++)
-            {
-                if (s != "") s += ",";
-                s += m_heaps[i].Count.ToString();
-            }
+            for (int i = 0; i < NumberOfQueues; i++)
+                s += String.Format("{0,7} ",m_heaps[i].Count);
             return s;
         }
 
+#endregion PublicMethods
+
 #region MinHeapItem
         private struct MinHeapItem : IComparable<MinHeapItem>
         {
diff --git a/OpenSim/Framework/RegionInfo.cs b/OpenSim/Framework/RegionInfo.cs
index daf0a25..239ce3d 100644
--- a/OpenSim/Framework/RegionInfo.cs
+++ b/OpenSim/Framework/RegionInfo.cs
@@ -369,6 +369,7 @@ namespace OpenSim.Framework
         private int m_physPrimMax = 0;
         private bool m_clampPrimSize = false;
         private int m_objectCapacity = 0;
+        private int m_agentCapacity = 0;
         private string m_regionType = String.Empty;
         private RegionLightShareData m_windlight = new RegionLightShareData();
         protected uint m_httpPort;
@@ -547,6 +548,11 @@ namespace OpenSim.Framework
             get { return m_objectCapacity; }
         }
 
+        public int AgentCapacity
+        {
+            get { return m_agentCapacity; }
+        }
+
         public byte AccessLevel
         {
             get { return (byte)Util.ConvertMaturityToAccessLevel((uint)RegionSettings.Maturity); }
@@ -821,6 +827,8 @@ namespace OpenSim.Framework
 
             m_objectCapacity = config.GetInt("MaxPrims", 15000);
 
+            m_agentCapacity = config.GetInt("MaxAgents", 100);
+
 
             // Multi-tenancy
             //
@@ -857,6 +865,9 @@ namespace OpenSim.Framework
             if (m_objectCapacity != 0)
                 config.Set("MaxPrims", m_objectCapacity);
 
+            if (m_agentCapacity != 0)
+                config.Set("MaxAgents", m_agentCapacity);
+
             if (ScopeID != UUID.Zero)
                 config.Set("ScopeID", ScopeID.ToString());
 
@@ -943,6 +954,9 @@ namespace OpenSim.Framework
             configMember.addConfigurationOption("object_capacity", ConfigurationOption.ConfigurationTypes.TYPE_INT32,
                                                 "Max objects this sim will hold", m_objectCapacity.ToString(), true);
 
+            configMember.addConfigurationOption("agent_capacity", ConfigurationOption.ConfigurationTypes.TYPE_INT32,
+                                                "Max avatars this sim will hold", m_agentCapacity.ToString(), true);
+
             configMember.addConfigurationOption("scope_id", ConfigurationOption.ConfigurationTypes.TYPE_UUID,
                                                 "Scope ID for this region", ScopeID.ToString(), true);
 
@@ -1055,6 +1069,9 @@ namespace OpenSim.Framework
                 case "object_capacity":
                     m_objectCapacity = (int)configuration_result;
                     break;
+                case "agent_capacity":
+                    m_agentCapacity = (int)configuration_result;
+                    break;
                 case "scope_id":
                     ScopeID = (UUID)configuration_result;
                     break;
diff --git a/OpenSim/Framework/Servers/VersionInfo.cs b/OpenSim/Framework/Servers/VersionInfo.cs
index c9d4c93..53a3f17 100644
--- a/OpenSim/Framework/Servers/VersionInfo.cs
+++ b/OpenSim/Framework/Servers/VersionInfo.cs
@@ -29,7 +29,7 @@ namespace OpenSim
 {
     public class VersionInfo
     {
-        private const string VERSION_NUMBER = "0.7.1";
+        private const string VERSION_NUMBER = "0.7.2";
         private const Flavour VERSION_FLAVOUR = Flavour.Dev;
 
         public enum Flavour
diff --git a/OpenSim/Framework/Tests/MundaneFrameworkTests.cs b/OpenSim/Framework/Tests/MundaneFrameworkTests.cs
index e7f8bfc..76de6be 100644
--- a/OpenSim/Framework/Tests/MundaneFrameworkTests.cs
+++ b/OpenSim/Framework/Tests/MundaneFrameworkTests.cs
@@ -115,7 +115,7 @@ namespace OpenSim.Framework.Tests
             position2 = new AgentPosition();
 
             Assert.IsFalse(position2.AgentID == position1.AgentID, "Test Error, position2 should be a blank uninitialized AgentPosition");
-            position2.Unpack(position1.Pack());
+            position2.Unpack(position1.Pack(), null);
 
             Assert.IsTrue(position2.AgentID == position1.AgentID, "Agent ID didn't unpack the same way it packed");
             Assert.IsTrue(position2.Position == position1.Position, "Position didn't unpack the same way it packed");
diff --git a/OpenSim/Framework/Util.cs b/OpenSim/Framework/Util.cs
index 5a5046e..aaa2724 100644
--- a/OpenSim/Framework/Util.cs
+++ b/OpenSim/Framework/Util.cs
@@ -1537,6 +1537,23 @@ namespace OpenSim.Framework
             return (diff >= 0) ? diff : (diff + EnvironmentTickCountMask + 1);
         }
 
+        // Returns value of Tick Count A - TickCount B accounting for wrapping of TickCount
+        // Assumes both tcA and tcB came from previous calls to Util.EnvironmentTickCount().
+        // A positive return value indicates A occured later than B
+        public static Int32 EnvironmentTickCountCompare(Int32 tcA, Int32 tcB)
+        {
+            // A, B and TC are all between 0 and 0x3fffffff
+            int tc = EnvironmentTickCount();
+
+            if (tc - tcA >= 0)
+                tcA += EnvironmentTickCountMask + 1;
+
+            if (tc - tcB >= 0)
+                tcB += EnvironmentTickCountMask + 1;
+
+            return tcA - tcB;
+        }
+
         /// <summary>
         /// Prints the call stack at any given point. Useful for debugging.
         /// </summary>