rework ReadMessages to return a Span

encompass-cs/Collections/MessageStore.cs

@@ -18,17 +18,17 @@ namespace Encompass
             return _stores[typeof(TMessage)] as TypedMessageStore<TMessage>;
         }
 
-        public void AddMessage<TMessage>(TMessage message) where TMessage : struct, IMessage
+        public void AddMessage<TMessage>(in TMessage message) where TMessage : struct, IMessage
         {
             Lookup<TMessage>().Add(message);
         }
 
-        public void AddMessage<TMessage>(TMessage message, double time) where TMessage : struct, IMessage
+        public void AddMessage<TMessage>(in TMessage message, double time) where TMessage : struct, IMessage
         {
             Lookup<TMessage>().Add(message, time);
         }
 
-        public void AddMessageIgnoringTimeDilation<TMessage>(TMessage message, double time) where TMessage : struct, IMessage
+        public void AddMessageIgnoringTimeDilation<TMessage>(in TMessage message, double time) where TMessage : struct, IMessage
         {
             Lookup<TMessage>().AddIgnoringTimeDilation(message, time);
         }
@@ -38,7 +38,7 @@ namespace Encompass
             return Lookup<TMessage>().First();
         }
 
-        public IEnumerable<TMessage> All<TMessage>() where TMessage : struct, IMessage
+        public Span<TMessage> All<TMessage>() where TMessage : struct, IMessage
         {
             return Lookup<TMessage>().All();
         }

encompass-cs/Collections/TypedMessageStore.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 
 namespace Encompass
@@ -10,12 +11,13 @@ namespace Encompass
 
     internal class TypedMessageStore<TMessage> : TypedMessageStore where TMessage : struct, IMessage
     {
-        private readonly List<int> _indices = new List<int>();
+        // messages are placed in a contiguous region
+        // so we can return the collection as a Span
+        private int _nextIndex = 0;
         private readonly TMessage[] _store = new TMessage[128];
         private readonly List<(TMessage, double)> _delayedStore = new List<(TMessage, double)>(128);
         private readonly List<(TMessage, double)> _delayedStoreIgnoringTimeDilation = new List<(TMessage, double)>(128);
         private readonly Dictionary<int, HashSet<int>> _entityToIndices = new Dictionary<int, HashSet<int>>();
-        private readonly IDManager _idManager = new IDManager();
 
         public override void ProcessDelayedMessages(double dilatedDelta, double realtimeDelta)
         {
@@ -56,8 +58,7 @@ namespace Encompass
 
         public void Add(in TMessage message)
         {
-            var index = _idManager.NextID();
+            var index = _nextIndex++;
-            _indices.Add(index);
             _store[index] = message;
             if (message is IHasEntity entityMessage)
             {
@@ -79,20 +80,17 @@ namespace Encompass
 
         public TMessage First()
         {
-            return _store[_indices[0]];
+            return _store[0];
         }
 
         public bool Any()
         {
-            return _indices.Count > 0;
+            return _nextIndex != 0;
         }
 
-        public IEnumerable<TMessage> All()
+        public Span<TMessage> All()
         {
-            foreach (var index in _indices)
+            return new Span<TMessage>(_store, 0, _nextIndex);
-            {
-                yield return _store[index];
-            }
         }
 
         public IEnumerable<TMessage> WithEntity(int entityID)
@@ -113,11 +111,7 @@ namespace Encompass
 
         public override void Clear()
         {
-            foreach (var index in _indices)
+            _nextIndex = 0;
-            {
-                _idManager.Free(index);
-            }
-            _indices.Clear();
             foreach (var set in _entityToIndices.Values)
             {
                 set.Clear();

encompass-cs/Engine.cs

@@ -529,7 +529,7 @@ namespace Encompass
         /// <exception cref="Encompass.Exceptions.IllegalSendException">
         /// Thrown when the Engine does not declare that it Sends the Message Type.
         /// </exception>
-        protected void SendMessage<TMessage>(TMessage message) where TMessage : struct, IMessage
+        protected void SendMessage<TMessage>(in TMessage message) where TMessage : struct, IMessage
         {
             if (!SendTypes.Contains(typeof(TMessage)))
             {
@@ -543,7 +543,7 @@ namespace Encompass
         /// Sends a message after the specified number of seconds, respecting time dilation.
         /// </summary>
         /// <param name="time">The time in seconds that will elapse before the message is sent.</param>
-        protected void SendMessage<TMessage>(TMessage message, double time) where TMessage : struct, IMessage
+        protected void SendMessage<TMessage>(in TMessage message, double time) where TMessage : struct, IMessage
         {
             _messageManager.AddMessage(message, time);
         }
@@ -552,7 +552,7 @@ namespace Encompass
         /// Sends a message after the specified number of seconds, ignoring time dilation.
         /// </summary>
         /// <param name="time">The time in seconds that will elapse before the message is sent.</param>
-        protected void SendMessageIgnoringTimeDilation<TMessage>(TMessage message, double time) where TMessage : struct, IMessage
+        protected void SendMessageIgnoringTimeDilation<TMessage>(in TMessage message, double time) where TMessage : struct, IMessage
         {
             _messageManager.AddMessageIgnoringTimeDilation(message, time);
         }
@@ -563,7 +563,7 @@ namespace Encompass
         /// <exception cref="Encompass.Exceptions.IllegalReadException">
         /// Thrown when the Engine does not declare that it Receives the specified Message Type.
         /// </exception>
-        protected IEnumerable<TMessage> ReadMessages<TMessage>() where TMessage : struct, IMessage
+        protected Span<TMessage> ReadMessages<TMessage>() where TMessage : struct, IMessage
         {
             CheckMessageRead<TMessage>();
             return _messageManager.GetMessagesByType<TMessage>();

encompass-cs/MessageManager.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 
 namespace Encompass
@@ -12,17 +13,17 @@ namespace Encompass
             _timeManager = timeManager;
         }
 
-        internal void AddMessage<TMessage>(TMessage message) where TMessage : struct, IMessage
+        internal void AddMessage<TMessage>(in TMessage message) where TMessage : struct, IMessage
         {
             _messageStore.AddMessage(message);
         }
 
-        internal void AddMessage<TMessage>(TMessage message, double time) where TMessage : struct, IMessage
+        internal void AddMessage<TMessage>(in TMessage message, double time) where TMessage : struct, IMessage
         {
             _messageStore.AddMessage(message, time);
         }
 
-        internal void AddMessageIgnoringTimeDilation<TMessage>(TMessage message, double time) where TMessage : struct, IMessage
+        internal void AddMessageIgnoringTimeDilation<TMessage>(in TMessage message, double time) where TMessage : struct, IMessage
         {
             _messageStore.AddMessageIgnoringTimeDilation(message, time);
         }
@@ -37,7 +38,7 @@ namespace Encompass
             _messageStore.ProcessDelayedMessages(dt * _timeManager.TimeDilationFactor, dt);
         }
 
-        internal IEnumerable<TMessage> GetMessagesByType<TMessage>() where TMessage : struct, IMessage
+        internal Span<TMessage> GetMessagesByType<TMessage>() where TMessage : struct, IMessage
         {
             return _messageStore.All<TMessage>();
         }

encompass-cs/UberEngine.cs

@@ -58,7 +58,9 @@ namespace Encompass
                 CallGenericMethod(type, "SendMessage", 1, new object[] { Activator.CreateInstance(type) });
                 CallGenericMethod(type, "SendMessage", 2, new object[] { Activator.CreateInstance(type), 1 });
                 CallGenericMethod(type, "ReadMessage", null);
-                CallGenericMethod(type, "ReadMessages", null);
+
+                // can't reflect on methods that return a span...
+                //CallGenericMethod(type, "ReadMessages", null);
                 CallGenericMethod(type, "SomeMessage", null);
                 if (typeof(IHasEntity).IsAssignableFrom(type))
                 {

encompass-cs/WorldBuilder.cs

@@ -68,7 +68,7 @@ namespace Encompass
         /// <summary>
         /// Specifies that the given Message should be sent immediately on the first World Update.
         /// </summary>
-        public void SendMessage<TMessage>(TMessage message) where TMessage : struct, IMessage
+        public void SendMessage<TMessage>(in TMessage message) where TMessage : struct, IMessage
         {
             _messageManager.AddMessage(message);
         }
@@ -76,7 +76,7 @@ namespace Encompass
         /// <summary>
         /// Specifies that the given Message should be sent after the specified number of seconds after the first World Update.
         /// </summary>
-        public void SendMessage<TMessage>(TMessage message, double time) where TMessage : struct, IMessage
+        public void SendMessage<TMessage>(in TMessage message, double time) where TMessage : struct, IMessage
         {
             _messageManager.AddMessage<TMessage>(message, time);
         }

test/ComponentTest.cs

@@ -45,7 +45,7 @@ namespace Tests
         {
             public override void Update(double dt)
             {
-                foreach (var addComponentTestMessage in ReadMessages<AddComponentTestMessage>())
+                foreach (ref readonly var addComponentTestMessage in ReadMessages<AddComponentTestMessage>())
                 {
                     Assert.IsTrue(HasComponent<MockComponent>(addComponentTestMessage.entity));
                     ref readonly var gottenComponent = ref GetComponent<MockComponent>(addComponentTestMessage.entity);

test/EngineTest.cs

@@ -20,7 +20,7 @@ namespace Tests
         static List<MockComponent> resultComponents;
         static MockComponent resultComponent;
 
-        static List<MockMessage> resultMessages = new List<MockMessage>();
+        static MockMessage[] resultMessages;
 
         [Reads(typeof(MockComponent))]
         public class ReadComponentsTestEngine : Engine
@@ -279,7 +279,7 @@ namespace Tests
         {
             public override void Update(double dt)
             {
-                resultMessages = this.ReadMessages<MockMessage>().ToList();
+                resultMessages = ReadMessages<MockMessage>().ToArray();
             }
         }
 
@@ -308,14 +308,14 @@ namespace Tests
             }
         }
 
-        static IEnumerable<MockMessage> emptyReadMessagesResult;
+        static MockMessage[] emptyReadMessagesResult;
 
         [Receives(typeof(MockMessage))]
         class ReadMessagesWhenNoneExistEngine : Engine
         {
             public override void Update(double dt)
             {
-                emptyReadMessagesResult = ReadMessages<MockMessage>();
+                emptyReadMessagesResult = ReadMessages<MockMessage>().ToArray();
             }
         }
 
@@ -799,7 +799,7 @@ namespace Tests
         [Test]
         public void EngineSendMessageDelayed()
         {
-            resultMessages.Clear();
+            Array.Clear(resultMessages, 0, resultMessages.Length);
 
             var worldBuilder = new WorldBuilder();
             worldBuilder.AddEngine(new ActivateTimeDilationEngine());
@@ -846,7 +846,7 @@ namespace Tests
         [Test]
         public void EngineSendMessageDelayedIgnoringTimeDilation()
         {
-            resultMessages.Clear();
+            Array.Clear(resultMessages, 0, resultMessages.Length);
 
             var worldBuilder = new WorldBuilder();
             worldBuilder.AddEngine(new ActivateTimeDilationEngine());

test/WorldBuilderTest.cs

@@ -5,6 +5,7 @@ using System.Collections.Generic;
 using Encompass.Exceptions;
 using System.Linq;
 using FluentAssertions;
+using System;
 
 namespace Tests
 {
@@ -479,20 +480,22 @@ namespace Tests
                 Assert.That(order.IndexOf(engineC), Is.LessThan(order.IndexOf(engineD)));
             }
 
-            static List<AMessage> resultMessages = new List<AMessage>();
+            static AMessage[] resultMessages;
 
             [Receives(typeof(AMessage))]
             class ReadMessageEngine : Engine
             {
                 public override void Update(double dt)
                 {
-                    resultMessages = ReadMessages<AMessage>().ToList();
+                    resultMessages = ReadMessages<AMessage>().ToArray();
                 }
             }
 
             [Test]
             public void SendMessageDelayed()
             {
+                resultMessages = Array.Empty<AMessage>();
+
                 var worldBuilder = new WorldBuilder();
                 worldBuilder.AddEngine(new ReadMessageEngine());