From 002cff1c2e206a5b15c05fb0908ec8283af32ff8 Mon Sep 17 00:00:00 2001
From: Evan Hemsley <evan@moonside.games>
Date: Sun, 22 Mar 2020 12:12:26 -0700
Subject: [PATCH] rework typed message store

---
 encompass-cs/Collections/TypedMessageStore.cs | 43 ++++++++++++-------
 test/ComponentTest.cs                         |  2 +-
 2 files changed, 29 insertions(+), 16 deletions(-)

diff --git a/encompass-cs/Collections/TypedMessageStore.cs b/encompass-cs/Collections/TypedMessageStore.cs
index 0a7a1e8..1a2c60c 100644
--- a/encompass-cs/Collections/TypedMessageStore.cs
+++ b/encompass-cs/Collections/TypedMessageStore.cs
@@ -10,10 +10,12 @@ namespace Encompass
 
     internal class TypedMessageStore<TMessage> : TypedMessageStore where TMessage : struct, IMessage
     {
-        private readonly List<TMessage> _store = new List<TMessage>(128);
+        private readonly List<int> _indices = new List<int>();
+        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, List<TMessage>> _entityToMessage = new Dictionary<int, List<TMessage>>();
+        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)
         {
@@ -52,56 +54,67 @@ namespace Encompass
             }
         }
 
-        public void Add(TMessage message)
+        public void Add(in TMessage message)
         {
-            _store.Add(message);
+            var index = _idManager.NextID();
+            _indices.Add(index);
+            _store[index] = message;
             if (message is IHasEntity entityMessage)
             {
                 var entityID = entityMessage.Entity.ID;
-                if (!_entityToMessage.ContainsKey(entityID)) { _entityToMessage.Add(entityID, new List<TMessage>()); }
-                _entityToMessage[entityID].Add(message);
+                if (!_entityToIndices.ContainsKey(entityID)) { _entityToIndices.Add(entityID, new HashSet<int>()); }
+                _entityToIndices[entityID].Add(index);
             }
         }
 
-        public void Add(TMessage message, double time)
+        public void Add(in TMessage message, double time)
         {
             _delayedStore.Add((message, time));
         }
 
-        public void AddIgnoringTimeDilation(TMessage message, double time)
+        public void AddIgnoringTimeDilation(in TMessage message, double time)
         {
             _delayedStoreIgnoringTimeDilation.Add((message, time));
         }
 
         public TMessage First()
         {
-            return _store[0];
+            return _store[_indices[0]];
         }
 
         public bool Any()
         {
-            return _store.Count > 0;
+            return _indices.Count > 0;
         }
 
         public IEnumerable<TMessage> All()
         {
-            return _store;
+            foreach (var index in _indices)
+            {
+                yield return _store[index];
+            }
         }
 
         public IEnumerable<TMessage> WithEntity(int entityID)
         {
-            return _entityToMessage.ContainsKey(entityID) ? _entityToMessage[entityID] : System.Linq.Enumerable.Empty<TMessage>();
+            if (_entityToIndices.ContainsKey(entityID))
+            {
+                foreach (var index in _entityToIndices[entityID])
+                {
+                    yield return _store[index];
+                }
+            }
         }
 
         public bool SomeWithEntity(int entityID)
         {
-            return _entityToMessage.ContainsKey(entityID) && _entityToMessage[entityID].Count > 0;
+            return _entityToIndices.ContainsKey(entityID) && _entityToIndices[entityID].Count > 0;
         }
 
         public override void Clear()
         {
-            _store.Clear();
-            foreach (var set in _entityToMessage.Values)
+            _indices.Clear();
+            foreach (var set in _entityToIndices.Values)
             {
                 set.Clear();
             }
diff --git a/test/ComponentTest.cs b/test/ComponentTest.cs
index 95c8f68..b8826b2 100644
--- a/test/ComponentTest.cs
+++ b/test/ComponentTest.cs
@@ -48,7 +48,7 @@ namespace Tests
                 foreach (var addComponentTestMessage in ReadMessages<AddComponentTestMessage>())
                 {
                     Assert.IsTrue(HasComponent<MockComponent>(addComponentTestMessage.entity));
-                    var gottenComponent = GetComponent<MockComponent>(addComponentTestMessage.entity);
+                    ref readonly var gottenComponent = ref GetComponent<MockComponent>(addComponentTestMessage.entity);
                     gottenComponent.Should().BeEquivalentTo(addComponentTestMessage.mockComponent);
                 }
             }