Updated EntityLayout component storage for better memory usage.

Author: Juiix

EntitiesDb/Data/Boxed.cs

@@ -0,0 +1,6 @@
+namespace EntitiesDb;
+
+internal sealed class Boxed<T> where T : unmanaged
+{
+    public T Value;
+}

EntitiesDb/Data/ComponentMetaData.cs

@@ -68,9 +68,8 @@ public void SetComponent(Chunk chunk, int listOffset, int listIndex, object valu
 			SetComponent(chunk.GetComponent(listOffset, listIndex, Size), value);
 		}
 
+		public abstract void SetBuffer(Chunk chunk, int listOffset, int listIndex, object list, bool overwrite);
 		public abstract void SetComponent(void* destination, object component);
-
-		public abstract void SetComponentBuffer(Chunk chunk, int listOffset, int listIndex, object list, bool overwrite);
     }
 
 	internal unsafe sealed class ComponentMetaData<T> : ComponentMetaData where T : unmanaged
@@ -114,7 +113,13 @@ public override void OnRemoveComponent(EventDispatcher eventDispatcher, uint ent
             eventDispatcher.OnRemoveComponent(entityId, ref component);
         }
 
-        public override unsafe void SetComponent(void* destination, object component) => *(T*)destination = (T)component;
+        public override unsafe void SetComponent(void* destination, object component)
+		{
+			T value;
+			if (component is Boxed<T> boxed) value = boxed.Value;
+            else value = (T)component;
+            *(T*)destination = value;
+        }
 
         private static int? GetInternalCapacity(Type type)
         {
@@ -132,7 +137,7 @@ private static bool IsZeroSize(Type type)
             return zeroSize;
         }
 
-        public override void SetComponentBuffer(Chunk chunk, int listOffset, int listIndex, object list, bool overwrite)
+        public override void SetBuffer(Chunk chunk, int listOffset, int listIndex, object list, bool overwrite)
         {
 			var typedList = (List<T>)list;
 			ref var buffer = ref chunk.GetComponent<ComponentBuffer<T>>(listOffset, listIndex, Stride);

EntitiesDb/EntitiesDb.csproj

@@ -9,7 +9,7 @@
     <PackageLicenseExpression>MIT</PackageLicenseExpression>
     <Copyright>2022, Unnamed Studios, LLC</Copyright>
     <GeneratePackageOnBuild>True</GeneratePackageOnBuild>
-    <VersionPrefix>2.1.1</VersionPrefix>
+    <VersionPrefix>2.1.2</VersionPrefix>
     <Version>$(VersionPrefix)</Version>
     <AssemblyVersion>$(VersionPrefix)</AssemblyVersion>
     <FileVersion>$(VersionPrefix)</FileVersion>

EntitiesDb/EntityDatabase.cs

@@ -1340,7 +1340,7 @@ private void SetComponentData(EntityReference entityReference, EntityLayout enti
                 if (metaData.Bufferable)
                 {
                     var overwrite = sourceArchetype?.ContainsType(pair.Key) ?? false;
-                    metaData.SetComponentBuffer(chunk, listOffset, entityReference.Indices.ListIndex, pair.Value, overwrite);
+                    metaData.SetBuffer(chunk, listOffset, entityReference.Indices.ListIndex, pair.Value, overwrite);
                 }
                 else
                 {

EntitiesDb/EntityLayout.cs

@@ -11,21 +11,6 @@ public sealed class EntityLayout
 		public IEnumerable<KeyValuePair<Type, object>> Added => _added;
         public IEnumerable<Type> Removed => _removed;
 
-        /// <summary>
-        /// Defines a component to be added.
-        /// Overwrites any previous Add or Remove of the same type.
-        /// </summary>
-        /// <typeparam name="T">Component type</typeparam>
-        /// <param name="component">The component to add</param>
-        /// <exception cref="BufferableException"></exception>
-        public void AddComponent<T>(T? component = default) where T : unmanaged
-        {
-            var metaData = ComponentMetaData<T>.Instance;
-            if (metaData.Bufferable) throw new BufferableException(typeof(T));
-			_removed.Remove(typeof(T));
-            _added[typeof(T)] = component;
-		}
-
         /// <summary>
         /// Defines a buffer component to be added.
         /// Overwrites any previous buffer Add or Remove of the same type.
@@ -40,31 +25,32 @@ public void AddBuffer<T>(ReadOnlySpan<T> components) where T : unmanaged
             if (metaData.ZeroSize) throw new ZeroSizeBufferException(typeof(T));
             if (!metaData.Bufferable) throw new InvalidBufferableException(typeof(T));
             _removed.Remove(typeof(T));
-            SetBufferComponents(metaData.Type, components);
+            SetBuffer(metaData.Type, components);
         }
 
-		/// <summary>
-		/// Clears Added and Removed components
-		/// </summary>
-		public void Clear()
-		{
-			_added.Clear();
-			_removed.Clear();
-		}
-
         /// <summary>
-        /// Defines a component to be removed.
+        /// Defines a component to be added.
         /// Overwrites any previous Add or Remove of the same type.
         /// </summary>
         /// <typeparam name="T">Component type</typeparam>
+        /// <param name="component">The component to add</param>
         /// <exception cref="BufferableException"></exception>
-        public void RemoveComponent<T>() where T : unmanaged
+        public void AddComponent<T>(T component = default) where T : unmanaged
         {
             var metaData = ComponentMetaData<T>.Instance;
             if (metaData.Bufferable) throw new BufferableException(typeof(T));
-            _added.Remove(typeof(T));
-            _removed.Add(typeof(T));
-		}
+            _removed.Remove(typeof(T));
+            SetComponent(metaData.Type, component);
+        }
+
+		/// <summary>
+		/// Clears Added and Removed components
+		/// </summary>
+		public void Clear()
+		{
+			_added.Clear();
+			_removed.Clear();
+        }
 
         /// <summary>
         /// Defines a buffer component to be removed.
@@ -83,7 +69,21 @@ public void RemoveBuffer<T>() where T : unmanaged
             _removed.Add(bufferType);
         }
 
-        private void SetBufferComponents<T>(Type componentType, ReadOnlySpan<T> components) where T : unmanaged
+        /// <summary>
+        /// Defines a component to be removed.
+        /// Overwrites any previous Add or Remove of the same type.
+        /// </summary>
+        /// <typeparam name="T">Component type</typeparam>
+        /// <exception cref="BufferableException"></exception>
+        public void RemoveComponent<T>() where T : unmanaged
+        {
+            var metaData = ComponentMetaData<T>.Instance;
+            if (metaData.Bufferable) throw new BufferableException(typeof(T));
+            _added.Remove(typeof(T));
+            _removed.Add(typeof(T));
+		}
+
+        private void SetBuffer<T>(Type componentType, ReadOnlySpan<T> components) where T : unmanaged
         {
             // re-use existing list if available
             List<T> list;
@@ -103,6 +103,22 @@ private void SetBufferComponents<T>(Type componentType, ReadOnlySpan<T> componen
                 list.Add(components[i]);
             }
         }
+
+        private void SetComponent<T>(Type componentType, T component) where T : unmanaged
+        {
+            // re-use existing boxed if available
+            Boxed<T> boxed;
+            if (!_added.TryGetValue(componentType, out var boxedObject))
+            {
+                boxed = (Boxed<T>)boxedObject;
+            }
+            else
+            {
+                boxed = new Boxed<T>();
+                _added.Add(typeof(T), boxed);
+            }
+            boxed.Value = component;
+        }
 	}
 }