ObjectActivator: Faster object instantiation using lambda expression compilation.

VAR.Json/JsonParser.cs

@@ -73,7 +73,7 @@ namespace VAR.Json
         private object ConvertToType(Dictionary<string, object> obj, Type type)
         {
             PropertyInfo[] typeProperties = Type_GetProperties(type);
-            object newObj = Activator.CreateInstance(type);
+            object newObj = ObjectActivator.CreateInstance(type);
             foreach (PropertyInfo prop in typeProperties)
             {
                 if (obj.ContainsKey(prop.Name))

VAR.Json/ObjectActivator.cs

@@ -0,0 +1,35 @@
+using System;
+using System.Collections.Generic;
+using System.Linq.Expressions;
+
+namespace VAR.Json
+{
+    public class ObjectActivator
+    {
+        private static Dictionary<Type, Func<object>> _creators = new Dictionary<Type, Func<object>>();
+
+        public static Func<object> GetLambdaNew(Type type)
+        {
+            if (_creators.ContainsKey(type))
+            {
+                return _creators[type];
+            }
+
+            lock (_creators)
+            {
+                NewExpression newExp = Expression.New(type);
+                LambdaExpression lambda = Expression.Lambda(typeof(Func<object>), newExp);
+                Func<object> compiledLambdaNew = (Func<object>)lambda.Compile();
+
+                _creators.Add(type, compiledLambdaNew);
+            }
+            return _creators[type];
+        }
+
+        public static object CreateInstance(Type type)
+        {
+            Func<object> creator = GetLambdaNew(type);
+            return creator();
+        }
+    }
+}

VAR.Json/VAR.Json.csproj

@@ -36,6 +36,7 @@
   <ItemGroup>
     <Compile Include="JsonParser.cs" />
     <Compile Include="JsonWriter.cs" />
+    <Compile Include="ObjectActivator.cs" />
     <Compile Include="ParserContext.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
   </ItemGroup>