add from giga-device, new branch added

StgSharp.Common/Data/ValueBox.cs

@@ -0,0 +1,94 @@
+//-----------------------------------------------------------------------
+//-----------------------------------------------------------------------
+//     file="ValueBox.cs"
+//     Project: StgSharp
+//     AuthorGroup: Nitload Space
+//     Copyright (c) Nitload Space. All rights reserved.
+//     
+//     Permission is hereby granted, free of charge, to any person 
+//     obtaining a copy of this software and associated documentation 
+//     files (the “Software”), to deal in the Software without restriction, 
+//     including without limitation the rights to use, copy, modify, merge,
+//     publish, distribute, sublicense, and/or sell copies of the Software, 
+//     and to permit persons to whom the Software is furnished to do so, 
+//     subject to the following conditions:
+//     
+//     The above copyright notice and 
+//     this permission notice shall be included in all copies 
+//     or substantial portions of the Software.
+//     
+//     THE SOFTWARE IS PROVIDED “AS IS”, 
+//     WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, 
+//     INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
+//     FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 
+//     IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, 
+//     DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, 
+//     ARISING FROM, OUT OF OR IN CONNECTION WITH 
+//     THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+//     
+//-----------------------------------------------------------------------
+//-----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+using System.Linq;
+using System.Runtime.CompilerServices;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace StgSharp.Data
+{
+    public interface IValueBox
+    {
+
+        ref object ValueReference { get; }
+
+        static virtual IValueBox<T> AsGeneric<T>(IValueBox box) where T: unmanaged
+        {
+            if (box is not IValueBox<T> genericBox) {
+                return null;
+            }
+            return genericBox;
+        }
+
+        static virtual bool IsGeneric<T>(IValueBox box) where T: unmanaged
+        {
+            return box is IValueBox<T>;
+        }
+
+    }
+
+    public interface IValueBox<T> where T: unmanaged
+    {
+
+        T Value { get; set; }
+
+    }
+
+    /// <summary>
+    ///   A class attempt to reduce cost of boxing, though still a bit slower than direct access to
+    ///   _origin value type instance.
+    /// </summary>
+    /// <typeparam name="T">
+    ///   Type of instance to be boxed.
+    /// </typeparam>
+    public class ValueBox<T> : IValueBox, IValueBox<T> where T: unmanaged
+    {
+
+        private T _value;
+
+        public ValueBox(T value)
+        {
+            _value = value;
+        }
+
+        public ref object ValueReference => ref Unsafe.As<T, object>(ref _value);
+
+        public T Value
+        {
+            get => _value;
+            set => _value = value;
+        }
+
+    }
+}