Added generic Octet<T> type

src/ImageSharp/Common/Tuples/Octet{T}.cs

@@ -0,0 +1,74 @@
+// Copyright (c) Six Labors and contributors.
+// Licensed under the Apache License, Version 2.0.
+
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+using SixLabors.ImageSharp.Tuples;
+
+namespace SixLabors.ImageSharp.Common.Tuples
+{
+    /// <summary>
+    /// Contains 8 element value tuples of various types.
+    /// </summary>
+    [StructLayout(LayoutKind.Sequential)]
+    internal struct Octet<T>
+        where T : unmanaged
+    {
+        public T V0;
+        public T V1;
+        public T V2;
+        public T V3;
+        public T V4;
+        public T V5;
+        public T V6;
+        public T V7;
+
+        /// <inheritdoc/>
+        public override readonly string ToString()
+        {
+            return $"{nameof(Octet)}<{typeof(T)}>({this.V0},{this.V1},{this.V2},{this.V3},{this.V4},{this.V5},{this.V6},{this.V7})";
+        }
+    }
+
+    /// <summary>
+    /// Extension methods for the <see cref="Octet{T}"/> type.
+    /// </summary>
+    internal static class OctetExtensions
+    {
+        /// <summary>
+        /// Loads the fields in a target <see cref="Octet{T}"/> of <see cref="uint"/> from one of <see cref="byte"/> type.
+        /// </summary>
+        /// <param name="destination">The target <see cref="Octet{T}"/> of <see cref="uint"/> instance.</param>
+        /// <param name="source">The source <see cref="Octet{T}"/> of <see cref="byte"/> instance.</param>
+        [MethodImpl(InliningOptions.ShortMethod)]
+        public static void LoadFrom(ref this Octet<uint> destination, ref Octet<byte> source)
+        {
+            destination.V0 = source.V0;
+            destination.V1 = source.V1;
+            destination.V2 = source.V2;
+            destination.V3 = source.V3;
+            destination.V4 = source.V4;
+            destination.V5 = source.V5;
+            destination.V6 = source.V6;
+            destination.V7 = source.V7;
+        }
+
+        /// <summary>
+        /// Loads the fields in a target <see cref="Octet{T}"/> of <see cref="byte"/> from one of <see cref="uint"/> type.
+        /// </summary>
+        /// <param name="destination">The target <see cref="Octet{T}"/> of <see cref="byte"/> instance.</param>
+        /// <param name="source">The source <see cref="Octet{T}"/> of <see cref="uint"/> instance.</param>
+        [MethodImpl(InliningOptions.ShortMethod)]
+        public static void LoadFrom(ref this Octet<byte> destination, ref Octet<uint> source)
+        {
+            destination.V0 = (byte)source.V0;
+            destination.V1 = (byte)source.V1;
+            destination.V2 = (byte)source.V2;
+            destination.V3 = (byte)source.V3;
+            destination.V4 = (byte)source.V4;
+            destination.V5 = (byte)source.V5;
+            destination.V6 = (byte)source.V6;
+            destination.V7 = (byte)source.V7;
+        }
+    }
+}