feat: Initial commit of NullObject

ICD.Common.Utils/ICD.Common.Utils_SimplSharp.csproj

@@ -129,6 +129,7 @@
     <Compile Include="IO\eSeekOrigin.cs" />
     <Compile Include="IO\IcdStreamWriter.cs" />
     <Compile Include="Json\ToStringJsonConverter.cs" />
+    <Compile Include="NullObject.cs" />
     <Compile Include="ProcessorUtils.SimplSharp.cs" />
     <Compile Include="ProcessorUtils.Standard.cs" />
     <Compile Include="ProgramUtils.SimplSharp.cs" />

ICD.Common.Utils/NullObject.cs

@@ -0,0 +1,105 @@
+using System;
+
+namespace ICD.Common.Utils
+{
+	/// <summary>
+	/// Convenience wrapper for supporting null keys in hash tables.
+	/// </summary>
+	/// <typeparam name="T"></typeparam>
+	public struct NullObject<T> : IEquatable<NullObject<T>>
+	{
+		#region Properties
+
+		public T Item { get; private set; }
+
+		public bool IsNull { get; private set; }
+
+		public static NullObject<T> Null { get { return new NullObject<T>(); } }
+
+		#endregion
+
+		#region Constructors
+
+		/// <summary>
+		/// Constructor.
+		/// </summary>
+		/// <param name="item"></param>
+		public NullObject(T item)
+// ReSharper disable CompareNonConstrainedGenericWithNull
+			: this(item, item == null)
+// ReSharper restore CompareNonConstrainedGenericWithNull
+		{
+		}
+
+		/// <summary>
+		/// Constructor.
+		/// </summary>
+		/// <param name="item"></param>
+		/// <param name="isnull"></param>
+		private NullObject(T item, bool isnull)
+			: this()
+		{
+			IsNull = isnull;
+			Item = item;
+		}
+
+		#endregion
+
+		public override string ToString()
+		{
+// ReSharper disable CompareNonConstrainedGenericWithNull
+			return Item == null ? "NULL" : Item.ToString();
+// ReSharper restore CompareNonConstrainedGenericWithNull
+		}
+
+		#region Casting
+
+		public static implicit operator T(NullObject<T> nullObject)
+		{
+			return nullObject.Item;
+		}
+
+		public static implicit operator NullObject<T>(T item)
+		{
+			return new NullObject<T>(item);
+		}
+
+		#endregion
+
+		#region Equality
+
+		public override bool Equals(object obj)
+		{
+			if (obj == null)
+				return IsNull;
+
+			if (!(obj is NullObject<T>))
+				return false;
+
+			return Equals((NullObject<T>)obj);
+		}
+
+		public bool Equals(NullObject<T> other)
+		{
+			if (IsNull)
+				return other.IsNull;
+
+			return !other.IsNull && Item.Equals(other.Item);
+		}
+
+		public override int GetHashCode()
+		{
+			if (IsNull)
+				return 0;
+
+			var result = Item.GetHashCode();
+
+			if (result >= 0)
+				result++;
+
+			return result;
+		}
+
+		#endregion
+	}
+}