Adding Domain and IPAddress comparer

AMWD.Common/Comparer/IPAddressComparer.cs

@@ -0,0 +1,71 @@
+using System.Collections.Generic;
+using System.Net;
+
+namespace AMWD.Common.Comparer
+{
+	/// <summary>
+	/// Defines a method to compare two IP addresses.
+	/// </summary>
+	public class IPAddressComparer : IComparer<IPAddress>
+	{
+		/// <summary>
+		/// Compares two IP addresses and returns a value indicating whether one is less than,
+		/// equal to, or greater than the other.
+		/// </summary>
+		/// <param name="x">The first IP address.</param>
+		/// <param name="y">The second IP address.</param>
+		/// <returns>
+		/// A signed integer that indicates the relative values of x and y, as shown in the following table.
+		/// <list type="table">
+		///   <listheader>
+		///     <term>Value</term>
+		///     <description>Meaning</description>
+		///   </listheader>
+		///   <item>
+		///     <term>Less than zero</term>
+		///     <description>x is less than y.</description>
+		///   </item>
+		///   <item>
+		///     <term>Zero</term>
+		///     <description>x equals y.</description>
+		///   </item>
+		///   <item>
+		///     <term>Greater than zero</term>
+		///     <description>x is greater than y.</description>
+		///   </item>
+		/// </list>
+		/// </returns>
+		public int Compare(IPAddress x, IPAddress y)
+		{
+			if (x == null && y == null)
+				return 0;
+
+			if (x == null)
+				return -1;
+
+			if (y == null)
+				return 1;
+
+			byte[] xBytes = x.GetAddressBytes();
+			byte[] yBytes = y.GetAddressBytes();
+
+			// Make IPv4 and IPv6 comparable
+			byte[] left = xBytes.Length == 16
+				? xBytes
+				: [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 255, 255, xBytes[0], xBytes[1], xBytes[2], xBytes[3]];
+			byte[] right = yBytes.Length == 16
+				? yBytes
+				: [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 255, 255, yBytes[0], yBytes[1], yBytes[2], yBytes[3]];
+
+			// Compare byte for byte
+			for (int i = 0; i < left.Length; i++)
+			{
+				int result = left[i].CompareTo(right[i]);
+				if (result != 0)
+					return result;
+			}
+
+			return 0;
+		}
+	}
+}