Adding IPNetwork to Converter/Formatters

AMWD.Common/Formatters/IPNetworkFormatter.cs

@@ -0,0 +1,59 @@
+using System;
+using System.Linq;
+using System.Net;
+using Microsoft.AspNetCore.HttpOverrides;
+
+namespace MessagePack.Formatters
+{
+	/// <summary>
+	/// Serialization of an <see cref="IPNetwork"/> to and from <see cref="MessagePack"/>.
+	/// </summary>
+	[System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
+	public class IPNetworkFormatter : IMessagePackFormatter<IPNetwork>
+	{
+		/// <inheritdoc/>
+		public IPNetwork Deserialize(ref MessagePackReader reader, MessagePackSerializerOptions options)
+		{
+			if (reader.IsNil)
+				return null;
+
+			byte[] bytes = options.Resolver.GetFormatterWithVerify<byte[]>().Deserialize(ref reader, options);
+			return DeserializeInternal(bytes);
+		}
+
+		/// <inheritdoc/>
+		public void Serialize(ref MessagePackWriter writer, IPNetwork value, MessagePackSerializerOptions options)
+		{
+			if (value == null)
+			{
+				writer.WriteNil();
+				return;
+			}
+
+			byte[] bytes = SerializeInternal(value);
+			options.Resolver.GetFormatterWithVerify<byte[]>().Serialize(ref writer, bytes, options);
+		}
+
+		internal static byte[] SerializeInternal(IPNetwork network)
+		{
+			// IP network prefix has a maximum of 128 bit - therefore the length can be covered with a byte.
+			byte prefixLength = (byte)network.PrefixLength;
+			byte[] prefixBytes = network.Prefix.GetAddressBytes();
+
+			byte[] bytes = new byte[prefixBytes.Length + 1];
+			bytes[0] = prefixLength;
+			Array.Copy(prefixBytes, 0, bytes, 1, prefixBytes.Length);
+
+			return bytes;
+		}
+
+		internal static IPNetwork DeserializeInternal(byte[] bytes)
+		{
+			byte prefixLength = bytes[0];
+			byte[] prefixBytes = bytes.Skip(1).ToArray();
+
+			var prefix = new IPAddress(prefixBytes);
+			return new IPNetwork(prefix, prefixLength);
+		}
+	}
+}