added yaml library

thirdparty/yaml/Null.cs

@@ -0,0 +1,100 @@
+//     ====================================================================================================
+//     YAML Parser for the .NET Framework
+//     ====================================================================================================
+//
+//     Copyright (c) 2006
+//         Christophe Lambrechts
+//         Jonathan Slenders
+//
+//     ====================================================================================================
+//     This file is part of the .NET YAML Parser.
+// 
+//     This .NET YAML parser is free software; you can redistribute it and/or modify
+//     it under the terms of the GNU Lesser General Public License as published by
+//     the Free Software Foundation; either version 2.1 of the License, or
+//     (at your option) any later version.
+// 
+//     The .NET YAML parser is distributed in the hope that it will be useful,
+//     but WITHOUT ANY WARRANTY; without even the implied warranty of
+//     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//     GNU Lesser General Public License for more details.
+// 
+//     You should have received a copy of the GNU Lesser General Public License
+//     along with Foobar; if not, write to the Free Software
+//     Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USAusing System.Reflection;
+//     ====================================================================================================
+
+using System;
+
+namespace Yaml
+{
+	/// <summary>
+	///   Class for storing a Yaml Null node
+	///   tag:yaml.org,2002:null
+	/// </summary>
+	public class Null : Scalar
+	{
+		/// <summary> Null Constructor </summary>
+		public Null () : base ("tag:yaml.org,2002:null", NodeType.Null) { }
+
+		/// <summary> Parse a null node </summary>
+		public Null (ParseStream stream) :
+				base ("tag:yaml.org,2002:null", NodeType.Null)
+		{
+			// An empty string is a valid null node
+			if (stream.EOF)
+				return;
+
+			else
+			{
+				// Read the first 4 chars
+				char [] chars = new char [8];
+				int length = 0;
+				for (int i = 0; i < chars.Length && ! stream.EOF; i ++)
+				{
+					chars [i] = stream.Char;
+					length ++;
+					stream.Next ();
+				}
+
+				// Compare
+				if (length == 1)
+				{
+					string s = "" + chars [0];
+
+					// Canonical notation
+					if (s == "~")
+						return;
+				}
+				if (length == 4)
+				{
+					string s = "" + chars [0] + chars [1] + chars [2] + chars [3];
+
+					// null, Null, NULL
+					if (s == "NULL" || s == "Null" || s == "null")
+						return;
+				}
+
+				throw new ParseException (stream, "Not NULL");
+			}
+		}
+
+		/// <summary> Content property </summary>
+		public object Content
+		{
+			get { return null; }
+		}
+
+		/// <summary> To String </summary>
+		public override string ToString ()
+		{
+			return "[NULL]~[/NULL]";
+		}
+
+		/// <summary> Write to YAML </summary>
+		protected internal override void Write (WriteStream stream)
+		{
+			stream.Append ("~");
+		}
+	}
+}