//
// System.Text.SurrogateEncoder.cs
//
// Author:
//   Kornél Pál <http://www.kornelpal.hu/>
//
// Copyright (C) 2006 Kornél Pál
//

//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//

//
// These proxy classes implement IObjectReference.GetRealObject() that returns
// an instance of the appropriate Encoding, Encoder or Decoder class.
// As a result serialized objects of these types will transparently be
// deserialized to instances of the above described classes.
//
// Use SerializationInfo.SetType() in ISerializable.GetObjectData() method of
// serializable classes to serialize their instances using a proxy class.
//
// All of these proxy classes are non-public thus they only have to be
// serialization compatible with .NET Framework.
//

//
// .NET Framework 1.x uses this class for GB18030 encoder and
// .NET Framework 2.0 can deserialize it using a proxy.
// This class supports serialization compatibility.
//

using System;
using System.Runtime.Serialization;

namespace System.Text
{
	[Serializable]
	internal sealed class SurrogateEncoder : ISerializable, IObjectReference
	{
		private Encoding encoding;
		private Encoder realObject;

		private SurrogateEncoder (SerializationInfo info, StreamingContext context)
		{
			if (info == null)
				throw new ArgumentNullException ("info");

			this.encoding = (Encoding) info.GetValue ("m_encoding", typeof (Encoding));
		}

		public void GetObjectData (SerializationInfo info, StreamingContext context)
		{
			throw new ArgumentException ("This class cannot be serialized.");
		}

		public object GetRealObject (StreamingContext context)
		{
			if (this.realObject == null)
				this.realObject = this.encoding.GetEncoder ();

			return this.realObject;
		}
	}
}