//
// Mono.VisualC.Interop.CppField.cs: Represents a field in a native C++ object
//
// Author:
//   Alexander Corrado (alexander.corrado@gmail.com)
//   Andreia Gaita (shana@spoiledcat.net)
//
// Copyright (C) 2010 Alexander Corrado
//
// 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.

using System;
using System.Runtime.InteropServices;

namespace Mono.VisualC.Interop {
	public class CppField<T> {
		private int fieldOffset;

		public CppField (int fieldOffset)
		{
			this.fieldOffset = fieldOffset;
		}

		public T this [CppInstancePtr ip] {
			get {
				Type retType = typeof (T);
				object retVal;
				if (retType.Equals (typeof (Byte)))
					retVal = Marshal.ReadByte (ip.Native, fieldOffset);
				else if (retType.Equals (typeof (Int16)))
					retVal = Marshal.ReadInt16 (ip.Native, fieldOffset);
				else if (retType.Equals (typeof (Int32)))
					retVal = Marshal.ReadInt32 (ip.Native, fieldOffset);
				else throw new NotImplementedException ("Cannot read C++ fields of type " + retType.Name);

				return (T)retVal;
			}
			set {
				Type setType = typeof (T);
				object setVal = value;
				if (setType.Equals (typeof (Byte)))
					Marshal.WriteByte (ip.Native, fieldOffset, (byte)setVal);
				else if (setType.Equals (typeof (Int16)))
					Marshal.WriteInt16 (ip.Native, fieldOffset, (Int16)setVal);
				else if (setType.Equals (typeof (Int32)))
					Marshal.WriteInt32 (ip.Native, fieldOffset, (Int32)setVal);
				else throw new NotImplementedException ("Cannot write C++ fields of type " + setType.Name);
			}
		}
	}
}