/*
 * Util.NonNullable.cs
 * Authors: Adam Nabinger
 * Copyright (c) 2007-2008 Cornell University

 This program is free software; you can redistribute it and/or
 modify it under the terms of the GNU General Public License
 as published by the Free Software Foundation; either version 2
 of the License, or (at your option) any later version.

 This program 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 General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program; if not, write to the Free Software
 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
*/

using System;
using System.Diagnostics;

namespace Util
{
	[DebuggerStepThrough]
	public struct NonNullable<T> where T : class
	{
		private readonly T Value;

		private NonNullable(T Value)
		{
			if (Value == null)
			{
				throw new ArgumentNullException(string.Empty,"Value cannot be null.");
			}

			this.Value = Value;
		}

		public static implicit operator NonNullable<T>(T value)
		{
			return new NonNullable<T>(value);
		}

		public static implicit operator T(NonNullable<T> value)
		{
			return value.Value;
		}

		public bool Equals(NonNullable<T> other)
		{
			return Value.Equals(other.Value);
		}

		public static bool operator ==(NonNullable<T> one, NonNullable<T> two)
		{
			return one.Equals(two);
		}

		public static bool operator !=(NonNullable<T> one, NonNullable<T> two)
		{
			return !one.Equals(two);
		}

		public override bool Equals(object obj)
		{
			return Value.Equals(obj);
		}

		public override int GetHashCode()
		{
			return Value.GetHashCode();
		}

		public override string ToString()
		{
			return Value.ToString();
		}
	}
}