UndoStack.cs

/*
 * Copyright (c) 2007 Philipp Garcia (phil@gotraxx.org)
 * 
 * This file is part of GoTraxx (www.gotraxx.org).
 * 
 * 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.
 * 
 * This license governs use of the accompanying software. If you use the software, you 
 * accept this license. If you do not accept the license, do not use the software.
 * 
 * Permission is granted to anyone to use this software for any noncommercial purpose, 
 * and to alter it and redistribute it freely, subject to the following restrictions:
 * 
 * 1. The origin of this software must not be misrepresented; you must not claim that 
 *    you wrote the original software. 
 * 
 * 2. Altered source versions must be plainly marked as such, and must not be 
 *    misrepresented as being the original software.
 * 
 * 3. If you bring a patent claim against the original author or any contributor over 
 *    patents that you claim are infringed by the software, your patent license from 
 *    such contributor to the software ends automatically.
 * 
 * 4. This software may not be used in whole, nor in part, to enter any competition 
 *    without written permission from the original author. 
 * 
 * 5. This notice may not be removed or altered from any source distribution.
 * 
 */


using System;
using System.Collections.Generic;
using System.Text;

namespace GoTraxx
{
	class UndoStack
	{
		protected GoBoard Board;
		protected Stack<UndoBase> UndoObjects;

		public UndoStack(GoBoard goBoard)
		{
			Board = goBoard;
			UndoObjects = new Stack<UndoBase>();
		}

		public void Add(UndoBase pUndoObject)
		{
			UndoObjects.Push(pUndoObject);
		}

		public void Mark()
		{
			UndoObjects.Push(null);
		}

		public void Clear()
		{
			UndoObjects.Clear();
		}

		public bool CanUndo()
		{
			return (UndoObjects.Count != 0);
		}

		public void Undo()
		{
			if (UndoObjects.Count == 0)
				return;

			while (UndoObjects.Count != 0)
			{
				UndoBase lUndoObject = UndoObjects.Pop();

				if (lUndoObject == null)
					return;
				
//				Console.WriteLine("Undo> " + lUndoObject.ToString());

				lUndoObject.Undo(Board);
			}
		}
	}
}