/*
 * Util.Benchmarker.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.
*/

#if DEBUG

using System.Diagnostics;
using System.Globalization;

namespace Util
{
    /// <summary>
    /// For Testing.
    /// </summary>
	public delegate void TestFunction();

	/// <summary>
	/// This is a test class, used for comparing the performance of two selections of code.
	/// </summary>
	public static class Benchmarker
	{
        /// <summary>
        /// For Testing. Compare the relative performance of two functions.
        /// </summary>
		public static void FightToTheDeath(TestFunction alpha, TestFunction beta)
		{
			unchecked
			{
				Stopwatch timer = new Stopwatch();
				timer.Start();
				// Exercise the JIT
				while (timer.Elapsed.TotalMilliseconds < 1000)
				{
					alpha();
					beta();
				}
				timer.Stop();
				timer.Reset();
				// Start timing
				double AlphaTotal = 0;
				double BetaTotal = 0;
				int n = 1;
				for (; ; )
				{
					timer.Start();
					for (int i = n; i > 0; --i)
					{
						alpha();
					}
					timer.Stop();
					double timeA = timer.Elapsed.TotalMilliseconds;
					System.Console.Write("Alpha: ");
					System.Console.WriteLine(timeA);
					AlphaTotal += timeA;
					timer.Reset();
					timer.Start();
					for (int i = n; i > 0; --i)
					{
						beta();
					}
					timer.Stop();
					double timeB = timer.Elapsed.TotalMilliseconds;
					System.Console.Write("Beta : ");
					System.Console.WriteLine(timeB);
					BetaTotal += timeB;
					timer.Reset();
					double diff = AlphaTotal - BetaTotal;
					if (diff < 0)
					{
						diff = -diff;
						System.Console.Write("Alpha is faster by ");
						System.Console.Write(diff);
						System.Console.Write(" - ");
						System.Console.WriteLine(((2 * diff) / (AlphaTotal + BetaTotal)).ToString("P0", CultureInfo.CurrentCulture));
					}
					else
					{
						System.Console.Write("Beta is faster by ");
						System.Console.Write(diff);
						System.Console.Write(" - ");
						System.Console.WriteLine(((2 * diff) / (AlphaTotal + BetaTotal)).ToString("P0", CultureInfo.CurrentCulture));
					}
					n = n << 1;
					if (n <= 0)
					{
						return;
					}
				}
			}
		}
	}
}

#endif