using System;

using System.Collections.Generic;

using System.Text;

using System.Runtime.InteropServices;

using System.Diagnostics.CodeAnalysis;

namespace Aga.Controls

{

	/// <summary>

	/// High resolution timer, used to test performance

	/// </summary>

	public static class TimeCounter

	{

		private static Int64 _start;

		/// <summary>

		/// Start time counting

		/// </summary>

		public static void Start()

		{

			_start = 0;

			QueryPerformanceCounter(ref _start);

		}

		public static Int64 GetStartValue()

		{

			Int64 t = 0;

			QueryPerformanceCounter(ref t);

			return t;

		}

		/// <summary>

		/// Finish time counting

		/// </summary>

		/// <returns>time in seconds elapsed from Start till Finish	</returns>

		public static double Finish()

		{

			return Finish(_start);

		}

		public static double Finish(Int64 start)

		{

			Int64 finish = 0;

			QueryPerformanceCounter(ref finish);

			Int64 freq = 0;

			QueryPerformanceFrequency(ref freq);

			return (finish - start) / (double)freq;

		}

		[DllImport("Kernel32.dll")]

		[return: MarshalAs(UnmanagedType.Bool)]

		static extern bool QueryPerformanceCounter(ref Int64 performanceCount);

		[DllImport("Kernel32.dll")]

		[return: MarshalAs(UnmanagedType.Bool)]

		static extern bool QueryPerformanceFrequency(ref Int64 frequency);

	}

}