High Precision Interval Timer

Often it is desirable to be able to "time" certain block of code to determine the number of seconds elapsed.

Often it is desirable to be able to "time" certain block of code to determine the number of seconds elapsed.

Here is a simple C# class I threw together that uses the QueryPerformanceCounter and QueryPerformanceFrequency APIs to calibrate a time to the highest possible precision (converted to decimal fractions of a second in the FormatString) for the particular CPU. Just put this into an empty C# Class Library and compile it:

using System;
using System.Runtime.InteropServices;

namespace PAB.Util
{
/// <summary>
/// Summary description for IntervalTimer.
/// </summary>
public class IntervalTimer
{
[DllImport("kernel32.dll")]
static extern private int QueryPerformanceCounter(out long count);

[DllImport("kernel32.dll")]
static extern private int QueryPerformanceFrequency(out long count);


public enum TimerState {NotStarted, Stopped, Started}

private TimerState state;
private long ticksAtStart;
private long intervalTicks;
private static long frequency;
private static int decimalPlaces;
private static string formatString;
private static bool initialized = false;


public IntervalTimer()
{
if (!initialized)
{
QueryPerformanceFrequency(out frequency);
decimalPlaces = (int)Math.Log10(frequency);
formatString = String.Format("Interval: {{0:F{0}}} seconds ({{1}} ticks)", decimalPlaces);
initialized = true;
}
state = TimerState.NotStarted;
}

public void Start()
{
state = TimerState.Started;
ticksAtStart = CurrentTicks;
}

public void Stop()
{
intervalTicks = CurrentTicks - ticksAtStart;
state = TimerState.Stopped;
}

public float GetSeconds()
{
if (state != TimerState.Stopped)
throw new TimerNotStoppedException();
return (float)intervalTicks/(float)frequency;
}

public long GetTicks()
{
if (state != TimerState.Stopped)
throw new TimerNotStoppedException();
return intervalTicks;
}

private long CurrentTicks
{
get
{
long ticks;
QueryPerformanceCounter(out ticks);
return ticks;
}
}

public override string ToString()
{
if (state != TimerState.Stopped)
return "Interval timer, state: " + state.ToString();
return String.Format(formatString, GetSeconds(), intervalTicks);
}

}

public class TimerNotStoppedException : ApplicationException
{
public TimerNotStoppedException()
: base("Timer is either still running or has not been started")
{
}
}
}





Submission Date:  9/23/2005 3:20:25 PM
Submitted By:  Peter Bromberg
My Home Page:  http://www.eggheadcafe.com