#pragma once
#include <windows.h>

struct CpuTimer
{
  void Start() 
  {
    QueryPerformanceCounter(&m_start);
  }

  void Stop() 
  {
    QueryPerformanceCounter(&m_stop);
  }

  // Returns elapsed time in milliseconds (ms)
  double Elapsed()
  {
    return (m_stop.QuadPart - m_start.QuadPart - m_overhead) * 1000.0 / m_freq.QuadPart;
  }

private:

  // Returns the overhead of the timer in ticks
  static LONGLONG GetOverhead()
  {
    CpuTimer t;
    t.Start();
    t.Stop();
    return t.m_stop.QuadPart - t.m_start.QuadPart;
  }

  LARGE_INTEGER m_start;
  LARGE_INTEGER m_stop;
  static LARGE_INTEGER m_freq;
  static LONGLONG m_overhead;
};