/*
 * Linux/Windows 系统高精度计时器
 */

#ifndef __LX_TIMER_H__
#define __LX_TIMER_H__

#ifdef WIN32
	#include <Windows.h>
#elif linux
	#include <sys/time.h>
#endif

class LxTimer
{
public:
	LxTimer();
	void   start();
	double stop();   // 返回从 start 到 stop 所经历的时间（单位:秒）

private:
#ifdef  WIN32
	double dSystemFreq; 
	BOOL   flag;
	double dStartTime;
	double dStopTime;
#elif  linux
	struct timeval tvStart;
	struct timeval tvStop;
#endif
};

#endif


#include "LxTimer.h"

#ifdef  WIN32
	#include <Windows.h>
#elif  linux
	#include <sys/time.h>
#endif

#ifdef WIN32
LxTimer::LxTimer()
{
	LARGE_INTEGER sysFreq;  // 计时器频率
	flag = QueryPerformanceFrequency( &sysFreq );
	if ( flag )
	{
		dSystemFreq = (double)sysFreq.QuadPart;
	}
}

void LxTimer::start()
{
	LARGE_INTEGER t;
	flag &= QueryPerformanceCounter( &t );
	if ( !flag )
		return;
	dStartTime = (double)t.QuadPart;
}

double LxTimer::stop()
{
	LARGE_INTEGER t;
	flag &= QueryPerformanceCounter( &t );

	if ( !flag )
		return -1.0;
	
	dStopTime = (double)t.QuadPart;
	return ( dStopTime - dStartTime ) / dSystemFreq;
}

#elif  linux

LxTimer::LxTimer(){}

void LxTimer::start()
{
	gettimeofday( &tvStart, NULL );
}

double LxTimer::stop()
{
	gettimeofday( &tvStop, NULL );
	return (double)(tvStop.tv_sec - tvStart.tv_sec)
		+ (double)(tvStop.tv_usec - tvStart.tv_usec)/1000000.0;
}

#endif