/*
  計時類，用于測量運行時間
  作者:sf.tk
  最后修改時間:2005.7.2
*/
#pragma once
#include <windows.h>

namespace our
{	
	class Time
	{
	public:	
        Time();
		~Time();
		void start();  //開始計時
		void end();    //停止計時
		double time_milli();   //以毫秒精度輸出所用時間
		double time_micro();   //以微秒精度輸出所用時間 
	private:
		double _start,_end;    //起止時間(毫秒)
		LARGE_INTEGER BegTicks,EndTicks,TicksCount;  //計時器起止周期,頻率
		bool flag;   //標(biāo)志計時狀態(tài)
		DWORD dwOldProcessP,dwOldThreadP; //保存原來的進程和線程狀態(tài)
	};

	inline Time::Time():_start(0),_end(0),flag(false)
	{
		dwOldProcessP = GetPriorityClass(GetCurrentProcess());   //保存當(dāng)前進程狀態(tài)
		dwOldThreadP = GetThreadPriority(GetCurrentThread());    //保存當(dāng)前線程狀態(tài)
		SetPriorityClass(GetCurrentProcess(), ABOVE_NORMAL_PRIORITY_CLASS);          //設(shè)置該進程優(yōu)先級為最高
		SetThreadPriority(GetCurrentThread(), THREAD_PRIORITY_ABOVE_NORMAL);    //設(shè)置該線程優(yōu)先級為最高
		QueryPerformanceFrequency(&TicksCount);  //取得計時器頻率
	}

	inline Time::~Time()
	{
		//恢復(fù)原進程和線程狀態(tài)
		SetThreadPriority(GetCurrentThread(), dwOldThreadP);
        SetPriorityClass(GetCurrentProcess(), dwOldProcessP);
	}
    
	inline void Time::start()
	{
		_start=GetTickCount();
		QueryPerformanceCounter(&BegTicks); //取得計時器當(dāng)前值
		flag=false;
	}

	inline void Time::end()
	{
		_end=GetTickCount();
		QueryPerformanceCounter(&EndTicks); //取得計時器當(dāng)前值
		flag=true;
	}

	inline double Time::time_milli()
	{
		if(flag==true)
		    return (_end - _start)/1000;
		else
			return -1;  //計時失敗
	}

	inline double Time::time_micro()
	{
		if(flag==true)
		    return double (EndTicks.QuadPart-BegTicks.QuadPart)/TicksCount.QuadPart;
		else
			return -1;  //計時失敗
	}
}