buaagc

大恒的时间差类，精确到微秒级

class CStopWatch

{ 

public: 

/// 构造函数 

CStopWatch()

{ 

Start(); 

} 

/// 开始计时

void Start() 

{ 

QueryPerformanceCounter(&m_StartTime);

} 

/// 停止计时,ms

double Stop() 

{

QueryPerformanceCounter(&m_StopTime);

double theElapsedTime = ElapsedTime();

m_StartTime = m_StopTime; 

return theElapsedTime;

} 

/// 获取时间差 

double ElapsedTime() 

{ 

LARGE_INTEGER timerFrequency; QueryPerformanceFrequency(&timerFrequency); 

__int64 oldTicks = ((__int64)m_StartTime.HighPart << 32) + (__int64)m_StartTime.LowPart;

__int64 newTicks = ((__int64)m_StopTime.HighPart << 32) + (__int64)m_StopTime.LowPart; 

long double timeDifference = (long double) (newTicks - oldTicks); 

long double ticksPerSecond = (long double) (((__int64)timerFrequency.HighPart << 32) + (__int64)timerFrequency.LowPart); 

return (double)(timeDifference * 1000/ ticksPerSecond); 

}

protected: 

LARGE_INTEGER m_StartTime;   ///< 开始时间

    LARGE_INTEGER m_StopTime;    ///< 停止时间 

};