Two systemtime comparison differences (seconds, days ...) ) Method of

Original posted Address:

Http://topic.csdn.net/t/20040707/08/3151675.html

I processed it a little bit:

====================begin====================

time_t FileTimeToTime_t(const FILETIME &ft)  
{  
    ULARGE_INTEGER ui;  
    ui.LowPart = ft.dwLowDateTime;  
    ui.HighPart = ft.dwHighDateTime;  
    return ((LONGLONG)(ui.QuadPart - 116444736000000000) / 10000000);  
}  
  
int GetDiffSeconds(const SYSTEMTIME &t1, const SYSTEMTIME &t2)  
{  
    FILETIME fTime1 = { 0, 0 };  
    FILETIME fTime2 = { 0, 0 };  
    SystemTimeToFileTime(&t1, &fTime1);  
    SystemTimeToFileTime(&t2, &fTime2);  
  
    time_t tt1 = FileTimeToTime_t(fTime1);  
    time_t tt2 = FileTimeToTime_t(fTime2);  
  
    return (int)(tt2 - tt1);  
}  
  
int GetDiffDays(const SYSTEMTIME &t1, const SYSTEMTIME &t2)  
{  
    int diffSeconds = GetDiffSeconds(t1, t2);  
    return diffSeconds / (24 * 3600);  
}  

====================end====================

By the way, I'll add one: reverse-push SYSTEMTIME after N-day systemtime

void Time_tToFileTime(FILETIME &ft, time_t time)  
{  
    ULARGE_INTEGER ui;  
    ui.QuadPart = (LONGLONG)(time * 10000000) + (LONGLONG)(116444736000000000);  
    ft.dwLowDateTime = ui.LowPart;  
    ft.dwHighDateTime = ui.HighPart;  
}  
  
void GetOffsetDaysTime(const SYSTEMTIME &stSrc, int offDays, SYSTEMTIME &stDst)  
{  
    FILETIME fTimeSrc = { 0, 0 };  
    SystemTimeToFileTime(&stSrc, &fTimeSrc);  
    time_t tmSrc = FileTimeToTime_t(fTimeSrc);  
    time_t tmDst = tmSrc + SEC_OF_DAY * offDays;  
    FILETIME fTimeDst = { 0, 0 };  
    Time_tToFileTime(fTimeDst, tmDst);  
    FileTimeToSystemTime(&fTimeDst, &stDst);  
}