Windows FILETIME 与UNIX时间的转换

windows FILETIME时间从1601/01/01 零时零分零秒开始计时，windows每个时钟滴答将计数加一，每个时钟滴答的间隔是100 nanoseconds（纳秒，1秒=10的九次方纳秒），即每个时钟滴答= 10 （-7）秒。

unix、linux时间是从1970/01/01零时零分零秒开始计数，每秒计数加1. 197001/01与1601/01/01的时间间隔是11644473600秒。

所以从windows滴答时间转化为unix时间的代码为：

#define WINDOWS_TICK 10000000  //10的7次方
#define SEC_TO_UNIX_EPOCH 11644473600LL //1601与1970的时间间隔

unsigned WindowsTickToUnixSeconds(long long windowsTicks)
{
     return (unsigned)(windowsTicks / WINDOWS_TICK - SEC_TO_UNIX_EPOCH);
}

从timeval转化为FILETIME的代码为：

void FileTimeToTimeval(FILETIME *pFileTime, struct timeval *pTimeval)
{
    CalcOffsetFrom1601To1970(); //11644473600LL*10^7
    ULONGLONG ul64FileTime = 0;

    ul64FileTime |= pFileTime->dwHighDateTime;
    ul64FileTime <<= 32;
    ul64FileTime |= pFileTime->dwLowDateTime;

    ul64FileTime -= g_ullOffsetFrom1601To1970;
    pTimeval->tv_sec = (long)(ul64FileTime / 10000000);
    pTimeval->tv_usec = (long)((ul64FileTime % 10000000) / 10);
}

void TimevalToFileTime(struct timeval *pTimeval, FILETIME *pFileTime)
{
    CalcOffsetFrom1601To1970();
    ULONGLONG x = pTimeval->tv_sec * NSPERSEC + pTimeval->tv_usec * 10;
    x += g_ullOffsetFrom1601To1970;
    pFileTime->dwHighDateTime = (ULONG)(x >> 32);
    pFileTime->dwLowDateTime = (ULONG)x;
}