time.h

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/*
 * Copyright 2018, 2020 Free Software Foundation, Inc.
 *
 * This file is part of VOLK
 *
 * SPDX-License-Identifier: LGPL-3.0-or-later
 */
 
#ifndef _MSC_VER // [
#error "Use this header only with Microsoft Visual C++ compilers!"
#endif // _MSC_VER ]
 
#ifndef _MSC_SYS_TIME_H_
#define _MSC_SYS_TIME_H_
 
// prevent windows.h from clobbering min and max functions with macros
#ifndef NOMINMAX
#define NOMINMAX
#endif
 
// https://learn.microsoft.com/en-us/archive/msdn-technet-forums/430449b3-f6dd-4e18-84de-eebd26a8d668
#include < time.h >
#include <windows.h> //I've omitted this line.
#if defined(_MSC_VER) || defined(_MSC_EXTENSIONS)
#define DELTA_EPOCH_IN_MICROSECS 11644473600000000Ui64
#else
#define DELTA_EPOCH_IN_MICROSECS 11644473600000000ULL
#endif
 
#if _MSC_VER < 1900
struct timespec {
 
    time_t tv_sec; /* Seconds since 00:00:00 GMT, */
 
    /* 1 January 1970 */
 
    long tv_nsec; /* Additional nanoseconds since */
 
    /* tv_sec */
};
#endif
 
struct timezone {
    int tz_minuteswest; /* minutes W of Greenwich */
    int tz_dsttime;     /* type of dst correction */
};
 
static inline int gettimeofday(struct timeval* tv, struct timezone* tz)
{
    FILETIME ft;
    unsigned __int64 tmpres = 0;
    static int tzflag;
 
    if (NULL != tv) {
        GetSystemTimeAsFileTime(&ft);
 
        tmpres |= ft.dwHighDateTime;
        tmpres <<= 32;
        tmpres |= ft.dwLowDateTime;
 
        /*converting file time to unix epoch*/
        tmpres -= DELTA_EPOCH_IN_MICROSECS;
        tv->tv_sec = (long)(tmpres / 1000000UL);
        tv->tv_usec = (long)(tmpres % 1000000UL);
    }
 
    if (NULL != tz) {
        if (!tzflag) {
            _tzset();
            tzflag++;
        }
        tz->tz_minuteswest = _timezone / 60;
        tz->tz_dsttime = _daylight;
    }
 
    return 0;
}
 
#endif //_MSC_SYS_TIME_H_