/* 
* Author: Ugo Varetto - ugovaretto@gmail.com
* This code is distributed under the terms of the Apache Software License version 2.0
* https://opensource.org/licenses/Apache-2.0
*/

#include <time.h>
#include <windows.h>

#if defined(_MSC_VER) || defined(_MSC_EXTENSIONS)
#define DELTA_EPOCH_IN_MICROSECS  11644473600000000Ui64
#else
#define DELTA_EPOCH_IN_MICROSECS  11644473600000000ULL
#endif

struct timezone 
{
	int  tz_minuteswest; /* minutes W of Greenwich */
	int  tz_dsttime;     /* type of dst correction */
};

int gettimeofday(struct timeval *tv, struct timezone *tz)
{
	FILETIME ft;
	unsigned __int64 tmpres = 0;
	static int tzflag = 0;

	if (NULL != tv)
	{
		GetSystemTimeAsFileTime(&ft);

		tmpres |= ft.dwHighDateTime;
		tmpres <<= 32;
		tmpres |= ft.dwLowDateTime;

		tmpres /= 10;  /*convert into microseconds*/
					   /*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;
}
