/***********************************************************************

*                                                                      *

*               This software is part of the ast package               *

*          Copyright (c) 1985-2011 AT&T Intellectual Property          *

*                      and is licensed under the                       *

*                 Eclipse Public License, Version 1.0                  *

*                    by AT&T Intellectual Property                     *

*                                                                      *

*                A copy of the License is available at                 *

*          http://www.eclipse.org/org/documents/epl-v10.html           *

*         (with md5 checksum b35adb5213ca9657e911e9befb180842)         *

*                                                                      *

*              Information and Software Systems Research               *

*                            AT&T Research                             *

*                           Florham Park NJ                            *

*                                                                      *

*                 Glenn Fowler <gsf@research.att.com>                  *

*                  David Korn <dgk@research.att.com>                   *

*                   Phong Vo <kpv@research.att.com>                    *

*                                                                      *

***********************************************************************/

#pragma prototyped

/*

 * Glenn Fowler

 * AT&T Research

 *

 * Time_t conversion support

 */

#include <tmx.h>

#include "FEATURE/tmlib"

/*

 * convert Tm_t to Time_t

 *

 * if west==TM_LOCALZONE then the local timezone is used

 * otherwise west is the number of minutes west

 * of GMT with DST taken into account

 *

 * this routine works with a copy of Tm_t to avoid clashes

 * with other tm*() that may return static Tm_t*

 */

Time_t

tmxtime(register Tm_t* tm, int west)

{

	register Time_t		t;

	register Tm_leap_t*	lp;

	register int32_t	y;

	int			n;

	int			sec;

	time_t			now;

	struct tm*		tl;

	Tm_t*			to;

	Tm_t			ts;

	ts = *tm;

	to = tm;

	tm = &ts;

	tmset(tm_info.zone);

	tmfix(tm);

	y = tm->tm_year;

	if (y < 69 || y > (TMX_MAXYEAR - 1900))

		return TMX_NOTIME;

	y--;

	t = y * 365 + y / 4 - y / 100 + (y + (1900 - 1600)) / 400 - (1970 - 1901) * 365 - (1970 - 1901) / 4;

	if ((n = tm->tm_mon) > 11)

		n = 11;

	y += 1901;

	if (n > 1 && tmisleapyear(y))

		t++;

	t += tm_data.sum[n] + tm->tm_mday - 1;

	t *= 24;

	t += tm->tm_hour;

	t *= 60;

	t += tm->tm_min;

	t *= 60;

	t += sec = tm->tm_sec;

	if (west != TM_UTCZONE && !(tm_info.flags & TM_UTC))

	{

		/*

		 * time zone adjustments

		 */

		if (west == TM_LOCALZONE)

		{

			t += tm_info.zone->west * 60;

			if (!tm_info.zone->daylight)

				tm->tm_isdst = 0;

			else

			{

				y = tm->tm_year;

				tm->tm_year = tmequiv(tm) - 1900;

				now = tmxsec(tmxtime(tm, tm_info.zone->west));

				tm->tm_year = y;

				if (!(tl = tmlocaltime(&now)))

					return TMX_NOTIME;

				if (tm->tm_isdst = tl->tm_isdst)

					t += tm_info.zone->dst * 60;

			}

		}

		else

		{

			t += west * 60;

			if (!tm_info.zone->daylight)

				tm->tm_isdst = 0;

			else if (tm->tm_isdst < 0)

			{

				y = tm->tm_year;

				tm->tm_year = tmequiv(tm) - 1900;

				tm->tm_isdst = 0;

				now = tmxsec(tmxtime(tm, tm_info.zone->west));

				tm->tm_year = y;

				if (!(tl = tmlocaltime(&now)))

					return TMX_NOTIME;

				tm->tm_isdst = tl->tm_isdst;

			}

		}

	}

	else if (tm->tm_isdst)

		tm->tm_isdst = 0;

	*to = *tm;

	if (tm_info.flags & TM_LEAP)

	{

		/*

		 * leap second adjustments

		 */

		for (lp = &tm_data.leap[0]; t < lp->time - (lp+1)->total; lp++);

		t += lp->total;

		n = lp->total - (lp+1)->total;

		if (t <= (lp->time + n) && (n > 0 && sec > 59 || n < 0 && sec > (59 + n) && sec <= 59))

			t -= n;

	}

	return tmxsns(t, tm->tm_nsec);

}