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att
GitHub Repository: att/ast
 Path: blob/master/src/lib/libast/tm/tmxtime.c
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/***********************************************************************

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*                                                                      *

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*               This software is part of the ast package               *

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

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*                      and is licensed under the                       *

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*                 Eclipse Public License, Version 1.0                  *

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*                    by AT&T Intellectual Property                     *

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*                                                                      *

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*                A copy of the License is available at                 *

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

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*         (with md5 checksum b35adb5213ca9657e911e9befb180842)         *

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*                                                                      *

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*              Information and Software Systems Research               *

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*                            AT&T Research                             *

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*                           Florham Park NJ                            *

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*                                                                      *

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*                 Glenn Fowler <[email protected]>                  *

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*                  David Korn <[email protected]>                   *

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*                   Phong Vo <[email protected]>                    *

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*                                                                      *

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

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#pragma prototyped

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/*

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 * Glenn Fowler

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 * AT&T Research

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 *

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 * Time_t conversion support

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 */

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#include <tmx.h>

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#include "FEATURE/tmlib"

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/*

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 * convert Tm_t to Time_t

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 *

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

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 * otherwise west is the number of minutes west

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 * of GMT with DST taken into account

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 *

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

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

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 */

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Time_t

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tmxtime(register Tm_t* tm, int west)

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{

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	register Time_t		t;

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	register Tm_leap_t*	lp;

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	register int32_t	y;

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	int			n;

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	int			sec;

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	time_t			now;

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	struct tm*		tl;

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	Tm_t*			to;

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	Tm_t			ts;

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	ts = *tm;

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	to = tm;

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	tm = &ts;

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	tmset(tm_info.zone);

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	tmfix(tm);

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	y = tm->tm_year;

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

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		return TMX_NOTIME;

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	y--;

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

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

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		n = 11;

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	y += 1901;

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

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		t++;

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

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	t *= 24;

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	t += tm->tm_hour;

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	t *= 60;

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	t += tm->tm_min;

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	t *= 60;

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	t += sec = tm->tm_sec;

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

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	{

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		/*

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		 * time zone adjustments

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		 */

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		if (west == TM_LOCALZONE)

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		{

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

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			if (!tm_info.zone->daylight)

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				tm->tm_isdst = 0;

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			else

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			{

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				y = tm->tm_year;

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

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

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				tm->tm_year = y;

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

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					return TMX_NOTIME;

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

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

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			}

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		}

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		else

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		{

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			t += west * 60;

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			if (!tm_info.zone->daylight)

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				tm->tm_isdst = 0;

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			else if (tm->tm_isdst < 0)

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			{

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				y = tm->tm_year;

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

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				tm->tm_isdst = 0;

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

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				tm->tm_year = y;

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

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					return TMX_NOTIME;

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				tm->tm_isdst = tl->tm_isdst;

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			}

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		}

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	}

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	else if (tm->tm_isdst)

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		tm->tm_isdst = 0;

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	*to = *tm;

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	if (tm_info.flags & TM_LEAP)

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	{

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		/*

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		 * leap second adjustments

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		 */

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

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		t += lp->total;

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

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

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			t -= n;

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	}

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	return tmxsns(t, tm->tm_nsec);

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}

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