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att
GitHub Repository: att/ast
 Path: blob/master/src/lib/libast/tm/tmxmake.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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 * return Tm_t for t

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 * time zone and leap seconds accounted for in return value

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 */

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Tm_t*

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tmxtm(register Tm_t* tm, Time_t t, Tm_zone_t* zone)

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{

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	register struct tm*	tp;

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	register Tm_leap_t*	lp;

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	Time_t			x;

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	time_t			now;

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	int			leapsec;

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	int			y;

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	uint32_t		n;

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	int32_t			o;

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#if TMX_FLOAT

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	Time_t			z;

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	uint32_t		i;

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#endif

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	tmset(tm_info.zone);

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	leapsec = 0;

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	if ((tm_info.flags & (TM_ADJUST|TM_LEAP)) == (TM_ADJUST|TM_LEAP) && (n = tmxsec(t)))

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	{

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

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		if (lp->total)

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		{

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			if (n == lp->time && (leapsec = (lp->total - (lp+1)->total)) < 0)

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				leapsec = 0;

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			t = tmxsns(n - lp->total, tmxnsec(t));

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		}

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	}

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	x = tmxsec(t);

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	if (!(tm->tm_zone = zone))

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	{

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		if (tm_info.flags & TM_UTC)

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			tm->tm_zone = &tm_data.zone[2];

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		else

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			tm->tm_zone = tm_info.zone;

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	}

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	if ((o = 60 * tm->tm_zone->west) && x > o)

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	{

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		x -= o;

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		o = 0;

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	}

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#if TMX_FLOAT

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	i = x / (24 * 60 * 60);

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	z = i;

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	n = x - z * (24 * 60 * 60);

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	tm->tm_sec = n % 60 + leapsec;

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	n /= 60;

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	tm->tm_min = n % 60;

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	n /= 60;

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	tm->tm_hour = n % 24;

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#define x	i

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#else

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	tm->tm_sec = x % 60 + leapsec;

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	x /= 60;

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	tm->tm_min = x % 60;

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	x /= 60;

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	tm->tm_hour = x % 24;

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	x /= 24;

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#endif

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	tm->tm_wday = (x + 4) % 7;

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	tm->tm_year = (400 * (x + 25202)) / 146097 + 1;

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	n = tm->tm_year - 1;

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

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	tm->tm_mon = 0;

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	tm->tm_mday = x + 1;

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	tm->tm_nsec = tmxnsec(t);

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	tmfix(tm);

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	n += 1900;

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	tm->tm_isdst = 0;

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	if (tm->tm_zone->daylight)

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	{

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		if ((y = tmequiv(tm) - 1900) == tm->tm_year)

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			now = tmxsec(t);

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		else

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		{

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			Tm_t	te;

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			te = *tm;

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			te.tm_year = y;

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			now = tmxsec(tmxtime(&te, tm->tm_zone->west));

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		}

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		if ((tp = tmlocaltime(&now)) && ((tm->tm_isdst = tp->tm_isdst) || o))

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		{

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			tm->tm_min -= o / 60 + (tm->tm_isdst ? tm->tm_zone->dst : 0);

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			tmfix(tm);

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		}

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	}

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	return tm;

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}

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/*

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 * return Tm_t for t

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 * time zone and leap seconds accounted for in return value

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 */

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Tm_t*

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tmxmake(Time_t t)

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{

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	static Tm_t		ts;

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	return tmxtm(&ts, t, NiL);

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}

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