xref: /onnv-gate/usr/src/lib/libast/common/tm/tmweek.c (revision 12068:08a39a083754)
14887Schin /***********************************************************************
24887Schin *                                                                      *
34887Schin *               This software is part of the ast package               *
4*12068SRoger.Faulkner@Oracle.COM *          Copyright (c) 1985-2010 AT&T Intellectual Property          *
54887Schin *                      and is licensed under the                       *
64887Schin *                  Common Public License, Version 1.0                  *
78462SApril.Chin@Sun.COM *                    by AT&T Intellectual Property                     *
84887Schin *                                                                      *
94887Schin *                A copy of the License is available at                 *
104887Schin *            http://www.opensource.org/licenses/cpl1.0.txt             *
114887Schin *         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
124887Schin *                                                                      *
134887Schin *              Information and Software Systems Research               *
144887Schin *                            AT&T Research                             *
154887Schin *                           Florham Park NJ                            *
164887Schin *                                                                      *
174887Schin *                 Glenn Fowler <gsf@research.att.com>                  *
184887Schin *                  David Korn <dgk@research.att.com>                   *
194887Schin *                   Phong Vo <kpv@research.att.com>                    *
204887Schin *                                                                      *
214887Schin ***********************************************************************/
224887Schin #pragma prototyped
234887Schin /*
244887Schin  * Glenn Fowler
254887Schin  * AT&T Research
264887Schin  *
274887Schin  * Time_t conversion support
284887Schin  */
294887Schin 
304887Schin #include <tmx.h>
314887Schin 
324887Schin static unsigned char	offset[7][3] =
334887Schin {
344887Schin 	{ 7, 6, 6 },
354887Schin 	{ 1, 7, 7 },
364887Schin 	{ 2, 1, 8 },
374887Schin 	{ 3, 2, 9 },
384887Schin 	{ 4, 3, 10},
394887Schin 	{ 5, 4, 4 },
404887Schin 	{ 6, 5, 5 },
414887Schin };
424887Schin 
434887Schin /*
444887Schin  * type is week type
454887Schin  *	0 sunday first day of week
464887Schin  *	1 monday first day of week
474887Schin  *	2 monday first day of iso week
484887Schin  * if week<0 then return week for tm
494887Schin  * if day<0 then set tm to first day of week
504887Schin  * otherwise set tm to day in week
514887Schin  * and return tm->tm_yday
524887Schin  */
534887Schin 
544887Schin int
tmweek(Tm_t * tm,int type,int week,int day)554887Schin tmweek(Tm_t* tm, int type, int week, int day)
564887Schin {
574887Schin 	int	d;
584887Schin 
594887Schin 	if (week < 0)
604887Schin 	{
614887Schin 		if ((day = tm->tm_wday - tm->tm_yday % 7) < 0)
624887Schin 			day += 7;
634887Schin 		week = (tm->tm_yday + offset[day][type]) / 7;
644887Schin 		if (type == 2)
654887Schin 		{
664887Schin 			if (!week)
674887Schin 				week = (day > 0 && day < 6 || tmisleapyear(tm->tm_year - 1)) ? 53 : 52;
684887Schin 			else if (week == 53 && (tm->tm_wday + (31 - tm->tm_mday)) < 4)
694887Schin 				week = 1;
704887Schin 		}
714887Schin 		return week;
724887Schin 	}
734887Schin 	if (day < 0)
744887Schin 		day = type != 0;
754887Schin 	tm->tm_mon = 0;
764887Schin 	tm->tm_mday = 1;
774887Schin 	tmfix(tm);
784887Schin 	d = tm->tm_wday;
794887Schin 	tm->tm_mday = week * 7 - offset[d][type] + ((day || type != 2) ? day : 7);
804887Schin 	tmfix(tm);
814887Schin 	if (d = tm->tm_wday - day)
824887Schin 	{
834887Schin 		tm->tm_mday -= d;
844887Schin 		tmfix(tm);
854887Schin 	}
864887Schin 	return tm->tm_yday;
874887Schin }
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