xref: /titanic_50/usr/src/lib/libast/common/tm/tmxtime.c (revision 3e14f97f673e8a630f076077de35afdd43dc1587)
1 /***********************************************************************
2 *                                                                      *
3 *               This software is part of the ast package               *
4 *          Copyright (c) 1985-2010 AT&T Intellectual Property          *
5 *                      and is licensed under the                       *
6 *                  Common Public License, Version 1.0                  *
7 *                    by AT&T Intellectual Property                     *
8 *                                                                      *
9 *                A copy of the License is available at                 *
10 *            http://www.opensource.org/licenses/cpl1.0.txt             *
11 *         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
12 *                                                                      *
13 *              Information and Software Systems Research               *
14 *                            AT&T Research                             *
15 *                           Florham Park NJ                            *
16 *                                                                      *
17 *                 Glenn Fowler <gsf@research.att.com>                  *
18 *                  David Korn <dgk@research.att.com>                   *
19 *                   Phong Vo <kpv@research.att.com>                    *
20 *                                                                      *
21 ***********************************************************************/
22 #pragma prototyped
23 /*
24  * Glenn Fowler
25  * AT&T Research
26  *
27  * Time_t conversion support
28  */
29 
30 #include <tmx.h>
31 
32 #include "FEATURE/tmlib"
33 
34 /*
35  * convert Tm_t to Time_t
36  *
37  * if west==TM_LOCALZONE then the local timezone is used
38  * otherwise west is the number of minutes west
39  * of GMT with DST taken into account
40  *
41  * this routine works with a copy of Tm_t to avoid clashes
42  * with other tm*() that may return static Tm_t*
43  */
44 
45 Time_t
tmxtime(register Tm_t * tm,int west)46 tmxtime(register Tm_t* tm, int west)
47 {
48 	register Time_t		t;
49 	register Tm_leap_t*	lp;
50 	register int32_t	y;
51 	int			n;
52 	int			sec;
53 	time_t			now;
54 	struct tm*		tl;
55 	Tm_t*			to;
56 	Tm_t			ts;
57 
58 	ts = *tm;
59 	to = tm;
60 	tm = &ts;
61 	tmset(tm_info.zone);
62 	tmfix(tm);
63 	y = tm->tm_year;
64 	if (y < 69 || y > (TMX_MAXYEAR - 1900))
65 		return TMX_NOTIME;
66 	y--;
67 	t = y * 365 + y / 4 - y / 100 + (y + (1900 - 1600)) / 400 - (1970 - 1901) * 365 - (1970 - 1901) / 4;
68 	if ((n = tm->tm_mon) > 11)
69 		n = 11;
70 	y += 1901;
71 	if (n > 1 && tmisleapyear(y))
72 		t++;
73 	t += tm_data.sum[n] + tm->tm_mday - 1;
74 	t *= 24;
75 	t += tm->tm_hour;
76 	t *= 60;
77 	t += tm->tm_min;
78 	t *= 60;
79 	t += sec = tm->tm_sec;
80 	if (west != TM_UTCZONE && !(tm_info.flags & TM_UTC))
81 	{
82 		/*
83 		 * time zone adjustments
84 		 */
85 
86 		if (west == TM_LOCALZONE)
87 		{
88 			t += tm_info.zone->west * 60;
89 			if (!tm_info.zone->daylight)
90 				tm->tm_isdst = 0;
91 			else
92 			{
93 				y = tm->tm_year;
94 				tm->tm_year = tmequiv(tm) - 1900;
95 				now = tmxsec(tmxtime(tm, tm_info.zone->west));
96 				tm->tm_year = y;
97 				if (!(tl = tmlocaltime(&now)))
98 					return TMX_NOTIME;
99 				if (tm->tm_isdst = tl->tm_isdst)
100 					t += tm_info.zone->dst * 60;
101 			}
102 		}
103 		else
104 		{
105 			t += west * 60;
106 			if (!tm_info.zone->daylight)
107 				tm->tm_isdst = 0;
108 			else if (tm->tm_isdst < 0)
109 			{
110 				y = tm->tm_year;
111 				tm->tm_year = tmequiv(tm) - 1900;
112 				tm->tm_isdst = 0;
113 				now = tmxsec(tmxtime(tm, tm_info.zone->west));
114 				tm->tm_year = y;
115 				if (!(tl = tmlocaltime(&now)))
116 					return TMX_NOTIME;
117 				tm->tm_isdst = tl->tm_isdst;
118 			}
119 		}
120 	}
121 	else if (tm->tm_isdst)
122 		tm->tm_isdst = 0;
123 	*to = *tm;
124 	if (tm_info.flags & TM_LEAP)
125 	{
126 		/*
127 		 * leap second adjustments
128 		 */
129 
130 		for (lp = &tm_data.leap[0]; t < lp->time - (lp+1)->total; lp++);
131 		t += lp->total;
132 		n = lp->total - (lp+1)->total;
133 		if (t <= (lp->time + n) && (n > 0 && sec > 59 || n < 0 && sec > (59 + n) && sec <= 59))
134 			t -= n;
135 	}
136 	return tmxsns(t, tm->tm_nsec);
137 }
138