usr/src/lib/libast/common/tm/tmxtime.c

   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
  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 }