usr/src/lib/libast/common/tm/tmfix.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 conversion support
  28  */
  29
  30 #include <ast.h>
  31 #include <tmx.h>
  32
  33 #define DAYS(p) (tm_data.days[(p)->tm_mon]+((p)->tm_mon==1&&LEAP(p)))
  34 #define LEAP(p) (tmisleapyear((p)->tm_year))
  35
  36 /*
  37  * correct out of bounds fields in tm
  38  *
  39  * tm_isdst is not changed -- call tmxtm() to get that
  40  *
  41  * tm is the return value
  42  */
  43
  44 Tm_t*
  45 tmfix(register Tm_t* tm)
  46 {
  47         register int    n;
  48         register int    w;
  49         Tm_t*           p;
  50         time_t          t;
  51
  52         /*
  53          * check for special case that adjusts tm_wday at the end
  54          * this happens during
  55          *      nl_langinfo() => strftime() => tmfmt()
  56          */
  57
  58         if (w = !tm->tm_sec && !tm->tm_min && !tm->tm_mday && !tm->tm_year && !tm->tm_yday && !tm->tm_isdst)
  59         {
  60                 tm->tm_year = 99;
  61                 tm->tm_mday = 2;
  62         }
  63
  64         /*
  65          * adjust from shortest to longest units
  66          */
  67
  68         if ((n = tm->tm_nsec) < 0)
  69         {
  70                 tm->tm_sec -= (TMX_RESOLUTION - n) / TMX_RESOLUTION;
  71                 tm->tm_nsec = TMX_RESOLUTION - (-n) % TMX_RESOLUTION;
  72         }
  73         else if (n >= TMX_RESOLUTION)
  74         {
  75                 tm->tm_sec += n / TMX_RESOLUTION;
  76                 tm->tm_nsec %= TMX_RESOLUTION;
  77         }
  78         if ((n = tm->tm_sec) < 0)
  79         {
  80                 tm->tm_min -= (60 - n) / 60;
  81                 tm->tm_sec = 60 - (-n) % 60;
  82         }
  83         else if (n > (59 + TM_MAXLEAP))
  84         {
  85                 tm->tm_min += n / 60;
  86                 tm->tm_sec %= 60;
  87         }
  88         if ((n = tm->tm_min) < 0)
  89         {
  90                 tm->tm_hour -= (60 - n) / 60;
  91                 n = tm->tm_min = 60 - (-n) % 60;
  92         }
  93         if (n > 59)
  94         {
  95                 tm->tm_hour += n / 60;
  96                 tm->tm_min %= 60;
  97         }
  98         if ((n = tm->tm_hour) < 0)
  99         {
 100                 tm->tm_mday -= (23 - n) / 24;
 101                 tm->tm_hour = 24 - (-n) % 24;
 102         }
 103         else if (n >= 24)
 104         {
 105                 tm->tm_mday += n / 24;
 106                 tm->tm_hour %= 24;
 107         }
 108         if (tm->tm_mon >= 12)
 109         {
 110                 tm->tm_year += tm->tm_mon / 12;
 111                 tm->tm_mon %= 12;
 112         }
 113         else if (tm->tm_mon < 0)
 114         {
 115                 tm->tm_year--;
 116                 if ((tm->tm_mon += 12) < 0)
 117                 {
 118                         tm->tm_year += tm->tm_mon / 12;
 119                         tm->tm_mon = (-tm->tm_mon) % 12;
 120                 }
 121         }
 122         while (tm->tm_mday < -365)
 123         {
 124                 tm->tm_year--;
 125                 tm->tm_mday += 365 + LEAP(tm);
 126         }
 127         while (tm->tm_mday > 365)
 128         {
 129                 tm->tm_mday -= 365 + LEAP(tm);
 130                 tm->tm_year++;
 131         }
 132         while (tm->tm_mday < 1)
 133         {
 134                 if (--tm->tm_mon < 0)
 135                 {
 136                         tm->tm_mon = 11;
 137                         tm->tm_year--;
 138                 }
 139                 tm->tm_mday += DAYS(tm);
 140         }
 141         while (tm->tm_mday > (n = DAYS(tm)))
 142         {
 143                 tm->tm_mday -= n;
 144                 if (++tm->tm_mon > 11)
 145                 {
 146                         tm->tm_mon = 0;
 147                         tm->tm_year++;
 148                 }
 149         }
 150         if (w)
 151         {
 152                 w = tm->tm_wday;
 153                 t = tmtime(tm, TM_LOCALZONE);
 154                 p = tmmake(&t);
 155                 if (w = (w - p->tm_wday))
 156                 {
 157                         if (w < 0)
 158                                 w += 7;
 159                         tm->tm_wday += w;
 160                         if ((tm->tm_mday += w) > DAYS(tm))
 161                                 tm->tm_mday -= 7;
 162                 }
 163         }
 164         tm->tm_yday = tm_data.sum[tm->tm_mon] + (tm->tm_mon > 1 && LEAP(tm)) + tm->tm_mday - 1;
 165         n = tm->tm_year + 1900 - 1;
 166         tm->tm_wday = (n + n / 4 - n / 100 + n / 400 + tm->tm_yday + 1) % 7;
 167
 168         /*
 169          * tm_isdst is adjusted by tmtime()
 170          */
 171
 172         return tm;
 173 }