mdw@git.distorted.org.uk Git - qmail/blob - datetime.c

   1 /* 19950925 */
   2 #include "datetime.h"
   3
   4 void datetime_tai(dt,t)
   5 struct datetime *dt;
   6 datetime_sec t;
   7 {
   8   int day;
   9   int tod;
  10   int year;
  11   int yday;
  12   int wday;
  13   int mon;
  14
  15   tod = t % 86400;
  16   day = t / 86400;
  17   if (tod < 0) { tod += 86400; --day; }
  18
  19   dt->hour = tod / 3600;
  20   tod %= 3600;
  21   dt->min = tod / 60;
  22   dt->sec = tod % 60;
  23
  24   wday = (day + 4) % 7; if (wday < 0) wday += 7;
  25   dt->wday = wday;
  26
  27   day -= 11017;
  28   /* day 0 is march 1, 2000 */
  29   year = 5 + day / 146097;
  30   day = day % 146097; if (day < 0) { day += 146097; --year; }
  31   /* from now on, day is nonnegative */
  32   year *= 4;
  33   if (day == 146096) { year += 3; day = 36524; }
  34   else { year += day / 36524; day %= 36524; }
  35   year *= 25;
  36   year += day / 1461;
  37   day %= 1461;
  38   year *= 4;
  39   yday = (day < 306);
  40   if (day == 1460) { year += 3; day = 365; }
  41   else { year += day / 365; day %= 365; }
  42   yday += day;
  43
  44   day *= 10;
  45   mon = (day + 5) / 306;
  46   day = day + 5 - 306 * mon;
  47   day /= 10;
  48   if (mon >= 10) { yday -= 306; ++year; mon -= 10; }
  49   else { yday += 59; mon += 2; }
  50
  51   dt->yday = yday;
  52   dt->year = year - 1900;
  53   dt->mon = mon;
  54   dt->mday = day + 1;
  55 }