/* 19950925 */

#include "datetime.h"

void datetime_tai(dt,t)

struct datetime *dt;

datetime_sec t;

{

  int day;

  int tod;

  int year;

  int yday;

  int wday;

  int mon;

  tod = t % 86400;

  day = t / 86400;

  if (tod < 0) { tod += 86400; --day; }

  dt->hour = tod / 3600;

  tod %= 3600;

  dt->min = tod / 60;

  dt->sec = tod % 60;

  wday = (day + 4) % 7; if (wday < 0) wday += 7;

  dt->wday = wday;

  day -= 11017;

  /* day 0 is march 1, 2000 */

  year = 5 + day / 146097;

  day = day % 146097; if (day < 0) { day += 146097; --year; }

  /* from now on, day is nonnegative */

  year *= 4;

  if (day == 146096) { year += 3; day = 36524; }

  else { year += day / 36524; day %= 36524; }

  year *= 25;

  year += day / 1461;

  day %= 1461;

  year *= 4;

  yday = (day < 306);

  if (day == 1460) { year += 3; day = 365; }

  else { year += day / 365; day %= 365; }

  yday += day;

  day *= 10;

  mon = (day + 5) / 306;

  day = day + 5 - 306 * mon;

  day /= 10;

  if (mon >= 10) { yday -= 306; ++year; mon -= 10; }

  else { yday += 59; mon += 2; }

  dt->yday = yday;

  dt->year = year - 1900;

  dt->mon = mon;

  dt->mday = day + 1;

}