datetime.c (1136B)
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 }