| 1 | #include "datetime.h" |
| 2 | |
| 3 | /* roughly 100x faster than mktime() */ |
| 4 | datetime_sec datetime_untai(dt) |
| 5 | struct datetime *dt; |
| 6 | { |
| 7 | int year; |
| 8 | int day; |
| 9 | int mon; |
| 10 | |
| 11 | year = dt->year + 1900; |
| 12 | |
| 13 | mon = dt->mon; |
| 14 | if (mon >= 2) { mon -= 2; } |
| 15 | else { mon += 10; --year; } |
| 16 | |
| 17 | day = (dt->mday - 1) * 10 + 5 + 306 * mon; |
| 18 | day /= 10; |
| 19 | |
| 20 | if (day == 365) { year -= 3; day = 1460; } |
| 21 | else { day += 365 * (year % 4); } |
| 22 | year /= 4; |
| 23 | |
| 24 | day += 1461 * (year % 25); |
| 25 | year /= 25; |
| 26 | |
| 27 | if (day == 36524) { year -= 3; day = 146096; } |
| 28 | else { day += 36524 * (year % 4); } |
| 29 | year /= 4; |
| 30 | |
| 31 | day += 146097 * (year - 5); |
| 32 | day += 11017; |
| 33 | |
| 34 | return ((day * 24 + dt->hour) * 60 + dt->min) * 60 + dt->sec; |
| 35 | } |