/* Performs a addition of dates, times and durations.
*/
public static SchemaDateTime datetimeAdd(SchemaDateTime datetime, SchemaDuration duration) {
int months = duration.getYearMonthValue();
SchemaDateTime result = new SchemaDateTime(datetime);
result.setMonth(datetime.getMonth() + months);
int yearsOverflow;
if (result.getMonth() >= 1) yearsOverflow = (result.getMonth() - 1) / 12;
else yearsOverflow = (result.getMonth() - 12) / 12;
result.setMonth(result.getMonth() - yearsOverflow * 12);
if (yearsOverflow > 0 && result.getYear() < 0 && yearsOverflow >= -result.getYear())
result.setYear(result.getYear() + yearsOverflow + 1);
else if (yearsOverflow < 0 && result.getYear() > 0 && -yearsOverflow >= result.getYear())
result.setYear(result.getYear() + yearsOverflow - 1);
else result.setYear(result.getYear() + yearsOverflow);
boolean leapYear =
(result.getYear() % 4 == 0)
&& ((result.getYear() % 100 != 0) || (result.getYear() % 400 == 0));
int daysInMonth =
result.getMonth() == 2
? leapYear ? 29 : 28
: (30 + ((result.getMonth() & 1) ^ ((result.getMonth() >> 3) & 1)));
if (result.getDay() > daysInMonth) result.setDay(daysInMonth);
long tv =
result.getTimeValue() + duration.getDayTimeValue() + result.getTimezoneOffset() * 60000;
result.setTimeFromTimeValue(tv);
result.setDateFromTimeValue(tv);
return result;
}
/* Returns the day of week of the given datetime value. Sunday=1, Monday=2,...
*/
public static SchemaTypeNumber weekday(SchemaDateTime value) {
long a = (14 - value.getMonth()) / 12;
long m = value.getMonth() + 12 * a - 3;
long y = value.getYear() + 4800 - a;
long JD = value.getDay() + (153 * m + 2) / 5 + y * 365 + y / 4 - y / 100 + y / 400 - 32045;
return new SchemaInt((int) (JD % 7 + 1));
}
/* Returns the number of the week within the year of the given datetime value.
*/
public static SchemaTypeNumber weeknumber(SchemaDateTime value) {
long a = (14 - value.getMonth()) / 12;
long m = value.getMonth() + 12 * a - 3;
long y = value.getYear() + 4800 - a;
long JD = value.getDay() + (153 * m + 2) / 5 + y * 365 + y / 4 - y / 100 + y / 400 - 32045;
long d4 = (JD + 31741 - (JD % 7)) % 146097 % 36524 % 1461;
long L = d4 / 1460;
long d1 = ((d4 - L) % 365) + L;
return new SchemaInt((int) (d1 / 7 + 1));
}
/* Returns the day of the given datetime value.
*/
public static SchemaTypeNumber dayFromDatetime(SchemaDateTime value) {
return new SchemaInt(value.getDay());
}
