Julian operator+(Julian const & j, detail::packaged_year y) {
year_t year = j.year() + static_cast<year_t>(y.nYears_);
return Julian(
year, j.month(),
j.month() == 2 && j.day() == 29 && !is_julian_leapyear(year) ?
28 : j.day(), j.hour(), j.minute(), j.second());
}
Julian operator-(Julian const & j, detail::packaged_month m) {
year_t year = j.year() - m.nMonths_ / 12;
month_t month = j.month() - m.nMonths_ % 12;
double adjust = (month - 1) / 12 + (month - 12) / 12;
year += static_cast<year_t>(adjust);
month -= static_cast<month_t>(adjust * 12);
day_t day = j.day() < julian_days_in_month(month, is_julian_leapyear(year)) ?
j.day() : julian_days_in_month(month, is_julian_leapyear(year));
return Julian(year, month, day, j.hour(), j.minute(), j.second());
}