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| |
| #include "qglobal.h" |
| #include "qislamiccivilcalendar_p.h" |
| #include "qcalendarmath_p.h" |
| #include <QtCore/qmath.h> |
| |
| QT_BEGIN_NAMESPACE |
| |
| using namespace QRoundingDown; |
| |
| /*! |
| \since 5.14 |
| \internal |
| |
| \class QIslamicCivilCalendar |
| \inmodule QtCore |
| \brief Implements a commonly-used computed version of the Islamic calendar. |
| |
| \section1 Civil Islamic Calendar |
| |
| QIslamicCivilCalendar implements a tabular version of the Hijri calendar |
| which is known as the Islamic Civil Calendar. It has the same numbering of |
| years and months, but the months are determined by arithmetical rules rather |
| than by observation or astronomical calculations. |
| |
| \section2 Calendar Organization |
| |
| The civil calendar follows the usual tabular scheme of odd-numbered months |
| and the last month of each leap year being 30 days long, the rest being 29 |
| days long. Its determination of leap years follows a 30-year cycle, in each |
| of which the years 2, 5, 7, 10, 13, 16, 18, 21, 24, 26 and 29 are leap |
| years. |
| |
| \sa QHijriCalendar, QCalendar |
| */ |
| |
| QIslamicCivilCalendar::QIslamicCivilCalendar() |
| : QHijriCalendar(QStringLiteral("Islamic Civil"), QCalendar::System::IslamicCivil) |
| { |
| registerAlias(QStringLiteral("islamic-civil")); // CLDR name |
| registerAlias(QStringLiteral("islamicc")); // old CLDR name, still (2018) used by Mozilla |
| // Until we have a oncrete implementation that knows all the needed ephemerides: |
| registerAlias(QStringLiteral("Islamic")); |
| } |
| |
| QString QIslamicCivilCalendar::name() const |
| { |
| return QStringLiteral("Islamic Civil"); |
| } |
| |
| QCalendar::System QIslamicCivilCalendar::calendarSystem() const |
| { |
| return QCalendar::System::IslamicCivil; |
| } |
| |
| bool QIslamicCivilCalendar::isLeapYear(int year) const |
| { |
| if (year == QCalendar::Unspecified) |
| return false; |
| if (year < 0) |
| ++year; |
| return qMod(year * 11 + 14, 30) < 11; |
| } |
| |
| bool QIslamicCivilCalendar::dateToJulianDay(int year, int month, int day, qint64 *jd) const |
| { |
| Q_ASSERT(jd); |
| if (!isDateValid(year, month, day)) |
| return false; |
| if (year <= 0) |
| ++year; |
| *jd = qDiv(10631 * year - 10617, 30) |
| + qDiv(325 * month - 320, 11) |
| + day + 1948439; |
| return true; |
| } |
| |
| QCalendar::YearMonthDay QIslamicCivilCalendar::julianDayToDate(qint64 jd) const |
| { |
| const qint64 epoch = 1948440; |
| const int32_t k2 = 30 * (jd - epoch) + 15; |
| const int32_t k1 = 11 * qDiv(qMod(k2, 10631), 30) + 5; |
| int y = qDiv(k2, 10631) + 1; |
| const int month = qDiv(k1, 325) + 1; |
| const int day = qDiv(qMod(k1, 325), 11) + 1; |
| return QCalendar::YearMonthDay(y > 0 ? y : y - 1, month, day); |
| } |
| |
| QT_END_NAMESPACE |