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| |
| #include "qglobal.h" |
| #include "qjalalicalendar_p.h" |
| #include "qjalalicalendar_data_p.h" |
| #include "qcalendarmath_p.h" |
| #include <QtCore/qmath.h> |
| |
| QT_BEGIN_NAMESPACE |
| |
| using namespace QRoundingDown; |
| |
| // Constants |
| |
| static const qint64 cycleDays = 1029983; |
| static const int cycleYears = 2820; |
| static const double yearLength = 365.24219858156028368; // 365 + leapRatio; |
| static const qint64 jalaliEpoch = 2121446; // 475/01/01 AP, start of 2820 cycle |
| |
| // Calendar implementation |
| |
| static inline int cycle(qint64 jdn) |
| { |
| return qDiv(jdn - jalaliEpoch, cycleDays); |
| } |
| |
| qint64 cycleStart(int cycleNo) |
| { |
| return jalaliEpoch + cycleNo * cycleDays; |
| } |
| |
| qint64 firstDayOfYear(int year, int cycleNo) |
| { |
| qint64 firstDOYinEra = static_cast<qint64>(qFloor(year * yearLength)); |
| return jalaliEpoch + cycleNo * cycleDays + firstDOYinEra; |
| } |
| |
| /*! |
| \since 5.14 |
| |
| \class QJalaliCalendar |
| \inmodule QtCore |
| \brief The QJalaliCalendar class provides Jalali (Hijri Shamsi) calendar |
| system implementation. |
| |
| \section1 Solar Hijri Calendar System |
| |
| The Solar Hijri calendar, also called the Solar Hejri calendar, Shamsi |
| Hijri calendar or Jalali calendar, is the official calendar of Iran and |
| Afghanistan. It begins on the vernal equinox (Nowruz) as determined by |
| astronomical calculation for the Iran Standard Time meridian |
| (52.5°E or GMT+3.5h). This determination of starting moment is more accurate |
| than the Gregorian calendar for predicting the date of the vernal equinox, |
| because it uses astronomical observations rather than mathematical rules. |
| |
| \section2 Calendar Organization |
| |
| Each of the twelve months corresponds with a zodiac sign. The first six |
| months have 31 days, the next five have 30 days, and the last month has 29 |
| days in usual years but 30 days in leap years. The New Year's Day always |
| falls on the March equinox. |
| |
| \section2 Leap Year Rules |
| |
| The Solar Hijri calendar produces a five-year leap year interval after about |
| every seven four-year leap year intervals. It usually follows a 33-year |
| cycle with occasional interruptions by single 29-year or 37-year subcycles. |
| The reason for this behavior is that it tracks the observed vernal equinox. |
| By contrast, some less accurate predictive algorithms are in use based |
| on confusion between the average tropical year (365.2422 days, approximated |
| with near 128-year cycles or 2820-year great cycles) and the mean interval |
| between spring equinoxes (365.2424 days, approximated with a near 33-year |
| cycle). |
| |
| Source: \l {https://en.wikipedia.org/wiki/Solar_Hijri_calendar}{Wikipedia |
| page on Solar Hijri Calendar} |
| */ |
| |
| QJalaliCalendar::QJalaliCalendar() |
| : QCalendarBackend(QStringLiteral("Jalali"), QCalendar::System::Jalali) |
| { |
| registerAlias(QStringLiteral("Persian")); |
| } |
| |
| QString QJalaliCalendar::name() const |
| { |
| return QStringLiteral("Jalali"); |
| } |
| |
| QCalendar::System QJalaliCalendar::calendarSystem() const |
| { |
| return QCalendar::System::Jalali; |
| } |
| |
| bool QJalaliCalendar::isLeapYear(int year) const |
| { |
| if (year == QCalendar::Unspecified) |
| return false; |
| if (year < 0) |
| year++; |
| return qMod((year + 2346) * 683, 2820) < 683; |
| } |
| |
| bool QJalaliCalendar::isLunar() const |
| { |
| return false; |
| } |
| |
| bool QJalaliCalendar::isLuniSolar() const |
| { |
| return false; |
| } |
| |
| bool QJalaliCalendar::isSolar() const |
| { |
| return true; |
| } |
| |
| bool QJalaliCalendar::dateToJulianDay(int year, int month, int day, qint64 *jd) const |
| { |
| Q_ASSERT(jd); |
| if (!isDateValid(year, month, day)) |
| return false; |
| |
| const int y = year - (year < 0 ? 474 : 475); |
| const int c = qDiv(y, cycleYears); |
| const int yearInCycle = y - c * cycleYears; |
| int dayInYear = day; |
| for (int i = 1; i < month; ++i) |
| dayInYear += daysInMonth(i, year); |
| *jd = firstDayOfYear(yearInCycle, c) + dayInYear - 1; |
| return true; |
| } |
| |
| QCalendar::YearMonthDay QJalaliCalendar::julianDayToDate(qint64 jd) const |
| { |
| const int c = cycle(jd); |
| int yearInCycle = qFloor((jd - cycleStart(c)) / yearLength); |
| int year = yearInCycle + 475 + c * cycleYears; |
| int day = jd - firstDayOfYear(yearInCycle, c) + 1; |
| if (day > daysInYear(year <= 0 ? year - 1 : year)) { |
| year++; |
| day = 1; |
| } |
| if (year <= 0) |
| year--; |
| int month; |
| for (month = 1; month < 12; ++month) { |
| const int last = daysInMonth(month, year); |
| if (day <= last) |
| break; |
| day -= last; |
| } |
| return QCalendar::YearMonthDay(year, month, day); |
| } |
| |
| int QJalaliCalendar::daysInMonth(int month, int year) const |
| { |
| if (year && month > 0 && month <= 12) |
| return month < 7 ? 31 : month < 12 || isLeapYear(year) ? 30 : 29; |
| |
| return 0; |
| } |
| |
| const QCalendarLocale *QJalaliCalendar::localeMonthIndexData() const |
| { |
| return locale_data; |
| } |
| |
| const ushort *QJalaliCalendar::localeMonthData() const |
| { |
| return months_data; |
| } |
| |
| QT_END_NAMESPACE |