1 /* 2 * Copyright (C) 2020 Georg Zotti 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License 6 * as published by the Free Software Foundation; either version 2 7 * of the License, or (at your option) any later version. 8 * 9 * This program is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 * GNU General Public License for more details. 13 * 14 * You should have received a copy of the GNU General Public License 15 * along with this program; if not, write to the Free Software 16 * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA. 17 */ 18 19 #ifndef JULIANCALENDAR_HPP 20 #define JULIANCALENDAR_HPP 21 22 #include "Calendar.hpp" 23 24 //! Stellarium uses Julian Day numbers internally, and the conventional approach of using the Gregorian calendar for dates after 1582-10-15. 25 //! For dates before that, the Julian calendar is used, in the form finalized by Augustus and running unchanged since 8AD. 26 //! Some European countries, especially the Protestant countries, delayed the calendar switch well into the 18th century. 27 //! @note The implementation does not correctly represent the Roman Julian calendar valid from introduction by Julius Caesar to the reform by Augustus. 28 //! @note this implementation adheres to Calendrical Calculation's style of omitting a year zero. Negative years represent years B.C.E. 29 //! This is very much in contrast to Stellarium's usual behaviour, and also different from a year zero in CC's implementation of the Gregorian calendar. 30 31 class JulianCalendar : public Calendar 32 { 33 Q_OBJECT 34 35 public: 36 typedef enum {january=1, february, march, april, may, june, july, august, september, october, november, december } month; 37 38 JulianCalendar(double jd); 39 ~JulianCalendar()40 virtual ~JulianCalendar() Q_DECL_OVERRIDE {} 41 42 public slots: 43 virtual void retranslate() Q_DECL_OVERRIDE; 44 45 //! Set a calendar date from the Julian day number 46 virtual void setJD(double JD) Q_DECL_OVERRIDE; 47 48 //! set date from a vector of calendar date elements sorted from the largest to the smallest. 49 //! Year-Month[1...12]-Day[1...31] 50 virtual void setDate(QVector<int> parts) Q_DECL_OVERRIDE; 51 52 //! get a stringlist of calendar date elements sorted from the largest to the smallest. 53 //! Year, Month, MonthName, Day, DayName 54 virtual QStringList getDateStrings() const Q_DECL_OVERRIDE; 55 56 //! get a formatted complete string for a date 57 virtual QString getFormattedDateString() const Q_DECL_OVERRIDE; 58 59 public: 60 //! return name of week day. This is actually independent from any calendar, just a modulo of JD. 61 static QString weekday(double jd); 62 63 //! returns true for leap years 64 static bool isLeap(int year); 65 66 //! find RD number for date in the Julian calendar (may be used in other calendars!) 67 static int fixedFromJulian(QVector<int> julian); 68 //! find date in the Julian calendar from RD number (may be used in other calendars!) 69 static QVector<int> julianFromFixed(int rd); 70 71 constexpr static const int julianEpoch=-1; //! RD of January 1, AD1. 72 73 protected: 74 static QMap<int, QString> weekDayNames; 75 static QMap<int, QString> monthNames; 76 }; 77 78 #endif 79