| /* |
| ******************************************************************************** |
| * Copyright (C) 2003-2009, International Business Machines Corporation |
| * and others. All Rights Reserved. |
| ****************************************************************************** |
| * |
| * File ISLAMCAL.H |
| * |
| * Modification History: |
| * |
| * Date Name Description |
| * 10/14/2003 srl ported from java IslamicCalendar |
| ***************************************************************************** |
| */ |
| |
| #ifndef ISLAMCAL_H |
| #define ISLAMCAL_H |
| |
| #include "unicode/utypes.h" |
| |
| #if !UCONFIG_NO_FORMATTING |
| |
| #include "unicode/calendar.h" |
| |
| U_NAMESPACE_BEGIN |
| |
| /** |
| * <code>IslamicCalendar</code> is a subclass of <code>Calendar</code> |
| * that implements the Islamic civil and religious calendars. It |
| * is used as the civil calendar in most of the Arab world and the |
| * liturgical calendar of the Islamic faith worldwide. This calendar |
| * is also known as the "Hijri" calendar, since it starts at the time |
| * of Mohammed's emigration (or "hijra") to Medinah on Thursday, |
| * July 15, 622 AD (Julian). |
| * <p> |
| * The Islamic calendar is strictly lunar, and thus an Islamic year of twelve |
| * lunar months does not correspond to the solar year used by most other |
| * calendar systems, including the Gregorian. An Islamic year is, on average, |
| * about 354 days long, so each successive Islamic year starts about 11 days |
| * earlier in the corresponding Gregorian year. |
| * <p> |
| * Each month of the calendar starts when the new moon's crescent is visible |
| * at sunset. However, in order to keep the time fields in this class |
| * synchronized with those of the other calendars and with local clock time, |
| * we treat days and months as beginning at midnight, |
| * roughly 6 hours after the corresponding sunset. |
| * <p> |
| * There are two main variants of the Islamic calendar in existence. The first |
| * is the <em>civil</em> calendar, which uses a fixed cycle of alternating 29- |
| * and 30-day months, with a leap day added to the last month of 11 out of |
| * every 30 years. This calendar is easily calculated and thus predictable in |
| * advance, so it is used as the civil calendar in a number of Arab countries. |
| * This is the default behavior of a newly-created <code>IslamicCalendar</code> |
| * object. |
| * <p> |
| * The Islamic <em>religious</em> calendar, however, is based on the <em>observation</em> |
| * of the crescent moon. It is thus affected by the position at which the |
| * observations are made, seasonal variations in the time of sunset, the |
| * eccentricities of the moon's orbit, and even the weather at the observation |
| * site. This makes it impossible to calculate in advance, and it causes the |
| * start of a month in the religious calendar to differ from the civil calendar |
| * by up to three days. |
| * <p> |
| * Using astronomical calculations for the position of the sun and moon, the |
| * moon's illumination, and other factors, it is possible to determine the start |
| * of a lunar month with a fairly high degree of certainty. However, these |
| * calculations are extremely complicated and thus slow, so most algorithms, |
| * including the one used here, are only approximations of the true astronical |
| * calculations. At present, the approximations used in this class are fairly |
| * simplistic; they will be improved in later versions of the code. |
| * <p> |
| * The {@link #setCivil setCivil} method determines |
| * which approach is used to determine the start of a month. By default, the |
| * fixed-cycle civil calendar is used. However, if <code>setCivil(false)</code> |
| * is called, an approximation of the true lunar calendar will be used. |
| * |
| * @see GregorianCalendar |
| * |
| * @author Laura Werner |
| * @author Alan Liu |
| * @author Steven R. Loomis |
| * @internal |
| */ |
| class IslamicCalendar : public Calendar { |
| public: |
| //------------------------------------------------------------------------- |
| // Constants... |
| //------------------------------------------------------------------------- |
| /** |
| * Calendar type - civil or religious |
| * @internal |
| */ |
| enum ECivil { |
| ASTRONOMICAL, |
| CIVIL |
| }; |
| |
| /** |
| * Constants for the months |
| * @internal |
| */ |
| enum EMonths { |
| /** |
| * Constant for Muharram, the 1st month of the Islamic year. |
| * @internal |
| */ |
| MUHARRAM = 0, |
| |
| /** |
| * Constant for Safar, the 2nd month of the Islamic year. |
| * @internal |
| */ |
| SAFAR = 1, |
| |
| /** |
| * Constant for Rabi' al-awwal (or Rabi' I), the 3rd month of the Islamic year. |
| * @internal |
| */ |
| RABI_1 = 2, |
| |
| /** |
| * Constant for Rabi' al-thani or (Rabi' II), the 4th month of the Islamic year. |
| * @internal |
| */ |
| RABI_2 = 3, |
| |
| /** |
| * Constant for Jumada al-awwal or (Jumada I), the 5th month of the Islamic year. |
| * @internal |
| */ |
| JUMADA_1 = 4, |
| |
| /** |
| * Constant for Jumada al-thani or (Jumada II), the 6th month of the Islamic year. |
| * @internal |
| */ |
| JUMADA_2 = 5, |
| |
| /** |
| * Constant for Rajab, the 7th month of the Islamic year. |
| * @internal |
| */ |
| RAJAB = 6, |
| |
| /** |
| * Constant for Sha'ban, the 8th month of the Islamic year. |
| * @internal |
| */ |
| SHABAN = 7, |
| |
| /** |
| * Constant for Ramadan, the 9th month of the Islamic year. |
| * @internal |
| */ |
| RAMADAN = 8, |
| |
| /** |
| * Constant for Shawwal, the 10th month of the Islamic year. |
| * @internal |
| */ |
| SHAWWAL = 9, |
| |
| /** |
| * Constant for Dhu al-Qi'dah, the 11th month of the Islamic year. |
| * @internal |
| */ |
| DHU_AL_QIDAH = 10, |
| |
| /** |
| * Constant for Dhu al-Hijjah, the 12th month of the Islamic year. |
| * @internal |
| */ |
| DHU_AL_HIJJAH = 11, |
| |
| ISLAMIC_MONTH_MAX |
| }; |
| |
| |
| |
| //------------------------------------------------------------------------- |
| // Constructors... |
| //------------------------------------------------------------------------- |
| |
| /** |
| * Constructs an IslamicCalendar based on the current time in the default time zone |
| * with the given locale. |
| * |
| * @param aLocale The given locale. |
| * @param success Indicates the status of IslamicCalendar object construction. |
| * Returns U_ZERO_ERROR if constructed successfully. |
| * @param beCivil Whether the calendar should be civil (default-TRUE) or religious (FALSE) |
| * @internal |
| */ |
| IslamicCalendar(const Locale& aLocale, UErrorCode &success, ECivil beCivil = CIVIL); |
| |
| /** |
| * Copy Constructor |
| * @internal |
| */ |
| IslamicCalendar(const IslamicCalendar& other); |
| |
| /** |
| * Destructor. |
| * @internal |
| */ |
| virtual ~IslamicCalendar(); |
| |
| /** |
| * Determines whether this object uses the fixed-cycle Islamic civil calendar |
| * or an approximation of the religious, astronomical calendar. |
| * |
| * @param beCivil <code>CIVIL</code> to use the civil calendar, |
| * <code>ASTRONOMICAL</code> to use the astronomical calendar. |
| * @internal |
| */ |
| void setCivil(ECivil beCivil, UErrorCode &status); |
| |
| /** |
| * Returns <code>true</code> if this object is using the fixed-cycle civil |
| * calendar, or <code>false</code> if using the religious, astronomical |
| * calendar. |
| * @internal |
| */ |
| UBool isCivil(); |
| |
| |
| // TODO: copy c'tor, etc |
| |
| // clone |
| virtual Calendar* clone() const; |
| |
| private: |
| /** |
| * Determine whether a year is a leap year in the Islamic civil calendar |
| */ |
| static UBool civilLeapYear(int32_t year); |
| |
| /** |
| * Return the day # on which the given year starts. Days are counted |
| * from the Hijri epoch, origin 0. |
| */ |
| int32_t yearStart(int32_t year); |
| |
| /** |
| * Return the day # on which the given month starts. Days are counted |
| * from the Hijri epoch, origin 0. |
| * |
| * @param year The hijri year |
| * @param year The hijri month, 0-based |
| */ |
| int32_t monthStart(int32_t year, int32_t month) const; |
| |
| /** |
| * Find the day number on which a particular month of the true/lunar |
| * Islamic calendar starts. |
| * |
| * @param month The month in question, origin 0 from the Hijri epoch |
| * |
| * @return The day number on which the given month starts. |
| */ |
| int32_t trueMonthStart(int32_t month) const; |
| |
| /** |
| * Return the "age" of the moon at the given time; this is the difference |
| * in ecliptic latitude between the moon and the sun. This method simply |
| * calls CalendarAstronomer.moonAge, converts to degrees, |
| * and adjusts the resultto be in the range [-180, 180]. |
| * |
| * @param time The time at which the moon's age is desired, |
| * in millis since 1/1/1970. |
| */ |
| static double moonAge(UDate time, UErrorCode &status); |
| |
| //------------------------------------------------------------------------- |
| // Internal data.... |
| // |
| |
| /** |
| * <code>CIVIL</code> if this object uses the fixed-cycle Islamic civil calendar, |
| * and <code>ASTRONOMICAL</code> if it approximates the true religious calendar using |
| * astronomical calculations for the time of the new moon. |
| */ |
| ECivil civil; |
| |
| //---------------------------------------------------------------------- |
| // Calendar framework |
| //---------------------------------------------------------------------- |
| protected: |
| /** |
| * @internal |
| */ |
| virtual int32_t handleGetLimit(UCalendarDateFields field, ELimitType limitType) const; |
| |
| /** |
| * Return the length (in days) of the given month. |
| * |
| * @param year The hijri year |
| * @param year The hijri month, 0-based |
| * @internal |
| */ |
| virtual int32_t handleGetMonthLength(int32_t extendedYear, int32_t month) const; |
| |
| /** |
| * Return the number of days in the given Islamic year |
| * @internal |
| */ |
| virtual int32_t handleGetYearLength(int32_t extendedYear) const; |
| |
| //------------------------------------------------------------------------- |
| // Functions for converting from field values to milliseconds.... |
| //------------------------------------------------------------------------- |
| |
| // Return JD of start of given month/year |
| /** |
| * @internal |
| */ |
| virtual int32_t handleComputeMonthStart(int32_t eyear, int32_t month, UBool useMonth) const; |
| |
| //------------------------------------------------------------------------- |
| // Functions for converting from milliseconds to field values |
| //------------------------------------------------------------------------- |
| |
| /** |
| * @internal |
| */ |
| virtual int32_t handleGetExtendedYear(); |
| |
| /** |
| * Override Calendar to compute several fields specific to the Islamic |
| * calendar system. These are: |
| * |
| * <ul><li>ERA |
| * <li>YEAR |
| * <li>MONTH |
| * <li>DAY_OF_MONTH |
| * <li>DAY_OF_YEAR |
| * <li>EXTENDED_YEAR</ul> |
| * |
| * The DAY_OF_WEEK and DOW_LOCAL fields are already set when this |
| * method is called. The getGregorianXxx() methods return Gregorian |
| * calendar equivalents for the given Julian day. |
| * @internal |
| */ |
| virtual void handleComputeFields(int32_t julianDay, UErrorCode &status); |
| |
| // UObject stuff |
| public: |
| /** |
| * @return The class ID for this object. All objects of a given class have the |
| * same class ID. Objects of other classes have different class IDs. |
| * @internal |
| */ |
| virtual UClassID getDynamicClassID(void) const; |
| |
| /** |
| * Return the class ID for this class. This is useful only for comparing to a return |
| * value from getDynamicClassID(). For example: |
| * |
| * Base* polymorphic_pointer = createPolymorphicObject(); |
| * if (polymorphic_pointer->getDynamicClassID() == |
| * Derived::getStaticClassID()) ... |
| * |
| * @return The class ID for all objects of this class. |
| * @internal |
| */ |
| U_I18N_API static UClassID U_EXPORT2 getStaticClassID(void); |
| |
| /** |
| * return the calendar type, "buddhist". |
| * |
| * @return calendar type |
| * @internal |
| */ |
| virtual const char * getType() const; |
| |
| private: |
| IslamicCalendar(); // default constructor not implemented |
| |
| // Default century. |
| protected: |
| |
| /** |
| * (Overrides Calendar) Return true if the current date for this Calendar is in |
| * Daylight Savings Time. Recognizes DST_OFFSET, if it is set. |
| * |
| * @param status Fill-in parameter which receives the status of this operation. |
| * @return True if the current date for this Calendar is in Daylight Savings Time, |
| * false, otherwise. |
| * @internal |
| */ |
| virtual UBool inDaylightTime(UErrorCode& status) const; |
| |
| |
| /** |
| * Returns TRUE because the Islamic Calendar does have a default century |
| * @internal |
| */ |
| virtual UBool haveDefaultCentury() const; |
| |
| /** |
| * Returns the date of the start of the default century |
| * @return start of century - in milliseconds since epoch, 1970 |
| * @internal |
| */ |
| virtual UDate defaultCenturyStart() const; |
| |
| /** |
| * Returns the year in which the default century begins |
| * @internal |
| */ |
| virtual int32_t defaultCenturyStartYear() const; |
| |
| private: // default century stuff. |
| /** |
| * The system maintains a static default century start date. This is initialized |
| * the first time it is used. Before then, it is set to SYSTEM_DEFAULT_CENTURY to |
| * indicate an uninitialized state. Once the system default century date and year |
| * are set, they do not change. |
| */ |
| static UDate fgSystemDefaultCenturyStart; |
| |
| /** |
| * See documentation for systemDefaultCenturyStart. |
| */ |
| static int32_t fgSystemDefaultCenturyStartYear; |
| |
| /** |
| * Default value that indicates the defaultCenturyStartYear is unitialized |
| */ |
| static const int32_t fgSystemDefaultCenturyYear; |
| |
| /** |
| * start of default century, as a date |
| */ |
| static const UDate fgSystemDefaultCentury; |
| |
| /** |
| * Returns the beginning date of the 100-year window that dates |
| * with 2-digit years are considered to fall within. |
| */ |
| UDate internalGetDefaultCenturyStart(void) const; |
| |
| /** |
| * Returns the first year of the 100-year window that dates with |
| * 2-digit years are considered to fall within. |
| */ |
| int32_t internalGetDefaultCenturyStartYear(void) const; |
| |
| /** |
| * Initializes the 100-year window that dates with 2-digit years |
| * are considered to fall within so that its start date is 80 years |
| * before the current time. |
| */ |
| static void initializeSystemDefaultCentury(void); |
| }; |
| |
| U_NAMESPACE_END |
| |
| #endif |
| #endif |
| |
| |
| |