432 lines
13 KiB
C++
432 lines
13 KiB
C++
// © 2016 and later: Unicode, Inc. and others.
|
|
// License & terms of use: http://www.unicode.org/copyright.html
|
|
/*
|
|
********************************************************************************
|
|
* Copyright (C) 2003-2013, 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 U_I18N_API IslamicCalendar : public Calendar {
|
|
public:
|
|
//-------------------------------------------------------------------------
|
|
// Constants...
|
|
//-------------------------------------------------------------------------
|
|
|
|
/**
|
|
* Calendar type - civil or religious or um alqura
|
|
* @internal
|
|
*/
|
|
enum ECalculationType {
|
|
ASTRONOMICAL,
|
|
CIVIL,
|
|
UMALQURA,
|
|
TBLA
|
|
};
|
|
|
|
/**
|
|
* 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 type The Islamic calendar calculation type. The default value is CIVIL.
|
|
* @internal
|
|
*/
|
|
IslamicCalendar(const Locale& aLocale, UErrorCode &success, ECalculationType type = CIVIL);
|
|
|
|
/**
|
|
* Copy Constructor
|
|
* @internal
|
|
*/
|
|
IslamicCalendar(const IslamicCalendar& other);
|
|
|
|
/**
|
|
* Destructor.
|
|
* @internal
|
|
*/
|
|
virtual ~IslamicCalendar();
|
|
|
|
/**
|
|
* Sets Islamic calendar calculation type used by this instance.
|
|
*
|
|
* @param type The calendar calculation type, <code>CIVIL</code> to use the civil
|
|
* calendar, <code>ASTRONOMICAL</code> to use the astronomical calendar.
|
|
* @internal
|
|
*/
|
|
void setCalculationType(ECalculationType type, 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) const;
|
|
|
|
/**
|
|
* 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.
|
|
*/
|
|
ECalculationType cType;
|
|
|
|
//----------------------------------------------------------------------
|
|
// 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:
|
|
/**
|
|
* 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 U_CALLCONV initializeSystemDefaultCentury(void);
|
|
};
|
|
|
|
U_NAMESPACE_END
|
|
|
|
#endif
|
|
#endif
|
|
|
|
|
|
|