// © 2016 and later: Unicode, Inc. and others. // License & terms of use: http://www.unicode.org/copyright.html /* ***************************************************************************** * Copyright (C) 2007-2013, International Business Machines Corporation * and others. All Rights Reserved. ***************************************************************************** * * File CHNSECAL.H * * Modification History: * * Date Name Description * 9/18/2007 ajmacher ported from java ChineseCalendar ***************************************************************************** */ #ifndef CHNSECAL_H #define CHNSECAL_H #include "unicode/utypes.h" #if !UCONFIG_NO_FORMATTING #include "unicode/calendar.h" #include "unicode/timezone.h" U_NAMESPACE_BEGIN /** * ChineseCalendar is a concrete subclass of {@link Calendar} * that implements a traditional Chinese calendar. The traditional Chinese * calendar is a lunisolar calendar: Each month starts on a new moon, and * the months are numbered according to solar events, specifically, to * guarantee that month 11 always contains the winter solstice. In order * to accomplish this, leap months are inserted in certain years. Leap * months are numbered the same as the month they follow. The decision of * which month is a leap month depends on the relative movements of the sun * and moon. * *

This class defines one addition field beyond those defined by * Calendar: The IS_LEAP_MONTH field takes the * value of 0 for normal months, or 1 for leap months. * *

All astronomical computations are performed with respect to a time * zone of GMT+8:00 and a longitude of 120 degrees east. Although some * calendars implement a historically more accurate convention of using * Beijing's local longitude (116 degrees 25 minutes east) and time zone * (GMT+7:45:40) for dates before 1929, we do not implement this here. * *

Years are counted in two different ways in the Chinese calendar. The * first method is by sequential numbering from the 61st year of the reign * of Huang Di, 2637 BCE, which is designated year 1 on the Chinese * calendar. The second method uses 60-year cycles from the same starting * point, which is designated year 1 of cycle 1. In this class, the * EXTENDED_YEAR field contains the sequential year count. * The ERA field contains the cycle number, and the * YEAR field contains the year of the cycle, a value between * 1 and 60. * *

There is some variation in what is considered the starting point of * the calendar, with some sources starting in the first year of the reign * of Huang Di, rather than the 61st. This gives continuous year numbers * 60 years greater and cycle numbers one greater than what this class * implements. * *

Because ChineseCalendar defines an additional field and * redefines the way the ERA field is used, it requires a new * format class, ChineseDateFormat. As always, use the * methods DateFormat.getXxxInstance(Calendar cal,...) to * obtain a formatter for this calendar. * *

References:

* *

* This class should only be subclassed to implement variants of the Chinese lunar calendar.

*

* ChineseCalendar usually should be instantiated using * {@link com.ibm.icu.util.Calendar#getInstance(ULocale)} passing in a ULocale * with the tag "@calendar=chinese".

* * @see com.ibm.icu.text.ChineseDateFormat * @see com.ibm.icu.util.Calendar * @author Alan Liu * @internal */ class U_I18N_API ChineseCalendar : public Calendar { public: //------------------------------------------------------------------------- // Constructors... //------------------------------------------------------------------------- /** * Constructs a ChineseCalendar 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 ChineseCalendar object construction. * Returns U_ZERO_ERROR if constructed successfully. * @internal */ ChineseCalendar(const Locale& aLocale, UErrorCode &success); protected: /** * Constructs a ChineseCalendar based on the current time in the default time zone * with the given locale, using the specified epoch year and time zone for * astronomical calculations. * * @param aLocale The given locale. * @param epochYear The epoch year to use for calculation. * @param zoneAstroCalc The TimeZone to use for astronomical calculations. If null, * will be set appropriately for Chinese calendar (UTC + 8:00). * @param success Indicates the status of ChineseCalendar object construction; * if successful, will not be changed to an error value. * @internal */ ChineseCalendar(const Locale& aLocale, int32_t epochYear, const TimeZone* zoneAstroCalc, UErrorCode &success); public: /** * Copy Constructor * @internal */ ChineseCalendar(const ChineseCalendar& other); /** * Destructor. * @internal */ virtual ~ChineseCalendar(); // clone virtual ChineseCalendar* clone() const; private: //------------------------------------------------------------------------- // Internal data.... //------------------------------------------------------------------------- UBool isLeapYear; int32_t fEpochYear; // Start year of this Chinese calendar instance. const TimeZone* fZoneAstroCalc; // Zone used for the astronomical calculation // of this Chinese calendar instance. //---------------------------------------------------------------------- // Calendar framework //---------------------------------------------------------------------- protected: virtual int32_t handleGetLimit(UCalendarDateFields field, ELimitType limitType) const; virtual int32_t handleGetMonthLength(int32_t extendedYear, int32_t month) const; virtual int32_t handleComputeMonthStart(int32_t eyear, int32_t month, UBool useMonth) const; virtual int32_t handleGetExtendedYear(); virtual void handleComputeFields(int32_t julianDay, UErrorCode &status); virtual const UFieldResolutionTable* getFieldResolutionTable() const; public: virtual void add(UCalendarDateFields field, int32_t amount, UErrorCode &status); virtual void add(EDateFields field, int32_t amount, UErrorCode &status); virtual void roll(UCalendarDateFields field, int32_t amount, UErrorCode &status); virtual void roll(EDateFields field, int32_t amount, UErrorCode &status); //---------------------------------------------------------------------- // Internal methods & astronomical calculations //---------------------------------------------------------------------- private: static const UFieldResolutionTable CHINESE_DATE_PRECEDENCE[]; double daysToMillis(double days) const; double millisToDays(double millis) const; virtual int32_t winterSolstice(int32_t gyear) const; virtual int32_t newMoonNear(double days, UBool after) const; virtual int32_t synodicMonthsBetween(int32_t day1, int32_t day2) const; virtual int32_t majorSolarTerm(int32_t days) const; virtual UBool hasNoMajorSolarTerm(int32_t newMoon) const; virtual UBool isLeapMonthBetween(int32_t newMoon1, int32_t newMoon2) const; virtual void computeChineseFields(int32_t days, int32_t gyear, int32_t gmonth, UBool setAllFields); virtual int32_t newYear(int32_t gyear) const; virtual void offsetMonth(int32_t newMoon, int32_t dom, int32_t delta); const TimeZone* getChineseCalZoneAstroCalc(void) const; // 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 */ static UClassID U_EXPORT2 getStaticClassID(void); /** * return the calendar type, "chinese". * * @return calendar type * @internal */ virtual const char * getType() const; 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. /** * 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; ChineseCalendar(); // default constructor not implemented }; U_NAMESPACE_END #endif #endif