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Diffstat (limited to 'intl/icu/source/i18n/chnsecal.h')
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diff --git a/intl/icu/source/i18n/chnsecal.h b/intl/icu/source/i18n/chnsecal.h new file mode 100644 index 000000000..e9e9515b4 --- /dev/null +++ b/intl/icu/source/i18n/chnsecal.h @@ -0,0 +1,283 @@ +// Copyright (C) 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 + +/** + * <code>ChineseCalendar</code> 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. + * + * <p>This class defines one addition field beyond those defined by + * <code>Calendar</code>: The <code>IS_LEAP_MONTH</code> field takes the + * value of 0 for normal months, or 1 for leap months. + * + * <p>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. + * + * <p>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 + * <code>EXTENDED_YEAR</code> field contains the sequential year count. + * The <code>ERA</code> field contains the cycle number, and the + * <code>YEAR</code> field contains the year of the cycle, a value between + * 1 and 60. + * + * <p>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. + * + * <p>Because <code>ChineseCalendar</code> defines an additional field and + * redefines the way the <code>ERA</code> field is used, it requires a new + * format class, <code>ChineseDateFormat</code>. As always, use the + * methods <code>DateFormat.getXxxInstance(Calendar cal,...)</code> to + * obtain a formatter for this calendar. + * + * <p>References:<ul> + * + * <li>Dershowitz and Reingold, <i>Calendrical Calculations</i>, + * Cambridge University Press, 1997</li> + * + * <li>Helmer Aslaksen's + * <a href="http://www.math.nus.edu.sg/aslaksen/calendar/chinese.shtml"> + * Chinese Calendar page</a></li> + * + * <li>The <a href="http://www.tondering.dk/claus/calendar.html"> + * Calendar FAQ</a></li> + * + * </ul> + * + * <p> + * This class should only be subclassed to implement variants of the Chinese lunar calendar.</p> + * <p> + * ChineseCalendar usually should be instantiated using + * {@link com.ibm.icu.util.Calendar#getInstance(ULocale)} passing in a <code>ULocale</code> + * with the tag <code>"@calendar=chinese"</code>.</p> + * + * @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 Calendar* 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 |