text: /*
  ********************************************************************************
  *   Copyright (C) 1997-2014, International Business Machines
  *   Corporation and others.  All Rights Reserved.
  ********************************************************************************
  *
  * File CALENDAR.H
  *
  * Modification History:
  *
  *   Date        Name        Description
  *   04/22/97    aliu        Expanded and corrected comments and other header
  *                           contents.
  *   05/01/97    aliu        Made equals(), before(), after() arguments const.
  *   05/20/97    aliu        Replaced fAreFieldsSet with fAreFieldsInSync and
  *                           fAreAllFieldsSet.
  *   07/27/98    stephen     Sync up with JDK 1.2
  *   11/15/99    weiv        added YEAR_WOY and DOW_LOCAL
  *                           to EDateFields
  *    8/19/2002  srl         Removed Javaisms
  *   11/07/2003  srl         Update, clean up documentation.
  ********************************************************************************
  */
  
  #ifndef CALENDAR_H
  #define CALENDAR_H
  
  #include "unicode/utypes.h"
  
  /**
   * \file
   * \brief C++ API: Calendar object
   */
  #if !UCONFIG_NO_FORMATTING
  
  #include "unicode/uobject.h"
  #include "unicode/locid.h"
  #include "unicode/timezone.h"
  #include "unicode/ucal.h"
  #include "unicode/umisc.h"
  
  U_NAMESPACE_BEGIN
  
  class ICUServiceFactory;
  
  /**
   * @internal
   */
  typedef int32_t UFieldResolutionTable[12][8];
  
  class BasicTimeZone;
  /**
   * <code>Calendar</code> is an abstract base class for converting between
   * a <code>UDate</code> object and a set of integer fields such as
   * <code>YEAR</code>, <code>MONTH</code>, <code>DAY</code>, <code>HOUR</code>,
   * and so on. (A <code>UDate</code> object represents a specific instant in
   * time with millisecond precision. See UDate
   * for information about the <code>UDate</code> class.)
   *
   * <p>
   * Subclasses of <code>Calendar</code> interpret a <code>UDate</code>
   * according to the rules of a specific calendar system.
   * The most commonly used subclass of <code>Calendar</code> is
   * <code>GregorianCalendar</code>. Other subclasses could represent
   * the various types of lunar calendars in use in many parts of the world.
   *
   * <p>
   * <b>NOTE</b>: (ICU 2.6) The subclass interface should be considered unstable
   * - it WILL change.
   *
   * <p>
   * Like other locale-sensitive classes, <code>Calendar</code> provides a
   * static method, <code>createInstance</code>, for getting a generally useful
   * object of this type. <code>Calendar</code>'s <code>createInstance</code> method
   * returns the appropriate <code>Calendar</code> subclass whose
   * time fields have been initialized with the current date and time:
   * \htmlonly<blockquote>\endhtmlonly
   * <pre>
   * Calendar *rightNow = Calendar::createInstance(errCode);
   * </pre>
   * \htmlonly</blockquote>\endhtmlonly
   *
   * <p>
   * A <code>Calendar</code> object can produce all the time field values
   * needed to implement the date-time formatting for a particular language
   * and calendar style (for example, Japanese-Gregorian, Japanese-Traditional).
   *
   * <p>
   * When computing a <code>UDate</code> from time fields, some special circumstances
   * may arise: there may be insufficient information to compute the
   * <code>UDate</code> (such as only year and month but no day in the month),
   * there may be inconsistent information (such as "Tuesday, July 15, 1996"
   * -- July 15, 1996 is actually a Monday), or the input time might be ambiguous
   * because of time zone transition.
   *
   * <p>
   * <strong>Insufficient information.</strong> The calendar will use default
   * information to specify the missing fields. This may vary by calendar; for
   * the Gregorian calendar, the default for a field is the same as that of the
   * start of the epoch: i.e., YEAR = 1970, MONTH = JANUARY, DATE = 1, etc.
   *
   * <p>
   * <strong>Inconsistent information.</strong> If fields conflict, the calendar
   * will give preference to fields set more recently. For example, when
   * determining the day, the calendar will look for one of the following
   * combinations of fields.  The most recent combination, as determined by the
   * most recently set single field, will be used.
   *
   * \htmlonly<blockquote>\endhtmlonly
   * <pre>
   * MONTH + DAY_OF_MONTH
   * MONTH + WEEK_OF_MONTH + DAY_OF_WEEK
   * MONTH + DAY_OF_WEEK_IN_MONTH + DAY_OF_WEEK
   * DAY_OF_YEAR
   * DAY_OF_WEEK + WEEK_OF_YEAR
   * </pre>
   * \htmlonly</blockquote>\endhtmlonly
   *
   * For the time of day:
   *
   * \htmlonly<blockquote>\endhtmlonly
   * <pre>
   * HOUR_OF_DAY
   * AM_PM + HOUR
   * </pre>
   * \htmlonly</blockquote>\endhtmlonly
   *
   * <p>
   * <strong>Ambiguous Wall Clock Time.</strong> When time offset from UTC has
   * changed, it produces an ambiguous time slot around the transition. For example,
   * many US locations observe daylight saving time. On the date switching to daylight
   * saving time in US, wall clock time jumps from 12:59 AM (standard) to 2:00 AM
   * (daylight). Therefore, wall clock time from 1:00 AM to 1:59 AM do not exist on
   * the date. When the input wall time fall into this missing time slot, the ICU
   * Calendar resolves the time using the UTC offset before the transition by default.
   * In this example, 1:30 AM is interpreted as 1:30 AM standard time (non-exist),
   * so the final result will be 2:30 AM daylight time.
   *
   * <p>On the date switching back to standard time, wall clock time is moved back one
   * hour at 2:00 AM. So wall clock time from 1:00 AM to 1:59 AM occur twice. In this
   * case, the ICU Calendar resolves the time using the UTC offset after the transition
   * by default. For example, 1:30 AM on the date is resolved as 1:30 AM standard time.
   *
   * <p>Ambiguous wall clock time resolution behaviors can be customized by Calendar APIs
   * {@link #setRepeatedWallTimeOption} and {@link #setSkippedWallTimeOption}.
   * These methods are available in ICU 49 or later versions.
   *
   * <p>
   * <strong>Note:</strong> for some non-Gregorian calendars, different
   * fields may be necessary for complete disambiguation. For example, a full
   * specification of the historial Arabic astronomical calendar requires year,
   * month, day-of-month <em>and</em> day-of-week in some cases.
   *
   * <p>
   * <strong>Note:</strong> There are certain possible ambiguities in
   * interpretation of certain singular times, which are resolved in the
   * following ways:
   * <ol>
   *     <li> 24:00:00 "belongs" to the following day. That is,
   *          23:59 on Dec 31, 1969 &lt; 24:00 on Jan 1, 1970 &lt; 24:01:00 on Jan 1, 1970
   *
   *     <li> Although historically not precise, midnight also belongs to "am",
   *          and noon belongs to "pm", so on the same day,
   *          12:00 am (midnight) &lt; 12:01 am, and 12:00 pm (noon) &lt; 12:01 pm
   * </ol>
   *
   * <p>
   * The date or time format strings are not part of the definition of a
   * calendar, as those must be modifiable or overridable by the user at
   * runtime. Use {@link DateFormat}
   * to format dates.
   *
   * <p>
   * <code>Calendar</code> provides an API for field "rolling", where fields
   * can be incremented or decremented, but wrap around. For example, rolling the
   * month up in the date <code>December 12, <b>1996</b></code> results in
   * <code>January 12, <b>1996</b></code>.
   *
   * <p>
   * <code>Calendar</code> also provides a date arithmetic function for
   * adding the specified (signed) amount of time to a particular time field.
   * For example, subtracting 5 days from the date <code>September 12, 1996</code>
   * results in <code>September 7, 1996</code>.
   *
   * <p><big><b>Supported range</b></big>
   *
   * <p>The allowable range of <code>Calendar</code> has been
   * narrowed. <code>GregorianCalendar</code> used to attempt to support
   * the range of dates with millisecond values from
   * <code>Long.MIN_VALUE</code> to <code>Long.MAX_VALUE</code>.
   * The new <code>Calendar</code> protocol specifies the
   * maximum range of supportable dates as those having Julian day numbers
   * of <code>-0x7F000000</code> to <code>+0x7F000000</code>. This
   * corresponds to years from ~5,800,000 BCE to ~5,800,000 CE. Programmers
   * should use the protected constants in <code>Calendar</code> to
   * specify an extremely early or extremely late date.</p>
   *
   * @stable ICU 2.0
   */
  class U_I18N_API Calendar : public UObject {
  public:
  
      /**
       * Field IDs for date and time. Used to specify date/time fields. ERA is calendar
       * specific. Example ranges given are for illustration only; see specific Calendar
       * subclasses for actual ranges.
       * @deprecated ICU 2.6. Use C enum UCalendarDateFields defined in ucal.h
       */
      enum EDateFields {
  #ifndef U_HIDE_DEPRECATED_API
  /*
   * ERA may be defined on other platforms. To avoid any potential problems undefined it here.
   */
  #ifdef ERA
  #undef ERA
  #endif
          ERA,                  // Example: 0..1
          YEAR,                 // Example: 1..big number
          MONTH,                // Example: 0..11
          WEEK_OF_YEAR,         // Example: 1..53
          WEEK_OF_MONTH,        // Example: 1..4
          DATE,                 // Example: 1..31
          DAY_OF_YEAR,          // Example: 1..365
          DAY_OF_WEEK,          // Example: 1..7
          DAY_OF_WEEK_IN_MONTH, // Example: 1..4, may be specified as -1
          AM_PM,                // Example: 0..1
          HOUR,                 // Example: 0..11
          HOUR_OF_DAY,          // Example: 0..23
          MINUTE,               // Example: 0..59
          SECOND,               // Example: 0..59
          MILLISECOND,          // Example: 0..999
          ZONE_OFFSET,          // Example: -12*U_MILLIS_PER_HOUR..12*U_MILLIS_PER_HOUR
          DST_OFFSET,           // Example: 0 or U_MILLIS_PER_HOUR
          YEAR_WOY,             // 'Y' Example: 1..big number - Year of Week of Year
          DOW_LOCAL,            // 'e' Example: 1..7 - Day of Week / Localized
  
          EXTENDED_YEAR,
          JULIAN_DAY,
          MILLISECONDS_IN_DAY,
          IS_LEAP_MONTH,
  
          FIELD_COUNT = UCAL_FIELD_COUNT // See ucal.h for other fields.
  #endif /* U_HIDE_DEPRECATED_API */
      };
  
  #ifndef U_HIDE_DEPRECATED_API
      /**
       * Useful constant for days of week. Note: Calendar day-of-week is 1-based. Clients
       * who create locale resources for the field of first-day-of-week should be aware of
       * this. For instance, in US locale, first-day-of-week is set to 1, i.e., SUNDAY.
       * @deprecated ICU 2.6. Use C enum UCalendarDaysOfWeek defined in ucal.h
       */
      enum EDaysOfWeek {
          SUNDAY = 1,
          MONDAY,
          TUESDAY,
          WEDNESDAY,
          THURSDAY,
          FRIDAY,
          SATURDAY
      };
  
      /**
       * Useful constants for month. Note: Calendar month is 0-based.
       * @deprecated ICU 2.6. Use C enum UCalendarMonths defined in ucal.h
       */
      enum EMonths {
          JANUARY,
          FEBRUARY,
          MARCH,
          APRIL,
          MAY,
          JUNE,
          JULY,
          AUGUST,
          SEPTEMBER,
          OCTOBER,
          NOVEMBER,
          DECEMBER,
          UNDECIMBER
      };
  
      /**
       * Useful constants for hour in 12-hour clock. Used in GregorianCalendar.
       * @deprecated ICU 2.6. Use C enum UCalendarAMPMs defined in ucal.h
       */
      enum EAmpm {
          AM,
          PM
      };
  #endif  /* U_HIDE_DEPRECATED_API */
  
      /**
       * destructor
       * @stable ICU 2.0
       */
      virtual ~Calendar();
  
      /**
       * Create and return a polymorphic copy of this calendar.
       *
       * @return    a polymorphic copy of this calendar.
       * @stable ICU 2.0
       */
      virtual Calendar* clone(void) const = 0;
  
      /**
       * Creates a Calendar using the default timezone and locale. Clients are responsible
       * for deleting the object returned.
       *
       * @param success  Indicates the success/failure of Calendar creation. Filled in
       *                 with U_ZERO_ERROR if created successfully, set to a failure result
       *                 otherwise. U_MISSING_RESOURCE_ERROR will be returned if the resource data
       *                 requests a calendar type which has not been installed.
       * @return         A Calendar if created successfully. NULL otherwise.
       * @stable ICU 2.0
       */
      static Calendar* U_EXPORT2 createInstance(UErrorCode& success);
  
      /**
       * Creates a Calendar using the given timezone and the default locale.
       * The Calendar takes ownership of zoneToAdopt; the
       * client must not delete it.
       *
       * @param zoneToAdopt  The given timezone to be adopted.
       * @param success      Indicates the success/failure of Calendar creation. Filled in
       *                     with U_ZERO_ERROR if created successfully, set to a failure result
       *                     otherwise.
       * @return             A Calendar if created successfully. NULL otherwise.
       * @stable ICU 2.0
       */
      static Calendar* U_EXPORT2 createInstance(TimeZone* zoneToAdopt, UErrorCode& success);
  
      /**
       * Creates a Calendar using the given timezone and the default locale.  The TimeZone
       * is _not_ adopted; the client is still responsible for deleting it.
       *
       * @param zone  The timezone.
       * @param success      Indicates the success/failure of Calendar creation. Filled in
       *                     with U_ZERO_ERROR if created successfully, set to a failure result
       *                     otherwise.
       * @return             A Calendar if created successfully. NULL otherwise.
       * @stable ICU 2.0
       */
      static Calendar* U_EXPORT2 createInstance(const TimeZone& zone, UErrorCode& success);
  
      /**
       * Creates a Calendar using the default timezone and the given locale.
       *
       * @param aLocale  The given locale.
       * @param success  Indicates the success/failure of Calendar creation. Filled in
       *                 with U_ZERO_ERROR if created successfully, set to a failure result
       *                 otherwise.
       * @return         A Calendar if created successfully. NULL otherwise.
       * @stable ICU 2.0
       */
      static Calendar* U_EXPORT2 createInstance(const Locale& aLocale, UErrorCode& success);
  
      /**
       * Creates a Calendar using the given timezone and given locale.
       * The Calendar takes ownership of zoneToAdopt; the
       * client must not delete it.
       *
       * @param zoneToAdopt  The given timezone to be adopted.
       * @param aLocale      The given locale.
       * @param success      Indicates the success/failure of Calendar creation. Filled in
       *                     with U_ZERO_ERROR if created successfully, set to a failure result
       *                     otherwise.
       * @return             A Calendar if created successfully. NULL otherwise.
       * @stable ICU 2.0
       */
      static Calendar* U_EXPORT2 createInstance(TimeZone* zoneToAdopt, const Locale& aLocale, UErrorCode& success);
  
      /**
       * Gets a Calendar using the given timezone and given locale.  The TimeZone
       * is _not_ adopted; the client is still responsible for deleting it.
       *
       * @param zone         The given timezone.
       * @param aLocale      The given locale.
       * @param success      Indicates the success/failure of Calendar creation. Filled in
       *                     with U_ZERO_ERROR if created successfully, set to a failure result
       *                     otherwise.
       * @return             A Calendar if created successfully. NULL otherwise.
       * @stable ICU 2.0
       */
      static Calendar* U_EXPORT2 createInstance(const TimeZone& zone, const Locale& aLocale, UErrorCode& success);
  
      /**
       * Returns a list of the locales for which Calendars are installed.
       *
       * @param count  Number of locales returned.
       * @return       An array of Locale objects representing the set of locales for which
       *               Calendars are installed.  The system retains ownership of this list;
       *               the caller must NOT delete it. Does not include user-registered Calendars.
       * @stable ICU 2.0
       */
      static const Locale* U_EXPORT2 getAvailableLocales(int32_t& count);
  
  
      /**
       * Given a key and a locale, returns an array of string values in a preferred
       * order that would make a difference. These are all and only those values where
       * the open (creation) of the service with the locale formed from the input locale
       * plus input keyword and that value has different behavior than creation with the
       * input locale alone.
       * @param key           one of the keys supported by this service.  For now, only
       *                      "calendar" is supported.
       * @param locale        the locale
       * @param commonlyUsed  if set to true it will return only commonly used values
       *                      with the given locale in preferred order.  Otherwise,
       *                      it will return all the available values for the locale.
       * @param status        ICU Error Code
       * @return a string enumeration over keyword values for the given key and the locale.
       * @stable ICU 4.2
       */
      static StringEnumeration* U_EXPORT2 getKeywordValuesForLocale(const char* key,
                      const Locale& locale, UBool commonlyUsed, UErrorCode& status);
  
      /**
       * Returns the current UTC (GMT) time measured in milliseconds since 0:00:00 on 1/1/70
       * (derived from the system time).
       *
       * @return   The current UTC time in milliseconds.
       * @stable ICU 2.0
       */
      static UDate U_EXPORT2 getNow(void);
  
      /**
       * Gets this Calendar's time as milliseconds. May involve recalculation of time due
       * to previous calls to set time field values. The time specified is non-local UTC
       * (GMT) time. Although this method is const, this object may actually be changed
       * (semantically const).
       *
       * @param status  Output param set to success/failure code on exit. If any value
       *                previously set in the time field is invalid or restricted by
       *                leniency, this will be set to an error status.
       * @return        The current time in UTC (GMT) time, or zero if the operation
       *                failed.
       * @stable ICU 2.0
       */
      inline UDate getTime(UErrorCode& status) const { return getTimeInMillis(status); }
  
      /**
       * Sets this Calendar's current time with the given UDate. The time specified should
       * be in non-local UTC (GMT) time.
       *
       * @param date  The given UDate in UTC (GMT) time.
       * @param status  Output param set to success/failure code on exit. If any value
       *                set in the time field is invalid or restricted by
       *                leniency, this will be set to an error status.
       * @stable ICU 2.0
       */
      inline void setTime(UDate date, UErrorCode& status) { setTimeInMillis(date, status); }
  
      /**
       * Compares the equality of two Calendar objects. Objects of different subclasses
       * are considered unequal. This comparison is very exacting; two Calendar objects
       * must be in exactly the same state to be considered equal. To compare based on the
       * represented time, use equals() instead.
       *
       * @param that  The Calendar object to be compared with.
       * @return      True if the given Calendar is the same as this Calendar; false
       *              otherwise.
       * @stable ICU 2.0
       */
      virtual UBool operator==(const Calendar& that) const;
  
      /**
       * Compares the inequality of two Calendar objects.
       *
       * @param that  The Calendar object to be compared with.
       * @return      True if the given Calendar is not the same as this Calendar; false
       *              otherwise.
       * @stable ICU 2.0
       */
      UBool operator!=(const Calendar& that) const {return !operator==(that);}
  
      /**
       * Returns TRUE if the given Calendar object is equivalent to this
       * one.  An equivalent Calendar will behave exactly as this one
       * does, but it may be set to a different time.  By contrast, for
       * the operator==() method to return TRUE, the other Calendar must
       * be set to the same time.
       *
       * @param other the Calendar to be compared with this Calendar
       * @stable ICU 2.4
       */
      virtual UBool isEquivalentTo(const Calendar& other) const;
  
      /**
       * Compares the Calendar time, whereas Calendar::operator== compares the equality of
       * Calendar objects.
       *
       * @param when    The Calendar to be compared with this Calendar. Although this is a
       *                const parameter, the object may be modified physically
       *                (semantically const).
       * @param status  Output param set to success/failure code on exit. If any value
       *                previously set in the time field is invalid or restricted by
       *                leniency, this will be set to an error status.
       * @return        True if the current time of this Calendar is equal to the time of
       *                Calendar when; false otherwise.
       * @stable ICU 2.0
       */
      UBool equals(const Calendar& when, UErrorCode& status) const;
  
      /**
       * Returns true if this Calendar's current time is before "when"'s current time.
       *
       * @param when    The Calendar to be compared with this Calendar. Although this is a
       *                const parameter, the object may be modified physically
       *                (semantically const).
       * @param status  Output param set to success/failure code on exit. If any value
       *                previously set in the time field is invalid or restricted by
       *                leniency, this will be set to an error status.
       * @return        True if the current time of this Calendar is before the time of
       *                Calendar when; false otherwise.
       * @stable ICU 2.0
       */
      UBool before(const Calendar& when, UErrorCode& status) const;
  
      /**
       * Returns true if this Calendar's current time is after "when"'s current time.
       *
       * @param when    The Calendar to be compared with this Calendar. Although this is a
       *                const parameter, the object may be modified physically
       *                (semantically const).
       * @param status  Output param set to success/failure code on exit. If any value
       *                previously set in the time field is invalid or restricted by
       *                leniency, this will be set to an error status.
       * @return        True if the current time of this Calendar is after the time of
       *                Calendar when; false otherwise.
       * @stable ICU 2.0
       */
      UBool after(const Calendar& when, UErrorCode& status) const;
  
      /**
       * UDate Arithmetic function. Adds the specified (signed) amount of time to the given
       * time field, based on the calendar's rules. For example, to subtract 5 days from
       * the current time of the calendar, call add(Calendar::DATE, -5). When adding on
       * the month or Calendar::MONTH field, other fields like date might conflict and
       * need to be changed. For instance, adding 1 month on the date 01/31/96 will result
       * in 02/29/96.
       * Adding a positive value always means moving forward in time, so for the Gregorian calendar,
       * starting with 100 BC and adding +1 to year results in 99 BC (even though this actually reduces
       * the numeric value of the field itself).
       *
       * @param field   Specifies which date field to modify.
       * @param amount  The amount of time to be added to the field, in the natural unit
       *                for that field (e.g., days for the day fields, hours for the hour
       *                field.)
       * @param status  Output param set to success/failure code on exit. If any value
       *                previously set in the time field is invalid or restricted by
       *                leniency, this will be set to an error status.
       * @deprecated ICU 2.6. use add(UCalendarDateFields field, int32_t amount, UErrorCode& status) instead.
       */
      virtual void add(EDateFields field, int32_t amount, UErrorCode& status);
  
      /**
       * UDate Arithmetic function. Adds the specified (signed) amount of time to the given
       * time field, based on the calendar's rules. For example, to subtract 5 days from
       * the current time of the calendar, call add(Calendar::DATE, -5). When adding on
       * the month or Calendar::MONTH field, other fields like date might conflict and
       * need to be changed. For instance, adding 1 month on the date 01/31/96 will result
       * in 02/29/96.
       * Adding a positive value always means moving forward in time, so for the Gregorian calendar,
       * starting with 100 BC and adding +1 to year results in 99 BC (even though this actually reduces
       * the numeric value of the field itself).
       *
       * @param field   Specifies which date field to modify.
       * @param amount  The amount of time to be added to the field, in the natural unit
       *                for that field (e.g., days for the day fields, hours for the hour
       *                field.)
       * @param status  Output param set to success/failure code on exit. If any value
       *                previously set in the time field is invalid or restricted by
       *                leniency, this will be set to an error status.
       * @stable ICU 2.6.
       */
      virtual void add(UCalendarDateFields field, int32_t amount, UErrorCode& status);
  
  #ifndef U_HIDE_DEPRECATED_API
      /**
       * Time Field Rolling function. Rolls (up/down) a single unit of time on the given
       * time field. For example, to roll the current date up by one day, call
       * roll(Calendar::DATE, true). When rolling on the year or Calendar::YEAR field, it
       * will roll the year value in the range between getMinimum(Calendar::YEAR) and the
       * value returned by getMaximum(Calendar::YEAR). When rolling on the month or
       * Calendar::MONTH field, other fields like date might conflict and, need to be
       * changed. For instance, rolling the month up on the date 01/31/96 will result in
       * 02/29/96. Rolling up always means rolling forward in time (unless the limit of the
       * field is reached, in which case it may pin or wrap), so for Gregorian calendar,
       * starting with 100 BC and rolling the year up results in 99 BC.
       * When eras have a definite beginning and end (as in the Chinese calendar, or as in
       * most eras in the Japanese calendar) then rolling the year past either limit of the
       * era will cause the year to wrap around. When eras only have a limit at one end,
       * then attempting to roll the year past that limit will result in pinning the year
       * at that limit. Note that for most calendars in which era 0 years move forward in
       * time (such as Buddhist, Hebrew, or Islamic), it is possible for add or roll to
       * result in negative years for era 0 (that is the only way to represent years before
       * the calendar epoch).
       * When rolling on the hour-in-day or Calendar::HOUR_OF_DAY field, it will roll the
       * hour value in the range between 0 and 23, which is zero-based.
       * <P>
       * NOTE: Do not use this method -- use roll(EDateFields, int, UErrorCode&) instead.
       *
       * @param field   The time field.
       * @param up      Indicates if the value of the specified time field is to be rolled
       *                up or rolled down. Use true if rolling up, false otherwise.
       * @param status  Output param set to success/failure code on exit. If any value
       *                previously set in the time field is invalid or restricted by
       *                leniency, this will be set to an error status.
       * @deprecated ICU 2.6. Use roll(UCalendarDateFields field, UBool up, UErrorCode& status) instead.
       */
      inline void roll(EDateFields field, UBool up, UErrorCode& status);
  #endif  /* U_HIDE_DEPRECATED_API */
  
      /**
       * Time Field Rolling function. Rolls (up/down) a single unit of time on the given
       * time field. For example, to roll the current date up by one day, call
       * roll(Calendar::DATE, true). When rolling on the year or Calendar::YEAR field, it
       * will roll the year value in the range between getMinimum(Calendar::YEAR) and the
       * value returned by getMaximum(Calendar::YEAR). When rolling on the month or
       * Calendar::MONTH field, other fields like date might conflict and, need to be
       * changed. For instance, rolling the month up on the date 01/31/96 will result in
       * 02/29/96. Rolling up always means rolling forward in time (unless the limit of the
       * field is reached, in which case it may pin or wrap), so for Gregorian calendar,
       * starting with 100 BC and rolling the year up results in 99 BC.
       * When eras have a definite beginning and end (as in the Chinese calendar, or as in
       * most eras in the Japanese calendar) then rolling the year past either limit of the
       * era will cause the year to wrap around. When eras only have a limit at one end,
       * then attempting to roll the year past that limit will result in pinning the year
       * at that limit. Note that for most calendars in which era 0 years move forward in
       * time (such as Buddhist, Hebrew, or Islamic), it is possible for add or roll to
       * result in negative years for era 0 (that is the only way to represent years before
       * the calendar epoch).
       * When rolling on the hour-in-day or Calendar::HOUR_OF_DAY field, it will roll the
       * hour value in the range between 0 and 23, which is zero-based.
       * <P>
       * NOTE: Do not use this method -- use roll(UCalendarDateFields, int, UErrorCode&) instead.
       *
       * @param field   The time field.
       * @param up      Indicates if the value of the specified time field is to be rolled
       *                up or rolled down. Use true if rolling up, false otherwise.
       * @param status  Output param set to success/failure code on exit. If any value
       *                previously set in the time field is invalid or restricted by
       *                leniency, this will be set to an error status.
       * @stable ICU 2.6.
       */
      inline void roll(UCalendarDateFields field, UBool up, UErrorCode& status);
  
      /**
       * Time Field Rolling function. Rolls by the given amount on the given
       * time field. For example, to roll the current date up by one day, call
       * roll(Calendar::DATE, +1, status). When rolling on the month or
       * Calendar::MONTH field, other fields like date might conflict and, need to be
       * changed. For instance, rolling the month up on the date 01/31/96 will result in
       * 02/29/96. Rolling by a positive value always means rolling forward in time (unless
       * the limit of the field is reached, in which case it may pin or wrap), so for
       * Gregorian calendar, starting with 100 BC and rolling the year by + 1 results in 99 BC.
       * When eras have a definite beginning and end (as in the Chinese calendar, or as in
       * most eras in the Japanese calendar) then rolling the year past either limit of the
       * era will cause the year to wrap around. When eras only have a limit at one end,
       * then attempting to roll the year past that limit will result in pinning the year
       * at that limit. Note that for most calendars in which era 0 years move forward in
       * time (such as Buddhist, Hebrew, or Islamic), it is possible for add or roll to
       * result in negative years for era 0 (that is the only way to represent years before
       * the calendar epoch).
       * When rolling on the hour-in-day or Calendar::HOUR_OF_DAY field, it will roll the
       * hour value in the range between 0 and 23, which is zero-based.
       * <P>
       * The only difference between roll() and add() is that roll() does not change
       * the value of more significant fields when it reaches the minimum or maximum
       * of its range, whereas add() does.
       *
       * @param field   The time field.
       * @param amount  Indicates amount to roll.
       * @param status  Output param set to success/failure code on exit. If any value
       *                previously set in the time field is invalid, this will be set to
       *                an error status.
       * @deprecated ICU 2.6. Use roll(UCalendarDateFields field, int32_t amount, UErrorCode& status) instead.
       */
      virtual void roll(EDateFields field, int32_t amount, UErrorCode& status);
  
      /**
       * Time Field Rolling function. Rolls by the given amount on the given
       * time field. For example, to roll the current date up by one day, call
       * roll(Calendar::DATE, +1, status). When rolling on the month or
       * Calendar::MONTH field, other fields like date might conflict and, need to be
       * changed. For instance, rolling the month up on the date 01/31/96 will result in
       * 02/29/96. Rolling by a positive value always means rolling forward in time (unless
       * the limit of the field is reached, in which case it may pin or wrap), so for
       * Gregorian calendar, starting with 100 BC and rolling the year by + 1 results in 99 BC.
       * When eras have a definite beginning and end (as in the Chinese calendar, or as in
       * most eras in the Japanese calendar) then rolling the year past either limit of the
       * era will cause the year to wrap around. When eras only have a limit at one end,
       * then attempting to roll the year past that limit will result in pinning the year
       * at that limit. Note that for most calendars in which era 0 years move forward in
       * time (such as Buddhist, Hebrew, or Islamic), it is possible for add or roll to
       * result in negative years for era 0 (that is the only way to represent years before
       * the calendar epoch).
       * When rolling on the hour-in-day or Calendar::HOUR_OF_DAY field, it will roll the
       * hour value in the range between 0 and 23, which is zero-based.
       * <P>
       * The only difference between roll() and add() is that roll() does not change
       * the value of more significant fields when it reaches the minimum or maximum
       * of its range, whereas add() does.
       *
       * @param field   The time field.
       * @param amount  Indicates amount to roll.
       * @param status  Output param set to success/failure code on exit. If any value
       *                previously set in the time field is invalid, this will be set to
       *                an error status.
       * @stable ICU 2.6.
       */
      virtual void roll(UCalendarDateFields field, int32_t amount, UErrorCode& status);
  
      /**
       * Return the difference between the given time and the time this
       * calendar object is set to.  If this calendar is set
       * <em>before</em> the given time, the returned value will be
       * positive.  If this calendar is set <em>after</em> the given
       * time, the returned value will be negative.  The
       * <code>field</code> parameter specifies the units of the return
       * value.  For example, if <code>fieldDifference(when,
       * Calendar::MONTH)</code> returns 3, then this calendar is set to
       * 3 months before <code>when</code>, and possibly some addition
       * time less than one month.
       *
       * <p>As a side effect of this call, this calendar is advanced
       * toward <code>when</code> by the given amount.  That is, calling
       * this method has the side effect of calling <code>add(field,
       * n)</code>, where <code>n</code> is the return value.
       *
       * <p>Usage: To use this method, call it first with the largest
       * field of interest, then with progressively smaller fields.  For
       * example:
       *
       * <pre>
       * int y = cal->fieldDifference(when, Calendar::YEAR, err);
       * int m = cal->fieldDifference(when, Calendar::MONTH, err);
       * int d = cal->fieldDifference(when, Calendar::DATE, err);</pre>
       *
       * computes the difference between <code>cal</code> and
       * <code>when</code> in years, months, and days.
       *
       * <p>Note: <code>fieldDifference()</code> is
       * <em>asymmetrical</em>.  That is, in the following code:
       *
       * <pre>
       * cal->setTime(date1, err);
       * int m1 = cal->fieldDifference(date2, Calendar::MONTH, err);
       * int d1 = cal->fieldDifference(date2, Calendar::DATE, err);
       * cal->setTime(date2, err);
       * int m2 = cal->fieldDifference(date1, Calendar::MONTH, err);
       * int d2 = cal->fieldDifference(date1, Calendar::DATE, err);</pre>
       *
       * one might expect that <code>m1 == -m2 && d1 == -d2</code>.
       * However, this is not generally the case, because of
       * irregularities in the underlying calendar system (e.g., the
       * Gregorian calendar has a varying number of days per month).
       *
       * @param when the date to compare this calendar's time to
       * @param field the field in which to compute the result
       * @param status  Output param set to success/failure code on exit. If any value
       *                previously set in the time field is invalid, this will be set to
       *                an error status.
       * @return the difference, either positive or negative, between
       * this calendar's time and <code>when</code>, in terms of
       * <code>field</code>.
       * @deprecated ICU 2.6. Use fieldDifference(UDate when, UCalendarDateFields field, UErrorCode& status).
       */
      virtual int32_t fieldDifference(UDate when, EDateFields field, UErrorCode& status);
  
      /**
       * Return the difference between the given time and the time this
       * calendar object is set to.  If this calendar is set
       * <em>before</em> the given time, the returned value will be
       * positive.  If this calendar is set <em>after</em> the given
       * time, the returned value will be negative.  The
       * <code>field</code> parameter specifies the units of the return
       * value.  For example, if <code>fieldDifference(when,
       * Calendar::MONTH)</code> returns 3, then this calendar is set to
       * 3 months before <code>when</code>, and possibly some addition
       * time less than one month.
       *
       * <p>As a side effect of this call, this calendar is advanced
       * toward <code>when</code> by the given amount.  That is, calling
       * this method has the side effect of calling <code>add(field,
       * n)</code>, where <code>n</code> is the return value.
       *
       * <p>Usage: To use this method, call it first with the largest
       * field of interest, then with progressively smaller fields.  For
       * example:
       *
       * <pre>
       * int y = cal->fieldDifference(when, Calendar::YEAR, err);
       * int m = cal->fieldDifference(when, Calendar::MONTH, err);
       * int d = cal->fieldDifference(when, Calendar::DATE, err);</pre>
       *
       * computes the difference between <code>cal</code> and
       * <code>when</code> in years, months, and days.
       *
       * <p>Note: <code>fieldDifference()</code> is
       * <em>asymmetrical</em>.  That is, in the following code:
       *
       * <pre>
       * cal->setTime(date1, err);
       * int m1 = cal->fieldDifference(date2, Calendar::MONTH, err);
       * int d1 = cal->fieldDifference(date2, Calendar::DATE, err);
       * cal->setTime(date2, err);
       * int m2 = cal->fieldDifference(date1, Calendar::MONTH, err);
       * int d2 = cal->fieldDifference(date1, Calendar::DATE, err);</pre>
       *
       * one might expect that <code>m1 == -m2 && d1 == -d2</code>.
       * However, this is not generally the case, because of
       * irregularities in the underlying calendar system (e.g., the
       * Gregorian calendar has a varying number of days per month).
       *
       * @param when the date to compare this calendar's time to
       * @param field the field in which to compute the result
       * @param status  Output param set to success/failure code on exit. If any value
       *                previously set in the time field is invalid, this will be set to
       *                an error status.
       * @return the difference, either positive or negative, between
       * this calendar's time and <code>when</code>, in terms of
       * <code>field</code>.
       * @stable ICU 2.6.
       */
      virtual int32_t fieldDifference(UDate when, UCalendarDateFields field, UErrorCode& status);
  
      /**
       * Sets the calendar's time zone to be the one passed in. The Calendar takes ownership
       * of the TimeZone; the caller is no longer responsible for deleting it.  If the
       * given time zone is NULL, this function has no effect.
       *
       * @param value  The given time zone.
       * @stable ICU 2.0
       */
      void adoptTimeZone(TimeZone* value);
  
      /**
       * Sets the calendar's time zone to be the same as the one passed in. The TimeZone
       * passed in is _not_ adopted; the client is still responsible for deleting it.
       *
       * @param zone  The given time zone.
       * @stable ICU 2.0
       */
      void setTimeZone(const TimeZone& zone);
  
      /**
       * Returns a reference to the time zone owned by this calendar. The returned reference
       * is only valid until clients make another call to adoptTimeZone or setTimeZone,
       * or this Calendar is destroyed.
       *
       * @return   The time zone object associated with this calendar.
       * @stable ICU 2.0
       */
      const TimeZone& getTimeZone(void) const;
  
      /**
       * Returns the time zone owned by this calendar. The caller owns the returned object
       * and must delete it when done.  After this call, the new time zone associated
       * with this Calendar is the default TimeZone as returned by TimeZone::createDefault().
       *
       * @return   The time zone object which was associated with this calendar.
       * @stable ICU 2.0
       */
      TimeZone* orphanTimeZone(void);
  
      /**
       * Queries if the current date for this Calendar is in Daylight Savings Time.
       *
       * @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.
       * @stable ICU 2.0
       */
      virtual UBool inDaylightTime(UErrorCode& status) const = 0;
  
      /**
       * Specifies whether or not date/time interpretation is to be lenient. With lenient
       * interpretation, a date such as "February 942, 1996" will be treated as being
       * equivalent to the 941st day after February 1, 1996. With strict interpretation,
       * such dates will cause an error when computing time from the time field values
       * representing the dates.
       *
       * @param lenient  True specifies date/time interpretation to be lenient.
       *
       * @see            DateFormat#setLenient
       * @stable ICU 2.0
       */
      void setLenient(UBool lenient);
  
      /**
       * Tells whether date/time interpretation is to be lenient.
       *
       * @return   True tells that date/time interpretation is to be lenient.
       * @stable ICU 2.0
       */
      UBool isLenient(void) const;
  
      /**
       * Sets the behavior for handling wall time repeating multiple times
       * at negative time zone offset transitions. For example, 1:30 AM on
       * November 6, 2011 in US Eastern time (Ameirca/New_York) occurs twice;
       * 1:30 AM EDT, then 1:30 AM EST one hour later. When <code>UCAL_WALLTIME_FIRST</code>
       * is used, the wall time 1:30AM in this example will be interpreted as 1:30 AM EDT
       * (first occurrence). When <code>UCAL_WALLTIME_LAST</code> is used, it will be
       * interpreted as 1:30 AM EST (last occurrence). The default value is
       * <code>UCAL_WALLTIME_LAST</code>.
       * <p>
       * <b>Note:</b>When <code>UCAL_WALLTIME_NEXT_VALID</code> is not a valid
       * option for this. When the argument is neither <code>UCAL_WALLTIME_FIRST</code>
       * nor <code>UCAL_WALLTIME_LAST</code>, this method has no effect and will keep
       * the current setting.
       *
       * @param option the behavior for handling repeating wall time, either
       * <code>UCAL_WALLTIME_FIRST</code> or <code>UCAL_WALLTIME_LAST</code>.
       * @see #getRepeatedWallTimeOption
       * @stable ICU 49
       */
      void setRepeatedWallTimeOption(UCalendarWallTimeOption option);
  
      /**
       * Gets the behavior for handling wall time repeating multiple times
       * at negative time zone offset transitions.
       *
       * @return the behavior for handling repeating wall time, either
       * <code>UCAL_WALLTIME_FIRST</code> or <code>UCAL_WALLTIME_LAST</code>.
       * @see #setRepeatedWallTimeOption
       * @stable ICU 49
       */
      UCalendarWallTimeOption getRepeatedWallTimeOption(void) const;
  
      /**
       * Sets the behavior for handling skipped wall time at positive time zone offset
       * transitions. For example, 2:30 AM on March 13, 2011 in US Eastern time (America/New_York)
       * does not exist because the wall time jump from 1:59 AM EST to 3:00 AM EDT. When
       * <code>UCAL_WALLTIME_FIRST</code> is used, 2:30 AM is interpreted as 30 minutes before 3:00 AM
       * EDT, therefore, it will be resolved as 1:30 AM EST. When <code>UCAL_WALLTIME_LAST</code>
       * is used, 2:30 AM is interpreted as 31 minutes after 1:59 AM EST, therefore, it will be
       * resolved as 3:30 AM EDT. When <code>UCAL_WALLTIME_NEXT_VALID</code> is used, 2:30 AM will
       * be resolved as next valid wall time, that is 3:00 AM EDT. The default value is
       * <code>UCAL_WALLTIME_LAST</code>.
       * <p>
       * <b>Note:</b>This option is effective only when this calendar is lenient.
       * When the calendar is strict, such non-existing wall time will cause an error.
       *
       * @param option the behavior for handling skipped wall time at positive time zone
       * offset transitions, one of <code>UCAL_WALLTIME_FIRST</code>, <code>UCAL_WALLTIME_LAST</code> and
       * <code>UCAL_WALLTIME_NEXT_VALID</code>.
       * @see #getSkippedWallTimeOption
       *
       * @stable ICU 49
       */
      void setSkippedWallTimeOption(UCalendarWallTimeOption option);
  
      /**
       * Gets the behavior for handling skipped wall time at positive time zone offset
       * transitions.
       *
       * @return the behavior for handling skipped wall time, one of
       * <code>UCAL_WALLTIME_FIRST</code>, <code>UCAL_WALLTIME_LAST</code>
       * and <code>UCAL_WALLTIME_NEXT_VALID</code>.
       * @see #setSkippedWallTimeOption
       * @stable ICU 49
       */
      UCalendarWallTimeOption getSkippedWallTimeOption(void) const;
  
  #ifndef U_HIDE_DEPRECATED_API
      /**
       * Sets what the first day of the week is; e.g., Sunday in US, Monday in France.
       *
       * @param value  The given first day of the week.
       * @deprecated ICU 2.6. Use setFirstDayOfWeek(UCalendarDaysOfWeek value) instead.
       */
      void setFirstDayOfWeek(EDaysOfWeek value);
  #endif  /* U_HIDE_DEPRECATED_API */
  
      /**
       * Sets what the first day of the week is; e.g., Sunday in US, Monday in France.
       *
       * @param value  The given first day of the week.
       * @stable ICU 2.6.
       */
      void setFirstDayOfWeek(UCalendarDaysOfWeek value);
  
  #ifndef U_HIDE_DEPRECATED_API
      /**
       * Gets what the first day of the week is; e.g., Sunday in US, Monday in France.
       *
       * @return   The first day of the week.
       * @deprecated ICU 2.6 use the overload with error code
       */
      EDaysOfWeek getFirstDayOfWeek(void) const;
  #endif  /* U_HIDE_DEPRECATED_API */
  
      /**
       * Gets what the first day of the week is; e.g., Sunday in US, Monday in France.
       *
       * @param status error code
       * @return   The first day of the week.
       * @stable ICU 2.6
       */
      UCalendarDaysOfWeek getFirstDayOfWeek(UErrorCode &status) const;
  
      /**
       * Sets what the minimal days required in the first week of the year are; For
       * example, if the first week is defined as one that contains the first day of the
       * first month of a year, call the method with value 1. If it must be a full week,
       * use value 7.
       *
       * @param value  The given minimal days required in the first week of the year.
       * @stable ICU 2.0
       */
      void setMinimalDaysInFirstWeek(uint8_t value);
  
      /**
       * Gets what the minimal days required in the first week of the year are; e.g., if
       * the first week is defined as one that contains the first day of the first month
       * of a year, getMinimalDaysInFirstWeek returns 1. If the minimal days required must
       * be a full week, getMinimalDaysInFirstWeek returns 7.
       *
       * @return   The minimal days required in the first week of the year.
       * @stable ICU 2.0
       */
      uint8_t getMinimalDaysInFirstWeek(void) const;
  
      /**
       * Gets the minimum value for the given time field. e.g., for Gregorian
       * DAY_OF_MONTH, 1.
       *
       * @param field  The given time field.
       * @return       The minimum value for the given time field.
       * @deprecated ICU 2.6. Use getMinimum(UCalendarDateFields field) instead.
       */
      virtual int32_t getMinimum(EDateFields field) const;
  
      /**
       * Gets the minimum value for the given time field. e.g., for Gregorian
       * DAY_OF_MONTH, 1.
       *
       * @param field  The given time field.
       * @return       The minimum value for the given time field.
       * @stable ICU 2.6.
       */
      virtual int32_t getMinimum(UCalendarDateFields field) const;
  
      /**
       * Gets the maximum value for the given time field. e.g. for Gregorian DAY_OF_MONTH,
       * 31.
       *
       * @param field  The given time field.
       * @return       The maximum value for the given time field.
       * @deprecated ICU 2.6. Use getMaximum(UCalendarDateFields field) instead.
       */
      virtual int32_t getMaximum(EDateFields field) const;
  
      /**
       * Gets the maximum value for the given time field. e.g. for Gregorian DAY_OF_MONTH,
       * 31.
       *
       * @param field  The given time field.
       * @return       The maximum value for the given time field.
       * @stable ICU 2.6.
       */
      virtual int32_t getMaximum(UCalendarDateFields field) const;
  
      /**
       * Gets the highest minimum value for the given field if varies. Otherwise same as
       * getMinimum(). For Gregorian, no difference.
       *
       * @param field  The given time field.
       * @return       The highest minimum value for the given time field.
       * @deprecated ICU 2.6. Use getGreatestMinimum(UCalendarDateFields field) instead.
       */
      virtual int32_t getGreatestMinimum(EDateFields field) const;
  
      /**
       * Gets the highest minimum value for the given field if varies. Otherwise same as
       * getMinimum(). For Gregorian, no difference.
       *
       * @param field  The given time field.
       * @return       The highest minimum value for the given time field.
       * @stable ICU 2.6.
       */
      virtual int32_t getGreatestMinimum(UCalendarDateFields field) const;
  
      /**
       * Gets the lowest maximum value for the given field if varies. Otherwise same as
       * getMaximum(). e.g., for Gregorian DAY_OF_MONTH, 28.
       *
       * @param field  The given time field.
       * @return       The lowest maximum value for the given time field.
       * @deprecated ICU 2.6. Use getLeastMaximum(UCalendarDateFields field) instead.
       */
      virtual int32_t getLeastMaximum(EDateFields field) const;
  
      /**
       * Gets the lowest maximum value for the given field if varies. Otherwise same as
       * getMaximum(). e.g., for Gregorian DAY_OF_MONTH, 28.
       *
       * @param field  The given time field.
       * @return       The lowest maximum value for the given time field.
       * @stable ICU 2.6.
       */
      virtual int32_t getLeastMaximum(UCalendarDateFields field) const;
  
  #ifndef U_HIDE_DEPRECATED_API
      /**
       * Return the minimum value that this field could have, given the current date.
       * For the Gregorian calendar, this is the same as getMinimum() and getGreatestMinimum().
       *
       * The version of this function on Calendar uses an iterative algorithm to determine the
       * actual minimum value for the field.  There is almost always a more efficient way to
       * accomplish this (in most cases, you can simply return getMinimum()).  GregorianCalendar
       * overrides this function with a more efficient implementation.
       *
       * @param field    the field to determine the minimum of
       * @param status   Fill-in parameter which receives the status of this operation.
       * @return         the minimum of the given field for the current date of this Calendar
       * @deprecated ICU 2.6. Use getActualMinimum(UCalendarDateFields field, UErrorCode& status) instead.
       */
      int32_t getActualMinimum(EDateFields field, UErrorCode& status) const;
  #endif  /* U_HIDE_DEPRECATED_API */
  
      /**
       * Return the minimum value that this field could have, given the current date.
       * For the Gregorian calendar, this is the same as getMinimum() and getGreatestMinimum().
       *
       * The version of this function on Calendar uses an iterative algorithm to determine the
       * actual minimum value for the field.  There is almost always a more efficient way to
       * accomplish this (in most cases, you can simply return getMinimum()).  GregorianCalendar
       * overrides this function with a more efficient implementation.
       *
       * @param field    the field to determine the minimum of
       * @param status   Fill-in parameter which receives the status of this operation.
       * @return         the minimum of the given field for the current date of this Calendar
       * @stable ICU 2.6.
       */
      virtual int32_t getActualMinimum(UCalendarDateFields field, UErrorCode& status) const;
  
  #ifndef U_HIDE_DEPRECATED_API
      /**
       * Return the maximum value that this field could have, given the current date.
       * For example, with the date "Feb 3, 1997" and the DAY_OF_MONTH field, the actual
       * maximum would be 28; for "Feb 3, 1996" it s 29.  Similarly for a Hebrew calendar,
       * for some years the actual maximum for MONTH is 12, and for others 13.
       *
       * The version of this function on Calendar uses an iterative algorithm to determine the
       * actual maximum value for the field.  There is almost always a more efficient way to
       * accomplish this (in most cases, you can simply return getMaximum()).  GregorianCalendar
       * overrides this function with a more efficient implementation.
       *
       * @param field    the field to determine the maximum of
       * @param status   Fill-in parameter which receives the status of this operation.
       * @return         the maximum of the given field for the current date of this Calendar
       * @deprecated ICU 2.6. Use getActualMaximum(UCalendarDateFields field, UErrorCode& status) instead.
       */
      int32_t getActualMaximum(EDateFields field, UErrorCode& status) const;
  #endif  /* U_HIDE_DEPRECATED_API */
  
      /**
       * Return the maximum value that this field could have, given the current date.
       * For example, with the date "Feb 3, 1997" and the DAY_OF_MONTH field, the actual
       * maximum would be 28; for "Feb 3, 1996" it s 29.  Similarly for a Hebrew calendar,
       * for some years the actual maximum for MONTH is 12, and for others 13.
       *
       * The version of this function on Calendar uses an iterative algorithm to determine the
       * actual maximum value for the field.  There is almost always a more efficient way to
       * accomplish this (in most cases, you can simply return getMaximum()).  GregorianCalendar
       * overrides this function with a more efficient implementation.
       *
       * @param field    the field to determine the maximum of
       * @param status   Fill-in parameter which receives the status of this operation.
       * @return         the maximum of the given field for the current date of this Calendar
       * @stable ICU 2.6.
       */
      virtual int32_t getActualMaximum(UCalendarDateFields field, UErrorCode& status) const;
  
  #ifndef U_HIDE_DEPRECATED_API
      /**
       * Gets the value for a given time field. Recalculate the current time field values
       * if the time value has been changed by a call to setTime(). Return zero for unset
       * fields if any fields have been explicitly set by a call to set(). To force a
       * recomputation of all fields regardless of the previous state, call complete().
       * This method is semantically const, but may alter the object in memory.
       *
       * @param field  The given time field.
       * @param status Fill-in parameter which receives the status of the operation.
       * @return       The value for the given time field, or zero if the field is unset,
       *               and set() has been called for any other field.
       * @deprecated ICU 2.6. Use get(UCalendarDateFields field, UErrorCode& status) instead.
       */
      int32_t get(EDateFields field, UErrorCode& status) const;
  #endif  /* U_HIDE_DEPRECATED_API */
  
      /**
       * Gets the value for a given time field. Recalculate the current time field values
       * if the time value has been changed by a call to setTime(). Return zero for unset
       * fields if any fields have been explicitly set by a call to set(). To force a
       * recomputation of all fields regardless of the previous state, call complete().
       * This method is semantically const, but may alter the object in memory.
       *
       * @param field  The given time field.
       * @param status Fill-in parameter which receives the status of the operation.
       * @return       The value for the given time field, or zero if the field is unset,
       *               and set() has been called for any other field.
       * @stable ICU 2.6.
       */
      int32_t get(UCalendarDateFields field, UErrorCode& status) const;
  
  #ifndef U_HIDE_DEPRECATED_API
      /**
       * Determines if the given time field has a value set. This can affect in the
       * resolving of time in Calendar. Unset fields have a value of zero, by definition.
       *
       * @param field  The given time field.
       * @return   True if the given time field has a value set; false otherwise.
       * @deprecated ICU 2.6. Use isSet(UCalendarDateFields field) instead.
       */
      UBool isSet(EDateFields field) const;
  #endif  /* U_HIDE_DEPRECATED_API */
  
      /**
       * Determines if the given time field has a value set. This can affect in the
       * resolving of time in Calendar. Unset fields have a value of zero, by definition.
       *
       * @param field  The given time field.
       * @return   True if the given time field has a value set; false otherwise.
       * @stable ICU 2.6.
       */
      UBool isSet(UCalendarDateFields field) const;
  
  #ifndef U_HIDE_DEPRECATED_API
      /**
       * Sets the given time field with the given value.
       *
       * @param field  The given time field.
       * @param value  The value to be set for the given time field.
       * @deprecated ICU 2.6. Use set(UCalendarDateFields field, int32_t value) instead.
       */
      void set(EDateFields field, int32_t value);
  #endif  /* U_HIDE_DEPRECATED_API */
  
      /**
       * Sets the given time field with the given value.
       *
       * @param field  The given time field.
       * @param value  The value to be set for the given time field.
       * @stable ICU 2.6.
       */
      void set(UCalendarDateFields field, int32_t value);
  
      /**
       * Sets the values for the fields YEAR, MONTH, and DATE. Other field values are
       * retained; call clear() first if this is not desired.
       *
       * @param year   The value used to set the YEAR time field.
       * @param month  The value used to set the MONTH time field. Month value is 0-based.
       *               e.g., 0 for January.
       * @param date   The value used to set the DATE time field.
       * @stable ICU 2.0
       */
      void set(int32_t year, int32_t month, int32_t date);
  
      /**
       * Sets the values for the fields YEAR, MONTH, DATE, HOUR_OF_DAY, and MINUTE. Other
       * field values are retained; call clear() first if this is not desired.
       *
       * @param year    The value used to set the YEAR time field.
       * @param month   The value used to set the MONTH time field. Month value is
       *                0-based. E.g., 0 for January.
       * @param date    The value used to set the DATE time field.
       * @param hour    The value used to set the HOUR_OF_DAY time field.
       * @param minute  The value used to set the MINUTE time field.
       * @stable ICU 2.0
       */
      void set(int32_t year, int32_t month, int32_t date, int32_t hour, int32_t minute);
  
      /**
       * Sets the values for the fields YEAR, MONTH, DATE, HOUR_OF_DAY, MINUTE, and SECOND.
       * Other field values are retained; call clear() first if this is not desired.
       *
       * @param year    The value used to set the YEAR time field.
       * @param month   The value used to set the MONTH time field. Month value is
       *                0-based. E.g., 0 for January.
       * @param date    The value used to set the DATE time field.
       * @param hour    The value used to set the HOUR_OF_DAY time field.
       * @param minute  The value used to set the MINUTE time field.
       * @param second  The value used to set the SECOND time field.
       * @stable ICU 2.0
       */
      void set(int32_t year, int32_t month, int32_t date, int32_t hour, int32_t minute, int32_t second);
  
      /**
       * Clears the values of all the time fields, making them both unset and assigning
       * them a value of zero. The field values will be determined during the next
       * resolving of time into time fields.
       * @stable ICU 2.0
       */
      void clear(void);
  
  #ifndef U_HIDE_DEPRECATED_API
      /**
       * Clears the value in the given time field, both making it unset and assigning it a
       * value of zero. This field value will be determined during the next resolving of
       * time into time fields.
       *
       * @param field  The time field to be cleared.
       * @deprecated ICU 2.6. Use clear(UCalendarDateFields field) instead.
       */
      void clear(EDateFields field);
  #endif  /* U_HIDE_DEPRECATED_API */
  
      /**
       * Clears the value in the given time field, both making it unset and assigning it a
       * value of zero. This field value will be determined during the next resolving of
       * time into time fields.
       *
       * @param field  The time field to be cleared.
       * @stable ICU 2.6.
       */
      void clear(UCalendarDateFields field);
  
      /**
       * Returns a unique class ID POLYMORPHICALLY. Pure virtual method. This method is to
       * implement a simple version of RTTI, since not all C++ compilers support genuine
       * RTTI. Polymorphic operator==() and clone() methods call this method.
       * <P>
       * Concrete subclasses of Calendar must implement getDynamicClassID() and also a
       * static method and data member:
       *
       *      static UClassID getStaticClassID() { return (UClassID)&amp;fgClassID; }
       *      static char fgClassID;
       *
       * @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.
       * @stable ICU 2.0
       */
      virtual UClassID getDynamicClassID(void) const = 0;
  
      /**
       * Returns the calendar type name string for this Calendar object.
       * The returned string is the legacy ICU calendar attribute value,
       * for example, "gregorian" or "japanese".
       *
       * See type="old type name" for the calendar attribute of locale IDs
       * at http://www.unicode.org/reports/tr35/#Key_Type_Definitions
       *
       * Sample code for getting the LDML/BCP 47 calendar key value:
       * \code
       * const char *calType = cal->getType();
       * if (0 == strcmp(calType, "unknown")) {
       *     // deal with unknown calendar type
       * } else {
       *     string localeID("root@calendar=");
       *     localeID.append(calType);
       *     char langTag[100];
       *     UErrorCode errorCode = U_ZERO_ERROR;
       *     int32_t length = uloc_toLanguageTag(localeID.c_str(), langTag, (int32_t)sizeof(langTag), TRUE, &errorCode);
       *     if (U_FAILURE(errorCode)) {
       *         // deal with errors & overflow
       *     }
       *     string lang(langTag, length);
       *     size_t caPos = lang.find("-ca-");
       *     lang.erase(0, caPos + 4);
       *     // lang now contains the LDML calendar type
       * }
       * \endcode
       *
       * @return legacy calendar type name string
       * @stable ICU 49
       */
      virtual const char * getType() const = 0;
  
      /**
       * Returns whether the given day of the week is a weekday, a weekend day,
       * or a day that transitions from one to the other, for the locale and
       * calendar system associated with this Calendar (the locale's region is
       * often the most determinant factor). If a transition occurs at midnight,
       * then the days before and after the transition will have the
       * type UCAL_WEEKDAY or UCAL_WEEKEND. If a transition occurs at a time
       * other than midnight, then the day of the transition will have
       * the type UCAL_WEEKEND_ONSET or UCAL_WEEKEND_CEASE. In this case, the
       * method getWeekendTransition() will return the point of
       * transition.
       * @param dayOfWeek The day of the week whose type is desired (UCAL_SUNDAY..UCAL_SATURDAY).
       * @param status The error code for the operation.
       * @return The UCalendarWeekdayType for the day of the week.
       * @stable ICU 4.4
       */
      virtual UCalendarWeekdayType getDayOfWeekType(UCalendarDaysOfWeek dayOfWeek, UErrorCode &status) const;
  
      /**
       * Returns the time during the day at which the weekend begins or ends in
       * this calendar system.  If getDayOfWeekType() returns UCAL_WEEKEND_ONSET
       * for the specified dayOfWeek, return the time at which the weekend begins.
       * If getDayOfWeekType() returns UCAL_WEEKEND_CEASE for the specified dayOfWeek,
       * return the time at which the weekend ends. If getDayOfWeekType() returns
       * some other UCalendarWeekdayType for the specified dayOfWeek, is it an error condition
       * (U_ILLEGAL_ARGUMENT_ERROR).
       * @param dayOfWeek The day of the week for which the weekend transition time is
       * desired (UCAL_SUNDAY..UCAL_SATURDAY).
       * @param status The error code for the operation.
       * @return The milliseconds after midnight at which the weekend begins or ends.
       * @stable ICU 4.4
       */
      virtual int32_t getWeekendTransition(UCalendarDaysOfWeek dayOfWeek, UErrorCode &status) const;
  
      /**
       * Returns TRUE if the given UDate is in the weekend in
       * this calendar system.
       * @param date The UDate in question.
       * @param status The error code for the operation.
       * @return TRUE if the given UDate is in the weekend in
       * this calendar system, FALSE otherwise.
       * @stable ICU 4.4
       */
      virtual UBool isWeekend(UDate date, UErrorCode &status) const;
  
      /**
       * Returns TRUE if this Calendar's current date-time is in the weekend in
       * this calendar system.
       * @return TRUE if this Calendar's current date-time is in the weekend in
       * this calendar system, FALSE otherwise.
       * @stable ICU 4.4
       */
      virtual UBool isWeekend(void) const;
  
  protected:
  
       /**
        * Constructs a Calendar with the default time zone as returned by
        * TimeZone::createInstance(), and the default locale.
        *
        * @param success  Indicates the status of Calendar object construction. Returns
        *                 U_ZERO_ERROR if constructed successfully.
       * @stable ICU 2.0
        */
      Calendar(UErrorCode& success);
  
      /**
       * Copy constructor
       *
       * @param source    Calendar object to be copied from
       * @stable ICU 2.0
       */
      Calendar(const Calendar& source);
  
      /**
       * Default assignment operator
       *
       * @param right    Calendar object to be copied
       * @stable ICU 2.0
       */
      Calendar& operator=(const Calendar& right);
  
      /**
       * Constructs a Calendar with the given time zone and locale. Clients are no longer
       * responsible for deleting the given time zone object after it's adopted.
       *
       * @param zone     The given time zone.
       * @param aLocale  The given locale.
       * @param success  Indicates the status of Calendar object construction. Returns
       *                 U_ZERO_ERROR if constructed successfully.
       * @stable ICU 2.0
       */
      Calendar(TimeZone* zone, const Locale& aLocale, UErrorCode& success);
  
      /**
       * Constructs a Calendar with the given time zone and locale.
       *
       * @param zone     The given time zone.
       * @param aLocale  The given locale.
       * @param success  Indicates the status of Calendar object construction. Returns
       *                 U_ZERO_ERROR if constructed successfully.
       * @stable ICU 2.0
       */
      Calendar(const TimeZone& zone, const Locale& aLocale, UErrorCode& success);
  
      /**
       * Converts Calendar's time field values to GMT as milliseconds.
       *
       * @param status  Output param set to success/failure code on exit. If any value
       *                previously set in the time field is invalid or restricted by
       *                leniency, this will be set to an error status.
       * @stable ICU 2.0
       */
      virtual void computeTime(UErrorCode& status);
  
      /**
       * Converts GMT as milliseconds to time field values. This allows you to sync up the
       * time field values with a new time that is set for the calendar.  This method
       * does NOT recompute the time first; to recompute the time, then the fields, use
       * the method complete().
       *
       * @param status  Output param set to success/failure code on exit. If any value
       *                previously set in the time field is invalid or restricted by
       *                leniency, this will be set to an error status.
       * @stable ICU 2.0
       */
      virtual void computeFields(UErrorCode& status);
  
      /**
       * Gets this Calendar's current time as a long.
       *
       * @param status  Output param set to success/failure code on exit. If any value
       *                previously set in the time field is invalid or restricted by
       *                leniency, this will be set to an error status.
       * @return the current time as UTC milliseconds from the epoch.
       * @stable ICU 2.0
       */
      double getTimeInMillis(UErrorCode& status) const;
  
      /**
       * Sets this Calendar's current time from the given long value.
       * @param millis  the new time in UTC milliseconds from the epoch.
       * @param status  Output param set to success/failure code on exit. If any value
       *                previously set in the time field is invalid or restricted by
       *                leniency, this will be set to an error status.
       * @stable ICU 2.0
       */
      void setTimeInMillis( double millis, UErrorCode& status );
  
      /**
       * Recomputes the current time from currently set fields, and then fills in any
       * unset fields in the time field list.
       *
       * @param status  Output param set to success/failure code on exit. If any value
       *                previously set in the time field is invalid or restricted by
       *                leniency, this will be set to an error status.
       * @stable ICU 2.0
       */
      void complete(UErrorCode& status);
  
  #ifndef U_HIDE_DEPRECATED_API
      /**
       * Gets the value for a given time field. Subclasses can use this function to get
       * field values without forcing recomputation of time.
       *
       * @param field  The given time field.
       * @return       The value for the given time field.
       * @deprecated ICU 2.6. Use internalGet(UCalendarDateFields field) instead.
       */
      inline int32_t internalGet(EDateFields field) const {return fFields[field];}
  #endif  /* U_HIDE_DEPRECATED_API */
  
  #ifndef U_HIDE_INTERNAL_API
      /**
       * Gets the value for a given time field. Subclasses can use this function to get
       * field values without forcing recomputation of time. If the field's stamp is UNSET,
       * the defaultValue is used.
       *
       * @param field  The given time field.
       * @param defaultValue a default value used if the field is unset.
       * @return       The value for the given time field.
       * @internal
       */
      inline int32_t internalGet(UCalendarDateFields field, int32_t defaultValue) const {return fStamp[field]>kUnset ? fFields[field] : defaultValue;}
  
      /**
       * Gets the value for a given time field. Subclasses can use this function to get
       * field values without forcing recomputation of time.
       *
       * @param field  The given time field.
       * @return       The value for the given time field.
       * @internal
       */
      inline int32_t internalGet(UCalendarDateFields field) const {return fFields[field];}
  #endif  /* U_HIDE_INTERNAL_API */
  
  #ifndef U_HIDE_DEPRECATED_API
      /**
       * Sets the value for a given time field.  This is a fast internal method for
       * subclasses.  It does not affect the areFieldsInSync, isTimeSet, or areAllFieldsSet
       * flags.
       *
       * @param field    The given time field.
       * @param value    The value for the given time field.
       * @deprecated ICU 2.6. Use internalSet(UCalendarDateFields field, int32_t value) instead.
       */
      void internalSet(EDateFields field, int32_t value);
  #endif  /* U_HIDE_DEPRECATED_API */
  
      /**
       * Sets the value for a given time field.  This is a fast internal method for
       * subclasses.  It does not affect the areFieldsInSync, isTimeSet, or areAllFieldsSet
       * flags.
       *
       * @param field    The given time field.
       * @param value    The value for the given time field.
       * @stable ICU 2.6.
       */
      inline void internalSet(UCalendarDateFields field, int32_t value);
  
      /**
       * Prepare this calendar for computing the actual minimum or maximum.
       * This method modifies this calendar's fields; it is called on a
       * temporary calendar.
       * @internal
       */
      virtual void prepareGetActual(UCalendarDateFields field, UBool isMinimum, UErrorCode &status);
  
      /**
       * Limit enums. Not in sync with UCalendarLimitType (refers to internal fields).
       * @internal
       */
      enum ELimitType {
  #ifndef U_HIDE_INTERNAL_API
        UCAL_LIMIT_MINIMUM = 0,
        UCAL_LIMIT_GREATEST_MINIMUM,
        UCAL_LIMIT_LEAST_MAXIMUM,
        UCAL_LIMIT_MAXIMUM,
        UCAL_LIMIT_COUNT
  #endif  /* U_HIDE_INTERNAL_API */
      };
  
      /**
       * Subclass API for defining limits of different types.
       * Subclasses must implement this method to return limits for the
       * following fields:
       *
       * <pre>UCAL_ERA
       * UCAL_YEAR
       * UCAL_MONTH
       * UCAL_WEEK_OF_YEAR
       * UCAL_WEEK_OF_MONTH
       * UCAL_DATE (DAY_OF_MONTH on Java)
       * UCAL_DAY_OF_YEAR
       * UCAL_DAY_OF_WEEK_IN_MONTH
       * UCAL_YEAR_WOY
       * UCAL_EXTENDED_YEAR</pre>
       *
       * @param field one of the above field numbers
       * @param limitType one of <code>MINIMUM</code>, <code>GREATEST_MINIMUM</code>,
       * <code>LEAST_MAXIMUM</code>, or <code>MAXIMUM</code>
       * @internal
       */
      virtual int32_t handleGetLimit(UCalendarDateFields field, ELimitType limitType) const = 0;
  
      /**
       * Return a limit for a field.
       * @param field the field, from <code>0..UCAL_MAX_FIELD</code>
       * @param limitType the type specifier for the limit
       * @see #ELimitType
       * @internal
       */
      virtual int32_t getLimit(UCalendarDateFields field, ELimitType limitType) const;
  
  
      /**
       * Return the Julian day number of day before the first day of the
       * given month in the given extended year.  Subclasses should override
       * this method to implement their calendar system.
       * @param eyear the extended year
       * @param month the zero-based month, or 0 if useMonth is false
       * @param useMonth if false, compute the day before the first day of
       * the given year, otherwise, compute the day before the first day of
       * the given month
       * @return the Julian day number of the day before the first
       * day of the given month and year
       * @internal
       */
      virtual int32_t handleComputeMonthStart(int32_t eyear, int32_t month,
                                                     UBool useMonth) const  = 0;
  
      /**
       * Return the number of days in the given month of the given extended
       * year of this calendar system.  Subclasses should override this
       * method if they can provide a more correct or more efficient
       * implementation than the default implementation in Calendar.
       * @internal
       */
      virtual int32_t handleGetMonthLength(int32_t extendedYear, int32_t month) const ;
  
      /**
       * Return the number of days in the given extended year of this
       * calendar system.  Subclasses should override this method if they can
       * provide a more correct or more efficient implementation than the
       * default implementation in Calendar.
       * @stable ICU 2.0
       */
      virtual int32_t handleGetYearLength(int32_t eyear) const;
  
  
      /**
       * Return the extended year defined by the current fields.  This will
       * use the UCAL_EXTENDED_YEAR field or the UCAL_YEAR and supra-year fields (such
       * as UCAL_ERA) specific to the calendar system, depending on which set of
       * fields is newer.
       * @return the extended year
       * @internal
       */
      virtual int32_t handleGetExtendedYear() = 0;
  
      /**
       * Subclasses may override this.  This method calls
       * handleGetMonthLength() to obtain the calendar-specific month
       * length.
       * @param bestField which field to use to calculate the date
       * @return julian day specified by calendar fields.
       * @internal
       */
      virtual int32_t handleComputeJulianDay(UCalendarDateFields bestField);
  
      /**
       * Subclasses must override this to convert from week fields
       * (YEAR_WOY and WEEK_OF_YEAR) to an extended year in the case
       * where YEAR, EXTENDED_YEAR are not set.
       * The Calendar implementation assumes yearWoy is in extended gregorian form
       * @return the extended year, UCAL_EXTENDED_YEAR
       * @internal
       */
      virtual int32_t handleGetExtendedYearFromWeekFields(int32_t yearWoy, int32_t woy);
  
      /**
       * Validate a single field of this calendar.  Subclasses should
       * override this method to validate any calendar-specific fields.
       * Generic fields can be handled by
       * <code>Calendar::validateField()</code>.
       * @see #validateField(int, int, int, int&)
       * @internal
       */
      virtual void validateField(UCalendarDateFields field, UErrorCode &status);
  
  #ifndef U_HIDE_INTERNAL_API
      /**
       * Compute the Julian day from fields.  Will determine whether to use
       * the JULIAN_DAY field directly, or other fields.
       * @return the julian day
       * @internal
       */
      int32_t computeJulianDay();
  
      /**
       * Compute the milliseconds in the day from the fields.  This is a
       * value from 0 to 23:59:59.999 inclusive, unless fields are out of
       * range, in which case it can be an arbitrary value.  This value
       * reflects local zone wall time.
       * @internal
       */
      int32_t computeMillisInDay();
  
      /**
       * This method can assume EXTENDED_YEAR has been set.
       * @param millis milliseconds of the date fields
       * @param millisInDay milliseconds of the time fields; may be out
       * or range.
       * @param ec Output param set to failure code on function return
       *          when this function fails.
       * @internal
       */
      int32_t computeZoneOffset(double millis, int32_t millisInDay, UErrorCode &ec);
  
  
      /**
       * Determine the best stamp in a range.
       * @param start first enum to look at
       * @param end last enum to look at
       * @param bestSoFar stamp prior to function call
       * @return the stamp value of the best stamp
       * @internal
       */
      int32_t newestStamp(UCalendarDateFields start, UCalendarDateFields end, int32_t bestSoFar) const;
  
      /**
       * Values for field resolution tables
       * @see #resolveFields
       * @internal
       */
      enum {
        /** Marker for end of resolve set (row or group). */
        kResolveSTOP = -1,
        /** Value to be bitwised "ORed" against resolve table field values for remapping.  Example: (UCAL_DATE | kResolveRemap) in 1st column will cause 'UCAL_DATE' to be returned, but will not examine the value of UCAL_DATE.  */
        kResolveRemap = 32
      };
  
      /**
       * Precedence table for Dates
       * @see #resolveFields
       * @internal
       */
      static const UFieldResolutionTable kDatePrecedence[];
  
      /**
       * Precedence table for Year
       * @see #resolveFields
       * @internal
       */
      static const UFieldResolutionTable kYearPrecedence[];
  
      /**
       * Precedence table for Day of Week
       * @see #resolveFields
       * @internal
       */
      static const UFieldResolutionTable kDOWPrecedence[];
  
      /**
       * Given a precedence table, return the newest field combination in
       * the table, or UCAL_FIELD_COUNT if none is found.
       *
       * <p>The precedence table is a 3-dimensional array of integers.  It
       * may be thought of as an array of groups.  Each group is an array of
       * lines.  Each line is an array of field numbers.  Within a line, if
       * all fields are set, then the time stamp of the line is taken to be
       * the stamp of the most recently set field.  If any field of a line is
       * unset, then the line fails to match.  Within a group, the line with
       * the newest time stamp is selected.  The first field of the line is
       * returned to indicate which line matched.
       *
       * <p>In some cases, it may be desirable to map a line to field that
       * whose stamp is NOT examined.  For example, if the best field is
       * DAY_OF_WEEK then the DAY_OF_WEEK_IN_MONTH algorithm may be used.  In
       * order to do this, insert the value <code>kResolveRemap | F</code> at
       * the start of the line, where <code>F</code> is the desired return
       * field value.  This field will NOT be examined; it only determines
       * the return value if the other fields in the line are the newest.
       *
       * <p>If all lines of a group contain at least one unset field, then no
       * line will match, and the group as a whole will fail to match.  In
       * that case, the next group will be processed.  If all groups fail to
       * match, then UCAL_FIELD_COUNT is returned.
       * @internal
       */
      UCalendarDateFields resolveFields(const UFieldResolutionTable *precedenceTable);
  #endif  /* U_HIDE_INTERNAL_API */
  
  
      /**
       * @internal
       */
      virtual const UFieldResolutionTable* getFieldResolutionTable() const;
  
  #ifndef U_HIDE_INTERNAL_API
      /**
       * Return the field that is newer, either defaultField, or
       * alternateField.  If neither is newer or neither is set, return defaultField.
       * @internal
       */
      UCalendarDateFields newerField(UCalendarDateFields defaultField, UCalendarDateFields alternateField) const;
  #endif  /* U_HIDE_INTERNAL_API */
  
  
  private:
      /**
       * Helper function for calculating limits by trial and error
       * @param field The field being investigated
       * @param startValue starting (least max) value of field
       * @param endValue ending (greatest max) value of field
       * @param status return type
       * @internal
       */
      int32_t getActualHelper(UCalendarDateFields field, int32_t startValue, int32_t endValue, UErrorCode &status) const;
  
  
  protected:
      /**
       * The flag which indicates if the current time is set in the calendar.
       * @stable ICU 2.0
       */
      UBool      fIsTimeSet;
  
      /**
       * True if the fields are in sync with the currently set time of this Calendar.
       * If false, then the next attempt to get the value of a field will
       * force a recomputation of all fields from the current value of the time
       * field.
       * <P>
       * This should really be named areFieldsInSync, but the old name is retained
       * for backward compatibility.
       * @stable ICU 2.0
       */
      UBool      fAreFieldsSet;
  
      /**
       * True if all of the fields have been set.  This is initially false, and set to
       * true by computeFields().
       * @stable ICU 2.0
       */
      UBool      fAreAllFieldsSet;
  
      /**
       * True if all fields have been virtually set, but have not yet been
       * computed.  This occurs only in setTimeInMillis().  A calendar set
       * to this state will compute all fields from the time if it becomes
       * necessary, but otherwise will delay such computation.
       * @stable ICU 3.0
       */
      UBool fAreFieldsVirtuallySet;
  
      /**
       * Get the current time without recomputing.
       *
       * @return     the current time without recomputing.
       * @stable ICU 2.0
       */
      UDate        internalGetTime(void) const     { return fTime; }
  
      /**
       * Set the current time without affecting flags or fields.
       *
       * @param time    The time to be set
       * @return        the current time without recomputing.
       * @stable ICU 2.0
       */
      void        internalSetTime(UDate time)     { fTime = time; }
  
      /**
       * The time fields containing values into which the millis is computed.
       * @stable ICU 2.0
       */
      int32_t     fFields[UCAL_FIELD_COUNT];
  
      /**
       * The flags which tell if a specified time field for the calendar is set.
       * @deprecated ICU 2.8 use (fStamp[n]!=kUnset)
       */
      UBool      fIsSet[UCAL_FIELD_COUNT];
  
      /** Special values of stamp[]
       * @stable ICU 2.0
       */
      enum {
          kUnset                 = 0,
          kInternallySet,
          kMinimumUserStamp
      };
  
      /**
       * Pseudo-time-stamps which specify when each field was set. There
       * are two special values, UNSET and INTERNALLY_SET. Values from
       * MINIMUM_USER_SET to Integer.MAX_VALUE are legal user set values.
       * @stable ICU 2.0
       */
      int32_t        fStamp[UCAL_FIELD_COUNT];
  
      /**
       * Subclasses may override this method to compute several fields
       * specific to each calendar system.  These are:
       *
       * <ul><li>ERA
       * <li>YEAR
       * <li>MONTH
       * <li>DAY_OF_MONTH
       * <li>DAY_OF_YEAR
       * <li>EXTENDED_YEAR</ul>
       *
       * Subclasses can refer to the DAY_OF_WEEK and DOW_LOCAL fields, which
       * will be set when this method is called.  Subclasses can also call
       * the getGregorianXxx() methods to obtain Gregorian calendar
       * equivalents for the given Julian day.
       *
       * <p>In addition, subclasses should compute any subclass-specific
       * fields, that is, fields from BASE_FIELD_COUNT to
       * getFieldCount() - 1.
       *
       * <p>The default implementation in <code>Calendar</code> implements
       * a pure proleptic Gregorian calendar.
       * @internal
       */
      virtual void handleComputeFields(int32_t julianDay, UErrorCode &status);
  
  #ifndef U_HIDE_INTERNAL_API
      /**
       * Return the extended year on the Gregorian calendar as computed by
       * <code>computeGregorianFields()</code>.
       * @internal
       */
      int32_t getGregorianYear() const {
          return fGregorianYear;
      }
  
      /**
       * Return the month (0-based) on the Gregorian calendar as computed by
       * <code>computeGregorianFields()</code>.
       * @internal
       */
      int32_t getGregorianMonth() const {
          return fGregorianMonth;
      }
  
      /**
       * Return the day of year (1-based) on the Gregorian calendar as
       * computed by <code>computeGregorianFields()</code>.
       * @internal
       */
      int32_t getGregorianDayOfYear() const {
          return fGregorianDayOfYear;
      }
  
      /**
       * Return the day of month (1-based) on the Gregorian calendar as
       * computed by <code>computeGregorianFields()</code>.
       * @internal
       */
      int32_t getGregorianDayOfMonth() const {
        return fGregorianDayOfMonth;
      }
  #endif  /* U_HIDE_INTERNAL_API */
  
      /**
       * Called by computeJulianDay.  Returns the default month (0-based) for the year,
       * taking year and era into account.  Defaults to 0 for Gregorian, which doesn't care.
       * @param eyear The extended year
       * @internal
       */
      virtual int32_t getDefaultMonthInYear(int32_t eyear) ;
  
  
      /**
       * Called by computeJulianDay.  Returns the default day (1-based) for the month,
       * taking currently-set year and era into account.  Defaults to 1 for Gregorian.
       * @param eyear the extended year
       * @param month the month in the year
       * @internal
       */
      virtual int32_t getDefaultDayInMonth(int32_t eyear, int32_t month);
  
      //-------------------------------------------------------------------------
      // Protected utility methods for use by subclasses.  These are very handy
      // for implementing add, roll, and computeFields.
      //-------------------------------------------------------------------------
  
      /**
       * Adjust the specified field so that it is within
       * the allowable range for the date to which this calendar is set.
       * For example, in a Gregorian calendar pinning the {@link #UCalendarDateFields DAY_OF_MONTH}
       * field for a calendar set to April 31 would cause it to be set
       * to April 30.
       * <p>
       * <b>Subclassing:</b>
       * <br>
       * This utility method is intended for use by subclasses that need to implement
       * their own overrides of {@link #roll roll} and {@link #add add}.
       * <p>
       * <b>Note:</b>
       * <code>pinField</code> is implemented in terms of
       * {@link #getActualMinimum getActualMinimum}
       * and {@link #getActualMaximum getActualMaximum}.  If either of those methods uses
       * a slow, iterative algorithm for a particular field, it would be
       * unwise to attempt to call <code>pinField</code> for that field.  If you
       * really do need to do so, you should override this method to do
       * something more efficient for that field.
       * <p>
       * @param field The calendar field whose value should be pinned.
       * @param status Output param set to failure code on function return
       *          when this function fails.
       *
       * @see #getActualMinimum
       * @see #getActualMaximum
       * @stable ICU 2.0
       */
      virtual void pinField(UCalendarDateFields field, UErrorCode& status);
  
      /**
       * Return the week number of a day, within a period. This may be the week number in
       * a year or the week number in a month. Usually this will be a value >= 1, but if
       * some initial days of the period are excluded from week 1, because
       * {@link #getMinimalDaysInFirstWeek getMinimalDaysInFirstWeek} is > 1, then
       * the week number will be zero for those
       * initial days. This method requires the day number and day of week for some
       * known date in the period in order to determine the day of week
       * on the desired day.
       * <p>
       * <b>Subclassing:</b>
       * <br>
       * This method is intended for use by subclasses in implementing their
       * {@link #computeTime computeTime} and/or {@link #computeFields computeFields} methods.
       * It is often useful in {@link #getActualMinimum getActualMinimum} and
       * {@link #getActualMaximum getActualMaximum} as well.
       * <p>
       * This variant is handy for computing the week number of some other
       * day of a period (often the first or last day of the period) when its day
       * of the week is not known but the day number and day of week for some other
       * day in the period (e.g. the current date) <em>is</em> known.
       * <p>
       * @param desiredDay    The {@link #UCalendarDateFields DAY_OF_YEAR} or
       *              {@link #UCalendarDateFields DAY_OF_MONTH} whose week number is desired.
       *              Should be 1 for the first day of the period.
       *
       * @param dayOfPeriod   The {@link #UCalendarDateFields DAY_OF_YEAR}
       *              or {@link #UCalendarDateFields DAY_OF_MONTH} for a day in the period whose
       *              {@link #UCalendarDateFields DAY_OF_WEEK} is specified by the
       *              <code>knownDayOfWeek</code> parameter.
       *              Should be 1 for first day of period.
       *
       * @param dayOfWeek  The {@link #UCalendarDateFields DAY_OF_WEEK} for the day
       *              corresponding to the <code>knownDayOfPeriod</code> parameter.
       *              1-based with 1=Sunday.
       *
       * @return      The week number (one-based), or zero if the day falls before
       *              the first week because
       *              {@link #getMinimalDaysInFirstWeek getMinimalDaysInFirstWeek}
       *              is more than one.
       *
       * @stable ICU 2.8
       */
      int32_t weekNumber(int32_t desiredDay, int32_t dayOfPeriod, int32_t dayOfWeek);
  
  
  #ifndef U_HIDE_INTERNAL_API
      /**
       * Return the week number of a day, within a period. This may be the week number in
       * a year, or the week number in a month. Usually this will be a value >= 1, but if
       * some initial days of the period are excluded from week 1, because
       * {@link #getMinimalDaysInFirstWeek getMinimalDaysInFirstWeek} is > 1,
       * then the week number will be zero for those
       * initial days. This method requires the day of week for the given date in order to
       * determine the result.
       * <p>
       * <b>Subclassing:</b>
       * <br>
       * This method is intended for use by subclasses in implementing their
       * {@link #computeTime computeTime} and/or {@link #computeFields computeFields} methods.
       * It is often useful in {@link #getActualMinimum getActualMinimum} and
       * {@link #getActualMaximum getActualMaximum} as well.
       * <p>
       * @param dayOfPeriod   The {@link #UCalendarDateFields DAY_OF_YEAR} or
       *                      {@link #UCalendarDateFields DAY_OF_MONTH} whose week number is desired.
       *                      Should be 1 for the first day of the period.
       *
       * @param dayOfWeek     The {@link #UCalendarDateFields DAY_OF_WEEK} for the day
       *                      corresponding to the <code>dayOfPeriod</code> parameter.
       *                      1-based with 1=Sunday.
       *
       * @return      The week number (one-based), or zero if the day falls before
       *              the first week because
       *              {@link #getMinimalDaysInFirstWeek getMinimalDaysInFirstWeek}
       *              is more than one.
       * @internal
       */
      inline int32_t weekNumber(int32_t dayOfPeriod, int32_t dayOfWeek);
  
      /**
       * returns the local DOW, valid range 0..6
       * @internal
       */
      int32_t getLocalDOW();
  #endif  /* U_HIDE_INTERNAL_API */
  
  private:
  
      /**
       * The next available value for fStamp[]
       */
      int32_t fNextStamp;// = MINIMUM_USER_STAMP;
  
      /**
       * Recalculates the time stamp array (fStamp).
       * Resets fNextStamp to lowest next stamp value.
       */
      void recalculateStamp();
  
      /**
       * The current time set for the calendar.
       */
      UDate        fTime;
  
      /**
       * @see   #setLenient
       */
      UBool      fLenient;
  
      /**
       * Time zone affects the time calculation done by Calendar. Calendar subclasses use
       * the time zone data to produce the local time. Always set; never NULL.
       */
      TimeZone*   fZone;
  
      /**
       * Option for rpeated wall time
       * @see #setRepeatedWallTimeOption
       */
      UCalendarWallTimeOption fRepeatedWallTime;
  
      /**
       * Option for skipped wall time
       * @see #setSkippedWallTimeOption
       */
      UCalendarWallTimeOption fSkippedWallTime;
  
      /**
       * Both firstDayOfWeek and minimalDaysInFirstWeek are locale-dependent. They are
       * used to figure out the week count for a specific date for a given locale. These
       * must be set when a Calendar is constructed. For example, in US locale,
       * firstDayOfWeek is SUNDAY; minimalDaysInFirstWeek is 1. They are used to figure
       * out the week count for a specific date for a given locale. These must be set when
       * a Calendar is constructed.
       */
      UCalendarDaysOfWeek fFirstDayOfWeek;
      uint8_t     fMinimalDaysInFirstWeek;
      UCalendarDaysOfWeek fWeekendOnset;
      int32_t fWeekendOnsetMillis;
      UCalendarDaysOfWeek fWeekendCease;
      int32_t fWeekendCeaseMillis;
  
      /**
       * Sets firstDayOfWeek and minimalDaysInFirstWeek. Called at Calendar construction
       * time.
       *
       * @param desiredLocale  The given locale.
       * @param type           The calendar type identifier, e.g: gregorian, buddhist, etc.
       * @param success        Indicates the status of setting the week count data from
       *                       the resource for the given locale. Returns U_ZERO_ERROR if
       *                       constructed successfully.
       */
      void        setWeekData(const Locale& desiredLocale, const char *type, UErrorCode& success);
  
      /**
       * Recompute the time and update the status fields isTimeSet
       * and areFieldsSet.  Callers should check isTimeSet and only
       * call this method if isTimeSet is false.
       *
       * @param status  Output param set to success/failure code on exit. If any value
       *                previously set in the time field is invalid or restricted by
       *                leniency, this will be set to an error status.
       */
      void updateTime(UErrorCode& status);
  
      /**
       * The Gregorian year, as computed by computeGregorianFields() and
       * returned by getGregorianYear().
       * @see #computeGregorianFields
       */
      int32_t fGregorianYear;
  
      /**
       * The Gregorian month, as computed by computeGregorianFields() and
       * returned by getGregorianMonth().
       * @see #computeGregorianFields
       */
      int32_t fGregorianMonth;
  
      /**
       * The Gregorian day of the year, as computed by
       * computeGregorianFields() and returned by getGregorianDayOfYear().
       * @see #computeGregorianFields
       */
      int32_t fGregorianDayOfYear;
  
      /**
       * The Gregorian day of the month, as computed by
       * computeGregorianFields() and returned by getGregorianDayOfMonth().
       * @see #computeGregorianFields
       */
      int32_t fGregorianDayOfMonth;
  
      /* calculations */
  
      /**
       * Compute the Gregorian calendar year, month, and day of month from
       * the given Julian day.  These values are not stored in fields, but in
       * member variables gregorianXxx.  Also compute the DAY_OF_WEEK and
       * DOW_LOCAL fields.
       */
      void computeGregorianAndDOWFields(int32_t julianDay, UErrorCode &ec);
  
  protected:
  
      /**
       * Compute the Gregorian calendar year, month, and day of month from the
       * Julian day.  These values are not stored in fields, but in member
       * variables gregorianXxx.  They are used for time zone computations and by
       * subclasses that are Gregorian derivatives.  Subclasses may call this
       * method to perform a Gregorian calendar millis->fields computation.
       */
      void computeGregorianFields(int32_t julianDay, UErrorCode &ec);
  
  private:
  
      /**
       * Compute the fields WEEK_OF_YEAR, YEAR_WOY, WEEK_OF_MONTH,
       * DAY_OF_WEEK_IN_MONTH, and DOW_LOCAL from EXTENDED_YEAR, YEAR,
       * DAY_OF_WEEK, and DAY_OF_YEAR.  The latter fields are computed by the
       * subclass based on the calendar system.
       *
       * <p>The YEAR_WOY field is computed simplistically.  It is equal to YEAR
       * most of the time, but at the year boundary it may be adjusted to YEAR-1
       * or YEAR+1 to reflect the overlap of a week into an adjacent year.  In
       * this case, a simple increment or decrement is performed on YEAR, even
       * though this may yield an invalid YEAR value.  For instance, if the YEAR
       * is part of a calendar system with an N-year cycle field CYCLE, then
       * incrementing the YEAR may involve incrementing CYCLE and setting YEAR
       * back to 0 or 1.  This is not handled by this code, and in fact cannot be
       * simply handled without having subclasses define an entire parallel set of
       * fields for fields larger than or equal to a year.  This additional
       * complexity is not warranted, since the intention of the YEAR_WOY field is
       * to support ISO 8601 notation, so it will typically be used with a
       * proleptic Gregorian calendar, which has no field larger than a year.
       */
      void computeWeekFields(UErrorCode &ec);
  
  
      /**
       * Ensure that each field is within its valid range by calling {@link
       * #validateField(int, int&)} on each field that has been set.  This method
       * should only be called if this calendar is not lenient.
       * @see #isLenient
       * @see #validateField(int, int&)
       * @internal
       */
      void validateFields(UErrorCode &status);
  
      /**
       * Validate a single field of this calendar given its minimum and
       * maximum allowed value.  If the field is out of range,
       * <code>U_ILLEGAL_ARGUMENT_ERROR</code> will be set.  Subclasses may
       * use this method in their implementation of {@link
       * #validateField(int, int&)}.
       * @internal
       */
      void validateField(UCalendarDateFields field, int32_t min, int32_t max, UErrorCode& status);
  
   protected:
  #ifndef U_HIDE_INTERNAL_API
      /**
       * Convert a quasi Julian date to the day of the week. The Julian date used here is
       * not a true Julian date, since it is measured from midnight, not noon. Return
       * value is one-based.
       *
       * @param julian  The given Julian date number.
       * @return   Day number from 1..7 (SUN..SAT).
       * @internal
       */
      static uint8_t julianDayToDayOfWeek(double julian);
  #endif  /* U_HIDE_INTERNAL_API */
  
   private:
      char validLocale[ULOC_FULLNAME_CAPACITY];
      char actualLocale[ULOC_FULLNAME_CAPACITY];
  
   public:
  #if !UCONFIG_NO_SERVICE
      /**
       * INTERNAL FOR 2.6 --  Registration.
       */
  
  #ifndef U_HIDE_INTERNAL_API
      /**
       * Return a StringEnumeration over the locales available at the time of the call,
       * including registered locales.
       * @return a StringEnumeration over the locales available at the time of the call
       * @internal
       */
      static StringEnumeration* getAvailableLocales(void);
  
      /**
       * Register a new Calendar factory.  The factory will be adopted.
       * INTERNAL in 2.6
       *
       * Because ICU may choose to cache Calendars internally, this must
       * be called at application startup, prior to any calls to
       * Calendar::createInstance to avoid undefined behavior.
       *
       * @param toAdopt the factory instance to be adopted
       * @param status the in/out status code, no special meanings are assigned
       * @return a registry key that can be used to unregister this factory
       * @internal
       */
      static URegistryKey registerFactory(ICUServiceFactory* toAdopt, UErrorCode& status);
  
      /**
       * Unregister a previously-registered CalendarFactory using the key returned from the
       * register call.  Key becomes invalid after a successful call and should not be used again.
       * The CalendarFactory corresponding to the key will be deleted.
       * INTERNAL in 2.6
       *
       * Because ICU may choose to cache Calendars internally, this should
       * be called during application shutdown, after all calls to
       * Calendar::createInstance to avoid undefined behavior.
       *
       * @param key the registry key returned by a previous call to registerFactory
       * @param status the in/out status code, no special meanings are assigned
       * @return TRUE if the factory for the key was successfully unregistered
       * @internal
       */
      static UBool unregister(URegistryKey key, UErrorCode& status);
  #endif  /* U_HIDE_INTERNAL_API */
  
      /**
       * Multiple Calendar Implementation
       * @internal
       */
      friend class CalendarFactory;
  
      /**
       * Multiple Calendar Implementation
       * @internal
       */
      friend class CalendarService;
  
      /**
       * Multiple Calendar Implementation
       * @internal
       */
      friend class DefaultCalendarFactory;
  #endif /* !UCONFIG_NO_SERVICE */
  
      /**
       * @return TRUE if this calendar has a default century (i.e. 03 -> 2003)
       * @internal
       */
      virtual UBool haveDefaultCentury() const = 0;
  
      /**
       * @return the start of the default century, as a UDate
       * @internal
       */
      virtual UDate defaultCenturyStart() const = 0;
      /**
       * @return the beginning year of the default century, as a year
       * @internal
       */
      virtual int32_t defaultCenturyStartYear() const = 0;
  
      /** Get the locale for this calendar object. You can choose between valid and actual locale.
       *  @param type type of the locale we're looking for (valid or actual)
       *  @param status error code for the operation
       *  @return the locale
       *  @stable ICU 2.8
       */
      Locale getLocale(ULocDataLocaleType type, UErrorCode &status) const;
  
      /**
       * @return      The related Gregorian year; will be obtained by modifying the value
       *              obtained by get from UCAL_EXTENDED_YEAR field
       * @internal
       */
      virtual int32_t getRelatedYear(UErrorCode &status) const;
  
      /**
       * @param year  The related Gregorian year to set; will be modified as necessary then
       *              set in UCAL_EXTENDED_YEAR field
       * @internal
       */
      virtual void setRelatedYear(int32_t year);
  
  #ifndef U_HIDE_INTERNAL_API
      /** Get the locale for this calendar object. You can choose between valid and actual locale.
       *  @param type type of the locale we're looking for (valid or actual)
       *  @param status error code for the operation
       *  @return the locale
       *  @internal
       */
      const char* getLocaleID(ULocDataLocaleType type, UErrorCode &status) const;
  #endif  /* U_HIDE_INTERNAL_API */
  
  private:
      /**
       * Cast TimeZone used by this object to BasicTimeZone, or NULL if the TimeZone
       * is not an instance of BasicTimeZone.
       */
      BasicTimeZone* getBasicTimeZone() const;
  
      /**
       * Find the previous zone transtion near the given time.
       * @param base The base time, inclusive
       * @param transitionTime Receives the result time
       * @param status The error status
       * @return TRUE if a transition is found.
       */
      UBool getImmediatePreviousZoneTransition(UDate base, UDate *transitionTime, UErrorCode& status) const;
  
  public:
  #ifndef U_HIDE_INTERNAL_API
      /**
       * Creates a new Calendar from a Locale for the cache.
       * This method does not set the time or timezone in returned calendar.
       * @param locale the locale.
       * @param status any error returned here.
       * @return the new Calendar object with no time or timezone set.
       * @internal For ICU use only.
       */
      static Calendar * U_EXPORT2 makeInstance(
              const Locale &locale, UErrorCode &status);
  
      /**
       * Get the calendar type for given locale.
       * @param locale the locale
       * @param typeBuffer calendar type returned here
       * @param typeBufferSize The size of typeBuffer in bytes. If the type
       *   can't fit in the buffer, this method sets status to
       *   U_BUFFER_OVERFLOW_ERROR
       * @param status error, if any, returned here.
       * @internal For ICU use only.
       */
      static void U_EXPORT2 getCalendarTypeFromLocale(
              const Locale &locale,
              char *typeBuffer,
              int32_t typeBufferSize,
              UErrorCode &status);
  #endif  /* U_HIDE_INTERNAL_API */
  };
  
  // -------------------------------------
  
  inline Calendar*
  Calendar::createInstance(TimeZone* zone, UErrorCode& errorCode)
  {
      // since the Locale isn't specified, use the default locale
      return createInstance(zone, Locale::getDefault(), errorCode);
  }
  
  // -------------------------------------
  
  inline void
  Calendar::roll(UCalendarDateFields field, UBool up, UErrorCode& status)
  {
      roll(field, (int32_t)(up ? +1 : -1), status);
  }
  
  #ifndef U_HIDE_DEPRECATED_API
  inline void
  Calendar::roll(EDateFields field, UBool up, UErrorCode& status)
  {
      roll((UCalendarDateFields) field, up, status);
  }
  #endif  /* U_HIDE_DEPRECATED_API */
  
  
  // -------------------------------------
  
  /**
   * Fast method for subclasses.  The caller must maintain fUserSetDSTOffset and
   * fUserSetZoneOffset, as well as the isSet[] array.
   */
  
  inline void
  Calendar::internalSet(UCalendarDateFields field, int32_t value)
  {
      fFields[field] = value;
      fStamp[field] = kInternallySet;
      fIsSet[field]     = TRUE; // Remove later
  }
  
  
  #ifndef U_HIDE_INTERNAL_API
  inline int32_t  Calendar::weekNumber(int32_t dayOfPeriod, int32_t dayOfWeek)
  {
    return weekNumber(dayOfPeriod, dayOfPeriod, dayOfWeek);
  }
  #endif  /* U_HIDE_INTERNAL_API */
  
  U_NAMESPACE_END
  
  #endif /* #if !UCONFIG_NO_FORMATTING */
  
  #endif // _CALENDAR
  