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1 // © 2016 and later: Unicode, Inc. and others.
2 // License & terms of use: http://www.unicode.org/copyright.html
3 /*
4 ********************************************************************************
5 *   Copyright (C) 1997-2014, International Business Machines
6 *   Corporation and others.  All Rights Reserved.
7 ********************************************************************************
8 *
9 * File CALENDAR.H
10 *
11 * Modification History:
12 *
13 *   Date        Name        Description
14 *   04/22/97    aliu        Expanded and corrected comments and other header
15 *                           contents.
16 *   05/01/97    aliu        Made equals(), before(), after() arguments const.
17 *   05/20/97    aliu        Replaced fAreFieldsSet with fAreFieldsInSync and
18 *                           fAreAllFieldsSet.
19 *   07/27/98    stephen     Sync up with JDK 1.2
20 *   11/15/99    weiv        added YEAR_WOY and DOW_LOCAL
21 *                           to EDateFields
22 *    8/19/2002  srl         Removed Javaisms
23 *   11/07/2003  srl         Update, clean up documentation.
24 ********************************************************************************
25 */
26 
27 #ifndef CALENDAR_H
28 #define CALENDAR_H
29 
30 #include "unicode/utypes.h"
31 
32 #if U_SHOW_CPLUSPLUS_API
33 
34 /**
35  * \file
36  * \brief C++ API: Calendar object
37  */
38 #if !UCONFIG_NO_FORMATTING
39 
40 #include "unicode/uobject.h"
41 #include "unicode/locid.h"
42 #include "unicode/timezone.h"
43 #include "unicode/ucal.h"
44 #include "unicode/umisc.h"
45 
46 U_NAMESPACE_BEGIN
47 
48 class ICUServiceFactory;
49 
50 /**
51  * @internal
52  */
53 typedef int32_t UFieldResolutionTable[12][8];
54 
55 class BasicTimeZone;
56 /**
57  * `Calendar` is an abstract base class for converting between
58  * a `UDate` object and a set of integer fields such as
59  * `YEAR`, `MONTH`, `DAY`, `HOUR`, and so on.
60  * (A `UDate` object represents a specific instant in
61  * time with millisecond precision. See UDate
62  * for information about the `UDate` class.)
63  *
64  * Subclasses of `Calendar` interpret a `UDate`
65  * according to the rules of a specific calendar system.
66  * The most commonly used subclass of `Calendar` is
67  * `GregorianCalendar`. Other subclasses could represent
68  * the various types of lunar calendars in use in many parts of the world.
69  *
70  * **NOTE**: (ICU 2.6) The subclass interface should be considered unstable -
71  * it WILL change.
72  *
73  * Like other locale-sensitive classes, `Calendar` provides a
74  * static method, `createInstance`, for getting a generally useful
75  * object of this type. `Calendar`'s `createInstance` method
76  * returns the appropriate `Calendar` subclass whose
77  * time fields have been initialized with the current date and time:
78  *
79  *     Calendar *rightNow = Calendar::createInstance(errCode);
80  *
81  * A `Calendar` object can produce all the time field values
82  * needed to implement the date-time formatting for a particular language
83  * and calendar style (for example, Japanese-Gregorian, Japanese-Traditional).
84  *
85  * When computing a `UDate` from time fields, some special circumstances
86  * may arise: there may be insufficient information to compute the
87  * `UDate` (such as only year and month but no day in the month),
88  * there may be inconsistent information (such as "Tuesday, July 15, 1996"
89  * -- July 15, 1996 is actually a Monday), or the input time might be ambiguous
90  * because of time zone transition.
91  *
92  * **Insufficient information.** The calendar will use default
93  * information to specify the missing fields. This may vary by calendar; for
94  * the Gregorian calendar, the default for a field is the same as that of the
95  * start of the epoch: i.e., YEAR = 1970, MONTH = JANUARY, DATE = 1, etc.
96  *
97  * **Inconsistent information.** If fields conflict, the calendar
98  * will give preference to fields set more recently. For example, when
99  * determining the day, the calendar will look for one of the following
100  * combinations of fields.  The most recent combination, as determined by the
101  * most recently set single field, will be used.
102  *
103  *     MONTH + DAY_OF_MONTH
104  *     MONTH + WEEK_OF_MONTH + DAY_OF_WEEK
105  *     MONTH + DAY_OF_WEEK_IN_MONTH + DAY_OF_WEEK
106  *     DAY_OF_YEAR
107  *     DAY_OF_WEEK + WEEK_OF_YEAR
108  *
109  * For the time of day:
110  *
111  *     HOUR_OF_DAY
112  *     AM_PM + HOUR
113  *
114  * **Ambiguous Wall Clock Time.** When time offset from UTC has
115  * changed, it produces an ambiguous time slot around the transition. For example,
116  * many US locations observe daylight saving time. On the date switching to daylight
117  * saving time in US, wall clock time jumps from 12:59 AM (standard) to 2:00 AM
118  * (daylight). Therefore, wall clock time from 1:00 AM to 1:59 AM do not exist on
119  * the date. When the input wall time fall into this missing time slot, the ICU
120  * Calendar resolves the time using the UTC offset before the transition by default.
121  * In this example, 1:30 AM is interpreted as 1:30 AM standard time (non-exist),
122  * so the final result will be 2:30 AM daylight time.
123  *
124  * On the date switching back to standard time, wall clock time is moved back one
125  * hour at 2:00 AM. So wall clock time from 1:00 AM to 1:59 AM occur twice. In this
126  * case, the ICU Calendar resolves the time using the UTC offset after the transition
127  * by default. For example, 1:30 AM on the date is resolved as 1:30 AM standard time.
128  *
129  * Ambiguous wall clock time resolution behaviors can be customized by Calendar APIs
130  * {@link #setRepeatedWallTimeOption} and {@link #setSkippedWallTimeOption}.
131  * These methods are available in ICU 49 or later versions.
132  *
133  * **Note:** for some non-Gregorian calendars, different
134  * fields may be necessary for complete disambiguation. For example, a full
135  * specification of the historical Arabic astronomical calendar requires year,
136  * month, day-of-month *and* day-of-week in some cases.
137  *
138  * **Note:** There are certain possible ambiguities in
139  * interpretation of certain singular times, which are resolved in the
140  * following ways:
141  *
142  *   1. 24:00:00 "belongs" to the following day. That is,
143  *      23:59 on Dec 31, 1969 < 24:00 on Jan 1, 1970 < 24:01:00 on Jan 1, 1970
144  *   2. Although historically not precise, midnight also belongs to "am",
145  *      and noon belongs to "pm", so on the same day,
146  *      12:00 am (midnight) < 12:01 am, and 12:00 pm (noon) < 12:01 pm
147  *
148  * The date or time format strings are not part of the definition of a
149  * calendar, as those must be modifiable or overridable by the user at
150  * runtime. Use `DateFormat` to format dates.
151  *
152  * `Calendar` provides an API for field "rolling", where fields
153  * can be incremented or decremented, but wrap around. For example, rolling the
154  * month up in the date December 12, **1996** results in
155  * January 12, **1996**.
156  *
157  * `Calendar` also provides a date arithmetic function for
158  * adding the specified (signed) amount of time to a particular time field.
159  * For example, subtracting 5 days from the date `September 12, 1996`
160  * results in `September 7, 1996`.
161  *
162  * ***Supported range***
163  *
164  * The allowable range of `Calendar` has been narrowed. `GregorianCalendar` used
165  * to attempt to support the range of dates with millisecond values from
166  * `Long.MIN_VALUE` to `Long.MAX_VALUE`. The new `Calendar` protocol specifies the
167  * maximum range of supportable dates as those having Julian day numbers
168  * of `-0x7F000000` to `+0x7F000000`. This corresponds to years from ~5,800,000 BCE
169  * to ~5,800,000 CE. Programmers should use the protected constants in `Calendar` to
170  * specify an extremely early or extremely late date.
171  *
172  * <p>
173  * The Japanese calendar uses a combination of era name and year number.
174  * When an emperor of Japan abdicates and a new emperor ascends the throne,
175  * a new era is declared and year number is reset to 1. Even if the date of
176  * abdication is scheduled ahead of time, the new era name might not be
177  * announced until just before the date. In such case, ICU4C may include
178  * a start date of future era without actual era name, but not enabled
179  * by default. ICU4C users who want to test the behavior of the future era
180  * can enable the tentative era by:
181  * <ul>
182  * <li>Environment variable <code>ICU_ENABLE_TENTATIVE_ERA=true</code>.</li>
183  * </ul>
184  *
185  * @stable ICU 2.0
186  */
187 class U_I18N_API Calendar : public UObject {
188 public:
189 #ifndef U_FORCE_HIDE_DEPRECATED_API
190     /**
191      * Field IDs for date and time. Used to specify date/time fields. ERA is calendar
192      * specific. Example ranges given are for illustration only; see specific Calendar
193      * subclasses for actual ranges.
194      * @deprecated ICU 2.6. Use C enum UCalendarDateFields defined in ucal.h
195      */
196     enum EDateFields {
197 #ifndef U_HIDE_DEPRECATED_API
198 /*
199  * ERA may be defined on other platforms. To avoid any potential problems undefined it here.
200  */
201 #ifdef ERA
202 #undef ERA
203 #endif
204         ERA,                  // Example: 0..1
205         YEAR,                 // Example: 1..big number
206         MONTH,                // Example: 0..11
207         WEEK_OF_YEAR,         // Example: 1..53
208         WEEK_OF_MONTH,        // Example: 1..4
209         DATE,                 // Example: 1..31
210         DAY_OF_YEAR,          // Example: 1..365
211         DAY_OF_WEEK,          // Example: 1..7
212         DAY_OF_WEEK_IN_MONTH, // Example: 1..4, may be specified as -1
213         AM_PM,                // Example: 0..1
214         HOUR,                 // Example: 0..11
215         HOUR_OF_DAY,          // Example: 0..23
216         MINUTE,               // Example: 0..59
217         SECOND,               // Example: 0..59
218         MILLISECOND,          // Example: 0..999
219         ZONE_OFFSET,          // Example: -12*U_MILLIS_PER_HOUR..12*U_MILLIS_PER_HOUR
220         DST_OFFSET,           // Example: 0 or U_MILLIS_PER_HOUR
221         YEAR_WOY,             // 'Y' Example: 1..big number - Year of Week of Year
222         DOW_LOCAL,            // 'e' Example: 1..7 - Day of Week / Localized
223 
224         EXTENDED_YEAR,
225         JULIAN_DAY,
226         MILLISECONDS_IN_DAY,
227         IS_LEAP_MONTH,
228 
229         FIELD_COUNT = UCAL_FIELD_COUNT // See ucal.h for other fields.
230 #endif /* U_HIDE_DEPRECATED_API */
231     };
232 #endif  // U_FORCE_HIDE_DEPRECATED_API
233 
234 #ifndef U_HIDE_DEPRECATED_API
235     /**
236      * Useful constant for days of week. Note: Calendar day-of-week is 1-based. Clients
237      * who create locale resources for the field of first-day-of-week should be aware of
238      * this. For instance, in US locale, first-day-of-week is set to 1, i.e., SUNDAY.
239      * @deprecated ICU 2.6. Use C enum UCalendarDaysOfWeek defined in ucal.h
240      */
241     enum EDaysOfWeek {
242         SUNDAY = 1,
243         MONDAY,
244         TUESDAY,
245         WEDNESDAY,
246         THURSDAY,
247         FRIDAY,
248         SATURDAY
249     };
250 
251     /**
252      * Useful constants for month. Note: Calendar month is 0-based.
253      * @deprecated ICU 2.6. Use C enum UCalendarMonths defined in ucal.h
254      */
255     enum EMonths {
256         JANUARY,
257         FEBRUARY,
258         MARCH,
259         APRIL,
260         MAY,
261         JUNE,
262         JULY,
263         AUGUST,
264         SEPTEMBER,
265         OCTOBER,
266         NOVEMBER,
267         DECEMBER,
268         UNDECIMBER
269     };
270 
271     /**
272      * Useful constants for hour in 12-hour clock. Used in GregorianCalendar.
273      * @deprecated ICU 2.6. Use C enum UCalendarAMPMs defined in ucal.h
274      */
275     enum EAmpm {
276         AM,
277         PM
278     };
279 #endif  /* U_HIDE_DEPRECATED_API */
280 
281     /**
282      * destructor
283      * @stable ICU 2.0
284      */
285     virtual ~Calendar();
286 
287     /**
288      * Create and return a polymorphic copy of this calendar.
289      *
290      * @return    a polymorphic copy of this calendar.
291      * @stable ICU 2.0
292      */
293     virtual Calendar* clone() const = 0;
294 
295     /**
296      * Creates a Calendar using the default timezone and locale. Clients are responsible
297      * for deleting the object returned.
298      *
299      * @param success  Indicates the success/failure of Calendar creation. Filled in
300      *                 with U_ZERO_ERROR if created successfully, set to a failure result
301      *                 otherwise. U_MISSING_RESOURCE_ERROR will be returned if the resource data
302      *                 requests a calendar type which has not been installed.
303      * @return         A Calendar if created successfully. NULL otherwise.
304      * @stable ICU 2.0
305      */
306     static Calendar* U_EXPORT2 createInstance(UErrorCode& success);
307 
308     /**
309      * Creates a Calendar using the given timezone and the default locale.
310      * The Calendar takes ownership of zoneToAdopt; the
311      * client must not delete it.
312      *
313      * @param zoneToAdopt  The given timezone to be adopted.
314      * @param success      Indicates the success/failure of Calendar creation. Filled in
315      *                     with U_ZERO_ERROR if created successfully, set to a failure result
316      *                     otherwise.
317      * @return             A Calendar if created successfully. NULL otherwise.
318      * @stable ICU 2.0
319      */
320     static Calendar* U_EXPORT2 createInstance(TimeZone* zoneToAdopt, UErrorCode& success);
321 
322     /**
323      * Creates a Calendar using the given timezone and the default locale.  The TimeZone
324      * is _not_ adopted; the client is still responsible for deleting it.
325      *
326      * @param zone  The timezone.
327      * @param success      Indicates the success/failure of Calendar creation. Filled in
328      *                     with U_ZERO_ERROR if created successfully, set to a failure result
329      *                     otherwise.
330      * @return             A Calendar if created successfully. NULL otherwise.
331      * @stable ICU 2.0
332      */
333     static Calendar* U_EXPORT2 createInstance(const TimeZone& zone, UErrorCode& success);
334 
335     /**
336      * Creates a Calendar using the default timezone and the given locale.
337      *
338      * @param aLocale  The given locale.
339      * @param success  Indicates the success/failure of Calendar creation. Filled in
340      *                 with U_ZERO_ERROR if created successfully, set to a failure result
341      *                 otherwise.
342      * @return         A Calendar if created successfully. NULL otherwise.
343      * @stable ICU 2.0
344      */
345     static Calendar* U_EXPORT2 createInstance(const Locale& aLocale, UErrorCode& success);
346 
347     /**
348      * Creates a Calendar using the given timezone and given locale.
349      * The Calendar takes ownership of zoneToAdopt; the
350      * client must not delete it.
351      *
352      * @param zoneToAdopt  The given timezone to be adopted.
353      * @param aLocale      The given locale.
354      * @param success      Indicates the success/failure of Calendar creation. Filled in
355      *                     with U_ZERO_ERROR if created successfully, set to a failure result
356      *                     otherwise.
357      * @return             A Calendar if created successfully. NULL otherwise.
358      * @stable ICU 2.0
359      */
360     static Calendar* U_EXPORT2 createInstance(TimeZone* zoneToAdopt, const Locale& aLocale, UErrorCode& success);
361 
362     /**
363      * Gets a Calendar using the given timezone and given locale.  The TimeZone
364      * is _not_ adopted; the client is still responsible for deleting it.
365      *
366      * @param zone         The given timezone.
367      * @param aLocale      The given locale.
368      * @param success      Indicates the success/failure of Calendar creation. Filled in
369      *                     with U_ZERO_ERROR if created successfully, set to a failure result
370      *                     otherwise.
371      * @return             A Calendar if created successfully. NULL otherwise.
372      * @stable ICU 2.0
373      */
374     static Calendar* U_EXPORT2 createInstance(const TimeZone& zone, const Locale& aLocale, UErrorCode& success);
375 
376     /**
377      * Returns a list of the locales for which Calendars are installed.
378      *
379      * @param count  Number of locales returned.
380      * @return       An array of Locale objects representing the set of locales for which
381      *               Calendars are installed.  The system retains ownership of this list;
382      *               the caller must NOT delete it. Does not include user-registered Calendars.
383      * @stable ICU 2.0
384      */
385     static const Locale* U_EXPORT2 getAvailableLocales(int32_t& count);
386 
387 
388     /**
389      * Given a key and a locale, returns an array of string values in a preferred
390      * order that would make a difference. These are all and only those values where
391      * the open (creation) of the service with the locale formed from the input locale
392      * plus input keyword and that value has different behavior than creation with the
393      * input locale alone.
394      * @param key           one of the keys supported by this service.  For now, only
395      *                      "calendar" is supported.
396      * @param locale        the locale
397      * @param commonlyUsed  if set to true it will return only commonly used values
398      *                      with the given locale in preferred order.  Otherwise,
399      *                      it will return all the available values for the locale.
400      * @param status        ICU Error Code
401      * @return a string enumeration over keyword values for the given key and the locale.
402      * @stable ICU 4.2
403      */
404     static StringEnumeration* U_EXPORT2 getKeywordValuesForLocale(const char* key,
405                     const Locale& locale, UBool commonlyUsed, UErrorCode& status);
406 
407     /**
408      * Returns the current UTC (GMT) time measured in milliseconds since 0:00:00 on 1/1/70
409      * (derived from the system time).
410      *
411      * @return   The current UTC time in milliseconds.
412      * @stable ICU 2.0
413      */
414     static UDate U_EXPORT2 getNow(void);
415 
416     /**
417      * Gets this Calendar's time as milliseconds. May involve recalculation of time due
418      * to previous calls to set time field values. The time specified is non-local UTC
419      * (GMT) time. Although this method is const, this object may actually be changed
420      * (semantically const).
421      *
422      * @param status  Output param set to success/failure code on exit. If any value
423      *                previously set in the time field is invalid or restricted by
424      *                leniency, this will be set to an error status.
425      * @return        The current time in UTC (GMT) time, or zero if the operation
426      *                failed.
427      * @stable ICU 2.0
428      */
getTime(UErrorCode & status)429     inline UDate getTime(UErrorCode& status) const { return getTimeInMillis(status); }
430 
431     /**
432      * Sets this Calendar's current time with the given UDate. The time specified should
433      * be in non-local UTC (GMT) time.
434      *
435      * @param date  The given UDate in UTC (GMT) time.
436      * @param status  Output param set to success/failure code on exit. If any value
437      *                set in the time field is invalid or restricted by
438      *                leniency, this will be set to an error status.
439      * @stable ICU 2.0
440      */
setTime(UDate date,UErrorCode & status)441     inline void setTime(UDate date, UErrorCode& status) { setTimeInMillis(date, status); }
442 
443     /**
444      * Compares the equality of two Calendar objects. Objects of different subclasses
445      * are considered unequal. This comparison is very exacting; two Calendar objects
446      * must be in exactly the same state to be considered equal. To compare based on the
447      * represented time, use equals() instead.
448      *
449      * @param that  The Calendar object to be compared with.
450      * @return      True if the given Calendar is the same as this Calendar; false
451      *              otherwise.
452      * @stable ICU 2.0
453      */
454     virtual UBool operator==(const Calendar& that) const;
455 
456     /**
457      * Compares the inequality of two Calendar objects.
458      *
459      * @param that  The Calendar object to be compared with.
460      * @return      True if the given Calendar is not the same as this Calendar; false
461      *              otherwise.
462      * @stable ICU 2.0
463      */
464     UBool operator!=(const Calendar& that) const {return !operator==(that);}
465 
466     /**
467      * Returns TRUE if the given Calendar object is equivalent to this
468      * one.  An equivalent Calendar will behave exactly as this one
469      * does, but it may be set to a different time.  By contrast, for
470      * the operator==() method to return TRUE, the other Calendar must
471      * be set to the same time.
472      *
473      * @param other the Calendar to be compared with this Calendar
474      * @stable ICU 2.4
475      */
476     virtual UBool isEquivalentTo(const Calendar& other) const;
477 
478     /**
479      * Compares the Calendar time, whereas Calendar::operator== compares the equality of
480      * Calendar objects.
481      *
482      * @param when    The Calendar to be compared with this Calendar. Although this is a
483      *                const parameter, the object may be modified physically
484      *                (semantically const).
485      * @param status  Output param set to success/failure code on exit. If any value
486      *                previously set in the time field is invalid or restricted by
487      *                leniency, this will be set to an error status.
488      * @return        True if the current time of this Calendar is equal to the time of
489      *                Calendar when; false otherwise.
490      * @stable ICU 2.0
491      */
492     UBool equals(const Calendar& when, UErrorCode& status) const;
493 
494     /**
495      * Returns true if this Calendar's current time is before "when"'s current time.
496      *
497      * @param when    The Calendar to be compared with this Calendar. Although this is a
498      *                const parameter, the object may be modified physically
499      *                (semantically const).
500      * @param status  Output param set to success/failure code on exit. If any value
501      *                previously set in the time field is invalid or restricted by
502      *                leniency, this will be set to an error status.
503      * @return        True if the current time of this Calendar is before the time of
504      *                Calendar when; false otherwise.
505      * @stable ICU 2.0
506      */
507     UBool before(const Calendar& when, UErrorCode& status) const;
508 
509     /**
510      * Returns true if this Calendar's current time is after "when"'s current time.
511      *
512      * @param when    The Calendar to be compared with this Calendar. Although this is a
513      *                const parameter, the object may be modified physically
514      *                (semantically const).
515      * @param status  Output param set to success/failure code on exit. If any value
516      *                previously set in the time field is invalid or restricted by
517      *                leniency, this will be set to an error status.
518      * @return        True if the current time of this Calendar is after the time of
519      *                Calendar when; false otherwise.
520      * @stable ICU 2.0
521      */
522     UBool after(const Calendar& when, UErrorCode& status) const;
523 
524 #ifndef U_FORCE_HIDE_DEPRECATED_API
525     /**
526      * UDate Arithmetic function. Adds the specified (signed) amount of time to the given
527      * time field, based on the calendar's rules. For example, to subtract 5 days from
528      * the current time of the calendar, call add(Calendar::DATE, -5). When adding on
529      * the month or Calendar::MONTH field, other fields like date might conflict and
530      * need to be changed. For instance, adding 1 month on the date 01/31/96 will result
531      * in 02/29/96.
532      * Adding a positive value always means moving forward in time, so for the Gregorian calendar,
533      * starting with 100 BC and adding +1 to year results in 99 BC (even though this actually reduces
534      * the numeric value of the field itself).
535      *
536      * @param field   Specifies which date field to modify.
537      * @param amount  The amount of time to be added to the field, in the natural unit
538      *                for that field (e.g., days for the day fields, hours for the hour
539      *                field.)
540      * @param status  Output param set to success/failure code on exit. If any value
541      *                previously set in the time field is invalid or restricted by
542      *                leniency, this will be set to an error status.
543      * @deprecated ICU 2.6. use add(UCalendarDateFields field, int32_t amount, UErrorCode& status) instead.
544      */
545     virtual void add(EDateFields field, int32_t amount, UErrorCode& status);
546 #endif  // U_FORCE_HIDE_DEPRECATED_API
547 
548     /**
549      * UDate Arithmetic function. Adds the specified (signed) amount of time to the given
550      * time field, based on the calendar's rules. For example, to subtract 5 days from
551      * the current time of the calendar, call add(Calendar::DATE, -5). When adding on
552      * the month or Calendar::MONTH field, other fields like date might conflict and
553      * need to be changed. For instance, adding 1 month on the date 01/31/96 will result
554      * in 02/29/96.
555      * Adding a positive value always means moving forward in time, so for the Gregorian calendar,
556      * starting with 100 BC and adding +1 to year results in 99 BC (even though this actually reduces
557      * the numeric value of the field itself).
558      *
559      * @param field   Specifies which date field to modify.
560      * @param amount  The amount of time to be added to the field, in the natural unit
561      *                for that field (e.g., days for the day fields, hours for the hour
562      *                field.)
563      * @param status  Output param set to success/failure code on exit. If any value
564      *                previously set in the time field is invalid or restricted by
565      *                leniency, this will be set to an error status.
566      * @stable ICU 2.6.
567      */
568     virtual void add(UCalendarDateFields field, int32_t amount, UErrorCode& status);
569 
570 #ifndef U_HIDE_DEPRECATED_API
571     /**
572      * Time Field Rolling function. Rolls (up/down) a single unit of time on the given
573      * time field. For example, to roll the current date up by one day, call
574      * roll(Calendar::DATE, true). When rolling on the year or Calendar::YEAR field, it
575      * will roll the year value in the range between getMinimum(Calendar::YEAR) and the
576      * value returned by getMaximum(Calendar::YEAR). When rolling on the month or
577      * Calendar::MONTH field, other fields like date might conflict and, need to be
578      * changed. For instance, rolling the month up on the date 01/31/96 will result in
579      * 02/29/96. Rolling up always means rolling forward in time (unless the limit of the
580      * field is reached, in which case it may pin or wrap), so for Gregorian calendar,
581      * starting with 100 BC and rolling the year up results in 99 BC.
582      * When eras have a definite beginning and end (as in the Chinese calendar, or as in
583      * most eras in the Japanese calendar) then rolling the year past either limit of the
584      * era will cause the year to wrap around. When eras only have a limit at one end,
585      * then attempting to roll the year past that limit will result in pinning the year
586      * at that limit. Note that for most calendars in which era 0 years move forward in
587      * time (such as Buddhist, Hebrew, or Islamic), it is possible for add or roll to
588      * result in negative years for era 0 (that is the only way to represent years before
589      * the calendar epoch).
590      * When rolling on the hour-in-day or Calendar::HOUR_OF_DAY field, it will roll the
591      * hour value in the range between 0 and 23, which is zero-based.
592      * <P>
593      * NOTE: Do not use this method -- use roll(EDateFields, int, UErrorCode&) instead.
594      *
595      * @param field   The time field.
596      * @param up      Indicates if the value of the specified time field is to be rolled
597      *                up or rolled down. Use true if rolling up, false otherwise.
598      * @param status  Output param set to success/failure code on exit. If any value
599      *                previously set in the time field is invalid or restricted by
600      *                leniency, this will be set to an error status.
601      * @deprecated ICU 2.6. Use roll(UCalendarDateFields field, UBool up, UErrorCode& status) instead.
602      */
603     inline void roll(EDateFields field, UBool up, UErrorCode& status);
604 #endif  /* U_HIDE_DEPRECATED_API */
605 
606     /**
607      * Time Field Rolling function. Rolls (up/down) a single unit of time on the given
608      * time field. For example, to roll the current date up by one day, call
609      * roll(Calendar::DATE, true). When rolling on the year or Calendar::YEAR field, it
610      * will roll the year value in the range between getMinimum(Calendar::YEAR) and the
611      * value returned by getMaximum(Calendar::YEAR). When rolling on the month or
612      * Calendar::MONTH field, other fields like date might conflict and, need to be
613      * changed. For instance, rolling the month up on the date 01/31/96 will result in
614      * 02/29/96. Rolling up always means rolling forward in time (unless the limit of the
615      * field is reached, in which case it may pin or wrap), so for Gregorian calendar,
616      * starting with 100 BC and rolling the year up results in 99 BC.
617      * When eras have a definite beginning and end (as in the Chinese calendar, or as in
618      * most eras in the Japanese calendar) then rolling the year past either limit of the
619      * era will cause the year to wrap around. When eras only have a limit at one end,
620      * then attempting to roll the year past that limit will result in pinning the year
621      * at that limit. Note that for most calendars in which era 0 years move forward in
622      * time (such as Buddhist, Hebrew, or Islamic), it is possible for add or roll to
623      * result in negative years for era 0 (that is the only way to represent years before
624      * the calendar epoch).
625      * When rolling on the hour-in-day or Calendar::HOUR_OF_DAY field, it will roll the
626      * hour value in the range between 0 and 23, which is zero-based.
627      * <P>
628      * NOTE: Do not use this method -- use roll(UCalendarDateFields, int, UErrorCode&) instead.
629      *
630      * @param field   The time field.
631      * @param up      Indicates if the value of the specified time field is to be rolled
632      *                up or rolled down. Use true if rolling up, false otherwise.
633      * @param status  Output param set to success/failure code on exit. If any value
634      *                previously set in the time field is invalid or restricted by
635      *                leniency, this will be set to an error status.
636      * @stable ICU 2.6.
637      */
638     inline void roll(UCalendarDateFields field, UBool up, UErrorCode& status);
639 
640 #ifndef U_FORCE_HIDE_DEPRECATED_API
641     /**
642      * Time Field Rolling function. Rolls by the given amount on the given
643      * time field. For example, to roll the current date up by one day, call
644      * roll(Calendar::DATE, +1, status). When rolling on the month or
645      * Calendar::MONTH field, other fields like date might conflict and, need to be
646      * changed. For instance, rolling the month up on the date 01/31/96 will result in
647      * 02/29/96. Rolling by a positive value always means rolling forward in time (unless
648      * the limit of the field is reached, in which case it may pin or wrap), so for
649      * Gregorian calendar, starting with 100 BC and rolling the year by + 1 results in 99 BC.
650      * When eras have a definite beginning and end (as in the Chinese calendar, or as in
651      * most eras in the Japanese calendar) then rolling the year past either limit of the
652      * era will cause the year to wrap around. When eras only have a limit at one end,
653      * then attempting to roll the year past that limit will result in pinning the year
654      * at that limit. Note that for most calendars in which era 0 years move forward in
655      * time (such as Buddhist, Hebrew, or Islamic), it is possible for add or roll to
656      * result in negative years for era 0 (that is the only way to represent years before
657      * the calendar epoch).
658      * When rolling on the hour-in-day or Calendar::HOUR_OF_DAY field, it will roll the
659      * hour value in the range between 0 and 23, which is zero-based.
660      * <P>
661      * The only difference between roll() and add() is that roll() does not change
662      * the value of more significant fields when it reaches the minimum or maximum
663      * of its range, whereas add() does.
664      *
665      * @param field   The time field.
666      * @param amount  Indicates amount to roll.
667      * @param status  Output param set to success/failure code on exit. If any value
668      *                previously set in the time field is invalid, this will be set to
669      *                an error status.
670      * @deprecated ICU 2.6. Use roll(UCalendarDateFields field, int32_t amount, UErrorCode& status) instead.
671      */
672     virtual void roll(EDateFields field, int32_t amount, UErrorCode& status);
673 #endif  // U_FORCE_HIDE_DEPRECATED_API
674 
675     /**
676      * Time Field Rolling function. Rolls by the given amount on the given
677      * time field. For example, to roll the current date up by one day, call
678      * roll(Calendar::DATE, +1, status). When rolling on the month or
679      * Calendar::MONTH field, other fields like date might conflict and, need to be
680      * changed. For instance, rolling the month up on the date 01/31/96 will result in
681      * 02/29/96. Rolling by a positive value always means rolling forward in time (unless
682      * the limit of the field is reached, in which case it may pin or wrap), so for
683      * Gregorian calendar, starting with 100 BC and rolling the year by + 1 results in 99 BC.
684      * When eras have a definite beginning and end (as in the Chinese calendar, or as in
685      * most eras in the Japanese calendar) then rolling the year past either limit of the
686      * era will cause the year to wrap around. When eras only have a limit at one end,
687      * then attempting to roll the year past that limit will result in pinning the year
688      * at that limit. Note that for most calendars in which era 0 years move forward in
689      * time (such as Buddhist, Hebrew, or Islamic), it is possible for add or roll to
690      * result in negative years for era 0 (that is the only way to represent years before
691      * the calendar epoch).
692      * When rolling on the hour-in-day or Calendar::HOUR_OF_DAY field, it will roll the
693      * hour value in the range between 0 and 23, which is zero-based.
694      * <P>
695      * The only difference between roll() and add() is that roll() does not change
696      * the value of more significant fields when it reaches the minimum or maximum
697      * of its range, whereas add() does.
698      *
699      * @param field   The time field.
700      * @param amount  Indicates amount to roll.
701      * @param status  Output param set to success/failure code on exit. If any value
702      *                previously set in the time field is invalid, this will be set to
703      *                an error status.
704      * @stable ICU 2.6.
705      */
706     virtual void roll(UCalendarDateFields field, int32_t amount, UErrorCode& status);
707 
708 #ifndef U_FORCE_HIDE_DEPRECATED_API
709     /**
710      * Return the difference between the given time and the time this
711      * calendar object is set to.  If this calendar is set
712      * <em>before</em> the given time, the returned value will be
713      * positive.  If this calendar is set <em>after</em> the given
714      * time, the returned value will be negative.  The
715      * <code>field</code> parameter specifies the units of the return
716      * value.  For example, if <code>fieldDifference(when,
717      * Calendar::MONTH)</code> returns 3, then this calendar is set to
718      * 3 months before <code>when</code>, and possibly some addition
719      * time less than one month.
720      *
721      * <p>As a side effect of this call, this calendar is advanced
722      * toward <code>when</code> by the given amount.  That is, calling
723      * this method has the side effect of calling <code>add(field,
724      * n)</code>, where <code>n</code> is the return value.
725      *
726      * <p>Usage: To use this method, call it first with the largest
727      * field of interest, then with progressively smaller fields.  For
728      * example:
729      *
730      * <pre>
731      * int y = cal->fieldDifference(when, Calendar::YEAR, err);
732      * int m = cal->fieldDifference(when, Calendar::MONTH, err);
733      * int d = cal->fieldDifference(when, Calendar::DATE, err);</pre>
734      *
735      * computes the difference between <code>cal</code> and
736      * <code>when</code> in years, months, and days.
737      *
738      * <p>Note: <code>fieldDifference()</code> is
739      * <em>asymmetrical</em>.  That is, in the following code:
740      *
741      * <pre>
742      * cal->setTime(date1, err);
743      * int m1 = cal->fieldDifference(date2, Calendar::MONTH, err);
744      * int d1 = cal->fieldDifference(date2, Calendar::DATE, err);
745      * cal->setTime(date2, err);
746      * int m2 = cal->fieldDifference(date1, Calendar::MONTH, err);
747      * int d2 = cal->fieldDifference(date1, Calendar::DATE, err);</pre>
748      *
749      * one might expect that <code>m1 == -m2 && d1 == -d2</code>.
750      * However, this is not generally the case, because of
751      * irregularities in the underlying calendar system (e.g., the
752      * Gregorian calendar has a varying number of days per month).
753      *
754      * @param when the date to compare this calendar's time to
755      * @param field the field in which to compute the result
756      * @param status  Output param set to success/failure code on exit. If any value
757      *                previously set in the time field is invalid, this will be set to
758      *                an error status.
759      * @return the difference, either positive or negative, between
760      * this calendar's time and <code>when</code>, in terms of
761      * <code>field</code>.
762      * @deprecated ICU 2.6. Use fieldDifference(UDate when, UCalendarDateFields field, UErrorCode& status).
763      */
764     virtual int32_t fieldDifference(UDate when, EDateFields field, UErrorCode& status);
765 #endif  // U_FORCE_HIDE_DEPRECATED_API
766 
767     /**
768      * Return the difference between the given time and the time this
769      * calendar object is set to.  If this calendar is set
770      * <em>before</em> the given time, the returned value will be
771      * positive.  If this calendar is set <em>after</em> the given
772      * time, the returned value will be negative.  The
773      * <code>field</code> parameter specifies the units of the return
774      * value.  For example, if <code>fieldDifference(when,
775      * Calendar::MONTH)</code> returns 3, then this calendar is set to
776      * 3 months before <code>when</code>, and possibly some addition
777      * time less than one month.
778      *
779      * <p>As a side effect of this call, this calendar is advanced
780      * toward <code>when</code> by the given amount.  That is, calling
781      * this method has the side effect of calling <code>add(field,
782      * n)</code>, where <code>n</code> is the return value.
783      *
784      * <p>Usage: To use this method, call it first with the largest
785      * field of interest, then with progressively smaller fields.  For
786      * example:
787      *
788      * <pre>
789      * int y = cal->fieldDifference(when, Calendar::YEAR, err);
790      * int m = cal->fieldDifference(when, Calendar::MONTH, err);
791      * int d = cal->fieldDifference(when, Calendar::DATE, err);</pre>
792      *
793      * computes the difference between <code>cal</code> and
794      * <code>when</code> in years, months, and days.
795      *
796      * <p>Note: <code>fieldDifference()</code> is
797      * <em>asymmetrical</em>.  That is, in the following code:
798      *
799      * <pre>
800      * cal->setTime(date1, err);
801      * int m1 = cal->fieldDifference(date2, Calendar::MONTH, err);
802      * int d1 = cal->fieldDifference(date2, Calendar::DATE, err);
803      * cal->setTime(date2, err);
804      * int m2 = cal->fieldDifference(date1, Calendar::MONTH, err);
805      * int d2 = cal->fieldDifference(date1, Calendar::DATE, err);</pre>
806      *
807      * one might expect that <code>m1 == -m2 && d1 == -d2</code>.
808      * However, this is not generally the case, because of
809      * irregularities in the underlying calendar system (e.g., the
810      * Gregorian calendar has a varying number of days per month).
811      *
812      * @param when the date to compare this calendar's time to
813      * @param field the field in which to compute the result
814      * @param status  Output param set to success/failure code on exit. If any value
815      *                previously set in the time field is invalid, this will be set to
816      *                an error status.
817      * @return the difference, either positive or negative, between
818      * this calendar's time and <code>when</code>, in terms of
819      * <code>field</code>.
820      * @stable ICU 2.6.
821      */
822     virtual int32_t fieldDifference(UDate when, UCalendarDateFields field, UErrorCode& status);
823 
824     /**
825      * Sets the calendar's time zone to be the one passed in. The Calendar takes ownership
826      * of the TimeZone; the caller is no longer responsible for deleting it.  If the
827      * given time zone is NULL, this function has no effect.
828      *
829      * @param value  The given time zone.
830      * @stable ICU 2.0
831      */
832     void adoptTimeZone(TimeZone* value);
833 
834     /**
835      * Sets the calendar's time zone to be the same as the one passed in. The TimeZone
836      * passed in is _not_ adopted; the client is still responsible for deleting it.
837      *
838      * @param zone  The given time zone.
839      * @stable ICU 2.0
840      */
841     void setTimeZone(const TimeZone& zone);
842 
843     /**
844      * Returns a reference to the time zone owned by this calendar. The returned reference
845      * is only valid until clients make another call to adoptTimeZone or setTimeZone,
846      * or this Calendar is destroyed.
847      *
848      * @return   The time zone object associated with this calendar.
849      * @stable ICU 2.0
850      */
851     const TimeZone& getTimeZone(void) const;
852 
853     /**
854      * Returns the time zone owned by this calendar. The caller owns the returned object
855      * and must delete it when done.  After this call, the new time zone associated
856      * with this Calendar is the default TimeZone as returned by TimeZone::createDefault().
857      *
858      * @return   The time zone object which was associated with this calendar.
859      * @stable ICU 2.0
860      */
861     TimeZone* orphanTimeZone(void);
862 
863     /**
864      * Queries if the current date for this Calendar is in Daylight Savings Time.
865      *
866      * @param status Fill-in parameter which receives the status of this operation.
867      * @return   True if the current date for this Calendar is in Daylight Savings Time,
868      *           false, otherwise.
869      * @stable ICU 2.0
870      */
871     virtual UBool inDaylightTime(UErrorCode& status) const = 0;
872 
873     /**
874      * Specifies whether or not date/time interpretation is to be lenient. With lenient
875      * interpretation, a date such as "February 942, 1996" will be treated as being
876      * equivalent to the 941st day after February 1, 1996. With strict interpretation,
877      * such dates will cause an error when computing time from the time field values
878      * representing the dates.
879      *
880      * @param lenient  True specifies date/time interpretation to be lenient.
881      *
882      * @see            DateFormat#setLenient
883      * @stable ICU 2.0
884      */
885     void setLenient(UBool lenient);
886 
887     /**
888      * Tells whether date/time interpretation is to be lenient.
889      *
890      * @return   True tells that date/time interpretation is to be lenient.
891      * @stable ICU 2.0
892      */
893     UBool isLenient(void) const;
894 
895     /**
896      * Sets the behavior for handling wall time repeating multiple times
897      * at negative time zone offset transitions. For example, 1:30 AM on
898      * November 6, 2011 in US Eastern time (America/New_York) occurs twice;
899      * 1:30 AM EDT, then 1:30 AM EST one hour later. When <code>UCAL_WALLTIME_FIRST</code>
900      * is used, the wall time 1:30AM in this example will be interpreted as 1:30 AM EDT
901      * (first occurrence). When <code>UCAL_WALLTIME_LAST</code> is used, it will be
902      * interpreted as 1:30 AM EST (last occurrence). The default value is
903      * <code>UCAL_WALLTIME_LAST</code>.
904      * <p>
905      * <b>Note:</b>When <code>UCAL_WALLTIME_NEXT_VALID</code> is not a valid
906      * option for this. When the argument is neither <code>UCAL_WALLTIME_FIRST</code>
907      * nor <code>UCAL_WALLTIME_LAST</code>, this method has no effect and will keep
908      * the current setting.
909      *
910      * @param option the behavior for handling repeating wall time, either
911      * <code>UCAL_WALLTIME_FIRST</code> or <code>UCAL_WALLTIME_LAST</code>.
912      * @see #getRepeatedWallTimeOption
913      * @stable ICU 49
914      */
915     void setRepeatedWallTimeOption(UCalendarWallTimeOption option);
916 
917     /**
918      * Gets the behavior for handling wall time repeating multiple times
919      * at negative time zone offset transitions.
920      *
921      * @return the behavior for handling repeating wall time, either
922      * <code>UCAL_WALLTIME_FIRST</code> or <code>UCAL_WALLTIME_LAST</code>.
923      * @see #setRepeatedWallTimeOption
924      * @stable ICU 49
925      */
926     UCalendarWallTimeOption getRepeatedWallTimeOption(void) const;
927 
928     /**
929      * Sets the behavior for handling skipped wall time at positive time zone offset
930      * transitions. For example, 2:30 AM on March 13, 2011 in US Eastern time (America/New_York)
931      * does not exist because the wall time jump from 1:59 AM EST to 3:00 AM EDT. When
932      * <code>UCAL_WALLTIME_FIRST</code> is used, 2:30 AM is interpreted as 30 minutes before 3:00 AM
933      * EDT, therefore, it will be resolved as 1:30 AM EST. When <code>UCAL_WALLTIME_LAST</code>
934      * is used, 2:30 AM is interpreted as 31 minutes after 1:59 AM EST, therefore, it will be
935      * resolved as 3:30 AM EDT. When <code>UCAL_WALLTIME_NEXT_VALID</code> is used, 2:30 AM will
936      * be resolved as next valid wall time, that is 3:00 AM EDT. The default value is
937      * <code>UCAL_WALLTIME_LAST</code>.
938      * <p>
939      * <b>Note:</b>This option is effective only when this calendar is lenient.
940      * When the calendar is strict, such non-existing wall time will cause an error.
941      *
942      * @param option the behavior for handling skipped wall time at positive time zone
943      * offset transitions, one of <code>UCAL_WALLTIME_FIRST</code>, <code>UCAL_WALLTIME_LAST</code> and
944      * <code>UCAL_WALLTIME_NEXT_VALID</code>.
945      * @see #getSkippedWallTimeOption
946      *
947      * @stable ICU 49
948      */
949     void setSkippedWallTimeOption(UCalendarWallTimeOption option);
950 
951     /**
952      * Gets the behavior for handling skipped wall time at positive time zone offset
953      * transitions.
954      *
955      * @return the behavior for handling skipped wall time, one of
956      * <code>UCAL_WALLTIME_FIRST</code>, <code>UCAL_WALLTIME_LAST</code>
957      * and <code>UCAL_WALLTIME_NEXT_VALID</code>.
958      * @see #setSkippedWallTimeOption
959      * @stable ICU 49
960      */
961     UCalendarWallTimeOption getSkippedWallTimeOption(void) const;
962 
963 #ifndef U_HIDE_DEPRECATED_API
964     /**
965      * Sets what the first day of the week is; e.g., Sunday in US, Monday in France.
966      *
967      * @param value  The given first day of the week.
968      * @deprecated ICU 2.6. Use setFirstDayOfWeek(UCalendarDaysOfWeek value) instead.
969      */
970     void setFirstDayOfWeek(EDaysOfWeek value);
971 #endif  /* U_HIDE_DEPRECATED_API */
972 
973     /**
974      * Sets what the first day of the week is; e.g., Sunday in US, Monday in France.
975      *
976      * @param value  The given first day of the week.
977      * @stable ICU 2.6.
978      */
979     void setFirstDayOfWeek(UCalendarDaysOfWeek value);
980 
981 #ifndef U_HIDE_DEPRECATED_API
982     /**
983      * Gets what the first day of the week is; e.g., Sunday in US, Monday in France.
984      *
985      * @return   The first day of the week.
986      * @deprecated ICU 2.6 use the overload with error code
987      */
988     EDaysOfWeek getFirstDayOfWeek(void) const;
989 #endif  /* U_HIDE_DEPRECATED_API */
990 
991     /**
992      * Gets what the first day of the week is; e.g., Sunday in US, Monday in France.
993      *
994      * @param status error code
995      * @return   The first day of the week.
996      * @stable ICU 2.6
997      */
998     UCalendarDaysOfWeek getFirstDayOfWeek(UErrorCode &status) const;
999 
1000     /**
1001      * Sets what the minimal days required in the first week of the year are; For
1002      * example, if the first week is defined as one that contains the first day of the
1003      * first month of a year, call the method with value 1. If it must be a full week,
1004      * use value 7.
1005      *
1006      * @param value  The given minimal days required in the first week of the year.
1007      * @stable ICU 2.0
1008      */
1009     void setMinimalDaysInFirstWeek(uint8_t value);
1010 
1011     /**
1012      * Gets what the minimal days required in the first week of the year are; e.g., if
1013      * the first week is defined as one that contains the first day of the first month
1014      * of a year, getMinimalDaysInFirstWeek returns 1. If the minimal days required must
1015      * be a full week, getMinimalDaysInFirstWeek returns 7.
1016      *
1017      * @return   The minimal days required in the first week of the year.
1018      * @stable ICU 2.0
1019      */
1020     uint8_t getMinimalDaysInFirstWeek(void) const;
1021 
1022 #ifndef U_FORCE_HIDE_DEPRECATED_API
1023     /**
1024      * Gets the minimum value for the given time field. e.g., for Gregorian
1025      * DAY_OF_MONTH, 1.
1026      *
1027      * @param field  The given time field.
1028      * @return       The minimum value for the given time field.
1029      * @deprecated ICU 2.6. Use getMinimum(UCalendarDateFields field) instead.
1030      */
1031     virtual int32_t getMinimum(EDateFields field) const;
1032 #endif  // U_FORCE_HIDE_DEPRECATED_API
1033 
1034     /**
1035      * Gets the minimum value for the given time field. e.g., for Gregorian
1036      * DAY_OF_MONTH, 1.
1037      *
1038      * @param field  The given time field.
1039      * @return       The minimum value for the given time field.
1040      * @stable ICU 2.6.
1041      */
1042     virtual int32_t getMinimum(UCalendarDateFields field) const;
1043 
1044 #ifndef U_FORCE_HIDE_DEPRECATED_API
1045     /**
1046      * Gets the maximum value for the given time field. e.g. for Gregorian DAY_OF_MONTH,
1047      * 31.
1048      *
1049      * @param field  The given time field.
1050      * @return       The maximum value for the given time field.
1051      * @deprecated ICU 2.6. Use getMaximum(UCalendarDateFields field) instead.
1052      */
1053     virtual int32_t getMaximum(EDateFields field) const;
1054 #endif  // U_FORCE_HIDE_DEPRECATED_API
1055 
1056     /**
1057      * Gets the maximum value for the given time field. e.g. for Gregorian DAY_OF_MONTH,
1058      * 31.
1059      *
1060      * @param field  The given time field.
1061      * @return       The maximum value for the given time field.
1062      * @stable ICU 2.6.
1063      */
1064     virtual int32_t getMaximum(UCalendarDateFields field) const;
1065 
1066 #ifndef U_FORCE_HIDE_DEPRECATED_API
1067     /**
1068      * Gets the highest minimum value for the given field if varies. Otherwise same as
1069      * getMinimum(). For Gregorian, no difference.
1070      *
1071      * @param field  The given time field.
1072      * @return       The highest minimum value for the given time field.
1073      * @deprecated ICU 2.6. Use getGreatestMinimum(UCalendarDateFields field) instead.
1074      */
1075     virtual int32_t getGreatestMinimum(EDateFields field) const;
1076 #endif  // U_FORCE_HIDE_DEPRECATED_API
1077 
1078     /**
1079      * Gets the highest minimum value for the given field if varies. Otherwise same as
1080      * getMinimum(). For Gregorian, no difference.
1081      *
1082      * @param field  The given time field.
1083      * @return       The highest minimum value for the given time field.
1084      * @stable ICU 2.6.
1085      */
1086     virtual int32_t getGreatestMinimum(UCalendarDateFields field) const;
1087 
1088 #ifndef U_FORCE_HIDE_DEPRECATED_API
1089     /**
1090      * Gets the lowest maximum value for the given field if varies. Otherwise same as
1091      * getMaximum(). e.g., for Gregorian DAY_OF_MONTH, 28.
1092      *
1093      * @param field  The given time field.
1094      * @return       The lowest maximum value for the given time field.
1095      * @deprecated ICU 2.6. Use getLeastMaximum(UCalendarDateFields field) instead.
1096      */
1097     virtual int32_t getLeastMaximum(EDateFields field) const;
1098 #endif  // U_FORCE_HIDE_DEPRECATED_API
1099 
1100     /**
1101      * Gets the lowest maximum value for the given field if varies. Otherwise same as
1102      * getMaximum(). e.g., for Gregorian DAY_OF_MONTH, 28.
1103      *
1104      * @param field  The given time field.
1105      * @return       The lowest maximum value for the given time field.
1106      * @stable ICU 2.6.
1107      */
1108     virtual int32_t getLeastMaximum(UCalendarDateFields field) const;
1109 
1110 #ifndef U_HIDE_DEPRECATED_API
1111     /**
1112      * Return the minimum value that this field could have, given the current date.
1113      * For the Gregorian calendar, this is the same as getMinimum() and getGreatestMinimum().
1114      *
1115      * The version of this function on Calendar uses an iterative algorithm to determine the
1116      * actual minimum value for the field.  There is almost always a more efficient way to
1117      * accomplish this (in most cases, you can simply return getMinimum()).  GregorianCalendar
1118      * overrides this function with a more efficient implementation.
1119      *
1120      * @param field    the field to determine the minimum of
1121      * @param status   Fill-in parameter which receives the status of this operation.
1122      * @return         the minimum of the given field for the current date of this Calendar
1123      * @deprecated ICU 2.6. Use getActualMinimum(UCalendarDateFields field, UErrorCode& status) instead.
1124      */
1125     int32_t getActualMinimum(EDateFields field, UErrorCode& status) const;
1126 #endif  /* U_HIDE_DEPRECATED_API */
1127 
1128     /**
1129      * Return the minimum value that this field could have, given the current date.
1130      * For the Gregorian calendar, this is the same as getMinimum() and getGreatestMinimum().
1131      *
1132      * The version of this function on Calendar uses an iterative algorithm to determine the
1133      * actual minimum value for the field.  There is almost always a more efficient way to
1134      * accomplish this (in most cases, you can simply return getMinimum()).  GregorianCalendar
1135      * overrides this function with a more efficient implementation.
1136      *
1137      * @param field    the field to determine the minimum of
1138      * @param status   Fill-in parameter which receives the status of this operation.
1139      * @return         the minimum of the given field for the current date of this Calendar
1140      * @stable ICU 2.6.
1141      */
1142     virtual int32_t getActualMinimum(UCalendarDateFields field, UErrorCode& status) const;
1143 
1144 #ifndef U_HIDE_DEPRECATED_API
1145     /**
1146      * Return the maximum value that this field could have, given the current date.
1147      * For example, with the date "Feb 3, 1997" and the DAY_OF_MONTH field, the actual
1148      * maximum would be 28; for "Feb 3, 1996" it s 29.  Similarly for a Hebrew calendar,
1149      * for some years the actual maximum for MONTH is 12, and for others 13.
1150      *
1151      * The version of this function on Calendar uses an iterative algorithm to determine the
1152      * actual maximum value for the field.  There is almost always a more efficient way to
1153      * accomplish this (in most cases, you can simply return getMaximum()).  GregorianCalendar
1154      * overrides this function with a more efficient implementation.
1155      *
1156      * @param field    the field to determine the maximum of
1157      * @param status   Fill-in parameter which receives the status of this operation.
1158      * @return         the maximum of the given field for the current date of this Calendar
1159      * @deprecated ICU 2.6. Use getActualMaximum(UCalendarDateFields field, UErrorCode& status) instead.
1160      */
1161     int32_t getActualMaximum(EDateFields field, UErrorCode& status) const;
1162 #endif  /* U_HIDE_DEPRECATED_API */
1163 
1164     /**
1165      * Return the maximum value that this field could have, given the current date.
1166      * For example, with the date "Feb 3, 1997" and the DAY_OF_MONTH field, the actual
1167      * maximum would be 28; for "Feb 3, 1996" it s 29.  Similarly for a Hebrew calendar,
1168      * for some years the actual maximum for MONTH is 12, and for others 13.
1169      *
1170      * The version of this function on Calendar uses an iterative algorithm to determine the
1171      * actual maximum value for the field.  There is almost always a more efficient way to
1172      * accomplish this (in most cases, you can simply return getMaximum()).  GregorianCalendar
1173      * overrides this function with a more efficient implementation.
1174      *
1175      * @param field    the field to determine the maximum of
1176      * @param status   Fill-in parameter which receives the status of this operation.
1177      * @return         the maximum of the given field for the current date of this Calendar
1178      * @stable ICU 2.6.
1179      */
1180     virtual int32_t getActualMaximum(UCalendarDateFields field, UErrorCode& status) const;
1181 
1182 #ifndef U_HIDE_DEPRECATED_API
1183     /**
1184      * Gets the value for a given time field. Recalculate the current time field values
1185      * if the time value has been changed by a call to setTime(). Return zero for unset
1186      * fields if any fields have been explicitly set by a call to set(). To force a
1187      * recomputation of all fields regardless of the previous state, call complete().
1188      * This method is semantically const, but may alter the object in memory.
1189      *
1190      * @param field  The given time field.
1191      * @param status Fill-in parameter which receives the status of the operation.
1192      * @return       The value for the given time field, or zero if the field is unset,
1193      *               and set() has been called for any other field.
1194      * @deprecated ICU 2.6. Use get(UCalendarDateFields field, UErrorCode& status) instead.
1195      */
1196     int32_t get(EDateFields field, UErrorCode& status) const;
1197 #endif  /* U_HIDE_DEPRECATED_API */
1198 
1199     /**
1200      * Gets the value for a given time field. Recalculate the current time field values
1201      * if the time value has been changed by a call to setTime(). Return zero for unset
1202      * fields if any fields have been explicitly set by a call to set(). To force a
1203      * recomputation of all fields regardless of the previous state, call complete().
1204      * This method is semantically const, but may alter the object in memory.
1205      *
1206      * @param field  The given time field.
1207      * @param status Fill-in parameter which receives the status of the operation.
1208      * @return       The value for the given time field, or zero if the field is unset,
1209      *               and set() has been called for any other field.
1210      * @stable ICU 2.6.
1211      */
1212     int32_t get(UCalendarDateFields field, UErrorCode& status) const;
1213 
1214 #ifndef U_HIDE_DEPRECATED_API
1215     /**
1216      * Determines if the given time field has a value set. This can affect in the
1217      * resolving of time in Calendar. Unset fields have a value of zero, by definition.
1218      *
1219      * @param field  The given time field.
1220      * @return   True if the given time field has a value set; false otherwise.
1221      * @deprecated ICU 2.6. Use isSet(UCalendarDateFields field) instead.
1222      */
1223     UBool isSet(EDateFields field) const;
1224 #endif  /* U_HIDE_DEPRECATED_API */
1225 
1226     /**
1227      * Determines if the given time field has a value set. This can affect in the
1228      * resolving of time in Calendar. Unset fields have a value of zero, by definition.
1229      *
1230      * @param field  The given time field.
1231      * @return   True if the given time field has a value set; false otherwise.
1232      * @stable ICU 2.6.
1233      */
1234     UBool isSet(UCalendarDateFields field) const;
1235 
1236 #ifndef U_HIDE_DEPRECATED_API
1237     /**
1238      * Sets the given time field with the given value.
1239      *
1240      * @param field  The given time field.
1241      * @param value  The value to be set for the given time field.
1242      * @deprecated ICU 2.6. Use set(UCalendarDateFields field, int32_t value) instead.
1243      */
1244     void set(EDateFields field, int32_t value);
1245 #endif  /* U_HIDE_DEPRECATED_API */
1246 
1247     /**
1248      * Sets the given time field with the given value.
1249      *
1250      * @param field  The given time field.
1251      * @param value  The value to be set for the given time field.
1252      * @stable ICU 2.6.
1253      */
1254     void set(UCalendarDateFields field, int32_t value);
1255 
1256     /**
1257      * Sets the values for the fields YEAR, MONTH, and DATE. Other field values are
1258      * retained; call clear() first if this is not desired.
1259      *
1260      * @param year   The value used to set the YEAR time field.
1261      * @param month  The value used to set the MONTH time field. Month value is 0-based.
1262      *               e.g., 0 for January.
1263      * @param date   The value used to set the DATE time field.
1264      * @stable ICU 2.0
1265      */
1266     void set(int32_t year, int32_t month, int32_t date);
1267 
1268     /**
1269      * Sets the values for the fields YEAR, MONTH, DATE, HOUR_OF_DAY, and MINUTE. Other
1270      * field values are retained; call clear() first if this is not desired.
1271      *
1272      * @param year    The value used to set the YEAR time field.
1273      * @param month   The value used to set the MONTH time field. Month value is
1274      *                0-based. E.g., 0 for January.
1275      * @param date    The value used to set the DATE time field.
1276      * @param hour    The value used to set the HOUR_OF_DAY time field.
1277      * @param minute  The value used to set the MINUTE time field.
1278      * @stable ICU 2.0
1279      */
1280     void set(int32_t year, int32_t month, int32_t date, int32_t hour, int32_t minute);
1281 
1282     /**
1283      * Sets the values for the fields YEAR, MONTH, DATE, HOUR_OF_DAY, MINUTE, and SECOND.
1284      * Other field values are retained; call clear() first if this is not desired.
1285      *
1286      * @param year    The value used to set the YEAR time field.
1287      * @param month   The value used to set the MONTH time field. Month value is
1288      *                0-based. E.g., 0 for January.
1289      * @param date    The value used to set the DATE time field.
1290      * @param hour    The value used to set the HOUR_OF_DAY time field.
1291      * @param minute  The value used to set the MINUTE time field.
1292      * @param second  The value used to set the SECOND time field.
1293      * @stable ICU 2.0
1294      */
1295     void set(int32_t year, int32_t month, int32_t date, int32_t hour, int32_t minute, int32_t second);
1296 
1297     /**
1298      * Clears the values of all the time fields, making them both unset and assigning
1299      * them a value of zero. The field values will be determined during the next
1300      * resolving of time into time fields.
1301      * @stable ICU 2.0
1302      */
1303     void clear(void);
1304 
1305 #ifndef U_HIDE_DEPRECATED_API
1306     /**
1307      * Clears the value in the given time field, both making it unset and assigning it a
1308      * value of zero. This field value will be determined during the next resolving of
1309      * time into time fields.
1310      *
1311      * @param field  The time field to be cleared.
1312      * @deprecated ICU 2.6. Use clear(UCalendarDateFields field) instead.
1313      */
1314     void clear(EDateFields field);
1315 #endif  /* U_HIDE_DEPRECATED_API */
1316 
1317     /**
1318      * Clears the value in the given time field, both making it unset and assigning it a
1319      * value of zero. This field value will be determined during the next resolving of
1320      * time into time fields.
1321      *
1322      * @param field  The time field to be cleared.
1323      * @stable ICU 2.6.
1324      */
1325     void clear(UCalendarDateFields field);
1326 
1327     /**
1328      * Returns a unique class ID POLYMORPHICALLY. Pure virtual method. This method is to
1329      * implement a simple version of RTTI, since not all C++ compilers support genuine
1330      * RTTI. Polymorphic operator==() and clone() methods call this method.
1331      * <P>
1332      * Concrete subclasses of Calendar must implement getDynamicClassID() and also a
1333      * static method and data member:
1334      *
1335      *      static UClassID getStaticClassID() { return (UClassID)&amp;fgClassID; }
1336      *      static char fgClassID;
1337      *
1338      * @return   The class ID for this object. All objects of a given class have the
1339      *           same class ID. Objects of other classes have different class IDs.
1340      * @stable ICU 2.0
1341      */
1342     virtual UClassID getDynamicClassID(void) const = 0;
1343 
1344     /**
1345      * Returns the calendar type name string for this Calendar object.
1346      * The returned string is the legacy ICU calendar attribute value,
1347      * for example, "gregorian" or "japanese".
1348      *
1349      * See type="old type name" for the calendar attribute of locale IDs
1350      * at http://www.unicode.org/reports/tr35/#Key_Type_Definitions
1351      *
1352      * Sample code for getting the LDML/BCP 47 calendar key value:
1353      * \code
1354      * const char *calType = cal->getType();
1355      * if (0 == strcmp(calType, "unknown")) {
1356      *     // deal with unknown calendar type
1357      * } else {
1358      *     string localeID("root@calendar=");
1359      *     localeID.append(calType);
1360      *     char langTag[100];
1361      *     UErrorCode errorCode = U_ZERO_ERROR;
1362      *     int32_t length = uloc_toLanguageTag(localeID.c_str(), langTag, (int32_t)sizeof(langTag), TRUE, &errorCode);
1363      *     if (U_FAILURE(errorCode)) {
1364      *         // deal with errors & overflow
1365      *     }
1366      *     string lang(langTag, length);
1367      *     size_t caPos = lang.find("-ca-");
1368      *     lang.erase(0, caPos + 4);
1369      *     // lang now contains the LDML calendar type
1370      * }
1371      * \endcode
1372      *
1373      * @return legacy calendar type name string
1374      * @stable ICU 49
1375      */
1376     virtual const char * getType() const = 0;
1377 
1378     /**
1379      * Returns whether the given day of the week is a weekday, a weekend day,
1380      * or a day that transitions from one to the other, for the locale and
1381      * calendar system associated with this Calendar (the locale's region is
1382      * often the most determinant factor). If a transition occurs at midnight,
1383      * then the days before and after the transition will have the
1384      * type UCAL_WEEKDAY or UCAL_WEEKEND. If a transition occurs at a time
1385      * other than midnight, then the day of the transition will have
1386      * the type UCAL_WEEKEND_ONSET or UCAL_WEEKEND_CEASE. In this case, the
1387      * method getWeekendTransition() will return the point of
1388      * transition.
1389      * @param dayOfWeek The day of the week whose type is desired (UCAL_SUNDAY..UCAL_SATURDAY).
1390      * @param status The error code for the operation.
1391      * @return The UCalendarWeekdayType for the day of the week.
1392      * @stable ICU 4.4
1393      */
1394     virtual UCalendarWeekdayType getDayOfWeekType(UCalendarDaysOfWeek dayOfWeek, UErrorCode &status) const;
1395 
1396     /**
1397      * Returns the time during the day at which the weekend begins or ends in
1398      * this calendar system.  If getDayOfWeekType() returns UCAL_WEEKEND_ONSET
1399      * for the specified dayOfWeek, return the time at which the weekend begins.
1400      * If getDayOfWeekType() returns UCAL_WEEKEND_CEASE for the specified dayOfWeek,
1401      * return the time at which the weekend ends. If getDayOfWeekType() returns
1402      * some other UCalendarWeekdayType for the specified dayOfWeek, is it an error condition
1403      * (U_ILLEGAL_ARGUMENT_ERROR).
1404      * @param dayOfWeek The day of the week for which the weekend transition time is
1405      * desired (UCAL_SUNDAY..UCAL_SATURDAY).
1406      * @param status The error code for the operation.
1407      * @return The milliseconds after midnight at which the weekend begins or ends.
1408      * @stable ICU 4.4
1409      */
1410     virtual int32_t getWeekendTransition(UCalendarDaysOfWeek dayOfWeek, UErrorCode &status) const;
1411 
1412     /**
1413      * Returns TRUE if the given UDate is in the weekend in
1414      * this calendar system.
1415      * @param date The UDate in question.
1416      * @param status The error code for the operation.
1417      * @return TRUE if the given UDate is in the weekend in
1418      * this calendar system, FALSE otherwise.
1419      * @stable ICU 4.4
1420      */
1421     virtual UBool isWeekend(UDate date, UErrorCode &status) const;
1422 
1423     /**
1424      * Returns TRUE if this Calendar's current date-time is in the weekend in
1425      * this calendar system.
1426      * @return TRUE if this Calendar's current date-time is in the weekend in
1427      * this calendar system, FALSE otherwise.
1428      * @stable ICU 4.4
1429      */
1430     virtual UBool isWeekend(void) const;
1431 
1432 protected:
1433 
1434      /**
1435       * Constructs a Calendar with the default time zone as returned by
1436       * TimeZone::createInstance(), and the default locale.
1437       *
1438       * @param success  Indicates the status of Calendar object construction. Returns
1439       *                 U_ZERO_ERROR if constructed successfully.
1440      * @stable ICU 2.0
1441       */
1442     Calendar(UErrorCode& success);
1443 
1444     /**
1445      * Copy constructor
1446      *
1447      * @param source    Calendar object to be copied from
1448      * @stable ICU 2.0
1449      */
1450     Calendar(const Calendar& source);
1451 
1452     /**
1453      * Default assignment operator
1454      *
1455      * @param right    Calendar object to be copied
1456      * @stable ICU 2.0
1457      */
1458     Calendar& operator=(const Calendar& right);
1459 
1460     /**
1461      * Constructs a Calendar with the given time zone and locale. Clients are no longer
1462      * responsible for deleting the given time zone object after it's adopted.
1463      *
1464      * @param zone     The given time zone.
1465      * @param aLocale  The given locale.
1466      * @param success  Indicates the status of Calendar object construction. Returns
1467      *                 U_ZERO_ERROR if constructed successfully.
1468      * @stable ICU 2.0
1469      */
1470     Calendar(TimeZone* zone, const Locale& aLocale, UErrorCode& success);
1471 
1472     /**
1473      * Constructs a Calendar with the given time zone and locale.
1474      *
1475      * @param zone     The given time zone.
1476      * @param aLocale  The given locale.
1477      * @param success  Indicates the status of Calendar object construction. Returns
1478      *                 U_ZERO_ERROR if constructed successfully.
1479      * @stable ICU 2.0
1480      */
1481     Calendar(const TimeZone& zone, const Locale& aLocale, UErrorCode& success);
1482 
1483     /**
1484      * Converts Calendar's time field values to GMT as milliseconds.
1485      *
1486      * @param status  Output param set to success/failure code on exit. If any value
1487      *                previously set in the time field is invalid or restricted by
1488      *                leniency, this will be set to an error status.
1489      * @stable ICU 2.0
1490      */
1491     virtual void computeTime(UErrorCode& status);
1492 
1493     /**
1494      * Converts GMT as milliseconds to time field values. This allows you to sync up the
1495      * time field values with a new time that is set for the calendar.  This method
1496      * does NOT recompute the time first; to recompute the time, then the fields, use
1497      * the method complete().
1498      *
1499      * @param status  Output param set to success/failure code on exit. If any value
1500      *                previously set in the time field is invalid or restricted by
1501      *                leniency, this will be set to an error status.
1502      * @stable ICU 2.0
1503      */
1504     virtual void computeFields(UErrorCode& status);
1505 
1506     /**
1507      * Gets this Calendar's current time as a long.
1508      *
1509      * @param status  Output param set to success/failure code on exit. If any value
1510      *                previously set in the time field is invalid or restricted by
1511      *                leniency, this will be set to an error status.
1512      * @return the current time as UTC milliseconds from the epoch.
1513      * @stable ICU 2.0
1514      */
1515     double getTimeInMillis(UErrorCode& status) const;
1516 
1517     /**
1518      * Sets this Calendar's current time from the given long value.
1519      * @param millis  the new time in UTC milliseconds from the epoch.
1520      * @param status  Output param set to success/failure code on exit. If any value
1521      *                previously set in the time field is invalid or restricted by
1522      *                leniency, this will be set to an error status.
1523      * @stable ICU 2.0
1524      */
1525     void setTimeInMillis( double millis, UErrorCode& status );
1526 
1527     /**
1528      * Recomputes the current time from currently set fields, and then fills in any
1529      * unset fields in the time field list.
1530      *
1531      * @param status  Output param set to success/failure code on exit. If any value
1532      *                previously set in the time field is invalid or restricted by
1533      *                leniency, this will be set to an error status.
1534      * @stable ICU 2.0
1535      */
1536     void complete(UErrorCode& status);
1537 
1538 #ifndef U_HIDE_DEPRECATED_API
1539     /**
1540      * Gets the value for a given time field. Subclasses can use this function to get
1541      * field values without forcing recomputation of time.
1542      *
1543      * @param field  The given time field.
1544      * @return       The value for the given time field.
1545      * @deprecated ICU 2.6. Use internalGet(UCalendarDateFields field) instead.
1546      */
internalGet(EDateFields field)1547     inline int32_t internalGet(EDateFields field) const {return fFields[field];}
1548 #endif  /* U_HIDE_DEPRECATED_API */
1549 
1550 #ifndef U_HIDE_INTERNAL_API
1551     /**
1552      * Gets the value for a given time field. Subclasses can use this function to get
1553      * field values without forcing recomputation of time. If the field's stamp is UNSET,
1554      * the defaultValue is used.
1555      *
1556      * @param field  The given time field.
1557      * @param defaultValue a default value used if the field is unset.
1558      * @return       The value for the given time field.
1559      * @internal
1560      */
internalGet(UCalendarDateFields field,int32_t defaultValue)1561     inline int32_t internalGet(UCalendarDateFields field, int32_t defaultValue) const {return fStamp[field]>kUnset ? fFields[field] : defaultValue;}
1562 
1563     /**
1564      * Gets the value for a given time field. Subclasses can use this function to get
1565      * field values without forcing recomputation of time.
1566      *
1567      * @param field  The given time field.
1568      * @return       The value for the given time field.
1569      * @internal
1570      */
internalGet(UCalendarDateFields field)1571     inline int32_t internalGet(UCalendarDateFields field) const {return fFields[field];}
1572 #endif  /* U_HIDE_INTERNAL_API */
1573 
1574 #ifndef U_HIDE_DEPRECATED_API
1575     /**
1576      * Sets the value for a given time field.  This is a fast internal method for
1577      * subclasses.  It does not affect the areFieldsInSync, isTimeSet, or areAllFieldsSet
1578      * flags.
1579      *
1580      * @param field    The given time field.
1581      * @param value    The value for the given time field.
1582      * @deprecated ICU 2.6. Use internalSet(UCalendarDateFields field, int32_t value) instead.
1583      */
1584     void internalSet(EDateFields field, int32_t value);
1585 #endif  /* U_HIDE_DEPRECATED_API */
1586 
1587     /**
1588      * Sets the value for a given time field.  This is a fast internal method for
1589      * subclasses.  It does not affect the areFieldsInSync, isTimeSet, or areAllFieldsSet
1590      * flags.
1591      *
1592      * @param field    The given time field.
1593      * @param value    The value for the given time field.
1594      * @stable ICU 2.6.
1595      */
1596     inline void internalSet(UCalendarDateFields field, int32_t value);
1597 
1598     /**
1599      * Prepare this calendar for computing the actual minimum or maximum.
1600      * This method modifies this calendar's fields; it is called on a
1601      * temporary calendar.
1602      * @internal
1603      */
1604     virtual void prepareGetActual(UCalendarDateFields field, UBool isMinimum, UErrorCode &status);
1605 
1606     /**
1607      * Limit enums. Not in sync with UCalendarLimitType (refers to internal fields).
1608      * @internal
1609      */
1610     enum ELimitType {
1611 #ifndef U_HIDE_INTERNAL_API
1612       UCAL_LIMIT_MINIMUM = 0,
1613       UCAL_LIMIT_GREATEST_MINIMUM,
1614       UCAL_LIMIT_LEAST_MAXIMUM,
1615       UCAL_LIMIT_MAXIMUM,
1616       UCAL_LIMIT_COUNT
1617 #endif  /* U_HIDE_INTERNAL_API */
1618     };
1619 
1620     /**
1621      * Subclass API for defining limits of different types.
1622      * Subclasses must implement this method to return limits for the
1623      * following fields:
1624      *
1625      * <pre>UCAL_ERA
1626      * UCAL_YEAR
1627      * UCAL_MONTH
1628      * UCAL_WEEK_OF_YEAR
1629      * UCAL_WEEK_OF_MONTH
1630      * UCAL_DATE (DAY_OF_MONTH on Java)
1631      * UCAL_DAY_OF_YEAR
1632      * UCAL_DAY_OF_WEEK_IN_MONTH
1633      * UCAL_YEAR_WOY
1634      * UCAL_EXTENDED_YEAR</pre>
1635      *
1636      * @param field one of the above field numbers
1637      * @param limitType one of <code>MINIMUM</code>, <code>GREATEST_MINIMUM</code>,
1638      * <code>LEAST_MAXIMUM</code>, or <code>MAXIMUM</code>
1639      * @internal
1640      */
1641     virtual int32_t handleGetLimit(UCalendarDateFields field, ELimitType limitType) const = 0;
1642 
1643     /**
1644      * Return a limit for a field.
1645      * @param field the field, from <code>0..UCAL_MAX_FIELD</code>
1646      * @param limitType the type specifier for the limit
1647      * @see #ELimitType
1648      * @internal
1649      */
1650     virtual int32_t getLimit(UCalendarDateFields field, ELimitType limitType) const;
1651 
1652 
1653     /**
1654      * Return the Julian day number of day before the first day of the
1655      * given month in the given extended year.  Subclasses should override
1656      * this method to implement their calendar system.
1657      * @param eyear the extended year
1658      * @param month the zero-based month, or 0 if useMonth is false
1659      * @param useMonth if false, compute the day before the first day of
1660      * the given year, otherwise, compute the day before the first day of
1661      * the given month
1662      * @return the Julian day number of the day before the first
1663      * day of the given month and year
1664      * @internal
1665      */
1666     virtual int32_t handleComputeMonthStart(int32_t eyear, int32_t month,
1667                                                    UBool useMonth) const  = 0;
1668 
1669     /**
1670      * Return the number of days in the given month of the given extended
1671      * year of this calendar system.  Subclasses should override this
1672      * method if they can provide a more correct or more efficient
1673      * implementation than the default implementation in Calendar.
1674      * @internal
1675      */
1676     virtual int32_t handleGetMonthLength(int32_t extendedYear, int32_t month) const ;
1677 
1678     /**
1679      * Return the number of days in the given extended year of this
1680      * calendar system.  Subclasses should override this method if they can
1681      * provide a more correct or more efficient implementation than the
1682      * default implementation in Calendar.
1683      * @stable ICU 2.0
1684      */
1685     virtual int32_t handleGetYearLength(int32_t eyear) const;
1686 
1687 
1688     /**
1689      * Return the extended year defined by the current fields.  This will
1690      * use the UCAL_EXTENDED_YEAR field or the UCAL_YEAR and supra-year fields (such
1691      * as UCAL_ERA) specific to the calendar system, depending on which set of
1692      * fields is newer.
1693      * @return the extended year
1694      * @internal
1695      */
1696     virtual int32_t handleGetExtendedYear() = 0;
1697 
1698     /**
1699      * Subclasses may override this.  This method calls
1700      * handleGetMonthLength() to obtain the calendar-specific month
1701      * length.
1702      * @param bestField which field to use to calculate the date
1703      * @return julian day specified by calendar fields.
1704      * @internal
1705      */
1706     virtual int32_t handleComputeJulianDay(UCalendarDateFields bestField);
1707 
1708     /**
1709      * Subclasses must override this to convert from week fields
1710      * (YEAR_WOY and WEEK_OF_YEAR) to an extended year in the case
1711      * where YEAR, EXTENDED_YEAR are not set.
1712      * The Calendar implementation assumes yearWoy is in extended gregorian form
1713      * @return the extended year, UCAL_EXTENDED_YEAR
1714      * @internal
1715      */
1716     virtual int32_t handleGetExtendedYearFromWeekFields(int32_t yearWoy, int32_t woy);
1717 
1718     /**
1719      * Validate a single field of this calendar.  Subclasses should
1720      * override this method to validate any calendar-specific fields.
1721      * Generic fields can be handled by `Calendar::validateField()`.
1722      * @internal
1723      */
1724     virtual void validateField(UCalendarDateFields field, UErrorCode &status);
1725 
1726 #ifndef U_HIDE_INTERNAL_API
1727     /**
1728      * Compute the Julian day from fields.  Will determine whether to use
1729      * the JULIAN_DAY field directly, or other fields.
1730      * @return the julian day
1731      * @internal
1732      */
1733     int32_t computeJulianDay();
1734 
1735     /**
1736      * Compute the milliseconds in the day from the fields.  This is a
1737      * value from 0 to 23:59:59.999 inclusive, unless fields are out of
1738      * range, in which case it can be an arbitrary value.  This value
1739      * reflects local zone wall time.
1740      * @internal
1741      */
1742     double computeMillisInDay();
1743 
1744     /**
1745      * This method can assume EXTENDED_YEAR has been set.
1746      * @param millis milliseconds of the date fields
1747      * @param millisInDay milliseconds of the time fields; may be out
1748      * or range.
1749      * @param ec Output param set to failure code on function return
1750      *          when this function fails.
1751      * @internal
1752      */
1753     int32_t computeZoneOffset(double millis, double millisInDay, UErrorCode &ec);
1754 
1755 
1756     /**
1757      * Determine the best stamp in a range.
1758      * @param start first enum to look at
1759      * @param end last enum to look at
1760      * @param bestSoFar stamp prior to function call
1761      * @return the stamp value of the best stamp
1762      * @internal
1763      */
1764     int32_t newestStamp(UCalendarDateFields start, UCalendarDateFields end, int32_t bestSoFar) const;
1765 
1766     /**
1767      * Values for field resolution tables
1768      * @see #resolveFields
1769      * @internal
1770      */
1771     enum {
1772       /** Marker for end of resolve set (row or group). */
1773       kResolveSTOP = -1,
1774       /** 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.  */
1775       kResolveRemap = 32
1776     };
1777 
1778     /**
1779      * Precedence table for Dates
1780      * @see #resolveFields
1781      * @internal
1782      */
1783     static const UFieldResolutionTable kDatePrecedence[];
1784 
1785     /**
1786      * Precedence table for Year
1787      * @see #resolveFields
1788      * @internal
1789      */
1790     static const UFieldResolutionTable kYearPrecedence[];
1791 
1792     /**
1793      * Precedence table for Day of Week
1794      * @see #resolveFields
1795      * @internal
1796      */
1797     static const UFieldResolutionTable kDOWPrecedence[];
1798 
1799     /**
1800      * Given a precedence table, return the newest field combination in
1801      * the table, or UCAL_FIELD_COUNT if none is found.
1802      *
1803      * <p>The precedence table is a 3-dimensional array of integers.  It
1804      * may be thought of as an array of groups.  Each group is an array of
1805      * lines.  Each line is an array of field numbers.  Within a line, if
1806      * all fields are set, then the time stamp of the line is taken to be
1807      * the stamp of the most recently set field.  If any field of a line is
1808      * unset, then the line fails to match.  Within a group, the line with
1809      * the newest time stamp is selected.  The first field of the line is
1810      * returned to indicate which line matched.
1811      *
1812      * <p>In some cases, it may be desirable to map a line to field that
1813      * whose stamp is NOT examined.  For example, if the best field is
1814      * DAY_OF_WEEK then the DAY_OF_WEEK_IN_MONTH algorithm may be used.  In
1815      * order to do this, insert the value <code>kResolveRemap | F</code> at
1816      * the start of the line, where <code>F</code> is the desired return
1817      * field value.  This field will NOT be examined; it only determines
1818      * the return value if the other fields in the line are the newest.
1819      *
1820      * <p>If all lines of a group contain at least one unset field, then no
1821      * line will match, and the group as a whole will fail to match.  In
1822      * that case, the next group will be processed.  If all groups fail to
1823      * match, then UCAL_FIELD_COUNT is returned.
1824      * @internal
1825      */
1826     UCalendarDateFields resolveFields(const UFieldResolutionTable *precedenceTable);
1827 #endif  /* U_HIDE_INTERNAL_API */
1828 
1829 
1830     /**
1831      * @internal
1832      */
1833     virtual const UFieldResolutionTable* getFieldResolutionTable() const;
1834 
1835 #ifndef U_HIDE_INTERNAL_API
1836     /**
1837      * Return the field that is newer, either defaultField, or
1838      * alternateField.  If neither is newer or neither is set, return defaultField.
1839      * @internal
1840      */
1841     UCalendarDateFields newerField(UCalendarDateFields defaultField, UCalendarDateFields alternateField) const;
1842 #endif  /* U_HIDE_INTERNAL_API */
1843 
1844 
1845 private:
1846     /**
1847      * Helper function for calculating limits by trial and error
1848      * @param field The field being investigated
1849      * @param startValue starting (least max) value of field
1850      * @param endValue ending (greatest max) value of field
1851      * @param status return type
1852      * @internal
1853      */
1854     int32_t getActualHelper(UCalendarDateFields field, int32_t startValue, int32_t endValue, UErrorCode &status) const;
1855 
1856 
1857 protected:
1858     /**
1859      * The flag which indicates if the current time is set in the calendar.
1860      * @stable ICU 2.0
1861      */
1862     UBool      fIsTimeSet;
1863 
1864     /**
1865      * True if the fields are in sync with the currently set time of this Calendar.
1866      * If false, then the next attempt to get the value of a field will
1867      * force a recomputation of all fields from the current value of the time
1868      * field.
1869      * <P>
1870      * This should really be named areFieldsInSync, but the old name is retained
1871      * for backward compatibility.
1872      * @stable ICU 2.0
1873      */
1874     UBool      fAreFieldsSet;
1875 
1876     /**
1877      * True if all of the fields have been set.  This is initially false, and set to
1878      * true by computeFields().
1879      * @stable ICU 2.0
1880      */
1881     UBool      fAreAllFieldsSet;
1882 
1883     /**
1884      * True if all fields have been virtually set, but have not yet been
1885      * computed.  This occurs only in setTimeInMillis().  A calendar set
1886      * to this state will compute all fields from the time if it becomes
1887      * necessary, but otherwise will delay such computation.
1888      * @stable ICU 3.0
1889      */
1890     UBool fAreFieldsVirtuallySet;
1891 
1892     /**
1893      * Get the current time without recomputing.
1894      *
1895      * @return     the current time without recomputing.
1896      * @stable ICU 2.0
1897      */
internalGetTime(void)1898     UDate        internalGetTime(void) const     { return fTime; }
1899 
1900     /**
1901      * Set the current time without affecting flags or fields.
1902      *
1903      * @param time    The time to be set
1904      * @return        the current time without recomputing.
1905      * @stable ICU 2.0
1906      */
internalSetTime(UDate time)1907     void        internalSetTime(UDate time)     { fTime = time; }
1908 
1909     /**
1910      * The time fields containing values into which the millis is computed.
1911      * @stable ICU 2.0
1912      */
1913     int32_t     fFields[UCAL_FIELD_COUNT];
1914 
1915 #ifndef U_FORCE_HIDE_DEPRECATED_API
1916     /**
1917      * The flags which tell if a specified time field for the calendar is set.
1918      * @deprecated ICU 2.8 use (fStamp[n]!=kUnset)
1919      */
1920     UBool      fIsSet[UCAL_FIELD_COUNT];
1921 #endif  // U_FORCE_HIDE_DEPRECATED_API
1922 
1923     /** Special values of stamp[]
1924      * @stable ICU 2.0
1925      */
1926     enum {
1927         kUnset                 = 0,
1928         kInternallySet,
1929         kMinimumUserStamp
1930     };
1931 
1932     /**
1933      * Pseudo-time-stamps which specify when each field was set. There
1934      * are two special values, UNSET and INTERNALLY_SET. Values from
1935      * MINIMUM_USER_SET to Integer.MAX_VALUE are legal user set values.
1936      * @stable ICU 2.0
1937      */
1938     int32_t        fStamp[UCAL_FIELD_COUNT];
1939 
1940     /**
1941      * Subclasses may override this method to compute several fields
1942      * specific to each calendar system.  These are:
1943      *
1944      * <ul><li>ERA
1945      * <li>YEAR
1946      * <li>MONTH
1947      * <li>DAY_OF_MONTH
1948      * <li>DAY_OF_YEAR
1949      * <li>EXTENDED_YEAR</ul>
1950      *
1951      * Subclasses can refer to the DAY_OF_WEEK and DOW_LOCAL fields, which
1952      * will be set when this method is called.  Subclasses can also call
1953      * the getGregorianXxx() methods to obtain Gregorian calendar
1954      * equivalents for the given Julian day.
1955      *
1956      * <p>In addition, subclasses should compute any subclass-specific
1957      * fields, that is, fields from BASE_FIELD_COUNT to
1958      * getFieldCount() - 1.
1959      *
1960      * <p>The default implementation in <code>Calendar</code> implements
1961      * a pure proleptic Gregorian calendar.
1962      * @internal
1963      */
1964     virtual void handleComputeFields(int32_t julianDay, UErrorCode &status);
1965 
1966 #ifndef U_HIDE_INTERNAL_API
1967     /**
1968      * Return the extended year on the Gregorian calendar as computed by
1969      * <code>computeGregorianFields()</code>.
1970      * @internal
1971      */
getGregorianYear()1972     int32_t getGregorianYear() const {
1973         return fGregorianYear;
1974     }
1975 
1976     /**
1977      * Return the month (0-based) on the Gregorian calendar as computed by
1978      * <code>computeGregorianFields()</code>.
1979      * @internal
1980      */
getGregorianMonth()1981     int32_t getGregorianMonth() const {
1982         return fGregorianMonth;
1983     }
1984 
1985     /**
1986      * Return the day of year (1-based) on the Gregorian calendar as
1987      * computed by <code>computeGregorianFields()</code>.
1988      * @internal
1989      */
getGregorianDayOfYear()1990     int32_t getGregorianDayOfYear() const {
1991         return fGregorianDayOfYear;
1992     }
1993 
1994     /**
1995      * Return the day of month (1-based) on the Gregorian calendar as
1996      * computed by <code>computeGregorianFields()</code>.
1997      * @internal
1998      */
getGregorianDayOfMonth()1999     int32_t getGregorianDayOfMonth() const {
2000       return fGregorianDayOfMonth;
2001     }
2002 #endif  /* U_HIDE_INTERNAL_API */
2003 
2004     /**
2005      * Called by computeJulianDay.  Returns the default month (0-based) for the year,
2006      * taking year and era into account.  Defaults to 0 for Gregorian, which doesn't care.
2007      * @param eyear The extended year
2008      * @internal
2009      */
2010     virtual int32_t getDefaultMonthInYear(int32_t eyear) ;
2011 
2012 
2013     /**
2014      * Called by computeJulianDay.  Returns the default day (1-based) for the month,
2015      * taking currently-set year and era into account.  Defaults to 1 for Gregorian.
2016      * @param eyear the extended year
2017      * @param month the month in the year
2018      * @internal
2019      */
2020     virtual int32_t getDefaultDayInMonth(int32_t eyear, int32_t month);
2021 
2022     //-------------------------------------------------------------------------
2023     // Protected utility methods for use by subclasses.  These are very handy
2024     // for implementing add, roll, and computeFields.
2025     //-------------------------------------------------------------------------
2026 
2027     /**
2028      * Adjust the specified field so that it is within
2029      * the allowable range for the date to which this calendar is set.
2030      * For example, in a Gregorian calendar pinning the {@link #UCalendarDateFields DAY_OF_MONTH}
2031      * field for a calendar set to April 31 would cause it to be set
2032      * to April 30.
2033      * <p>
2034      * <b>Subclassing:</b>
2035      * <br>
2036      * This utility method is intended for use by subclasses that need to implement
2037      * their own overrides of {@link #roll roll} and {@link #add add}.
2038      * <p>
2039      * <b>Note:</b>
2040      * <code>pinField</code> is implemented in terms of
2041      * {@link #getActualMinimum getActualMinimum}
2042      * and {@link #getActualMaximum getActualMaximum}.  If either of those methods uses
2043      * a slow, iterative algorithm for a particular field, it would be
2044      * unwise to attempt to call <code>pinField</code> for that field.  If you
2045      * really do need to do so, you should override this method to do
2046      * something more efficient for that field.
2047      * <p>
2048      * @param field The calendar field whose value should be pinned.
2049      * @param status Output param set to failure code on function return
2050      *          when this function fails.
2051      *
2052      * @see #getActualMinimum
2053      * @see #getActualMaximum
2054      * @stable ICU 2.0
2055      */
2056     virtual void pinField(UCalendarDateFields field, UErrorCode& status);
2057 
2058     /**
2059      * Return the week number of a day, within a period. This may be the week number in
2060      * a year or the week number in a month. Usually this will be a value >= 1, but if
2061      * some initial days of the period are excluded from week 1, because
2062      * {@link #getMinimalDaysInFirstWeek getMinimalDaysInFirstWeek} is > 1, then
2063      * the week number will be zero for those
2064      * initial days. This method requires the day number and day of week for some
2065      * known date in the period in order to determine the day of week
2066      * on the desired day.
2067      * <p>
2068      * <b>Subclassing:</b>
2069      * <br>
2070      * This method is intended for use by subclasses in implementing their
2071      * {@link #computeTime computeTime} and/or {@link #computeFields computeFields} methods.
2072      * It is often useful in {@link #getActualMinimum getActualMinimum} and
2073      * {@link #getActualMaximum getActualMaximum} as well.
2074      * <p>
2075      * This variant is handy for computing the week number of some other
2076      * day of a period (often the first or last day of the period) when its day
2077      * of the week is not known but the day number and day of week for some other
2078      * day in the period (e.g. the current date) <em>is</em> known.
2079      * <p>
2080      * @param desiredDay    The {@link #UCalendarDateFields DAY_OF_YEAR} or
2081      *              {@link #UCalendarDateFields DAY_OF_MONTH} whose week number is desired.
2082      *              Should be 1 for the first day of the period.
2083      *
2084      * @param dayOfPeriod   The {@link #UCalendarDateFields DAY_OF_YEAR}
2085      *              or {@link #UCalendarDateFields DAY_OF_MONTH} for a day in the period whose
2086      *              {@link #UCalendarDateFields DAY_OF_WEEK} is specified by the
2087      *              <code>knownDayOfWeek</code> parameter.
2088      *              Should be 1 for first day of period.
2089      *
2090      * @param dayOfWeek  The {@link #UCalendarDateFields DAY_OF_WEEK} for the day
2091      *              corresponding to the <code>knownDayOfPeriod</code> parameter.
2092      *              1-based with 1=Sunday.
2093      *
2094      * @return      The week number (one-based), or zero if the day falls before
2095      *              the first week because
2096      *              {@link #getMinimalDaysInFirstWeek getMinimalDaysInFirstWeek}
2097      *              is more than one.
2098      *
2099      * @stable ICU 2.8
2100      */
2101     int32_t weekNumber(int32_t desiredDay, int32_t dayOfPeriod, int32_t dayOfWeek);
2102 
2103 
2104 #ifndef U_HIDE_INTERNAL_API
2105     /**
2106      * Return the week number of a day, within a period. This may be the week number in
2107      * a year, or the week number in a month. Usually this will be a value >= 1, but if
2108      * some initial days of the period are excluded from week 1, because
2109      * {@link #getMinimalDaysInFirstWeek getMinimalDaysInFirstWeek} is > 1,
2110      * then the week number will be zero for those
2111      * initial days. This method requires the day of week for the given date in order to
2112      * determine the result.
2113      * <p>
2114      * <b>Subclassing:</b>
2115      * <br>
2116      * This method is intended for use by subclasses in implementing their
2117      * {@link #computeTime computeTime} and/or {@link #computeFields computeFields} methods.
2118      * It is often useful in {@link #getActualMinimum getActualMinimum} and
2119      * {@link #getActualMaximum getActualMaximum} as well.
2120      * <p>
2121      * @param dayOfPeriod   The {@link #UCalendarDateFields DAY_OF_YEAR} or
2122      *                      {@link #UCalendarDateFields DAY_OF_MONTH} whose week number is desired.
2123      *                      Should be 1 for the first day of the period.
2124      *
2125      * @param dayOfWeek     The {@link #UCalendarDateFields DAY_OF_WEEK} for the day
2126      *                      corresponding to the <code>dayOfPeriod</code> parameter.
2127      *                      1-based with 1=Sunday.
2128      *
2129      * @return      The week number (one-based), or zero if the day falls before
2130      *              the first week because
2131      *              {@link #getMinimalDaysInFirstWeek getMinimalDaysInFirstWeek}
2132      *              is more than one.
2133      * @internal
2134      */
2135     inline int32_t weekNumber(int32_t dayOfPeriod, int32_t dayOfWeek);
2136 
2137     /**
2138      * returns the local DOW, valid range 0..6
2139      * @internal
2140      */
2141     int32_t getLocalDOW();
2142 #endif  /* U_HIDE_INTERNAL_API */
2143 
2144 private:
2145 
2146     /**
2147      * The next available value for fStamp[]
2148      */
2149     int32_t fNextStamp;// = MINIMUM_USER_STAMP;
2150 
2151     /**
2152      * Recalculates the time stamp array (fStamp).
2153      * Resets fNextStamp to lowest next stamp value.
2154      */
2155     void recalculateStamp();
2156 
2157     /**
2158      * The current time set for the calendar.
2159      */
2160     UDate        fTime;
2161 
2162     /**
2163      * @see   #setLenient
2164      */
2165     UBool      fLenient;
2166 
2167     /**
2168      * Time zone affects the time calculation done by Calendar. Calendar subclasses use
2169      * the time zone data to produce the local time. Always set; never NULL.
2170      */
2171     TimeZone*   fZone;
2172 
2173     /**
2174      * Option for repeated wall time
2175      * @see #setRepeatedWallTimeOption
2176      */
2177     UCalendarWallTimeOption fRepeatedWallTime;
2178 
2179     /**
2180      * Option for skipped wall time
2181      * @see #setSkippedWallTimeOption
2182      */
2183     UCalendarWallTimeOption fSkippedWallTime;
2184 
2185     /**
2186      * Both firstDayOfWeek and minimalDaysInFirstWeek are locale-dependent. They are
2187      * used to figure out the week count for a specific date for a given locale. These
2188      * must be set when a Calendar is constructed. For example, in US locale,
2189      * firstDayOfWeek is SUNDAY; minimalDaysInFirstWeek is 1. They are used to figure
2190      * out the week count for a specific date for a given locale. These must be set when
2191      * a Calendar is constructed.
2192      */
2193     UCalendarDaysOfWeek fFirstDayOfWeek;
2194     uint8_t     fMinimalDaysInFirstWeek;
2195     UCalendarDaysOfWeek fWeekendOnset;
2196     int32_t fWeekendOnsetMillis;
2197     UCalendarDaysOfWeek fWeekendCease;
2198     int32_t fWeekendCeaseMillis;
2199 
2200     /**
2201      * Sets firstDayOfWeek and minimalDaysInFirstWeek. Called at Calendar construction
2202      * time.
2203      *
2204      * @param desiredLocale  The given locale.
2205      * @param type           The calendar type identifier, e.g: gregorian, buddhist, etc.
2206      * @param success        Indicates the status of setting the week count data from
2207      *                       the resource for the given locale. Returns U_ZERO_ERROR if
2208      *                       constructed successfully.
2209      */
2210     void        setWeekData(const Locale& desiredLocale, const char *type, UErrorCode& success);
2211 
2212     /**
2213      * Recompute the time and update the status fields isTimeSet
2214      * and areFieldsSet.  Callers should check isTimeSet and only
2215      * call this method if isTimeSet is false.
2216      *
2217      * @param status  Output param set to success/failure code on exit. If any value
2218      *                previously set in the time field is invalid or restricted by
2219      *                leniency, this will be set to an error status.
2220      */
2221     void updateTime(UErrorCode& status);
2222 
2223     /**
2224      * The Gregorian year, as computed by computeGregorianFields() and
2225      * returned by getGregorianYear().
2226      * @see #computeGregorianFields
2227      */
2228     int32_t fGregorianYear;
2229 
2230     /**
2231      * The Gregorian month, as computed by computeGregorianFields() and
2232      * returned by getGregorianMonth().
2233      * @see #computeGregorianFields
2234      */
2235     int32_t fGregorianMonth;
2236 
2237     /**
2238      * The Gregorian day of the year, as computed by
2239      * computeGregorianFields() and returned by getGregorianDayOfYear().
2240      * @see #computeGregorianFields
2241      */
2242     int32_t fGregorianDayOfYear;
2243 
2244     /**
2245      * The Gregorian day of the month, as computed by
2246      * computeGregorianFields() and returned by getGregorianDayOfMonth().
2247      * @see #computeGregorianFields
2248      */
2249     int32_t fGregorianDayOfMonth;
2250 
2251     /* calculations */
2252 
2253     /**
2254      * Compute the Gregorian calendar year, month, and day of month from
2255      * the given Julian day.  These values are not stored in fields, but in
2256      * member variables gregorianXxx.  Also compute the DAY_OF_WEEK and
2257      * DOW_LOCAL fields.
2258      */
2259     void computeGregorianAndDOWFields(int32_t julianDay, UErrorCode &ec);
2260 
2261 protected:
2262 
2263     /**
2264      * Compute the Gregorian calendar year, month, and day of month from the
2265      * Julian day.  These values are not stored in fields, but in member
2266      * variables gregorianXxx.  They are used for time zone computations and by
2267      * subclasses that are Gregorian derivatives.  Subclasses may call this
2268      * method to perform a Gregorian calendar millis->fields computation.
2269      */
2270     void computeGregorianFields(int32_t julianDay, UErrorCode &ec);
2271 
2272 private:
2273 
2274     /**
2275      * Compute the fields WEEK_OF_YEAR, YEAR_WOY, WEEK_OF_MONTH,
2276      * DAY_OF_WEEK_IN_MONTH, and DOW_LOCAL from EXTENDED_YEAR, YEAR,
2277      * DAY_OF_WEEK, and DAY_OF_YEAR.  The latter fields are computed by the
2278      * subclass based on the calendar system.
2279      *
2280      * <p>The YEAR_WOY field is computed simplistically.  It is equal to YEAR
2281      * most of the time, but at the year boundary it may be adjusted to YEAR-1
2282      * or YEAR+1 to reflect the overlap of a week into an adjacent year.  In
2283      * this case, a simple increment or decrement is performed on YEAR, even
2284      * though this may yield an invalid YEAR value.  For instance, if the YEAR
2285      * is part of a calendar system with an N-year cycle field CYCLE, then
2286      * incrementing the YEAR may involve incrementing CYCLE and setting YEAR
2287      * back to 0 or 1.  This is not handled by this code, and in fact cannot be
2288      * simply handled without having subclasses define an entire parallel set of
2289      * fields for fields larger than or equal to a year.  This additional
2290      * complexity is not warranted, since the intention of the YEAR_WOY field is
2291      * to support ISO 8601 notation, so it will typically be used with a
2292      * proleptic Gregorian calendar, which has no field larger than a year.
2293      */
2294     void computeWeekFields(UErrorCode &ec);
2295 
2296 
2297     /**
2298      * Ensure that each field is within its valid range by calling {@link
2299      * #validateField(int, int&)} on each field that has been set.  This method
2300      * should only be called if this calendar is not lenient.
2301      * @see #isLenient
2302      * @see #validateField(int, int&)
2303      */
2304     void validateFields(UErrorCode &status);
2305 
2306     /**
2307      * Validate a single field of this calendar given its minimum and
2308      * maximum allowed value.  If the field is out of range,
2309      * <code>U_ILLEGAL_ARGUMENT_ERROR</code> will be set.  Subclasses may
2310      * use this method in their implementation of {@link
2311      * #validateField(int, int&)}.
2312      */
2313     void validateField(UCalendarDateFields field, int32_t min, int32_t max, UErrorCode& status);
2314 
2315  protected:
2316 #ifndef U_HIDE_INTERNAL_API
2317     /**
2318      * Convert a quasi Julian date to the day of the week. The Julian date used here is
2319      * not a true Julian date, since it is measured from midnight, not noon. Return
2320      * value is one-based.
2321      *
2322      * @param julian  The given Julian date number.
2323      * @return   Day number from 1..7 (SUN..SAT).
2324      * @internal
2325      */
2326     static uint8_t julianDayToDayOfWeek(double julian);
2327 #endif  /* U_HIDE_INTERNAL_API */
2328 
2329  private:
2330     char validLocale[ULOC_FULLNAME_CAPACITY];
2331     char actualLocale[ULOC_FULLNAME_CAPACITY];
2332 
2333  public:
2334 #if !UCONFIG_NO_SERVICE
2335     /**
2336      * INTERNAL FOR 2.6 --  Registration.
2337      */
2338 
2339 #ifndef U_HIDE_INTERNAL_API
2340     /**
2341      * Return a StringEnumeration over the locales available at the time of the call,
2342      * including registered locales.
2343      * @return a StringEnumeration over the locales available at the time of the call
2344      * @internal
2345      */
2346     static StringEnumeration* getAvailableLocales(void);
2347 
2348     /**
2349      * Register a new Calendar factory.  The factory will be adopted.
2350      * INTERNAL in 2.6
2351      *
2352      * Because ICU may choose to cache Calendars internally, this must
2353      * be called at application startup, prior to any calls to
2354      * Calendar::createInstance to avoid undefined behavior.
2355      *
2356      * @param toAdopt the factory instance to be adopted
2357      * @param status the in/out status code, no special meanings are assigned
2358      * @return a registry key that can be used to unregister this factory
2359      * @internal
2360      */
2361     static URegistryKey registerFactory(ICUServiceFactory* toAdopt, UErrorCode& status);
2362 
2363     /**
2364      * Unregister a previously-registered CalendarFactory using the key returned from the
2365      * register call.  Key becomes invalid after a successful call and should not be used again.
2366      * The CalendarFactory corresponding to the key will be deleted.
2367      * INTERNAL in 2.6
2368      *
2369      * Because ICU may choose to cache Calendars internally, this should
2370      * be called during application shutdown, after all calls to
2371      * Calendar::createInstance to avoid undefined behavior.
2372      *
2373      * @param key the registry key returned by a previous call to registerFactory
2374      * @param status the in/out status code, no special meanings are assigned
2375      * @return TRUE if the factory for the key was successfully unregistered
2376      * @internal
2377      */
2378     static UBool unregister(URegistryKey key, UErrorCode& status);
2379 #endif  /* U_HIDE_INTERNAL_API */
2380 
2381     /**
2382      * Multiple Calendar Implementation
2383      * @internal
2384      */
2385     friend class CalendarFactory;
2386 
2387     /**
2388      * Multiple Calendar Implementation
2389      * @internal
2390      */
2391     friend class CalendarService;
2392 
2393     /**
2394      * Multiple Calendar Implementation
2395      * @internal
2396      */
2397     friend class DefaultCalendarFactory;
2398 #endif /* !UCONFIG_NO_SERVICE */
2399 
2400     /**
2401      * @return TRUE if this calendar has a default century (i.e. 03 -> 2003)
2402      * @internal
2403      */
2404     virtual UBool haveDefaultCentury() const = 0;
2405 
2406     /**
2407      * @return the start of the default century, as a UDate
2408      * @internal
2409      */
2410     virtual UDate defaultCenturyStart() const = 0;
2411     /**
2412      * @return the beginning year of the default century, as a year
2413      * @internal
2414      */
2415     virtual int32_t defaultCenturyStartYear() const = 0;
2416 
2417     /** Get the locale for this calendar object. You can choose between valid and actual locale.
2418      *  @param type type of the locale we're looking for (valid or actual)
2419      *  @param status error code for the operation
2420      *  @return the locale
2421      *  @stable ICU 2.8
2422      */
2423     Locale getLocale(ULocDataLocaleType type, UErrorCode &status) const;
2424 
2425     /**
2426      * @return      The related Gregorian year; will be obtained by modifying the value
2427      *              obtained by get from UCAL_EXTENDED_YEAR field
2428      * @internal
2429      */
2430     virtual int32_t getRelatedYear(UErrorCode &status) const;
2431 
2432     /**
2433      * @param year  The related Gregorian year to set; will be modified as necessary then
2434      *              set in UCAL_EXTENDED_YEAR field
2435      * @internal
2436      */
2437     virtual void setRelatedYear(int32_t year);
2438 
2439 #ifndef U_HIDE_INTERNAL_API
2440     /** Get the locale for this calendar object. You can choose between valid and actual locale.
2441      *  @param type type of the locale we're looking for (valid or actual)
2442      *  @param status error code for the operation
2443      *  @return the locale
2444      *  @internal
2445      */
2446     const char* getLocaleID(ULocDataLocaleType type, UErrorCode &status) const;
2447 #endif  /* U_HIDE_INTERNAL_API */
2448 
2449 private:
2450     /**
2451      * Cast TimeZone used by this object to BasicTimeZone, or NULL if the TimeZone
2452      * is not an instance of BasicTimeZone.
2453      */
2454     BasicTimeZone* getBasicTimeZone() const;
2455 
2456     /**
2457      * Find the previous zone transition near the given time.
2458      * @param base The base time, inclusive
2459      * @param transitionTime Receives the result time
2460      * @param status The error status
2461      * @return TRUE if a transition is found.
2462      */
2463     UBool getImmediatePreviousZoneTransition(UDate base, UDate *transitionTime, UErrorCode& status) const;
2464 
2465 public:
2466 #ifndef U_HIDE_INTERNAL_API
2467     /**
2468      * Creates a new Calendar from a Locale for the cache.
2469      * This method does not set the time or timezone in returned calendar.
2470      * @param locale the locale.
2471      * @param status any error returned here.
2472      * @return the new Calendar object with no time or timezone set.
2473      * @internal For ICU use only.
2474      */
2475     static Calendar * U_EXPORT2 makeInstance(
2476             const Locale &locale, UErrorCode &status);
2477 
2478     /**
2479      * Get the calendar type for given locale.
2480      * @param locale the locale
2481      * @param typeBuffer calendar type returned here
2482      * @param typeBufferSize The size of typeBuffer in bytes. If the type
2483      *   can't fit in the buffer, this method sets status to
2484      *   U_BUFFER_OVERFLOW_ERROR
2485      * @param status error, if any, returned here.
2486      * @internal For ICU use only.
2487      */
2488     static void U_EXPORT2 getCalendarTypeFromLocale(
2489             const Locale &locale,
2490             char *typeBuffer,
2491             int32_t typeBufferSize,
2492             UErrorCode &status);
2493 #endif  /* U_HIDE_INTERNAL_API */
2494 };
2495 
2496 // -------------------------------------
2497 
2498 inline Calendar*
createInstance(TimeZone * zone,UErrorCode & errorCode)2499 Calendar::createInstance(TimeZone* zone, UErrorCode& errorCode)
2500 {
2501     // since the Locale isn't specified, use the default locale
2502     return createInstance(zone, Locale::getDefault(), errorCode);
2503 }
2504 
2505 // -------------------------------------
2506 
2507 inline void
roll(UCalendarDateFields field,UBool up,UErrorCode & status)2508 Calendar::roll(UCalendarDateFields field, UBool up, UErrorCode& status)
2509 {
2510     roll(field, (int32_t)(up ? +1 : -1), status);
2511 }
2512 
2513 #ifndef U_HIDE_DEPRECATED_API
2514 inline void
roll(EDateFields field,UBool up,UErrorCode & status)2515 Calendar::roll(EDateFields field, UBool up, UErrorCode& status)
2516 {
2517     roll((UCalendarDateFields) field, up, status);
2518 }
2519 #endif  /* U_HIDE_DEPRECATED_API */
2520 
2521 
2522 // -------------------------------------
2523 
2524 /**
2525  * Fast method for subclasses.  The caller must maintain fUserSetDSTOffset and
2526  * fUserSetZoneOffset, as well as the isSet[] array.
2527  */
2528 
2529 inline void
internalSet(UCalendarDateFields field,int32_t value)2530 Calendar::internalSet(UCalendarDateFields field, int32_t value)
2531 {
2532     fFields[field] = value;
2533     fStamp[field] = kInternallySet;
2534     fIsSet[field]     = TRUE; // Remove later
2535 }
2536 
2537 
2538 #ifndef U_HIDE_INTERNAL_API
weekNumber(int32_t dayOfPeriod,int32_t dayOfWeek)2539 inline int32_t  Calendar::weekNumber(int32_t dayOfPeriod, int32_t dayOfWeek)
2540 {
2541   return weekNumber(dayOfPeriod, dayOfPeriod, dayOfWeek);
2542 }
2543 #endif  /* U_HIDE_INTERNAL_API */
2544 
2545 U_NAMESPACE_END
2546 
2547 #endif /* #if !UCONFIG_NO_FORMATTING */
2548 
2549 #endif /* U_SHOW_CPLUSPLUS_API */
2550 
2551 #endif // _CALENDAR
2552