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