1 // © 2016 and later: Unicode, Inc. and others.
2 // License & terms of use: http://www.unicode.org/copyright.html
3 /*************************************************************************
4 * Copyright (c) 1997-2016, International Business Machines Corporation
5 * and others. All Rights Reserved.
6 **************************************************************************
7 *
8 * File TIMEZONE.H
9 *
10 * Modification History:
11 *
12 * Date Name Description
13 * 04/21/97 aliu Overhauled header.
14 * 07/09/97 helena Changed createInstance to createDefault.
15 * 08/06/97 aliu Removed dependency on internal header for Hashtable.
16 * 08/10/98 stephen Changed getDisplayName() API conventions to match
17 * 08/19/98 stephen Changed createTimeZone() to never return 0
18 * 09/02/98 stephen Sync to JDK 1.2 8/31
19 * - Added getOffset(... monthlen ...)
20 * - Added hasSameRules()
21 * 09/15/98 stephen Added getStaticClassID
22 * 12/03/99 aliu Moved data out of static table into icudata.dll.
23 * Hashtable replaced by new static data structures.
24 * 12/14/99 aliu Made GMT public.
25 * 08/15/01 grhoten Made GMT private and added the getGMT() function
26 **************************************************************************
27 */
28
29 #ifndef TIMEZONE_H
30 #define TIMEZONE_H
31
32 #include "unicode/utypes.h"
33
34 #if U_SHOW_CPLUSPLUS_API
35
36 /**
37 * \file
38 * \brief C++ API: TimeZone object
39 */
40
41 #if !UCONFIG_NO_FORMATTING
42
43 #include "unicode/uobject.h"
44 #include "unicode/unistr.h"
45 #include "unicode/ures.h"
46 #include "unicode/ucal.h"
47
48 U_NAMESPACE_BEGIN
49
50 class StringEnumeration;
51
52 /**
53 *
54 * <code>TimeZone</code> represents a time zone offset, and also figures out daylight
55 * savings.
56 *
57 * <p>
58 * Typically, you get a <code>TimeZone</code> using <code>createDefault</code>
59 * which creates a <code>TimeZone</code> based on the time zone where the program
60 * is running. For example, for a program running in Japan, <code>createDefault</code>
61 * creates a <code>TimeZone</code> object based on Japanese Standard Time.
62 *
63 * <p>
64 * You can also get a <code>TimeZone</code> using <code>createTimeZone</code> along
65 * with a time zone ID. For instance, the time zone ID for the US Pacific
66 * Time zone is "America/Los_Angeles". So, you can get a Pacific Time <code>TimeZone</code> object
67 * with:
68 * \htmlonly<blockquote>\endhtmlonly
69 * <pre>
70 * TimeZone *tz = TimeZone::createTimeZone("America/Los_Angeles");
71 * </pre>
72 * \htmlonly</blockquote>\endhtmlonly
73 * You can use the <code>createEnumeration</code> method to iterate through
74 * all the supported time zone IDs, or the <code>getCanonicalID</code> method to check
75 * if a time zone ID is supported or not. You can then choose a
76 * supported ID to get a <code>TimeZone</code>.
77 * If the time zone you want is not represented by one of the
78 * supported IDs, then you can create a custom time zone ID with
79 * the following syntax:
80 *
81 * \htmlonly<blockquote>\endhtmlonly
82 * <pre>
83 * GMT[+|-]hh[[:]mm]
84 * </pre>
85 * \htmlonly</blockquote>\endhtmlonly
86 *
87 * For example, you might specify GMT+14:00 as a custom
88 * time zone ID. The <code>TimeZone</code> that is returned
89 * when you specify a custom time zone ID uses the specified
90 * offset from GMT(=UTC) and does not observe daylight saving
91 * time. For example, you might specify GMT+14:00 as a custom
92 * time zone ID to create a TimeZone representing 14 hours ahead
93 * of GMT (with no daylight saving time). In addition,
94 * <code>getCanonicalID</code> can also be used to
95 * normalize a custom time zone ID.
96 *
97 * TimeZone is an abstract class representing a time zone. A TimeZone is needed for
98 * Calendar to produce local time for a particular time zone. A TimeZone comprises
99 * three basic pieces of information:
100 * <ul>
101 * <li>A time zone offset; that, is the number of milliseconds to add or subtract
102 * from a time expressed in terms of GMT to convert it to the same time in that
103 * time zone (without taking daylight savings time into account).</li>
104 * <li>Logic necessary to take daylight savings time into account if daylight savings
105 * time is observed in that time zone (e.g., the days and hours on which daylight
106 * savings time begins and ends).</li>
107 * <li>An ID. This is a text string that uniquely identifies the time zone.</li>
108 * </ul>
109 *
110 * (Only the ID is actually implemented in TimeZone; subclasses of TimeZone may handle
111 * daylight savings time and GMT offset in different ways. Currently we have the following
112 * TimeZone subclasses: RuleBasedTimeZone, SimpleTimeZone, and VTimeZone.)
113 * <P>
114 * The TimeZone class contains a static list containing a TimeZone object for every
115 * combination of GMT offset and daylight-savings time rules currently in use in the
116 * world, each with a unique ID. Each ID consists of a region (usually a continent or
117 * ocean) and a city in that region, separated by a slash, (for example, US Pacific
118 * Time is "America/Los_Angeles.") Because older versions of this class used
119 * three- or four-letter abbreviations instead, there is also a table that maps the older
120 * abbreviations to the newer ones (for example, "PST" maps to "America/Los_Angeles").
121 * Anywhere the API requires an ID, you can use either form.
122 * <P>
123 * To create a new TimeZone, you call the factory function TimeZone::createTimeZone()
124 * and pass it a time zone ID. You can use the createEnumeration() function to
125 * obtain a list of all the time zone IDs recognized by createTimeZone().
126 * <P>
127 * You can also use TimeZone::createDefault() to create a TimeZone. This function uses
128 * platform-specific APIs to produce a TimeZone for the time zone corresponding to
129 * the client's computer's physical location. For example, if you're in Japan (assuming
130 * your machine is set up correctly), TimeZone::createDefault() will return a TimeZone
131 * for Japanese Standard Time ("Asia/Tokyo").
132 */
133 class U_I18N_API TimeZone : public UObject {
134 public:
135 /**
136 * @stable ICU 2.0
137 */
138 virtual ~TimeZone();
139
140 /**
141 * Returns the "unknown" time zone.
142 * It behaves like the GMT/UTC time zone but has the
143 * <code>UCAL_UNKNOWN_ZONE_ID</code> = "Etc/Unknown".
144 * createTimeZone() returns a mutable clone of this time zone if the input ID is not recognized.
145 *
146 * @return the "unknown" time zone.
147 * @see UCAL_UNKNOWN_ZONE_ID
148 * @see createTimeZone
149 * @see getGMT
150 * @stable ICU 49
151 */
152 static const TimeZone& U_EXPORT2 getUnknown();
153
154 /**
155 * The GMT (=UTC) time zone has a raw offset of zero and does not use daylight
156 * savings time. This is a commonly used time zone.
157 *
158 * <p>Note: For backward compatibility reason, the ID used by the time
159 * zone returned by this method is "GMT", although the ICU's canonical
160 * ID for the GMT time zone is "Etc/GMT".
161 *
162 * @return the GMT/UTC time zone.
163 * @see getUnknown
164 * @stable ICU 2.0
165 */
166 static const TimeZone* U_EXPORT2 getGMT(void);
167
168 /**
169 * Creates a <code>TimeZone</code> for the given ID.
170 * @param ID the ID for a <code>TimeZone</code>, such as "America/Los_Angeles",
171 * or a custom ID such as "GMT-8:00".
172 * @return the specified <code>TimeZone</code>, or a mutable clone of getUnknown()
173 * if the given ID cannot be understood or if the given ID is "Etc/Unknown".
174 * The return result is guaranteed to be non-nullptr.
175 * If you require that the specific zone asked for be returned,
176 * compare the result with getUnknown() or check the ID of the return result.
177 * @stable ICU 2.0
178 */
179 static TimeZone* U_EXPORT2 createTimeZone(const UnicodeString& ID);
180
181 /**
182 * Returns an enumeration over system time zone IDs with the given
183 * filter conditions.
184 * @param zoneType The system time zone type.
185 * @param region The ISO 3166 two-letter country code or UN M.49
186 * three-digit area code. When nullptr, no filtering
187 * done by region.
188 * @param rawOffset An offset from GMT in milliseconds, ignoring
189 * the effect of daylight savings time, if any.
190 * When nullptr, no filtering done by zone offset.
191 * @param ec Output param to filled in with a success or
192 * an error.
193 * @return an enumeration object, owned by the caller.
194 * @stable ICU 4.8
195 */
196 static StringEnumeration* U_EXPORT2 createTimeZoneIDEnumeration(
197 USystemTimeZoneType zoneType,
198 const char* region,
199 const int32_t* rawOffset,
200 UErrorCode& ec);
201
202 #ifndef U_HIDE_DEPRECATED_API
203 /**
204 * Returns an enumeration over all recognized time zone IDs. (i.e.,
205 * all strings that createTimeZone() accepts)
206 *
207 * @return an enumeration object, owned by the caller.
208 * @deprecated ICU 70 Use createEnumeration(UErrorCode&) instead.
209 */
210 static StringEnumeration* U_EXPORT2 createEnumeration();
211 #endif // U_HIDE_DEPRECATED_API
212
213 /**
214 * Returns an enumeration over all recognized time zone IDs. (i.e.,
215 * all strings that createTimeZone() accepts)
216 *
217 * @param status Receives the status.
218 * @return an enumeration object, owned by the caller.
219 * @stable ICU 70
220 */
221 static StringEnumeration* U_EXPORT2 createEnumeration(UErrorCode& status);
222
223 #ifndef U_HIDE_DEPRECATED_API
224 /**
225 * Returns an enumeration over time zone IDs with a given raw
226 * offset from GMT. There may be several times zones with the
227 * same GMT offset that differ in the way they handle daylight
228 * savings time. For example, the state of Arizona doesn't
229 * observe daylight savings time. If you ask for the time zone
230 * IDs corresponding to GMT-7:00, you'll get back an enumeration
231 * over two time zone IDs: "America/Denver," which corresponds to
232 * Mountain Standard Time in the winter and Mountain Daylight Time
233 * in the summer, and "America/Phoenix", which corresponds to
234 * Mountain Standard Time year-round, even in the summer.
235 *
236 * @param rawOffset an offset from GMT in milliseconds, ignoring
237 * the effect of daylight savings time, if any
238 * @return an enumeration object, owned by the caller
239 * @deprecated ICU 70 Use createEnumerationForRawOffset(int32_t,UErrorCode&) instead.
240 */
241 static StringEnumeration* U_EXPORT2 createEnumeration(int32_t rawOffset);
242 #endif // U_HIDE_DEPRECATED_API
243
244 /**
245 * Returns an enumeration over time zone IDs with a given raw
246 * offset from GMT. There may be several times zones with the
247 * same GMT offset that differ in the way they handle daylight
248 * savings time. For example, the state of Arizona doesn't
249 * observe daylight savings time. If you ask for the time zone
250 * IDs corresponding to GMT-7:00, you'll get back an enumeration
251 * over two time zone IDs: "America/Denver," which corresponds to
252 * Mountain Standard Time in the winter and Mountain Daylight Time
253 * in the summer, and "America/Phoenix", which corresponds to
254 * Mountain Standard Time year-round, even in the summer.
255 *
256 * @param rawOffset an offset from GMT in milliseconds, ignoring
257 * the effect of daylight savings time, if any
258 * @param status Receives the status.
259 * @return an enumeration object, owned by the caller
260 * @stable ICU 70
261 */
262 static StringEnumeration* U_EXPORT2 createEnumerationForRawOffset(int32_t rawOffset, UErrorCode& status);
263
264 #ifndef U_HIDE_DEPRECATED_API
265 /**
266 * Returns an enumeration over time zone IDs associated with the
267 * given region. Some zones are affiliated with no region
268 * (e.g., "UTC"); these may also be retrieved, as a group.
269 *
270 * @param region The ISO 3166 two-letter country code, or nullptr to
271 * retrieve zones not affiliated with any region.
272 * @return an enumeration object, owned by the caller
273 * @deprecated ICU 70 Use createEnumerationForRegion(const char*,UErrorCode&) instead.
274 */
275 static StringEnumeration* U_EXPORT2 createEnumeration(const char* region);
276 #endif // U_HIDE_DEPRECATED_API
277
278 /**
279 * Returns an enumeration over time zone IDs associated with the
280 * given region. Some zones are affiliated with no region
281 * (e.g., "UTC"); these may also be retrieved, as a group.
282 *
283 * @param region The ISO 3166 two-letter country code, or nullptr to
284 * retrieve zones not affiliated with any region.
285 * @param status Receives the status.
286 * @return an enumeration object, owned by the caller
287 * @stable ICU 70
288 */
289 static StringEnumeration* U_EXPORT2 createEnumerationForRegion(const char* region, UErrorCode& status);
290
291 /**
292 * Returns the number of IDs in the equivalency group that
293 * includes the given ID. An equivalency group contains zones
294 * that have the same GMT offset and rules.
295 *
296 * <p>The returned count includes the given ID; it is always >= 1.
297 * The given ID must be a system time zone. If it is not, returns
298 * zero.
299 * @param id a system time zone ID
300 * @return the number of zones in the equivalency group containing
301 * 'id', or zero if 'id' is not a valid system ID
302 * @see #getEquivalentID
303 * @stable ICU 2.0
304 */
305 static int32_t U_EXPORT2 countEquivalentIDs(const UnicodeString& id);
306
307 /**
308 * Returns an ID in the equivalency group that
309 * includes the given ID. An equivalency group contains zones
310 * that have the same GMT offset and rules.
311 *
312 * <p>The given index must be in the range 0..n-1, where n is the
313 * value returned by <code>countEquivalentIDs(id)</code>. For
314 * some value of 'index', the returned value will be equal to the
315 * given id. If the given id is not a valid system time zone, or
316 * if 'index' is out of range, then returns an empty string.
317 * @param id a system time zone ID
318 * @param index a value from 0 to n-1, where n is the value
319 * returned by <code>countEquivalentIDs(id)</code>
320 * @return the ID of the index-th zone in the equivalency group
321 * containing 'id', or an empty string if 'id' is not a valid
322 * system ID or 'index' is out of range
323 * @see #countEquivalentIDs
324 * @stable ICU 2.0
325 */
326 static const UnicodeString U_EXPORT2 getEquivalentID(const UnicodeString& id,
327 int32_t index);
328
329 /**
330 * Creates an instance of TimeZone detected from the current host
331 * system configuration. If the host system detection routines fail,
332 * or if they specify a TimeZone or TimeZone offset which is not
333 * recognized, then the special TimeZone "Etc/Unknown" is returned.
334 *
335 * Note that ICU4C does not change the default time zone unless
336 * `TimeZone::adoptDefault(TimeZone*)` or
337 * `TimeZone::setDefault(const TimeZone&)` is explicitly called by a
338 * user. This method does not update the current ICU's default,
339 * and may return a different TimeZone from the one returned by
340 * `TimeZone::createDefault()`.
341 *
342 * <p>This function is not thread safe.</p>
343 *
344 * @return A new instance of TimeZone detected from the current host system
345 * configuration.
346 * @see adoptDefault
347 * @see setDefault
348 * @see createDefault
349 * @see getUnknown
350 * @stable ICU 55
351 */
352 static TimeZone* U_EXPORT2 detectHostTimeZone();
353
354 /**
355 * Creates a new copy of the default TimeZone for this host. Unless the default time
356 * zone has already been set using adoptDefault() or setDefault(), the default is
357 * determined by querying the host system configuration. If the host system detection
358 * routines fail, or if they specify a TimeZone or TimeZone offset which is not
359 * recognized, then the special TimeZone "Etc/Unknown" is instantiated and made the
360 * default.
361 *
362 * @return A default TimeZone. Clients are responsible for deleting the time zone
363 * object returned.
364 * @see getUnknown
365 * @stable ICU 2.0
366 */
367 static TimeZone* U_EXPORT2 createDefault(void);
368
369 #ifndef U_HIDE_INTERNAL_API
370 /**
371 * If the locale contains the timezone keyword, creates a copy of that TimeZone.
372 * Otherwise, create the default timezone.
373 *
374 * @param locale a locale which may contains 'timezone' keyword/value.
375 * @return A TimeZone. Clients are responsible for deleting the time zone
376 * object returned.
377 * @internal
378 */
379 static TimeZone* U_EXPORT2 forLocaleOrDefault(const Locale& locale);
380 #endif /* U_HIDE_INTERNAL_API */
381
382 /**
383 * Sets the default time zone (i.e., what's returned by createDefault()) to be the
384 * specified time zone. If nullptr is specified for the time zone, the default time
385 * zone is set to the default host time zone. This call adopts the TimeZone object
386 * passed in; the client is no longer responsible for deleting it.
387 *
388 * @param zone A pointer to the new TimeZone object to use as the default.
389 * @stable ICU 2.0
390 */
391 static void U_EXPORT2 adoptDefault(TimeZone* zone);
392
393 #ifndef U_HIDE_SYSTEM_API
394 /**
395 * Same as adoptDefault(), except that the TimeZone object passed in is NOT adopted;
396 * the caller remains responsible for deleting it.
397 *
398 * @param zone The given timezone.
399 * @system
400 * @stable ICU 2.0
401 */
402 static void U_EXPORT2 setDefault(const TimeZone& zone);
403 #endif /* U_HIDE_SYSTEM_API */
404
405 /**
406 * Returns the timezone data version currently used by ICU.
407 * @param status Output param to filled in with a success or an error.
408 * @return the version string, such as "2007f"
409 * @stable ICU 3.8
410 */
411 static const char* U_EXPORT2 getTZDataVersion(UErrorCode& status);
412
413 /**
414 * Returns the canonical system timezone ID or the normalized
415 * custom time zone ID for the given time zone ID.
416 * @param id The input time zone ID to be canonicalized.
417 * @param canonicalID Receives the canonical system time zone ID
418 * or the custom time zone ID in normalized format.
419 * @param status Receives the status. When the given time zone ID
420 * is neither a known system time zone ID nor a
421 * valid custom time zone ID, U_ILLEGAL_ARGUMENT_ERROR
422 * is set.
423 * @return A reference to the result.
424 * @stable ICU 4.0
425 */
426 static UnicodeString& U_EXPORT2 getCanonicalID(const UnicodeString& id,
427 UnicodeString& canonicalID, UErrorCode& status);
428
429 /**
430 * Returns the canonical system time zone ID or the normalized
431 * custom time zone ID for the given time zone ID.
432 * @param id The input time zone ID to be canonicalized.
433 * @param canonicalID Receives the canonical system time zone ID
434 * or the custom time zone ID in normalized format.
435 * @param isSystemID Receives if the given ID is a known system
436 * time zone ID.
437 * @param status Receives the status. When the given time zone ID
438 * is neither a known system time zone ID nor a
439 * valid custom time zone ID, U_ILLEGAL_ARGUMENT_ERROR
440 * is set.
441 * @return A reference to the result.
442 * @stable ICU 4.0
443 */
444 static UnicodeString& U_EXPORT2 getCanonicalID(const UnicodeString& id,
445 UnicodeString& canonicalID, UBool& isSystemID, UErrorCode& status);
446
447
448 #ifndef U_HIDE_DRAFT_API
449 /**
450 * Returns the preferred time zone ID in the IANA time zone database for the given time zone ID.
451 * There are two types of preferred IDs. The first type is the one defined in zone.tab file,
452 * such as "America/Los_Angeles". The second types is the one defined for zones not associated
453 * with a specific region, but not defined with "Link" syntax such as "Etc/GMT+10".
454 *
455 * <p>Note: For most of valid time zone IDs, this method returns an ID same as getCanonicalID().
456 * getCanonicalID() is based on canonical time zone IDs defined in Unicode CLDR.
457 * These canonical time zone IDs in CLDR were based on very old version of the time zone database.
458 * In the IANA time zone database, some IDs were updated since then. This API returns a newer
459 * time zone ID. For example, CLDR defines "Asia/Calcutta" as the canonical time zone ID. This
460 * method returns "Asia/Kolkata" instead.
461 * <p> "Etc/Unknown" is a special time zone ID defined by CLDR. There are no corresponding zones
462 * in the IANA time zone database. Therefore, this API returns U_ILLEGAL_ARGUMENT_ERROR when the
463 * input ID is "Etc/Unknown".
464 *
465 * @param id The input time zone ID.
466 * @param ianaID Receives the preferred time zone ID in the IANA time zone database. When
467 * the given time zone ID is not a known time zone ID, this method sets an
468 * invalid (bogus) string.
469 * @param status Receives the status. When the given time zone ID is not a known time zone
470 * ID, U_ILLEGAL_ARGUMENT_ERROR is set.
471 * @return A reference to the result.
472 * @draft ICU 74
473 */
474 static UnicodeString& U_EXPORT2 getIanaID(const UnicodeString&id, UnicodeString& ianaID,
475 UErrorCode& status);
476 #endif // U_HIDE_DRAFT_API
477
478 /**
479 * Converts a system time zone ID to an equivalent Windows time zone ID. For example,
480 * Windows time zone ID "Pacific Standard Time" is returned for input "America/Los_Angeles".
481 *
482 * <p>There are system time zones that cannot be mapped to Windows zones. When the input
483 * system time zone ID is unknown or unmappable to a Windows time zone, then the result will be
484 * empty, but the operation itself remains successful (no error status set on return).
485 *
486 * <p>This implementation utilizes <a href="http://unicode.org/cldr/charts/supplemental/zone_tzid.html">
487 * Zone-Tzid mapping data</a>. The mapping data is updated time to time. To get the latest changes,
488 * please read the ICU user guide section <a href="https://unicode-org.github.io/icu/userguide/datetime/timezone#updating-the-time-zone-data">
489 * Updating the Time Zone Data</a>.
490 *
491 * @param id A system time zone ID.
492 * @param winid Receives a Windows time zone ID. When the input system time zone ID is unknown
493 * or unmappable to a Windows time zone ID, then an empty string is set on return.
494 * @param status Receives the status.
495 * @return A reference to the result (<code>winid</code>).
496 * @see getIDForWindowsID
497 *
498 * @stable ICU 52
499 */
500 static UnicodeString& U_EXPORT2 getWindowsID(const UnicodeString& id,
501 UnicodeString& winid, UErrorCode& status);
502
503 /**
504 * Converts a Windows time zone ID to an equivalent system time zone ID
505 * for a region. For example, system time zone ID "America/Los_Angeles" is returned
506 * for input Windows ID "Pacific Standard Time" and region "US" (or <code>null</code>),
507 * "America/Vancouver" is returned for the same Windows ID "Pacific Standard Time" and
508 * region "CA".
509 *
510 * <p>Not all Windows time zones can be mapped to system time zones. When the input
511 * Windows time zone ID is unknown or unmappable to a system time zone, then the result
512 * will be empty, but the operation itself remains successful (no error status set on return).
513 *
514 * <p>This implementation utilizes <a href="http://unicode.org/cldr/charts/supplemental/zone_tzid.html">
515 * Zone-Tzid mapping data</a>. The mapping data is updated time to time. To get the latest changes,
516 * please read the ICU user guide section <a href="https://unicode-org.github.io/icu/userguide/datetime/timezone#updating-the-time-zone-data">
517 * Updating the Time Zone Data</a>.
518 *
519 * @param winid A Windows time zone ID.
520 * @param region A NUL-terminated region code, or <code>nullptr</code> if no regional preference.
521 * @param id Receives a system time zone ID. When the input Windows time zone ID is unknown
522 * or unmappable to a system time zone ID, then an empty string is set on return.
523 * @param status Receives the status.
524 * @return A reference to the result (<code>id</code>).
525 * @see getWindowsID
526 *
527 * @stable ICU 52
528 */
529 static UnicodeString& U_EXPORT2 getIDForWindowsID(const UnicodeString& winid, const char* region,
530 UnicodeString& id, UErrorCode& status);
531
532 /**
533 * Returns true if the two TimeZones are equal. (The TimeZone version only compares
534 * IDs, but subclasses are expected to also compare the fields they add.)
535 *
536 * @param that The TimeZone object to be compared with.
537 * @return true if the given TimeZone is equal to this TimeZone; false
538 * otherwise.
539 * @stable ICU 2.0
540 */
541 virtual bool operator==(const TimeZone& that) const;
542
543 /**
544 * Returns true if the two TimeZones are NOT equal; that is, if operator==() returns
545 * false.
546 *
547 * @param that The TimeZone object to be compared with.
548 * @return true if the given TimeZone is not equal to this TimeZone; false
549 * otherwise.
550 * @stable ICU 2.0
551 */
552 bool operator!=(const TimeZone& that) const {return !operator==(that);}
553
554 /**
555 * Returns the TimeZone's adjusted GMT offset (i.e., the number of milliseconds to add
556 * to GMT to get local time in this time zone, taking daylight savings time into
557 * account) as of a particular reference date. The reference date is used to determine
558 * whether daylight savings time is in effect and needs to be figured into the offset
559 * that is returned (in other words, what is the adjusted GMT offset in this time zone
560 * at this particular date and time?). For the time zones produced by createTimeZone(),
561 * the reference data is specified according to the Gregorian calendar, and the date
562 * and time fields are local standard time.
563 *
564 * <p>Note: Don't call this method. Instead, call the getOffset(UDate...) overload,
565 * which returns both the raw and the DST offset for a given time. This method
566 * is retained only for backward compatibility.
567 *
568 * @param era The reference date's era
569 * @param year The reference date's year
570 * @param month The reference date's month (0-based; 0 is January)
571 * @param day The reference date's day-in-month (1-based)
572 * @param dayOfWeek The reference date's day-of-week (1-based; 1 is Sunday)
573 * @param millis The reference date's milliseconds in day, local standard time
574 * @param status Output param to filled in with a success or an error.
575 * @return The offset in milliseconds to add to GMT to get local time.
576 * @stable ICU 2.0
577 */
578 virtual int32_t getOffset(uint8_t era, int32_t year, int32_t month, int32_t day,
579 uint8_t dayOfWeek, int32_t millis, UErrorCode& status) const = 0;
580
581 /**
582 * Gets the time zone offset, for current date, modified in case of
583 * daylight savings. This is the offset to add *to* UTC to get local time.
584 *
585 * <p>Note: Don't call this method. Instead, call the getOffset(UDate...) overload,
586 * which returns both the raw and the DST offset for a given time. This method
587 * is retained only for backward compatibility.
588 *
589 * @param era the era of the given date.
590 * @param year the year in the given date.
591 * @param month the month in the given date.
592 * Month is 0-based. e.g., 0 for January.
593 * @param day the day-in-month of the given date.
594 * @param dayOfWeek the day-of-week of the given date.
595 * @param milliseconds the millis in day in <em>standard</em> local time.
596 * @param monthLength the length of the given month in days.
597 * @param status Output param to filled in with a success or an error.
598 * @return the offset to add *to* GMT to get local time.
599 * @stable ICU 2.0
600 */
601 virtual int32_t getOffset(uint8_t era, int32_t year, int32_t month, int32_t day,
602 uint8_t dayOfWeek, int32_t milliseconds,
603 int32_t monthLength, UErrorCode& status) const = 0;
604
605 /**
606 * Returns the time zone raw and GMT offset for the given moment
607 * in time. Upon return, local-millis = GMT-millis + rawOffset +
608 * dstOffset. All computations are performed in the proleptic
609 * Gregorian calendar. The default implementation in the TimeZone
610 * class delegates to the 8-argument getOffset().
611 *
612 * @param date moment in time for which to return offsets, in
613 * units of milliseconds from January 1, 1970 0:00 GMT, either GMT
614 * time or local wall time, depending on `local'.
615 * @param local if true, `date' is local wall time; otherwise it
616 * is in GMT time.
617 * @param rawOffset output parameter to receive the raw offset, that
618 * is, the offset not including DST adjustments
619 * @param dstOffset output parameter to receive the DST offset,
620 * that is, the offset to be added to `rawOffset' to obtain the
621 * total offset between local and GMT time. If DST is not in
622 * effect, this value is zero; otherwise it is a positive value,
623 * typically one hour.
624 * @param ec input-output error code
625 *
626 * @stable ICU 2.8
627 */
628 virtual void getOffset(UDate date, UBool local, int32_t& rawOffset,
629 int32_t& dstOffset, UErrorCode& ec) const;
630
631 /**
632 * Sets the TimeZone's raw GMT offset (i.e., the number of milliseconds to add
633 * to GMT to get local time, before taking daylight savings time into account).
634 *
635 * @param offsetMillis The new raw GMT offset for this time zone.
636 * @stable ICU 2.0
637 */
638 virtual void setRawOffset(int32_t offsetMillis) = 0;
639
640 /**
641 * Returns the TimeZone's raw GMT offset (i.e., the number of milliseconds to add
642 * to GMT to get local time, before taking daylight savings time into account).
643 *
644 * @return The TimeZone's raw GMT offset.
645 * @stable ICU 2.0
646 */
647 virtual int32_t getRawOffset(void) const = 0;
648
649 /**
650 * Fills in "ID" with the TimeZone's ID.
651 *
652 * @param ID Receives this TimeZone's ID.
653 * @return A reference to 'ID'
654 * @stable ICU 2.0
655 */
656 UnicodeString& getID(UnicodeString& ID) const;
657
658 /**
659 * Sets the TimeZone's ID to the specified value. This doesn't affect any other
660 * fields (for example, if you say<
661 * blockquote><pre>
662 * . TimeZone* foo = TimeZone::createTimeZone("America/New_York");
663 * . foo.setID("America/Los_Angeles");
664 * </pre>\htmlonly</blockquote>\endhtmlonly
665 * the time zone's GMT offset and daylight-savings rules don't change to those for
666 * Los Angeles. They're still those for New York. Only the ID has changed.)
667 *
668 * @param ID The new time zone ID.
669 * @stable ICU 2.0
670 */
671 void setID(const UnicodeString& ID);
672
673 /**
674 * Enum for use with getDisplayName
675 * @stable ICU 2.4
676 */
677 enum EDisplayType {
678 /**
679 * Selector for short display name
680 * @stable ICU 2.4
681 */
682 SHORT = 1,
683 /**
684 * Selector for long display name
685 * @stable ICU 2.4
686 */
687 LONG,
688 /**
689 * Selector for short generic display name
690 * @stable ICU 4.4
691 */
692 SHORT_GENERIC,
693 /**
694 * Selector for long generic display name
695 * @stable ICU 4.4
696 */
697 LONG_GENERIC,
698 /**
699 * Selector for short display name derived
700 * from time zone offset
701 * @stable ICU 4.4
702 */
703 SHORT_GMT,
704 /**
705 * Selector for long display name derived
706 * from time zone offset
707 * @stable ICU 4.4
708 */
709 LONG_GMT,
710 /**
711 * Selector for short display name derived
712 * from the time zone's fallback name
713 * @stable ICU 4.4
714 */
715 SHORT_COMMONLY_USED,
716 /**
717 * Selector for long display name derived
718 * from the time zone's fallback name
719 * @stable ICU 4.4
720 */
721 GENERIC_LOCATION
722 };
723
724 /**
725 * Returns a name of this time zone suitable for presentation to the user
726 * in the default locale.
727 * This method returns the long name, not including daylight savings.
728 * If the display name is not available for the locale,
729 * then this method returns a string in the localized GMT offset format
730 * such as <code>GMT[+-]HH:mm</code>.
731 * @param result the human-readable name of this time zone in the default locale.
732 * @return A reference to 'result'.
733 * @stable ICU 2.0
734 */
735 UnicodeString& getDisplayName(UnicodeString& result) const;
736
737 /**
738 * Returns a name of this time zone suitable for presentation to the user
739 * in the specified locale.
740 * This method returns the long name, not including daylight savings.
741 * If the display name is not available for the locale,
742 * then this method returns a string in the localized GMT offset format
743 * such as <code>GMT[+-]HH:mm</code>.
744 * @param locale the locale in which to supply the display name.
745 * @param result the human-readable name of this time zone in the given locale
746 * or in the default locale if the given locale is not recognized.
747 * @return A reference to 'result'.
748 * @stable ICU 2.0
749 */
750 UnicodeString& getDisplayName(const Locale& locale, UnicodeString& result) const;
751
752 /**
753 * Returns a name of this time zone suitable for presentation to the user
754 * in the default locale.
755 * If the display name is not available for the locale,
756 * then this method returns a string in the localized GMT offset format
757 * such as <code>GMT[+-]HH:mm</code>.
758 * @param inDaylight if true, return the daylight savings name.
759 * @param style
760 * @param result the human-readable name of this time zone in the default locale.
761 * @return A reference to 'result'.
762 * @stable ICU 2.0
763 */
764 UnicodeString& getDisplayName(UBool inDaylight, EDisplayType style, UnicodeString& result) const;
765
766 /**
767 * Returns a name of this time zone suitable for presentation to the user
768 * in the specified locale.
769 * If the display name is not available for the locale,
770 * then this method returns a string in the localized GMT offset format
771 * such as <code>GMT[+-]HH:mm</code>.
772 * @param inDaylight if true, return the daylight savings name.
773 * @param style
774 * @param locale the locale in which to supply the display name.
775 * @param result the human-readable name of this time zone in the given locale
776 * or in the default locale if the given locale is not recognized.
777 * @return A reference to 'result'.
778 * @stable ICU 2.0
779 */
780 UnicodeString& getDisplayName(UBool inDaylight, EDisplayType style, const Locale& locale, UnicodeString& result) const;
781
782 /**
783 * Queries if this time zone uses daylight savings time.
784 * @return true if this time zone uses daylight savings time,
785 * false, otherwise.
786 * <p><strong>Note:</strong>The default implementation of
787 * ICU TimeZone uses the tz database, which supports historic
788 * rule changes, for system time zones. With the implementation,
789 * there are time zones that used daylight savings time in the
790 * past, but no longer used currently. For example, Asia/Tokyo has
791 * never used daylight savings time since 1951. Most clients would
792 * expect that this method to return <code>false</code> for such case.
793 * The default implementation of this method returns <code>true</code>
794 * when the time zone uses daylight savings time in the current
795 * (Gregorian) calendar year.
796 * <p>In Java 7, <code>observesDaylightTime()</code> was added in
797 * addition to <code>useDaylightTime()</code>. In Java, <code>useDaylightTime()</code>
798 * only checks if daylight saving time is observed by the last known
799 * rule. This specification might not be what most users would expect
800 * if daylight saving time is currently observed, but not scheduled
801 * in future. In this case, Java's <code>userDaylightTime()</code> returns
802 * <code>false</code>. To resolve the issue, Java 7 added <code>observesDaylightTime()</code>,
803 * which takes the current rule into account. The method <code>observesDaylightTime()</code>
804 * was added in ICU4J for supporting API signature compatibility with JDK.
805 * In general, ICU4C also provides JDK compatible methods, but the current
806 * implementation <code>userDaylightTime()</code> serves the purpose
807 * (takes the current rule into account), <code>observesDaylightTime()</code>
808 * is not added in ICU4C. In addition to <code>useDaylightTime()</code>, ICU4C
809 * <code>BasicTimeZone</code> class (Note that <code>TimeZone::createTimeZone(const UnicodeString &ID)</code>
810 * always returns a <code>BasicTimeZone</code>) provides a series of methods allowing
811 * historic and future time zone rule iteration, so you can check if daylight saving
812 * time is observed or not within a given period.
813 *
814 * @stable ICU 2.0
815 */
816 virtual UBool useDaylightTime(void) const = 0;
817
818 #ifndef U_FORCE_HIDE_DEPRECATED_API
819 /**
820 * Queries if the given date is in daylight savings time in
821 * this time zone.
822 * This method is wasteful since it creates a new GregorianCalendar and
823 * deletes it each time it is called. This is a deprecated method
824 * and provided only for Java compatibility.
825 *
826 * @param date the given UDate.
827 * @param status Output param filled in with success/error code.
828 * @return true if the given date is in daylight savings time,
829 * false, otherwise.
830 * @deprecated ICU 2.4. Use Calendar::inDaylightTime() instead.
831 */
832 virtual UBool inDaylightTime(UDate date, UErrorCode& status) const = 0;
833 #endif // U_FORCE_HIDE_DEPRECATED_API
834
835 /**
836 * Returns true if this zone has the same rule and offset as another zone.
837 * That is, if this zone differs only in ID, if at all.
838 * @param other the <code>TimeZone</code> object to be compared with
839 * @return true if the given zone is the same as this one,
840 * with the possible exception of the ID
841 * @stable ICU 2.0
842 */
843 virtual UBool hasSameRules(const TimeZone& other) const;
844
845 /**
846 * Clones TimeZone objects polymorphically. Clients are responsible for deleting
847 * the TimeZone object cloned.
848 *
849 * @return A new copy of this TimeZone object.
850 * @stable ICU 2.0
851 */
852 virtual TimeZone* clone() const = 0;
853
854 /**
855 * Return the class ID for this class. This is useful only for
856 * comparing to a return value from getDynamicClassID().
857 * @return The class ID for all objects of this class.
858 * @stable ICU 2.0
859 */
860 static UClassID U_EXPORT2 getStaticClassID(void);
861
862 /**
863 * Returns a unique class ID POLYMORPHICALLY. This method is to
864 * implement a simple version of RTTI, since not all C++ compilers support genuine
865 * RTTI. Polymorphic operator==() and clone() methods call this method.
866 * <P>
867 * Concrete subclasses of TimeZone must use the UOBJECT_DEFINE_RTTI_IMPLEMENTATION
868 * macro from uobject.h in their implementation to provide correct RTTI information.
869 * @return The class ID for this object. All objects of a given class have the
870 * same class ID. Objects of other classes have different class IDs.
871 * @stable ICU 2.0
872 */
873 virtual UClassID getDynamicClassID(void) const override = 0;
874
875 /**
876 * Returns the amount of time to be added to local standard time
877 * to get local wall clock time.
878 * <p>
879 * The default implementation always returns 3600000 milliseconds
880 * (i.e., one hour) if this time zone observes Daylight Saving
881 * Time. Otherwise, 0 (zero) is returned.
882 * <p>
883 * If an underlying TimeZone implementation subclass supports
884 * historical Daylight Saving Time changes, this method returns
885 * the known latest daylight saving value.
886 *
887 * @return the amount of saving time in milliseconds
888 * @stable ICU 3.6
889 */
890 virtual int32_t getDSTSavings() const;
891
892 /**
893 * Gets the region code associated with the given
894 * system time zone ID. The region code is either ISO 3166
895 * 2-letter country code or UN M.49 3-digit area code.
896 * When the time zone is not associated with a specific location,
897 * for example - "Etc/UTC", "EST5EDT", then this method returns
898 * "001" (UN M.49 area code for World).
899 *
900 * @param id The system time zone ID.
901 * @param region Output buffer for receiving the region code.
902 * @param capacity The size of the output buffer.
903 * @param status Receives the status. When the given time zone ID
904 * is not a known system time zone ID,
905 * U_ILLEGAL_ARGUMENT_ERROR is set.
906 * @return The length of the output region code.
907 * @stable ICU 4.8
908 */
909 static int32_t U_EXPORT2 getRegion(const UnicodeString& id,
910 char *region, int32_t capacity, UErrorCode& status);
911
912 protected:
913
914 /**
915 * Default constructor. ID is initialized to the empty string.
916 * @stable ICU 2.0
917 */
918 TimeZone();
919
920 /**
921 * Construct a TimeZone with a given ID.
922 * @param id a system time zone ID
923 * @stable ICU 2.0
924 */
925 TimeZone(const UnicodeString &id);
926
927 /**
928 * Copy constructor.
929 * @param source the object to be copied.
930 * @stable ICU 2.0
931 */
932 TimeZone(const TimeZone& source);
933
934 /**
935 * Default assignment operator.
936 * @param right the object to be copied.
937 * @stable ICU 2.0
938 */
939 TimeZone& operator=(const TimeZone& right);
940
941 #ifndef U_HIDE_INTERNAL_API
942 /**
943 * Utility function. For internally loading rule data.
944 * @param top Top resource bundle for tz data
945 * @param ruleid ID of rule to load
946 * @param oldbundle Old bundle to reuse or nullptr
947 * @param status Status parameter
948 * @return either a new bundle or *oldbundle
949 * @internal
950 */
951 static UResourceBundle* loadRule(const UResourceBundle* top, const UnicodeString& ruleid, UResourceBundle* oldbundle, UErrorCode&status);
952 #endif /* U_HIDE_INTERNAL_API */
953
954 private:
955 friend class ZoneMeta;
956
957
958 static TimeZone* createCustomTimeZone(const UnicodeString&); // Creates a time zone based on the string.
959
960 /**
961 * Finds the given ID in the Olson tzdata. If the given ID is found in the tzdata,
962 * returns the pointer to the ID resource. This method is exposed through ZoneMeta class
963 * for ICU internal implementation and useful for building hashtable using a time zone
964 * ID as a key.
965 * @param id zone id string
966 * @return the pointer of the ID resource, or nullptr.
967 */
968 static const char16_t* findID(const UnicodeString& id);
969
970 /**
971 * Resolve a link in Olson tzdata. When the given id is known and it's not a link,
972 * the id itself is returned. When the given id is known and it is a link, then
973 * dereferenced zone id is returned. When the given id is unknown, then it returns
974 * nullptr.
975 * @param id zone id string
976 * @return the dereferenced zone or nullptr
977 */
978 static const char16_t* dereferOlsonLink(const UnicodeString& id);
979
980 /**
981 * Returns the region code associated with the given zone,
982 * or nullptr if the zone is not known.
983 * @param id zone id string
984 * @return the region associated with the given zone
985 */
986 static const char16_t* getRegion(const UnicodeString& id);
987
988 public:
989 #ifndef U_HIDE_INTERNAL_API
990 /**
991 * Returns the region code associated with the given zone,
992 * or nullptr if the zone is not known.
993 * @param id zone id string
994 * @param status Status parameter
995 * @return the region associated with the given zone
996 * @internal
997 */
998 static const char16_t* getRegion(const UnicodeString& id, UErrorCode& status);
999 #endif /* U_HIDE_INTERNAL_API */
1000
1001 private:
1002 /**
1003 * Parses the given custom time zone identifier
1004 * @param id id A string of the form GMT[+-]hh:mm, GMT[+-]hhmm, or
1005 * GMT[+-]hh.
1006 * @param sign Receives parsed sign, 1 for positive, -1 for negative.
1007 * @param hour Receives parsed hour field
1008 * @param minute Receives parsed minute field
1009 * @param second Receives parsed second field
1010 * @return Returns true when the given custom id is valid.
1011 */
1012 static UBool parseCustomID(const UnicodeString& id, int32_t& sign, int32_t& hour,
1013 int32_t& minute, int32_t& second);
1014
1015 /**
1016 * Parse a custom time zone identifier and return the normalized
1017 * custom time zone identifier for the given custom id string.
1018 * @param id a string of the form GMT[+-]hh:mm, GMT[+-]hhmm, or
1019 * GMT[+-]hh.
1020 * @param normalized Receives the normalized custom ID
1021 * @param status Receives the status. When the input ID string is invalid,
1022 * U_ILLEGAL_ARGUMENT_ERROR is set.
1023 * @return The normalized custom id string.
1024 */
1025 static UnicodeString& getCustomID(const UnicodeString& id, UnicodeString& normalized,
1026 UErrorCode& status);
1027
1028 /**
1029 * Returns the normalized custom time zone ID for the given offset fields.
1030 * @param hour offset hours
1031 * @param min offset minutes
1032 * @param sec offset seconds
1033 * @param negative sign of the offset, true for negative offset.
1034 * @param id Receives the format result (normalized custom ID)
1035 * @return The reference to id
1036 */
1037 static UnicodeString& formatCustomID(int32_t hour, int32_t min, int32_t sec,
1038 UBool negative, UnicodeString& id);
1039
1040 UnicodeString fID; // this time zone's ID
1041
1042 friend class TZEnumeration;
1043 };
1044
1045
1046 // -------------------------------------
1047
1048 inline UnicodeString&
getID(UnicodeString & ID)1049 TimeZone::getID(UnicodeString& ID) const
1050 {
1051 ID = fID;
1052 return ID;
1053 }
1054
1055 // -------------------------------------
1056
1057 inline void
setID(const UnicodeString & ID)1058 TimeZone::setID(const UnicodeString& ID)
1059 {
1060 fID = ID;
1061 }
1062 U_NAMESPACE_END
1063
1064 #endif /* #if !UCONFIG_NO_FORMATTING */
1065
1066 #endif /* U_SHOW_CPLUSPLUS_API */
1067
1068 #endif //_TIMEZONE
1069 //eof
1070