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