1 /*************************************************************************
2 * Copyright (c) 1997-2010, International Business Machines Corporation
3 * and others. All Rights Reserved.
4 **************************************************************************
5 *
6 * File TIMEZONE.H
7 *
8 * Modification History:
9 *
10 * Date Name Description
11 * 04/21/97 aliu Overhauled header.
12 * 07/09/97 helena Changed createInstance to createDefault.
13 * 08/06/97 aliu Removed dependency on internal header for Hashtable.
14 * 08/10/98 stephen Changed getDisplayName() API conventions to match
15 * 08/19/98 stephen Changed createTimeZone() to never return 0
16 * 09/02/98 stephen Sync to JDK 1.2 8/31
17 * - Added getOffset(... monthlen ...)
18 * - Added hasSameRules()
19 * 09/15/98 stephen Added getStaticClassID
20 * 12/03/99 aliu Moved data out of static table into icudata.dll.
21 * Hashtable replaced by new static data structures.
22 * 12/14/99 aliu Made GMT public.
23 * 08/15/01 grhoten Made GMT private and added the getGMT() function
24 **************************************************************************
25 */
26
27 #ifndef TIMEZONE_H
28 #define TIMEZONE_H
29
30 #include "unicode/utypes.h"
31
32 /**
33 * \file
34 * \brief C++ API: TimeZone object
35 */
36
37 #if !UCONFIG_NO_FORMATTING
38
39 #include "unicode/uobject.h"
40 #include "unicode/unistr.h"
41 #include "unicode/ures.h"
42
43 U_NAMESPACE_BEGIN
44
45 class StringEnumeration;
46
47 /**
48 *
49 * <code>TimeZone</code> represents a time zone offset, and also figures out daylight
50 * savings.
51 *
52 * <p>
53 * Typically, you get a <code>TimeZone</code> using <code>createDefault</code>
54 * which creates a <code>TimeZone</code> based on the time zone where the program
55 * is running. For example, for a program running in Japan, <code>createDefault</code>
56 * creates a <code>TimeZone</code> object based on Japanese Standard Time.
57 *
58 * <p>
59 * You can also get a <code>TimeZone</code> using <code>createTimeZone</code> along
60 * with a time zone ID. For instance, the time zone ID for the US Pacific
61 * Time zone is "America/Los_Angeles". So, you can get a Pacific Time <code>TimeZone</code> object
62 * with:
63 * \htmlonly<blockquote>\endhtmlonly
64 * <pre>
65 * TimeZone *tz = TimeZone::createTimeZone("America/Los_Angeles");
66 * </pre>
67 * \htmlonly</blockquote>\endhtmlonly
68 * You can use <code>getAvailableIDs</code> method to iterate through
69 * all the supported time zone IDs. You can then choose a
70 * supported ID to get a <code>TimeZone</code>.
71 * If the time zone you want is not represented by one of the
72 * supported IDs, then you can create a custom time zone ID with
73 * the following syntax:
74 *
75 * \htmlonly<blockquote>\endhtmlonly
76 * <pre>
77 * GMT[+|-]hh[[:]mm]
78 * </pre>
79 * \htmlonly</blockquote>\endhtmlonly
80 *
81 * For example, you might specify GMT+14:00 as a custom
82 * time zone ID. The <code>TimeZone</code> that is returned
83 * when you specify a custom time zone ID does not include
84 * daylight savings time.
85 *
86 * TimeZone is an abstract class representing a time zone. A TimeZone is needed for
87 * Calendar to produce local time for a particular time zone. A TimeZone comprises
88 * three basic pieces of information:
89 * <ul>
90 * <li>A time zone offset; that, is the number of milliseconds to add or subtract
91 * from a time expressed in terms of GMT to convert it to the same time in that
92 * time zone (without taking daylight savings time into account).</li>
93 * <li>Logic necessary to take daylight savings time into account if daylight savings
94 * time is observed in that time zone (e.g., the days and hours on which daylight
95 * savings time begins and ends).</li>
96 * <li>An ID. This is a text string that uniquely identifies the time zone.</li>
97 * </ul>
98 *
99 * (Only the ID is actually implemented in TimeZone; subclasses of TimeZone may handle
100 * daylight savings time and GMT offset in different ways. Currently we only have one
101 * TimeZone subclass: SimpleTimeZone.)
102 * <P>
103 * The TimeZone class contains a static list containing a TimeZone object for every
104 * combination of GMT offset and daylight-savings time rules currently in use in the
105 * world, each with a unique ID. Each ID consists of a region (usually a continent or
106 * ocean) and a city in that region, separated by a slash, (for example, US Pacific
107 * Time is "America/Los_Angeles.") Because older versions of this class used
108 * three- or four-letter abbreviations instead, there is also a table that maps the older
109 * abbreviations to the newer ones (for example, "PST" maps to "America/Los_Angeles").
110 * Anywhere the API requires an ID, you can use either form.
111 * <P>
112 * To create a new TimeZone, you call the factory function TimeZone::createTimeZone()
113 * and pass it a time zone ID. You can use the createEnumeration() function to
114 * obtain a list of all the time zone IDs recognized by createTimeZone().
115 * <P>
116 * You can also use TimeZone::createDefault() to create a TimeZone. This function uses
117 * platform-specific APIs to produce a TimeZone for the time zone corresponding to
118 * the client's computer's physical location. For example, if you're in Japan (assuming
119 * your machine is set up correctly), TimeZone::createDefault() will return a TimeZone
120 * for Japanese Standard Time ("Asia/Tokyo").
121 */
122 class U_I18N_API TimeZone : public UObject {
123 public:
124 /**
125 * @stable ICU 2.0
126 */
127 virtual ~TimeZone();
128
129 /**
130 * The GMT time zone has a raw offset of zero and does not use daylight
131 * savings time. This is a commonly used time zone.
132 * @return the GMT time zone.
133 * @stable ICU 2.0
134 */
135 static const TimeZone* U_EXPORT2 getGMT(void);
136
137 /**
138 * Creates a <code>TimeZone</code> for the given ID.
139 * @param ID the ID for a <code>TimeZone</code>, such as "America/Los_Angeles",
140 * or a custom ID such as "GMT-8:00".
141 * @return the specified <code>TimeZone</code>, or the GMT zone if the given ID
142 * cannot be understood. Return result guaranteed to be non-null. If you
143 * require that the specific zone asked for be returned, check the ID of the
144 * return result.
145 * @stable ICU 2.0
146 */
147 static TimeZone* U_EXPORT2 createTimeZone(const UnicodeString& ID);
148
149 /**
150 * Returns an enumeration over all recognized time zone IDs. (i.e.,
151 * all strings that createTimeZone() accepts)
152 *
153 * @return an enumeration object, owned by the caller.
154 * @stable ICU 2.4
155 */
156 static StringEnumeration* U_EXPORT2 createEnumeration();
157
158 /**
159 * Returns an enumeration over time zone IDs with a given raw
160 * offset from GMT. There may be several times zones with the
161 * same GMT offset that differ in the way they handle daylight
162 * savings time. For example, the state of Arizona doesn't
163 * observe daylight savings time. If you ask for the time zone
164 * IDs corresponding to GMT-7:00, you'll get back an enumeration
165 * over two time zone IDs: "America/Denver," which corresponds to
166 * Mountain Standard Time in the winter and Mountain Daylight Time
167 * in the summer, and "America/Phoenix", which corresponds to
168 * Mountain Standard Time year-round, even in the summer.
169 *
170 * @param rawOffset an offset from GMT in milliseconds, ignoring
171 * the effect of daylight savings time, if any
172 * @return an enumeration object, owned by the caller
173 * @stable ICU 2.4
174 */
175 static StringEnumeration* U_EXPORT2 createEnumeration(int32_t rawOffset);
176
177 /**
178 * Returns an enumeration over time zone IDs associated with the
179 * given country. Some zones are affiliated with no country
180 * (e.g., "UTC"); these may also be retrieved, as a group.
181 *
182 * @param country The ISO 3166 two-letter country code, or NULL to
183 * retrieve zones not affiliated with any country.
184 * @return an enumeration object, owned by the caller
185 * @stable ICU 2.4
186 */
187 static StringEnumeration* U_EXPORT2 createEnumeration(const char* country);
188
189 /**
190 * Returns the number of IDs in the equivalency group that
191 * includes the given ID. An equivalency group contains zones
192 * that have the same GMT offset and rules.
193 *
194 * <p>The returned count includes the given ID; it is always >= 1.
195 * The given ID must be a system time zone. If it is not, returns
196 * zero.
197 * @param id a system time zone ID
198 * @return the number of zones in the equivalency group containing
199 * 'id', or zero if 'id' is not a valid system ID
200 * @see #getEquivalentID
201 * @stable ICU 2.0
202 */
203 static int32_t U_EXPORT2 countEquivalentIDs(const UnicodeString& id);
204
205 /**
206 * Returns an ID in the equivalency group that
207 * includes the given ID. An equivalency group contains zones
208 * that have the same GMT offset and rules.
209 *
210 * <p>The given index must be in the range 0..n-1, where n is the
211 * value returned by <code>countEquivalentIDs(id)</code>. For
212 * some value of 'index', the returned value will be equal to the
213 * given id. If the given id is not a valid system time zone, or
214 * if 'index' is out of range, then returns an empty string.
215 * @param id a system time zone ID
216 * @param index a value from 0 to n-1, where n is the value
217 * returned by <code>countEquivalentIDs(id)</code>
218 * @return the ID of the index-th zone in the equivalency group
219 * containing 'id', or an empty string if 'id' is not a valid
220 * system ID or 'index' is out of range
221 * @see #countEquivalentIDs
222 * @stable ICU 2.0
223 */
224 static const UnicodeString U_EXPORT2 getEquivalentID(const UnicodeString& id,
225 int32_t index);
226
227 /**
228 * Creates a new copy of the default TimeZone for this host. Unless the default time
229 * zone has already been set using adoptDefault() or setDefault(), the default is
230 * determined by querying the system using methods in TPlatformUtilities. If the
231 * system routines fail, or if they specify a TimeZone or TimeZone offset which is not
232 * recognized, the TimeZone indicated by the ID kLastResortID is instantiated
233 * and made the default.
234 *
235 * @return A default TimeZone. Clients are responsible for deleting the time zone
236 * object returned.
237 * @stable ICU 2.0
238 */
239 static TimeZone* U_EXPORT2 createDefault(void);
240
241 /**
242 * Sets the default time zone (i.e., what's returned by createDefault()) to be the
243 * specified time zone. If NULL is specified for the time zone, the default time
244 * zone is set to the default host time zone. This call adopts the TimeZone object
245 * passed in; the clent is no longer responsible for deleting it.
246 *
247 * @param zone A pointer to the new TimeZone object to use as the default.
248 * @stable ICU 2.0
249 */
250 static void U_EXPORT2 adoptDefault(TimeZone* zone);
251
252 /**
253 * Same as adoptDefault(), except that the TimeZone object passed in is NOT adopted;
254 * the caller remains responsible for deleting it.
255 *
256 * @param zone The given timezone.
257 * @system
258 */
259 static void U_EXPORT2 setDefault(const TimeZone& zone);
260
261 /**
262 * Returns the timezone data version currently used by ICU.
263 * @param status Output param to filled in with a success or an error.
264 * @return the version string, such as "2007f"
265 * @stable ICU 3.8
266 */
267 static const char* U_EXPORT2 getTZDataVersion(UErrorCode& status);
268
269 /**
270 * Returns the canonical system timezone ID or the normalized
271 * custom time zone ID for the given time zone ID.
272 * @param id The input time zone ID to be canonicalized.
273 * @param canonicalID Receives the canonical system time zone ID
274 * or the custom time zone ID in normalized format.
275 * @param status Recevies the status. When the given time zone ID
276 * is neither a known system time zone ID nor a
277 * valid custom time zone ID, U_ILLEGAL_ARGUMENT_ERROR
278 * is set.
279 * @return A reference to the result.
280 * @stable ICU 4.0
281 */
282 static UnicodeString& U_EXPORT2 getCanonicalID(const UnicodeString& id,
283 UnicodeString& canonicalID, UErrorCode& status);
284
285 /**
286 * Returns the canonical system time zone ID or the normalized
287 * custom time zone ID for the given time zone ID.
288 * @param id The input time zone ID to be canonicalized.
289 * @param canonicalID Receives the canonical system time zone ID
290 * or the custom time zone ID in normalized format.
291 * @param isSystemID Receives if the given ID is a known system
292 * time zone ID.
293 * @param status Recevies the status. When the given time zone ID
294 * is neither a known system time zone ID nor a
295 * valid custom time zone ID, U_ILLEGAL_ARGUMENT_ERROR
296 * is set.
297 * @return A reference to the result.
298 * @stable ICU 4.0
299 */
300 static UnicodeString& U_EXPORT2 getCanonicalID(const UnicodeString& id,
301 UnicodeString& canonicalID, UBool& isSystemID, UErrorCode& status);
302
303 /**
304 * Returns true if the two TimeZones are equal. (The TimeZone version only compares
305 * IDs, but subclasses are expected to also compare the fields they add.)
306 *
307 * @param that The TimeZone object to be compared with.
308 * @return True if the given TimeZone is equal to this TimeZone; false
309 * otherwise.
310 * @stable ICU 2.0
311 */
312 virtual UBool operator==(const TimeZone& that) const;
313
314 /**
315 * Returns true if the two TimeZones are NOT equal; that is, if operator==() returns
316 * false.
317 *
318 * @param that The TimeZone object to be compared with.
319 * @return True if the given TimeZone is not equal to this TimeZone; false
320 * otherwise.
321 * @stable ICU 2.0
322 */
323 UBool operator!=(const TimeZone& that) const {return !operator==(that);}
324
325 /**
326 * Returns the TimeZone's adjusted GMT offset (i.e., the number of milliseconds to add
327 * to GMT to get local time in this time zone, taking daylight savings time into
328 * account) as of a particular reference date. The reference date is used to determine
329 * whether daylight savings time is in effect and needs to be figured into the offset
330 * that is returned (in other words, what is the adjusted GMT offset in this time zone
331 * at this particular date and time?). For the time zones produced by createTimeZone(),
332 * the reference data is specified according to the Gregorian calendar, and the date
333 * and time fields are local standard time.
334 *
335 * <p>Note: Don't call this method. Instead, call the getOffset(UDate...) overload,
336 * which returns both the raw and the DST offset for a given time. This method
337 * is retained only for backward compatibility.
338 *
339 * @param era The reference date's era
340 * @param year The reference date's year
341 * @param month The reference date's month (0-based; 0 is January)
342 * @param day The reference date's day-in-month (1-based)
343 * @param dayOfWeek The reference date's day-of-week (1-based; 1 is Sunday)
344 * @param millis The reference date's milliseconds in day, local standard time
345 * @param status Output param to filled in with a success or an error.
346 * @return The offset in milliseconds to add to GMT to get local time.
347 * @stable ICU 2.0
348 */
349 virtual int32_t getOffset(uint8_t era, int32_t year, int32_t month, int32_t day,
350 uint8_t dayOfWeek, int32_t millis, UErrorCode& status) const = 0;
351
352 /**
353 * Gets the time zone offset, for current date, modified in case of
354 * daylight savings. This is the offset to add *to* UTC to get local time.
355 *
356 * <p>Note: Don't call this method. Instead, call the getOffset(UDate...) overload,
357 * which returns both the raw and the DST offset for a given time. This method
358 * is retained only for backward compatibility.
359 *
360 * @param era the era of the given date.
361 * @param year the year in the given date.
362 * @param month the month in the given date.
363 * Month is 0-based. e.g., 0 for January.
364 * @param day the day-in-month of the given date.
365 * @param dayOfWeek the day-of-week of the given date.
366 * @param milliseconds the millis in day in <em>standard</em> local time.
367 * @param monthLength the length of the given month in days.
368 * @param status Output param to filled in with a success or an error.
369 * @return the offset to add *to* GMT to get local time.
370 * @stable ICU 2.0
371 */
372 virtual int32_t getOffset(uint8_t era, int32_t year, int32_t month, int32_t day,
373 uint8_t dayOfWeek, int32_t milliseconds,
374 int32_t monthLength, UErrorCode& status) const = 0;
375
376 /**
377 * Returns the time zone raw and GMT offset for the given moment
378 * in time. Upon return, local-millis = GMT-millis + rawOffset +
379 * dstOffset. All computations are performed in the proleptic
380 * Gregorian calendar. The default implementation in the TimeZone
381 * class delegates to the 8-argument getOffset().
382 *
383 * @param date moment in time for which to return offsets, in
384 * units of milliseconds from January 1, 1970 0:00 GMT, either GMT
385 * time or local wall time, depending on `local'.
386 * @param local if true, `date' is local wall time; otherwise it
387 * is in GMT time.
388 * @param rawOffset output parameter to receive the raw offset, that
389 * is, the offset not including DST adjustments
390 * @param dstOffset output parameter to receive the DST offset,
391 * that is, the offset to be added to `rawOffset' to obtain the
392 * total offset between local and GMT time. If DST is not in
393 * effect, this value is zero; otherwise it is a positive value,
394 * typically one hour.
395 * @param ec input-output error code
396 *
397 * @stable ICU 2.8
398 */
399 virtual void getOffset(UDate date, UBool local, int32_t& rawOffset,
400 int32_t& dstOffset, UErrorCode& ec) const;
401
402 /**
403 * Sets the TimeZone's raw GMT offset (i.e., the number of milliseconds to add
404 * to GMT to get local time, before taking daylight savings time into account).
405 *
406 * @param offsetMillis The new raw GMT offset for this time zone.
407 * @stable ICU 2.0
408 */
409 virtual void setRawOffset(int32_t offsetMillis) = 0;
410
411 /**
412 * Returns the TimeZone's raw GMT offset (i.e., the number of milliseconds to add
413 * to GMT to get local time, before taking daylight savings time into account).
414 *
415 * @return The TimeZone's raw GMT offset.
416 * @stable ICU 2.0
417 */
418 virtual int32_t getRawOffset(void) const = 0;
419
420 /**
421 * Fills in "ID" with the TimeZone's ID.
422 *
423 * @param ID Receives this TimeZone's ID.
424 * @return A reference to 'ID'
425 * @stable ICU 2.0
426 */
427 UnicodeString& getID(UnicodeString& ID) const;
428
429 /**
430 * Sets the TimeZone's ID to the specified value. This doesn't affect any other
431 * fields (for example, if you say<
432 * blockquote><pre>
433 * . TimeZone* foo = TimeZone::createTimeZone("America/New_York");
434 * . foo.setID("America/Los_Angeles");
435 * </pre>\htmlonly</blockquote>\endhtmlonly
436 * the time zone's GMT offset and daylight-savings rules don't change to those for
437 * Los Angeles. They're still those for New York. Only the ID has changed.)
438 *
439 * @param ID The new time zone ID.
440 * @stable ICU 2.0
441 */
442 void setID(const UnicodeString& ID);
443
444 /**
445 * Enum for use with getDisplayName
446 * @stable ICU 2.4
447 */
448 enum EDisplayType {
449 /**
450 * Selector for short display name
451 * @stable ICU 2.4
452 */
453 SHORT = 1,
454 /**
455 * Selector for long display name
456 * @stable ICU 2.4
457 */
458 LONG,
459 /**
460 * Selector for short generic display name
461 * @stable ICU 4.4
462 */
463 SHORT_GENERIC,
464 /**
465 * Selector for long generic display name
466 * @stable ICU 4.4
467 */
468 LONG_GENERIC,
469 /**
470 * Selector for short display name derived
471 * from time zone offset
472 * @stable ICU 4.4
473 */
474 SHORT_GMT,
475 /**
476 * Selector for long display name derived
477 * from time zone offset
478 * @stable ICU 4.4
479 */
480 LONG_GMT,
481 /**
482 * Selector for short display name derived
483 * from the time zone's fallback name
484 * @stable ICU 4.4
485 */
486 SHORT_COMMONLY_USED,
487 /**
488 * Selector for long display name derived
489 * from the time zone's fallback name
490 * @stable ICU 4.4
491 */
492 GENERIC_LOCATION
493 };
494
495 /**
496 * Returns a name of this time zone suitable for presentation to the user
497 * in the default locale.
498 * This method returns the long name, not including daylight savings.
499 * If the display name is not available for the locale,
500 * then this method returns a string in the format
501 * <code>GMT[+-]hh:mm</code>.
502 * @param result the human-readable name of this time zone in the default locale.
503 * @return A reference to 'result'.
504 * @stable ICU 2.0
505 */
506 UnicodeString& getDisplayName(UnicodeString& result) const;
507
508 /**
509 * Returns a name of this time zone suitable for presentation to the user
510 * in the specified locale.
511 * This method returns the long name, not including daylight savings.
512 * If the display name is not available for the locale,
513 * then this method returns a string in the format
514 * <code>GMT[+-]hh:mm</code>.
515 * @param locale the locale in which to supply the display name.
516 * @param result the human-readable name of this time zone in the given locale
517 * or in the default locale if the given locale is not recognized.
518 * @return A reference to 'result'.
519 * @stable ICU 2.0
520 */
521 UnicodeString& getDisplayName(const Locale& locale, UnicodeString& result) const;
522
523 /**
524 * Returns a name of this time zone suitable for presentation to the user
525 * in the default locale.
526 * If the display name is not available for the locale,
527 * then this method returns a string in the format
528 * <code>GMT[+-]hh:mm</code>.
529 * @param daylight if true, return the daylight savings name.
530 * @param style
531 * @param result the human-readable name of this time zone in the default locale.
532 * @return A reference to 'result'.
533 * @stable ICU 2.0
534 */
535 UnicodeString& getDisplayName(UBool daylight, EDisplayType style, UnicodeString& result) const;
536
537 /**
538 * Returns a name of this time zone suitable for presentation to the user
539 * in the specified locale.
540 * If the display name is not available for the locale,
541 * then this method returns a string in the format
542 * <code>GMT[+-]hh:mm</code>.
543 * @param daylight if true, return the daylight savings name.
544 * @param style
545 * @param locale the locale in which to supply the display name.
546 * @param result the human-readable name of this time zone in the given locale
547 * or in the default locale if the given locale is not recognized.
548 * @return A refence to 'result'.
549 * @stable ICU 2.0
550 */
551 UnicodeString& getDisplayName(UBool daylight, EDisplayType style, const Locale& locale, UnicodeString& result) const;
552
553 /**
554 * Queries if this time zone uses daylight savings time.
555 * @return true if this time zone uses daylight savings time,
556 * false, otherwise.
557 * @stable ICU 2.0
558 */
559 virtual UBool useDaylightTime(void) const = 0;
560
561 /**
562 * Queries if the given date is in daylight savings time in
563 * this time zone.
564 * This method is wasteful since it creates a new GregorianCalendar and
565 * deletes it each time it is called. This is a deprecated method
566 * and provided only for Java compatibility.
567 *
568 * @param date the given UDate.
569 * @param status Output param filled in with success/error code.
570 * @return true if the given date is in daylight savings time,
571 * false, otherwise.
572 * @deprecated ICU 2.4. Use Calendar::inDaylightTime() instead.
573 */
574 virtual UBool inDaylightTime(UDate date, UErrorCode& status) const = 0;
575
576 /**
577 * Returns true if this zone has the same rule and offset as another zone.
578 * That is, if this zone differs only in ID, if at all.
579 * @param other the <code>TimeZone</code> object to be compared with
580 * @return true if the given zone is the same as this one,
581 * with the possible exception of the ID
582 * @stable ICU 2.0
583 */
584 virtual UBool hasSameRules(const TimeZone& other) const;
585
586 /**
587 * Clones TimeZone objects polymorphically. Clients are responsible for deleting
588 * the TimeZone object cloned.
589 *
590 * @return A new copy of this TimeZone object.
591 * @stable ICU 2.0
592 */
593 virtual TimeZone* clone(void) const = 0;
594
595 /**
596 * Return the class ID for this class. This is useful only for
597 * comparing to a return value from getDynamicClassID().
598 * @return The class ID for all objects of this class.
599 * @stable ICU 2.0
600 */
601 static UClassID U_EXPORT2 getStaticClassID(void);
602
603 /**
604 * Returns a unique class ID POLYMORPHICALLY. This method is to
605 * implement a simple version of RTTI, since not all C++ compilers support genuine
606 * RTTI. Polymorphic operator==() and clone() methods call this method.
607 * <P>
608 * Concrete subclasses of TimeZone must use the UOBJECT_DEFINE_RTTI_IMPLEMENTATION
609 * macro from uobject.h in their implementation to provide correct RTTI information.
610 * @return The class ID for this object. All objects of a given class have the
611 * same class ID. Objects of other classes have different class IDs.
612 * @stable ICU 2.0
613 */
614 virtual UClassID getDynamicClassID(void) const = 0;
615
616 /**
617 * Returns the amount of time to be added to local standard time
618 * to get local wall clock time.
619 * <p>
620 * The default implementation always returns 3600000 milliseconds
621 * (i.e., one hour) if this time zone observes Daylight Saving
622 * Time. Otherwise, 0 (zero) is returned.
623 * <p>
624 * If an underlying TimeZone implementation subclass supports
625 * historical Daylight Saving Time changes, this method returns
626 * the known latest daylight saving value.
627 *
628 * @return the amount of saving time in milliseconds
629 * @stable ICU 3.6
630 */
631 virtual int32_t getDSTSavings() const;
632
633 protected:
634
635 /**
636 * Default constructor. ID is initialized to the empty string.
637 * @stable ICU 2.0
638 */
639 TimeZone();
640
641 /**
642 * Construct a TimeZone with a given ID.
643 * @param id a system time zone ID
644 * @stable ICU 2.0
645 */
646 TimeZone(const UnicodeString &id);
647
648 /**
649 * Copy constructor.
650 * @param source the object to be copied.
651 * @stable ICU 2.0
652 */
653 TimeZone(const TimeZone& source);
654
655 /**
656 * Default assignment operator.
657 * @param right the object to be copied.
658 * @stable ICU 2.0
659 */
660 TimeZone& operator=(const TimeZone& right);
661
662 /**
663 * Utility function. For internally loading rule data.
664 * @param top Top resource bundle for tz data
665 * @param ruleid ID of rule to load
666 * @param oldbundle Old bundle to reuse or NULL
667 * @param status Status parameter
668 * @return either a new bundle or *oldbundle
669 * @internal
670 */
671 static UResourceBundle* loadRule(const UResourceBundle* top, const UnicodeString& ruleid, UResourceBundle* oldbundle, UErrorCode&status);
672
673 private:
674 friend class ZoneMeta;
675
676
677 static TimeZone* createCustomTimeZone(const UnicodeString&); // Creates a time zone based on the string.
678
679 /**
680 * Resolve a link in Olson tzdata. When the given id is known and it's not a link,
681 * the id itself is returned. When the given id is known and it is a link, then
682 * dereferenced zone id is returned. When the given id is unknown, then it returns
683 * NULL.
684 * @param id zone id string
685 * @return the dereferenced zone or NULL
686 */
687 static const UChar* dereferOlsonLink(const UnicodeString& id);
688
689 /**
690 * Returns the region code associated with the given zone.
691 * @param id zone id string
692 * @return the region associated with the given zone
693 */
694 static const UChar* getRegion(const UnicodeString& id);
695
696 /**
697 * Parses the given custom time zone identifier
698 * @param id id A string of the form GMT[+-]hh:mm, GMT[+-]hhmm, or
699 * GMT[+-]hh.
700 * @param sign Receves parsed sign, 1 for positive, -1 for negative.
701 * @param hour Receives parsed hour field
702 * @param minute Receives parsed minute field
703 * @param second Receives parsed second field
704 * @return Returns TRUE when the given custom id is valid.
705 */
706 static UBool parseCustomID(const UnicodeString& id, int32_t& sign, int32_t& hour,
707 int32_t& min, int32_t& sec);
708
709 /**
710 * Parse a custom time zone identifier and return the normalized
711 * custom time zone identifier for the given custom id string.
712 * @param id a string of the form GMT[+-]hh:mm, GMT[+-]hhmm, or
713 * GMT[+-]hh.
714 * @param normalized Receives the normalized custom ID
715 * @param status Receives the status. When the input ID string is invalid,
716 * U_ILLEGAL_ARGUMENT_ERROR is set.
717 * @return The normalized custom id string.
718 */
719 static UnicodeString& getCustomID(const UnicodeString& id, UnicodeString& normalized,
720 UErrorCode& status);
721
722 /**
723 * Returns the normalized custome time zone ID for the given offset fields.
724 * @param hour offset hours
725 * @param min offset minutes
726 * @param sec offset seconds
727 * @param netative sign of the offset, TRUE for negative offset.
728 * @param id Receves the format result (normalized custom ID)
729 * @return The reference to id
730 */
731 static UnicodeString& formatCustomID(int32_t hour, int32_t min, int32_t sec,
732 UBool negative, UnicodeString& id);
733
734 /**
735 * Responsible for setting up DEFAULT_ZONE. Uses routines in TPlatformUtilities
736 * (i.e., platform-specific calls) to get the current system time zone. Failing
737 * that, uses the platform-specific default time zone. Failing that, uses GMT.
738 */
739 static void initDefault(void);
740
741 // See source file for documentation
742 /**
743 * Lookup the given name in our system zone table. If found,
744 * instantiate a new zone of that name and return it. If not
745 * found, return 0.
746 * @param name tthe given name of a system time zone.
747 * @return the TimeZone indicated by the 'name'.
748 */
749 static TimeZone* createSystemTimeZone(const UnicodeString& name);
750
751 UnicodeString fID; // this time zone's ID
752
753 };
754
755
756 // -------------------------------------
757
758 inline UnicodeString&
getID(UnicodeString & ID)759 TimeZone::getID(UnicodeString& ID) const
760 {
761 ID = fID;
762 return ID;
763 }
764
765 // -------------------------------------
766
767 inline void
setID(const UnicodeString & ID)768 TimeZone::setID(const UnicodeString& ID)
769 {
770 fID = ID;
771 }
772 U_NAMESPACE_END
773
774 #endif /* #if !UCONFIG_NO_FORMATTING */
775
776 #endif //_TIMEZONE
777 //eof
778