1/*************************************************************************
2* Copyright (c) 1997-2013, 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#include "unicode/ucal.h"
43
44U_NAMESPACE_BEGIN
45
46class StringEnumeration;
47
48/**
49 *
50 * <code>TimeZone</code> represents a time zone offset, and also figures out daylight
51 * savings.
52 *
53 * <p>
54 * Typically, you get a <code>TimeZone</code> using <code>createDefault</code>
55 * which creates a <code>TimeZone</code> based on the time zone where the program
56 * is running. For example, for a program running in Japan, <code>createDefault</code>
57 * creates a <code>TimeZone</code> object based on Japanese Standard Time.
58 *
59 * <p>
60 * You can also get a <code>TimeZone</code> using <code>createTimeZone</code> along
61 * with a time zone ID. For instance, the time zone ID for the US Pacific
62 * Time zone is "America/Los_Angeles". So, you can get a Pacific Time <code>TimeZone</code> object
63 * with:
64 * \htmlonly<blockquote>\endhtmlonly
65 * <pre>
66 * TimeZone *tz = TimeZone::createTimeZone("America/Los_Angeles");
67 * </pre>
68 * \htmlonly</blockquote>\endhtmlonly
69 * You can use <code>getAvailableIDs</code> method to iterate through
70 * all the supported time zone IDs, or getCanonicalID method to check
71 * if a time zone ID is supported or not.  You can then choose a
72 * supported ID to get a <code>TimeZone</code>.
73 * If the time zone you want is not represented by one of the
74 * supported IDs, then you can create a custom time zone ID with
75 * the following syntax:
76 *
77 * \htmlonly<blockquote>\endhtmlonly
78 * <pre>
79 * GMT[+|-]hh[[:]mm]
80 * </pre>
81 * \htmlonly</blockquote>\endhtmlonly
82 *
83 * For example, you might specify GMT+14:00 as a custom
84 * time zone ID.  The <code>TimeZone</code> that is returned
85 * when you specify a custom time zone ID uses the specified
86 * offset from GMT(=UTC) and does not observe daylight saving
87 * time. For example, you might specify GMT+14:00 as a custom
88 * time zone ID to create a TimeZone representing 14 hours ahead
89 * of GMT (with no daylight saving time). In addition,
90 * <code>getCanonicalID</code> can also be used to
91 * normalize a custom time zone ID.
92 *
93 * TimeZone is an abstract class representing a time zone.  A TimeZone is needed for
94 * Calendar to produce local time for a particular time zone.  A TimeZone comprises
95 * three basic pieces of information:
96 * <ul>
97 *    <li>A time zone offset; that, is the number of milliseconds to add or subtract
98 *      from a time expressed in terms of GMT to convert it to the same time in that
99 *      time zone (without taking daylight savings time into account).</li>
100 *    <li>Logic necessary to take daylight savings time into account if daylight savings
101 *      time is observed in that time zone (e.g., the days and hours on which daylight
102 *      savings time begins and ends).</li>
103 *    <li>An ID.  This is a text string that uniquely identifies the time zone.</li>
104 * </ul>
105 *
106 * (Only the ID is actually implemented in TimeZone; subclasses of TimeZone may handle
107 * daylight savings time and GMT offset in different ways.  Currently we have the following
108 * TimeZone subclasses: RuleBasedTimeZone, SimpleTimeZone, and VTimeZone.)
109 * <P>
110 * The TimeZone class contains a static list containing a TimeZone object for every
111 * combination of GMT offset and daylight-savings time rules currently in use in the
112 * world, each with a unique ID.  Each ID consists of a region (usually a continent or
113 * ocean) and a city in that region, separated by a slash, (for example, US Pacific
114 * Time is "America/Los_Angeles.")  Because older versions of this class used
115 * three- or four-letter abbreviations instead, there is also a table that maps the older
116 * abbreviations to the newer ones (for example, "PST" maps to "America/Los_Angeles").
117 * Anywhere the API requires an ID, you can use either form.
118 * <P>
119 * To create a new TimeZone, you call the factory function TimeZone::createTimeZone()
120 * and pass it a time zone ID.  You can use the createEnumeration() function to
121 * obtain a list of all the time zone IDs recognized by createTimeZone().
122 * <P>
123 * You can also use TimeZone::createDefault() to create a TimeZone.  This function uses
124 * platform-specific APIs to produce a TimeZone for the time zone corresponding to
125 * the client's computer's physical location.  For example, if you're in Japan (assuming
126 * your machine is set up correctly), TimeZone::createDefault() will return a TimeZone
127 * for Japanese Standard Time ("Asia/Tokyo").
128 */
129class U_I18N_API TimeZone : public UObject {
130public:
131    /**
132     * @stable ICU 2.0
133     */
134    virtual ~TimeZone();
135
136    /**
137     * Returns the "unknown" time zone.
138     * It behaves like the GMT/UTC time zone but has the
139     * <code>UCAL_UNKNOWN_ZONE_ID</code> = "Etc/Unknown".
140     * createTimeZone() returns a mutable clone of this time zone if the input ID is not recognized.
141     *
142     * @return the "unknown" time zone.
143     * @see UCAL_UNKNOWN_ZONE_ID
144     * @see createTimeZone
145     * @see getGMT
146     * @stable ICU 49
147     */
148    static const TimeZone& U_EXPORT2 getUnknown();
149
150    /**
151     * The GMT (=UTC) time zone has a raw offset of zero and does not use daylight
152     * savings time. This is a commonly used time zone.
153     *
154     * <p>Note: For backward compatibility reason, the ID used by the time
155     * zone returned by this method is "GMT", although the ICU's canonical
156     * ID for the GMT time zone is "Etc/GMT".
157     *
158     * @return the GMT/UTC time zone.
159     * @see getUnknown
160     * @stable ICU 2.0
161     */
162    static const TimeZone* U_EXPORT2 getGMT(void);
163
164    /**
165     * Creates a <code>TimeZone</code> for the given ID.
166     * @param ID the ID for a <code>TimeZone</code>, such as "America/Los_Angeles",
167     * or a custom ID such as "GMT-8:00".
168     * @return the specified <code>TimeZone</code>, or a mutable clone of getUnknown()
169     * if the given ID cannot be understood or if the given ID is "Etc/Unknown".
170     * The return result is guaranteed to be non-NULL.
171     * If you require that the specific zone asked for be returned,
172     * compare the result with getUnknown() or check the ID of the return result.
173     * @stable ICU 2.0
174     */
175    static TimeZone* U_EXPORT2 createTimeZone(const UnicodeString& ID);
176
177    /**
178     * Returns an enumeration over system time zone IDs with the given
179     * filter conditions.
180     * @param zoneType      The system time zone type.
181     * @param region        The ISO 3166 two-letter country code or UN M.49
182     *                      three-digit area code. When NULL, no filtering
183     *                      done by region.
184     * @param rawOffset     An offset from GMT in milliseconds, ignoring
185     *                      the effect of daylight savings time, if any.
186     *                      When NULL, no filtering done by zone offset.
187     * @param ec            Output param to filled in with a success or
188     *                      an error.
189     * @return an enumeration object, owned by the caller.
190     * @stable ICU 4.8
191     */
192    static StringEnumeration* U_EXPORT2 createTimeZoneIDEnumeration(
193        USystemTimeZoneType zoneType,
194        const char* region,
195        const int32_t* rawOffset,
196        UErrorCode& ec);
197
198    /**
199     * Returns an enumeration over all recognized time zone IDs. (i.e.,
200     * all strings that createTimeZone() accepts)
201     *
202     * @return an enumeration object, owned by the caller.
203     * @stable ICU 2.4
204     */
205    static StringEnumeration* U_EXPORT2 createEnumeration();
206
207    /**
208     * Returns an enumeration over time zone IDs with a given raw
209     * offset from GMT.  There may be several times zones with the
210     * same GMT offset that differ in the way they handle daylight
211     * savings time.  For example, the state of Arizona doesn't
212     * observe daylight savings time.  If you ask for the time zone
213     * IDs corresponding to GMT-7:00, you'll get back an enumeration
214     * over two time zone IDs: "America/Denver," which corresponds to
215     * Mountain Standard Time in the winter and Mountain Daylight Time
216     * in the summer, and "America/Phoenix", which corresponds to
217     * Mountain Standard Time year-round, even in the summer.
218     *
219     * @param rawOffset an offset from GMT in milliseconds, ignoring
220     * the effect of daylight savings time, if any
221     * @return an enumeration object, owned by the caller
222     * @stable ICU 2.4
223     */
224    static StringEnumeration* U_EXPORT2 createEnumeration(int32_t rawOffset);
225
226    /**
227     * Returns an enumeration over time zone IDs associated with the
228     * given country.  Some zones are affiliated with no country
229     * (e.g., "UTC"); these may also be retrieved, as a group.
230     *
231     * @param country The ISO 3166 two-letter country code, or NULL to
232     * retrieve zones not affiliated with any country.
233     * @return an enumeration object, owned by the caller
234     * @stable ICU 2.4
235     */
236    static StringEnumeration* U_EXPORT2 createEnumeration(const char* country);
237
238    /**
239     * Returns the number of IDs in the equivalency group that
240     * includes the given ID.  An equivalency group contains zones
241     * that have the same GMT offset and rules.
242     *
243     * <p>The returned count includes the given ID; it is always >= 1.
244     * The given ID must be a system time zone.  If it is not, returns
245     * zero.
246     * @param id a system time zone ID
247     * @return the number of zones in the equivalency group containing
248     * 'id', or zero if 'id' is not a valid system ID
249     * @see #getEquivalentID
250     * @stable ICU 2.0
251     */
252    static int32_t U_EXPORT2 countEquivalentIDs(const UnicodeString& id);
253
254    /**
255     * Returns an ID in the equivalency group that
256     * includes the given ID.  An equivalency group contains zones
257     * that have the same GMT offset and rules.
258     *
259     * <p>The given index must be in the range 0..n-1, where n is the
260     * value returned by <code>countEquivalentIDs(id)</code>.  For
261     * some value of 'index', the returned value will be equal to the
262     * given id.  If the given id is not a valid system time zone, or
263     * if 'index' is out of range, then returns an empty string.
264     * @param id a system time zone ID
265     * @param index a value from 0 to n-1, where n is the value
266     * returned by <code>countEquivalentIDs(id)</code>
267     * @return the ID of the index-th zone in the equivalency group
268     * containing 'id', or an empty string if 'id' is not a valid
269     * system ID or 'index' is out of range
270     * @see #countEquivalentIDs
271     * @stable ICU 2.0
272     */
273    static const UnicodeString U_EXPORT2 getEquivalentID(const UnicodeString& id,
274                                               int32_t index);
275
276    /**
277     * Creates a new copy of the default TimeZone for this host. Unless the default time
278     * zone has already been set using adoptDefault() or setDefault(), the default is
279     * determined by querying the system using methods in TPlatformUtilities. If the
280     * system routines fail, or if they specify a TimeZone or TimeZone offset which is not
281     * recognized, the TimeZone indicated by the ID kLastResortID is instantiated
282     * and made the default.
283     *
284     * @return   A default TimeZone. Clients are responsible for deleting the time zone
285     *           object returned.
286     * @stable ICU 2.0
287     */
288    static TimeZone* U_EXPORT2 createDefault(void);
289
290    /**
291     * Sets the default time zone (i.e., what's returned by createDefault()) to be the
292     * specified time zone.  If NULL is specified for the time zone, the default time
293     * zone is set to the default host time zone.  This call adopts the TimeZone object
294     * passed in; the client is no longer responsible for deleting it.
295     *
296     * <p>This function is not thread safe. It is an error for multiple threads
297     * to concurrently attempt to set the default time zone, or for any thread
298     * to attempt to reference the default zone while another thread is setting it.
299     *
300     * @param zone  A pointer to the new TimeZone object to use as the default.
301     * @stable ICU 2.0
302     */
303    static void U_EXPORT2 adoptDefault(TimeZone* zone);
304
305#ifndef U_HIDE_SYSTEM_API
306    /**
307     * Same as adoptDefault(), except that the TimeZone object passed in is NOT adopted;
308     * the caller remains responsible for deleting it.
309     *
310     * <p>See the thread safety note under adoptDefault().
311     *
312     * @param zone  The given timezone.
313     * @system
314     * @stable ICU 2.0
315     */
316    static void U_EXPORT2 setDefault(const TimeZone& zone);
317#endif  /* U_HIDE_SYSTEM_API */
318
319    /**
320     * Returns the timezone data version currently used by ICU.
321     * @param status Output param to filled in with a success or an error.
322     * @return the version string, such as "2007f"
323     * @stable ICU 3.8
324     */
325    static const char* U_EXPORT2 getTZDataVersion(UErrorCode& status);
326
327    /**
328     * Returns the canonical system timezone ID or the normalized
329     * custom time zone ID for the given time zone ID.
330     * @param id            The input time zone ID to be canonicalized.
331     * @param canonicalID   Receives the canonical system time zone ID
332     *                      or the custom time zone ID in normalized format.
333     * @param status        Recevies the status.  When the given time zone ID
334     *                      is neither a known system time zone ID nor a
335     *                      valid custom time zone ID, U_ILLEGAL_ARGUMENT_ERROR
336     *                      is set.
337     * @return A reference to the result.
338     * @stable ICU 4.0
339     */
340    static UnicodeString& U_EXPORT2 getCanonicalID(const UnicodeString& id,
341        UnicodeString& canonicalID, UErrorCode& status);
342
343    /**
344     * Returns the canonical system time zone ID or the normalized
345     * custom time zone ID for the given time zone ID.
346     * @param id            The input time zone ID to be canonicalized.
347     * @param canonicalID   Receives the canonical system time zone ID
348     *                      or the custom time zone ID in normalized format.
349     * @param isSystemID    Receives if the given ID is a known system
350     *                      time zone ID.
351     * @param status        Recevies the status.  When the given time zone ID
352     *                      is neither a known system time zone ID nor a
353     *                      valid custom time zone ID, U_ILLEGAL_ARGUMENT_ERROR
354     *                      is set.
355     * @return A reference to the result.
356     * @stable ICU 4.0
357     */
358    static UnicodeString& U_EXPORT2 getCanonicalID(const UnicodeString& id,
359        UnicodeString& canonicalID, UBool& isSystemID, UErrorCode& status);
360
361#ifndef U_HIDE_DRAFT_API
362    /**
363    * Converts a system time zone ID to an equivalent Windows time zone ID. For example,
364    * Windows time zone ID "Pacific Standard Time" is returned for input "America/Los_Angeles".
365    *
366    * <p>There are system time zones that cannot be mapped to Windows zones. When the input
367    * system time zone ID is unknown or unmappable to a Windows time zone, then the result will be
368    * empty, but the operation itself remains successful (no error status set on return).
369    *
370    * <p>This implementation utilizes <a href="http://unicode.org/cldr/charts/supplemental/zone_tzid.html">
371    * Zone-Tzid mapping data</a>. The mapping data is updated time to time. To get the latest changes,
372    * please read the ICU user guide section <a href="http://userguide.icu-project.org/datetime/timezone#TOC-Updating-the-Time-Zone-Data">
373    * Updating the Time Zone Data</a>.
374    *
375    * @param id        A system time zone ID.
376    * @param winid     Receives a Windows time zone ID. When the input system time zone ID is unknown
377    *                  or unmappable to a Windows time zone ID, then an empty string is set on return.
378    * @param status    Receives the status.
379    * @return          A reference to the result (<code>winid</code>).
380    * @see getIDForWindowsID
381    *
382    * @draft ICU 52
383    */
384    static UnicodeString& U_EXPORT2 getWindowsID(const UnicodeString& id,
385        UnicodeString& winid, UErrorCode& status);
386
387    /**
388    * Converts a Windows time zone ID to an equivalent system time zone ID
389    * for a region. For example, system time zone ID "America/Los_Angeles" is returned
390    * for input Windows ID "Pacific Standard Time" and region "US" (or <code>null</code>),
391    * "America/Vancouver" is returned for the same Windows ID "Pacific Standard Time" and
392    * region "CA".
393    *
394    * <p>Not all Windows time zones can be mapped to system time zones. When the input
395    * Windows time zone ID is unknown or unmappable to a system time zone, then the result
396    * will be empty, but the operation itself remains successful (no error status set on return).
397    *
398    * <p>This implementation utilizes <a href="http://unicode.org/cldr/charts/supplemental/zone_tzid.html">
399    * Zone-Tzid mapping data</a>. The mapping data is updated time to time. To get the latest changes,
400    * please read the ICU user guide section <a href="http://userguide.icu-project.org/datetime/timezone#TOC-Updating-the-Time-Zone-Data">
401    * Updating the Time Zone Data</a>.
402    *
403    * @param winid     A Windows time zone ID.
404    * @param region    A null-terminated region code, or <code>NULL</code> if no regional preference.
405    * @param id        Receives a system time zone ID. When the input Windows time zone ID is unknown
406    *                  or unmappable to a system time zone ID, then an empty string is set on return.
407    * @param status    Receives the status.
408    * @return          A reference to the result (<code>id</code>).
409    * @see getWindowsID
410    *
411    * @draft ICU 52
412    */
413    static UnicodeString& U_EXPORT2 getIDForWindowsID(const UnicodeString& winid, const char* region,
414        UnicodeString& id, UErrorCode& status);
415
416#endif /* U_HIDE_DRAFT_API */
417
418    /**
419     * Returns true if the two TimeZones are equal.  (The TimeZone version only compares
420     * IDs, but subclasses are expected to also compare the fields they add.)
421     *
422     * @param that  The TimeZone object to be compared with.
423     * @return      True if the given TimeZone is equal to this TimeZone; false
424     *              otherwise.
425     * @stable ICU 2.0
426     */
427    virtual UBool operator==(const TimeZone& that) const;
428
429    /**
430     * Returns true if the two TimeZones are NOT equal; that is, if operator==() returns
431     * false.
432     *
433     * @param that  The TimeZone object to be compared with.
434     * @return      True if the given TimeZone is not equal to this TimeZone; false
435     *              otherwise.
436     * @stable ICU 2.0
437     */
438    UBool operator!=(const TimeZone& that) const {return !operator==(that);}
439
440    /**
441     * Returns the TimeZone's adjusted GMT offset (i.e., the number of milliseconds to add
442     * to GMT to get local time in this time zone, taking daylight savings time into
443     * account) as of a particular reference date.  The reference date is used to determine
444     * whether daylight savings time is in effect and needs to be figured into the offset
445     * that is returned (in other words, what is the adjusted GMT offset in this time zone
446     * at this particular date and time?).  For the time zones produced by createTimeZone(),
447     * the reference data is specified according to the Gregorian calendar, and the date
448     * and time fields are local standard time.
449     *
450     * <p>Note: Don't call this method. Instead, call the getOffset(UDate...) overload,
451     * which returns both the raw and the DST offset for a given time. This method
452     * is retained only for backward compatibility.
453     *
454     * @param era        The reference date's era
455     * @param year       The reference date's year
456     * @param month      The reference date's month (0-based; 0 is January)
457     * @param day        The reference date's day-in-month (1-based)
458     * @param dayOfWeek  The reference date's day-of-week (1-based; 1 is Sunday)
459     * @param millis     The reference date's milliseconds in day, local standard time
460     * @param status     Output param to filled in with a success or an error.
461     * @return           The offset in milliseconds to add to GMT to get local time.
462     * @stable ICU 2.0
463     */
464    virtual int32_t getOffset(uint8_t era, int32_t year, int32_t month, int32_t day,
465                              uint8_t dayOfWeek, int32_t millis, UErrorCode& status) const = 0;
466
467    /**
468     * Gets the time zone offset, for current date, modified in case of
469     * daylight savings. This is the offset to add *to* UTC to get local time.
470     *
471     * <p>Note: Don't call this method. Instead, call the getOffset(UDate...) overload,
472     * which returns both the raw and the DST offset for a given time. This method
473     * is retained only for backward compatibility.
474     *
475     * @param era the era of the given date.
476     * @param year the year in the given date.
477     * @param month the month in the given date.
478     * Month is 0-based. e.g., 0 for January.
479     * @param day the day-in-month of the given date.
480     * @param dayOfWeek the day-of-week of the given date.
481     * @param milliseconds the millis in day in <em>standard</em> local time.
482     * @param monthLength the length of the given month in days.
483     * @param status     Output param to filled in with a success or an error.
484     * @return the offset to add *to* GMT to get local time.
485     * @stable ICU 2.0
486     */
487    virtual int32_t getOffset(uint8_t era, int32_t year, int32_t month, int32_t day,
488                           uint8_t dayOfWeek, int32_t milliseconds,
489                           int32_t monthLength, UErrorCode& status) const = 0;
490
491    /**
492     * Returns the time zone raw and GMT offset for the given moment
493     * in time.  Upon return, local-millis = GMT-millis + rawOffset +
494     * dstOffset.  All computations are performed in the proleptic
495     * Gregorian calendar.  The default implementation in the TimeZone
496     * class delegates to the 8-argument getOffset().
497     *
498     * @param date moment in time for which to return offsets, in
499     * units of milliseconds from January 1, 1970 0:00 GMT, either GMT
500     * time or local wall time, depending on `local'.
501     * @param local if true, `date' is local wall time; otherwise it
502     * is in GMT time.
503     * @param rawOffset output parameter to receive the raw offset, that
504     * is, the offset not including DST adjustments
505     * @param dstOffset output parameter to receive the DST offset,
506     * that is, the offset to be added to `rawOffset' to obtain the
507     * total offset between local and GMT time. If DST is not in
508     * effect, this value is zero; otherwise it is a positive value,
509     * typically one hour.
510     * @param ec input-output error code
511     *
512     * @stable ICU 2.8
513     */
514    virtual void getOffset(UDate date, UBool local, int32_t& rawOffset,
515                           int32_t& dstOffset, UErrorCode& ec) const;
516
517    /**
518     * Sets the TimeZone's raw GMT offset (i.e., the number of milliseconds to add
519     * to GMT to get local time, before taking daylight savings time into account).
520     *
521     * @param offsetMillis  The new raw GMT offset for this time zone.
522     * @stable ICU 2.0
523     */
524    virtual void setRawOffset(int32_t offsetMillis) = 0;
525
526    /**
527     * Returns the TimeZone's raw GMT offset (i.e., the number of milliseconds to add
528     * to GMT to get local time, before taking daylight savings time into account).
529     *
530     * @return   The TimeZone's raw GMT offset.
531     * @stable ICU 2.0
532     */
533    virtual int32_t getRawOffset(void) const = 0;
534
535    /**
536     * Fills in "ID" with the TimeZone's ID.
537     *
538     * @param ID  Receives this TimeZone's ID.
539     * @return    A reference to 'ID'
540     * @stable ICU 2.0
541     */
542    UnicodeString& getID(UnicodeString& ID) const;
543
544    /**
545     * Sets the TimeZone's ID to the specified value.  This doesn't affect any other
546     * fields (for example, if you say<
547     * blockquote><pre>
548     * .     TimeZone* foo = TimeZone::createTimeZone("America/New_York");
549     * .     foo.setID("America/Los_Angeles");
550     * </pre>\htmlonly</blockquote>\endhtmlonly
551     * the time zone's GMT offset and daylight-savings rules don't change to those for
552     * Los Angeles.  They're still those for New York.  Only the ID has changed.)
553     *
554     * @param ID  The new time zone ID.
555     * @stable ICU 2.0
556     */
557    void setID(const UnicodeString& ID);
558
559    /**
560     * Enum for use with getDisplayName
561     * @stable ICU 2.4
562     */
563    enum EDisplayType {
564        /**
565         * Selector for short display name
566         * @stable ICU 2.4
567         */
568        SHORT = 1,
569        /**
570         * Selector for long display name
571         * @stable ICU 2.4
572         */
573        LONG,
574        /**
575         * Selector for short generic display name
576         * @stable ICU 4.4
577         */
578        SHORT_GENERIC,
579        /**
580         * Selector for long generic display name
581         * @stable ICU 4.4
582         */
583        LONG_GENERIC,
584        /**
585         * Selector for short display name derived
586         * from time zone offset
587         * @stable ICU 4.4
588         */
589        SHORT_GMT,
590        /**
591         * Selector for long display name derived
592         * from time zone offset
593         * @stable ICU 4.4
594         */
595        LONG_GMT,
596        /**
597         * Selector for short display name derived
598         * from the time zone's fallback name
599         * @stable ICU 4.4
600         */
601        SHORT_COMMONLY_USED,
602        /**
603         * Selector for long display name derived
604         * from the time zone's fallback name
605         * @stable ICU 4.4
606         */
607        GENERIC_LOCATION
608    };
609
610    /**
611     * Returns a name of this time zone suitable for presentation to the user
612     * in the default locale.
613     * This method returns the long name, not including daylight savings.
614     * If the display name is not available for the locale,
615     * then this method returns a string in the format
616     * <code>GMT[+-]hh:mm</code>.
617     * @param result the human-readable name of this time zone in the default locale.
618     * @return       A reference to 'result'.
619     * @stable ICU 2.0
620     */
621    UnicodeString& getDisplayName(UnicodeString& result) const;
622
623    /**
624     * Returns a name of this time zone suitable for presentation to the user
625     * in the specified locale.
626     * This method returns the long name, not including daylight savings.
627     * If the display name is not available for the locale,
628     * then this method returns a string in the format
629     * <code>GMT[+-]hh:mm</code>.
630     * @param locale the locale in which to supply the display name.
631     * @param result the human-readable name of this time zone in the given locale
632     *               or in the default locale if the given locale is not recognized.
633     * @return       A reference to 'result'.
634     * @stable ICU 2.0
635     */
636    UnicodeString& getDisplayName(const Locale& locale, UnicodeString& result) const;
637
638    /**
639     * Returns a name of this time zone suitable for presentation to the user
640     * in the default locale.
641     * If the display name is not available for the locale,
642     * then this method returns a string in the format
643     * <code>GMT[+-]hh:mm</code>.
644     * @param daylight if true, return the daylight savings name.
645     * @param style
646     * @param result the human-readable name of this time zone in the default locale.
647     * @return       A reference to 'result'.
648     * @stable ICU 2.0
649     */
650    UnicodeString& getDisplayName(UBool daylight, EDisplayType style, UnicodeString& result) const;
651
652    /**
653     * Returns a name of this time zone suitable for presentation to the user
654     * in the specified locale.
655     * If the display name is not available for the locale,
656     * then this method returns a string in the format
657     * <code>GMT[+-]hh:mm</code>.
658     * @param daylight if true, return the daylight savings name.
659     * @param style
660     * @param locale the locale in which to supply the display name.
661     * @param result the human-readable name of this time zone in the given locale
662     *               or in the default locale if the given locale is not recognized.
663     * @return       A refence to 'result'.
664     * @stable ICU 2.0
665     */
666    UnicodeString& getDisplayName(UBool daylight, EDisplayType style, const Locale& locale, UnicodeString& result) const;
667
668    /**
669     * Queries if this time zone uses daylight savings time.
670     * @return true if this time zone uses daylight savings time,
671     * false, otherwise.
672     * <p><strong>Note:</strong>The default implementation of
673     * ICU TimeZone uses the tz database, which supports historic
674     * rule changes, for system time zones. With the implementation,
675     * there are time zones that used daylight savings time in the
676     * past, but no longer used currently. For example, Asia/Tokyo has
677     * never used daylight savings time since 1951. Most clients would
678     * expect that this method to return <code>FALSE</code> for such case.
679     * The default implementation of this method returns <code>TRUE</code>
680     * when the time zone uses daylight savings time in the current
681     * (Gregorian) calendar year.
682     * <p>In Java 7, <code>observesDaylightTime()</code> was added in
683     * addition to <code>useDaylightTime()</code>. In Java, <code>useDaylightTime()</code>
684     * only checks if daylight saving time is observed by the last known
685     * rule. This specification might not be what most users would expect
686     * if daylight saving time is currently observed, but not scheduled
687     * in future. In this case, Java's <code>userDaylightTime()</code> returns
688     * <code>false</code>. To resolve the issue, Java 7 added <code>observesDaylightTime()</code>,
689     * which takes the current rule into account. The method <code>observesDaylightTime()</code>
690     * was added in ICU4J for supporting API signature compatibility with JDK.
691     * In general, ICU4C also provides JDK compatible methods, but the current
692     * implementation <code>userDaylightTime()</code> serves the purpose
693     * (takes the current rule into account), <code>observesDaylightTime()</code>
694     * is not added in ICU4C. In addition to <code>useDaylightTime()</code>, ICU4C
695     * <code>BasicTimeZone</code> class (Note that <code>TimeZone::createTimeZone(const UnicodeString &ID)</code>
696     * always returns a <code>BasicTimeZone</code>) provides a series of methods allowing
697     * historic and future time zone rule iteration, so you can check if daylight saving
698     * time is observed or not within a given period.
699     *
700     * @stable ICU 2.0
701     */
702    virtual UBool useDaylightTime(void) const = 0;
703
704    /**
705     * Queries if the given date is in daylight savings time in
706     * this time zone.
707     * This method is wasteful since it creates a new GregorianCalendar and
708     * deletes it each time it is called. This is a deprecated method
709     * and provided only for Java compatibility.
710     *
711     * @param date the given UDate.
712     * @param status Output param filled in with success/error code.
713     * @return true if the given date is in daylight savings time,
714     * false, otherwise.
715     * @deprecated ICU 2.4. Use Calendar::inDaylightTime() instead.
716     */
717    virtual UBool inDaylightTime(UDate date, UErrorCode& status) const = 0;
718
719    /**
720     * Returns true if this zone has the same rule and offset as another zone.
721     * That is, if this zone differs only in ID, if at all.
722     * @param other the <code>TimeZone</code> object to be compared with
723     * @return true if the given zone is the same as this one,
724     * with the possible exception of the ID
725     * @stable ICU 2.0
726     */
727    virtual UBool hasSameRules(const TimeZone& other) const;
728
729    /**
730     * Clones TimeZone objects polymorphically. Clients are responsible for deleting
731     * the TimeZone object cloned.
732     *
733     * @return   A new copy of this TimeZone object.
734     * @stable ICU 2.0
735     */
736    virtual TimeZone* clone(void) const = 0;
737
738    /**
739     * Return the class ID for this class.  This is useful only for
740     * comparing to a return value from getDynamicClassID().
741     * @return The class ID for all objects of this class.
742     * @stable ICU 2.0
743     */
744    static UClassID U_EXPORT2 getStaticClassID(void);
745
746    /**
747     * Returns a unique class ID POLYMORPHICALLY. This method is to
748     * implement a simple version of RTTI, since not all C++ compilers support genuine
749     * RTTI. Polymorphic operator==() and clone() methods call this method.
750     * <P>
751     * Concrete subclasses of TimeZone must use the UOBJECT_DEFINE_RTTI_IMPLEMENTATION
752     *  macro from uobject.h in their implementation to provide correct RTTI information.
753     * @return   The class ID for this object. All objects of a given class have the
754     *           same class ID. Objects of other classes have different class IDs.
755     * @stable ICU 2.0
756     */
757    virtual UClassID getDynamicClassID(void) const = 0;
758
759    /**
760     * Returns the amount of time to be added to local standard time
761     * to get local wall clock time.
762     * <p>
763     * The default implementation always returns 3600000 milliseconds
764     * (i.e., one hour) if this time zone observes Daylight Saving
765     * Time. Otherwise, 0 (zero) is returned.
766     * <p>
767     * If an underlying TimeZone implementation subclass supports
768     * historical Daylight Saving Time changes, this method returns
769     * the known latest daylight saving value.
770     *
771     * @return the amount of saving time in milliseconds
772     * @stable ICU 3.6
773     */
774    virtual int32_t getDSTSavings() const;
775
776    /**
777     * Gets the region code associated with the given
778     * system time zone ID. The region code is either ISO 3166
779     * 2-letter country code or UN M.49 3-digit area code.
780     * When the time zone is not associated with a specific location,
781     * for example - "Etc/UTC", "EST5EDT", then this method returns
782     * "001" (UN M.49 area code for World).
783     *
784     * @param id            The system time zone ID.
785     * @param region        Output buffer for receiving the region code.
786     * @param capacity      The size of the output buffer.
787     * @param status        Receives the status.  When the given time zone ID
788     *                      is not a known system time zone ID,
789     *                      U_ILLEGAL_ARGUMENT_ERROR is set.
790     * @return The length of the output region code.
791     * @stable ICU 4.8
792     */
793    static int32_t U_EXPORT2 getRegion(const UnicodeString& id,
794        char *region, int32_t capacity, UErrorCode& status);
795
796protected:
797
798    /**
799     * Default constructor.  ID is initialized to the empty string.
800     * @stable ICU 2.0
801     */
802    TimeZone();
803
804    /**
805     * Construct a TimeZone with a given ID.
806     * @param id a system time zone ID
807     * @stable ICU 2.0
808     */
809    TimeZone(const UnicodeString &id);
810
811    /**
812     * Copy constructor.
813     * @param source the object to be copied.
814     * @stable ICU 2.0
815     */
816    TimeZone(const TimeZone& source);
817
818    /**
819     * Default assignment operator.
820     * @param right the object to be copied.
821     * @stable ICU 2.0
822     */
823    TimeZone& operator=(const TimeZone& right);
824
825#ifndef U_HIDE_INTERNAL_API
826    /**
827     * Utility function. For internally loading rule data.
828     * @param top Top resource bundle for tz data
829     * @param ruleid ID of rule to load
830     * @param oldbundle Old bundle to reuse or NULL
831     * @param status Status parameter
832     * @return either a new bundle or *oldbundle
833     * @internal
834     */
835    static UResourceBundle* loadRule(const UResourceBundle* top, const UnicodeString& ruleid, UResourceBundle* oldbundle, UErrorCode&status);
836#endif  /* U_HIDE_INTERNAL_API */
837
838private:
839    friend class ZoneMeta;
840
841
842    static TimeZone*        createCustomTimeZone(const UnicodeString&); // Creates a time zone based on the string.
843
844    /**
845     * Finds the given ID in the Olson tzdata. If the given ID is found in the tzdata,
846     * returns the pointer to the ID resource. This method is exposed through ZoneMeta class
847     * for ICU internal implementation and useful for building hashtable using a time zone
848     * ID as a key.
849     * @param id zone id string
850     * @return the pointer of the ID resource, or NULL.
851     */
852    static const UChar* findID(const UnicodeString& id);
853
854    /**
855     * Resolve a link in Olson tzdata.  When the given id is known and it's not a link,
856     * the id itself is returned.  When the given id is known and it is a link, then
857     * dereferenced zone id is returned.  When the given id is unknown, then it returns
858     * NULL.
859     * @param id zone id string
860     * @return the dereferenced zone or NULL
861     */
862    static const UChar* dereferOlsonLink(const UnicodeString& id);
863
864    /**
865     * Returns the region code associated with the given zone,
866     * or NULL if the zone is not known.
867     * @param id zone id string
868     * @return the region associated with the given zone
869     */
870    static const UChar* getRegion(const UnicodeString& id);
871
872  public:
873#ifndef U_HIDE_INTERNAL_API
874    /**
875     * Returns the region code associated with the given zone,
876     * or NULL if the zone is not known.
877     * @param id zone id string
878     * @param status Status parameter
879     * @return the region associated with the given zone
880     * @internal
881     */
882    static const UChar* getRegion(const UnicodeString& id, UErrorCode& status);
883#endif  /* U_HIDE_INTERNAL_API */
884
885  private:
886    /**
887     * Parses the given custom time zone identifier
888     * @param id id A string of the form GMT[+-]hh:mm, GMT[+-]hhmm, or
889     * GMT[+-]hh.
890     * @param sign Receves parsed sign, 1 for positive, -1 for negative.
891     * @param hour Receives parsed hour field
892     * @param minute Receives parsed minute field
893     * @param second Receives parsed second field
894     * @return Returns TRUE when the given custom id is valid.
895     */
896    static UBool parseCustomID(const UnicodeString& id, int32_t& sign, int32_t& hour,
897        int32_t& minute, int32_t& second);
898
899    /**
900     * Parse a custom time zone identifier and return the normalized
901     * custom time zone identifier for the given custom id string.
902     * @param id a string of the form GMT[+-]hh:mm, GMT[+-]hhmm, or
903     * GMT[+-]hh.
904     * @param normalized Receives the normalized custom ID
905     * @param status Receives the status.  When the input ID string is invalid,
906     * U_ILLEGAL_ARGUMENT_ERROR is set.
907     * @return The normalized custom id string.
908    */
909    static UnicodeString& getCustomID(const UnicodeString& id, UnicodeString& normalized,
910        UErrorCode& status);
911
912    /**
913     * Returns the normalized custome time zone ID for the given offset fields.
914     * @param hour offset hours
915     * @param min offset minutes
916     * @param sec offset seconds
917     * @param negative sign of the offset, TRUE for negative offset.
918     * @param id Receves the format result (normalized custom ID)
919     * @return The reference to id
920     */
921    static UnicodeString& formatCustomID(int32_t hour, int32_t min, int32_t sec,
922        UBool negative, UnicodeString& id);
923
924    UnicodeString           fID;    // this time zone's ID
925
926    friend class TZEnumeration;
927};
928
929
930// -------------------------------------
931
932inline UnicodeString&
933TimeZone::getID(UnicodeString& ID) const
934{
935    ID = fID;
936    return ID;
937}
938
939// -------------------------------------
940
941inline void
942TimeZone::setID(const UnicodeString& ID)
943{
944    fID = ID;
945}
946U_NAMESPACE_END
947
948#endif /* #if !UCONFIG_NO_FORMATTING */
949
950#endif //_TIMEZONE
951//eof
952