icuSources/i18n/unicode/timezone.h

   1 /*************************************************************************
   2 * Copyright (c) 1997-2008, 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 Pacific
  61  * Standard Time zone is "PST". So, you can get a PST <code>TimeZone</code> object
  62  * with:
  63  * \htmlonly<blockquote>\endhtmlonly
  64  * <pre>
  65  * TimeZone *tz = TimeZone::createTimeZone("PST");
  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, Pacific
 107  * Standard 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/LosAngeles").
 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>, either an abbreviation such as
 140      * "PST", a full name such as "America/Los_Angeles", or a custom ID
 141      * such as "GMT-8:00".
 142      * @return the specified <code>TimeZone</code>, or the GMT zone if the given ID
 143      * cannot be understood.  Return result guaranteed to be non-null.  If you
 144      * require that the specific zone asked for be returned, check the ID of the
 145      * return result.
 146      * @stable ICU 2.0
 147      */
 148     static TimeZone* U_EXPORT2 createTimeZone(const UnicodeString& ID);
 149
 150     /**
 151      * Returns an enumeration over all recognized time zone IDs. (i.e.,
 152      * all strings that createTimeZone() accepts)
 153      *
 154      * @return an enumeration object, owned by the caller.
 155      * @stable ICU 2.4
 156      */
 157     static StringEnumeration* U_EXPORT2 createEnumeration();
 158
 159     /**
 160      * Returns an enumeration over time zone IDs with a given raw
 161      * offset from GMT.  There may be several times zones with the
 162      * same GMT offset that differ in the way they handle daylight
 163      * savings time.  For example, the state of Arizona doesn't
 164      * observe daylight savings time.  If you ask for the time zone
 165      * IDs corresponding to GMT-7:00, you'll get back an enumeration
 166      * over two time zone IDs: "America/Denver," which corresponds to
 167      * Mountain Standard Time in the winter and Mountain Daylight Time
 168      * in the summer, and "America/Phoenix", which corresponds to
 169      * Mountain Standard Time year-round, even in the summer.
 170      *
 171      * @param rawOffset an offset from GMT in milliseconds, ignoring
 172      * the effect of daylight savings time, if any
 173      * @return an enumeration object, owned by the caller
 174      * @stable ICU 2.4
 175      */
 176     static StringEnumeration* U_EXPORT2 createEnumeration(int32_t rawOffset);
 177
 178     /**
 179      * Returns an enumeration over time zone IDs associated with the
 180      * given country.  Some zones are affiliated with no country
 181      * (e.g., "UTC"); these may also be retrieved, as a group.
 182      *
 183      * @param country The ISO 3166 two-letter country code, or NULL to
 184      * retrieve zones not affiliated with any country.
 185      * @return an enumeration object, owned by the caller
 186      * @stable ICU 2.4
 187      */
 188     static StringEnumeration* U_EXPORT2 createEnumeration(const char* country);
 189
 190 #ifdef U_USE_TIMEZONE_OBSOLETE_2_8
 191     /**
 192      * Returns a list of time zone IDs, one for each time zone with a given GMT offset.
 193      * The return value is a list because there may be several times zones with the same
 194      * GMT offset that differ in the way they handle daylight savings time.  For example,
 195      * the state of Arizona doesn't observe Daylight Savings time.  So if you ask for
 196      * the time zone IDs corresponding to GMT-7:00, you'll get back two time zone IDs:
 197      * "America/Denver," which corresponds to Mountain Standard Time in the winter and
 198      * Mountain Daylight Time in the summer, and "America/Phoenix", which corresponds to
 199      * Mountain Standard Time year-round, even in the summer.
 200      * <P>
 201      * The caller owns the list that is returned, but does not own the strings contained
 202      * in that list.  Delete the array with uprv_free(), but DON'T delete the elements in the array.
 203      *
 204      * <p>NOTE: uprv_free() is declared in the private header source/common/cmemory.h.
 205      *
 206      * @param rawOffset  An offset from GMT in milliseconds.
 207      * @param numIDs     Receives the number of items in the array that is returned.
 208      * @return           An array of UnicodeString pointers, where each UnicodeString is
 209      *                   a time zone ID for a time zone with the given GMT offset.  If
 210      *                   there is no timezone that matches the GMT offset
 211      *                   specified, NULL is returned.
 212      * @obsolete ICU 2.8.  Use createEnumeration(int32_t) instead since this API will be removed in that release.
 213      */
 214     static const UnicodeString** createAvailableIDs(int32_t rawOffset, int32_t& numIDs);
 215
 216     /**
 217      * Returns a list of time zone IDs associated with the given
 218      * country.  Some zones are affiliated with no country (e.g.,
 219      * "UTC"); these may also be retrieved, as a group.
 220      *
 221      * <P>The caller owns the list that is returned, but does not own
 222      * the strings contained in that list.  Delete the array with uprv_free(), but
 223      * <b>DON'T</b> delete the elements in the array.
 224      *
 225      * <p>NOTE: uprv_free() is declared in the private header source/common/cmemory.h.
 226      *
 227      * @param country The ISO 3166 two-letter country code, or NULL to
 228      * retrieve zones not affiliated with any country.
 229      * @param numIDs Receives the number of items in the array that is
 230      * returned.
 231      * @return An array of UnicodeString pointers, where each
 232      * UnicodeString is a time zone ID for a time zone with the given
 233      * country.  If there is no timezone that matches the country
 234      * specified, NULL is returned.
 235      * @obsolete ICU 2.8.  Use createEnumeration(const char*) instead since this API will be removed in that release.
 236      */
 237     static const UnicodeString** createAvailableIDs(const char* country,
 238                                                           int32_t& numIDs);
 239
 240     /**
 241      * Returns a list of all time zone IDs supported by the TimeZone class (i.e., all
 242      * IDs that it's legal to pass to createTimeZone()).  The caller owns the list that
 243      * is returned, but does not own the strings contained in that list.  Delete the array with uprv_free(),
 244      * but DON'T delete the elements in the array.
 245      *
 246      * <p>NOTE: uprv_free() is declared in the private header source/common/cmemory.h.
 247      *
 248      * @param numIDs  Receives the number of zone IDs returned.
 249      * @return        An array of UnicodeString pointers, where each is a time zone ID
 250      *                supported by the TimeZone class.
 251      * @obsolete ICU 2.8.  Use createEnumeration(void) instead since this API will be removed in that release.
 252      */
 253     static const UnicodeString** createAvailableIDs(int32_t& numIDs);
 254 #endif
 255
 256     /**
 257      * Returns the number of IDs 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 returned count includes the given ID; it is always >= 1.
 262      * The given ID must be a system time zone.  If it is not, returns
 263      * zero.
 264      * @param id a system time zone ID
 265      * @return the number of zones in the equivalency group containing
 266      * 'id', or zero if 'id' is not a valid system ID
 267      * @see #getEquivalentID
 268      * @stable ICU 2.0
 269      */
 270     static int32_t U_EXPORT2 countEquivalentIDs(const UnicodeString& id);
 271
 272     /**
 273      * Returns an ID in the equivalency group that
 274      * includes the given ID.  An equivalency group contains zones
 275      * that have the same GMT offset and rules.
 276      *
 277      * <p>The given index must be in the range 0..n-1, where n is the
 278      * value returned by <code>countEquivalentIDs(id)</code>.  For
 279      * some value of 'index', the returned value will be equal to the
 280      * given id.  If the given id is not a valid system time zone, or
 281      * if 'index' is out of range, then returns an empty string.
 282      * @param id a system time zone ID
 283      * @param index a value from 0 to n-1, where n is the value
 284      * returned by <code>countEquivalentIDs(id)</code>
 285      * @return the ID of the index-th zone in the equivalency group
 286      * containing 'id', or an empty string if 'id' is not a valid
 287      * system ID or 'index' is out of range
 288      * @see #countEquivalentIDs
 289      * @stable ICU 2.0
 290      */
 291     static const UnicodeString U_EXPORT2 getEquivalentID(const UnicodeString& id,
 292                                                int32_t index);
 293
 294     /**
 295      * Creates a new copy of the default TimeZone for this host. Unless the default time
 296      * zone has already been set using adoptDefault() or setDefault(), the default is
 297      * determined by querying the system using methods in TPlatformUtilities. If the
 298      * system routines fail, or if they specify a TimeZone or TimeZone offset which is not
 299      * recognized, the TimeZone indicated by the ID kLastResortID is instantiated
 300      * and made the default.
 301      *
 302      * @return   A default TimeZone. Clients are responsible for deleting the time zone
 303      *           object returned.
 304      * @stable ICU 2.0
 305      */
 306     static TimeZone* U_EXPORT2 createDefault(void);
 307
 308     /**
 309      * Sets the default time zone (i.e., what's returned by createDefault()) to be the
 310      * specified time zone.  If NULL is specified for the time zone, the default time
 311      * zone is set to the default host time zone.  This call adopts the TimeZone object
 312      * passed in; the clent is no longer responsible for deleting it.
 313      *
 314      * @param zone  A pointer to the new TimeZone object to use as the default.
 315      * @stable ICU 2.0
 316      */
 317     static void U_EXPORT2 adoptDefault(TimeZone* zone);
 318
 319     /**
 320      * Same as adoptDefault(), except that the TimeZone object passed in is NOT adopted;
 321      * the caller remains responsible for deleting it.
 322      *
 323      * @param zone  The given timezone.
 324      * @system
 325      */
 326     static void U_EXPORT2 setDefault(const TimeZone& zone);
 327
 328     /**
 329      * Returns the timezone data version currently used by ICU.
 330      * @param status Output param to filled in with a success or an error.
 331      * @return the version string, such as "2007f"
 332      * @stable ICU 4.0
 333      */
 334     static const char* U_EXPORT2 getTZDataVersion(UErrorCode& status);
 335
 336     /**
 337      * Returns the canonical system timezone ID or the normalized
 338      * custom time zone ID for the given time zone ID.
 339      * @param id            The input timezone ID to be canonicalized.
 340      * @param canonicalID   Receives the canonical system timezone ID
 341      *                      or the custom timezone ID in normalized format.
 342      * @param status        Recevies the status.  When the given timezone ID
 343      *                      is neither a known system time zone ID nor a
 344      *                      valid custom timezone ID, U_ILLEGAL_ARGUMENT_ERROR
 345      *                      is set.
 346      * @return A reference to the result.
 347      * @draft ICU 4.0
 348      */
 349     static UnicodeString& U_EXPORT2 getCanonicalID(const UnicodeString& id,
 350         UnicodeString& canonicalID, UErrorCode& status);
 351
 352     /**
 353      * Returns the canonical system timezone ID or the normalized
 354      * custom time zone ID for the given time zone ID.
 355      * @param id            The input timezone ID to be canonicalized.
 356      * @param canonicalID   Receives the canonical system timezone ID
 357      *                      or the custom timezone ID in normalized format.
 358      * @param isSystemID    Receives if the given ID is a known system
 359      *                      timezone ID.
 360      * @param status        Recevies the status.  When the given timezone ID
 361      *                      is neither a known system time zone ID nor a
 362      *                      valid custom timezone ID, U_ILLEGAL_ARGUMENT_ERROR
 363      *                      is set.
 364      * @return A reference to the result.
 365      * @draft ICU 4.0
 366      */
 367     static UnicodeString& U_EXPORT2 getCanonicalID(const UnicodeString& id,
 368         UnicodeString& canonicalID, UBool& isSystemID, UErrorCode& status);
 369
 370     /**
 371      * Returns true if the two TimeZones are equal.  (The TimeZone version only compares
 372      * IDs, but subclasses are expected to also compare the fields they add.)
 373      *
 374      * @param that  The TimeZone object to be compared with.
 375      * @return      True if the given TimeZone is equal to this TimeZone; false
 376      *              otherwise.
 377      * @stable ICU 2.0
 378      */
 379     virtual UBool operator==(const TimeZone& that) const;
 380
 381     /**
 382      * Returns true if the two TimeZones are NOT equal; that is, if operator==() returns
 383      * false.
 384      *
 385      * @param that  The TimeZone object to be compared with.
 386      * @return      True if the given TimeZone is not equal to this TimeZone; false
 387      *              otherwise.
 388      * @stable ICU 2.0
 389      */
 390     UBool operator!=(const TimeZone& that) const {return !operator==(that);}
 391
 392     /**
 393      * Returns the TimeZone's adjusted GMT offset (i.e., the number of milliseconds to add
 394      * to GMT to get local time in this time zone, taking daylight savings time into
 395      * account) as of a particular reference date.  The reference date is used to determine
 396      * whether daylight savings time is in effect and needs to be figured into the offset
 397      * that is returned (in other words, what is the adjusted GMT offset in this time zone
 398      * at this particular date and time?).  For the time zones produced by createTimeZone(),
 399      * the reference data is specified according to the Gregorian calendar, and the date
 400      * and time fields are local standard time.
 401      *
 402      * <p>Note: Don't call this method. Instead, call the getOffset(UDate...) overload,
 403      * which returns both the raw and the DST offset for a given time. This method
 404      * is retained only for backward compatibility.
 405      *
 406      * @param era        The reference date's era
 407      * @param year       The reference date's year
 408      * @param month      The reference date's month (0-based; 0 is January)
 409      * @param day        The reference date's day-in-month (1-based)
 410      * @param dayOfWeek  The reference date's day-of-week (1-based; 1 is Sunday)
 411      * @param millis     The reference date's milliseconds in day, local standard time
 412      * @param status     Output param to filled in with a success or an error.
 413      * @return           The offset in milliseconds to add to GMT to get local time.
 414      * @stable ICU 2.0
 415      */
 416     virtual int32_t getOffset(uint8_t era, int32_t year, int32_t month, int32_t day,
 417                               uint8_t dayOfWeek, int32_t millis, UErrorCode& status) const = 0;
 418
 419     /**
 420      * Gets the time zone offset, for current date, modified in case of
 421      * daylight savings. This is the offset to add *to* UTC to get local time.
 422      *
 423      * <p>Note: Don't call this method. Instead, call the getOffset(UDate...) overload,
 424      * which returns both the raw and the DST offset for a given time. This method
 425      * is retained only for backward compatibility.
 426      *
 427      * @param era the era of the given date.
 428      * @param year the year in the given date.
 429      * @param month the month in the given date.
 430      * Month is 0-based. e.g., 0 for January.
 431      * @param day the day-in-month of the given date.
 432      * @param dayOfWeek the day-of-week of the given date.
 433      * @param milliseconds the millis in day in <em>standard</em> local time.
 434      * @param monthLength the length of the given month in days.
 435      * @param status     Output param to filled in with a success or an error.
 436      * @return the offset to add *to* GMT to get local time.
 437      * @stable ICU 2.0
 438      */
 439     virtual int32_t getOffset(uint8_t era, int32_t year, int32_t month, int32_t day,
 440                            uint8_t dayOfWeek, int32_t milliseconds,
 441                            int32_t monthLength, UErrorCode& status) const = 0;
 442
 443     /**
 444      * Returns the time zone raw and GMT offset for the given moment
 445      * in time.  Upon return, local-millis = GMT-millis + rawOffset +
 446      * dstOffset.  All computations are performed in the proleptic
 447      * Gregorian calendar.  The default implementation in the TimeZone
 448      * class delegates to the 8-argument getOffset().
 449      *
 450      * @param date moment in time for which to return offsets, in
 451      * units of milliseconds from January 1, 1970 0:00 GMT, either GMT
 452      * time or local wall time, depending on `local'.
 453      * @param local if true, `date' is local wall time; otherwise it
 454      * is in GMT time.
 455      * @param rawOffset output parameter to receive the raw offset, that
 456      * is, the offset not including DST adjustments
 457      * @param dstOffset output parameter to receive the DST offset,
 458      * that is, the offset to be added to `rawOffset' to obtain the
 459      * total offset between local and GMT time. If DST is not in
 460      * effect, this value is zero; otherwise it is a positive value,
 461      * typically one hour.
 462      * @param ec input-output error code
 463      *
 464      * @stable ICU 2.8
 465      */
 466     virtual void getOffset(UDate date, UBool local, int32_t& rawOffset,
 467                            int32_t& dstOffset, UErrorCode& ec) const;
 468
 469     /**
 470      * Sets the TimeZone's raw GMT offset (i.e., the number of milliseconds to add
 471      * to GMT to get local time, before taking daylight savings time into account).
 472      *
 473      * @param offsetMillis  The new raw GMT offset for this time zone.
 474      * @stable ICU 2.0
 475      */
 476     virtual void setRawOffset(int32_t offsetMillis) = 0;
 477
 478     /**
 479      * Returns the TimeZone's raw GMT offset (i.e., the number of milliseconds to add
 480      * to GMT to get local time, before taking daylight savings time into account).
 481      *
 482      * @return   The TimeZone's raw GMT offset.
 483      * @stable ICU 2.0
 484      */
 485     virtual int32_t getRawOffset(void) const = 0;
 486
 487     /**
 488      * Fills in "ID" with the TimeZone's ID.
 489      *
 490      * @param ID  Receives this TimeZone's ID.
 491      * @return    A reference to 'ID'
 492      * @stable ICU 2.0
 493      */
 494     UnicodeString& getID(UnicodeString& ID) const;
 495
 496     /**
 497      * Sets the TimeZone's ID to the specified value.  This doesn't affect any other
 498      * fields (for example, if you say<
 499      * blockquote><pre>
 500      * .     TimeZone* foo = TimeZone::createTimeZone("America/New_York");
 501      * .     foo.setID("America/Los_Angeles");
 502      * </pre>\htmlonly</blockquote>\endhtmlonly
 503      * the time zone's GMT offset and daylight-savings rules don't change to those for
 504      * Los Angeles.  They're still those for New York.  Only the ID has changed.)
 505      *
 506      * @param ID  The new timezone ID.
 507      * @stable ICU 2.0
 508      */
 509     void setID(const UnicodeString& ID);
 510
 511     /**
 512      * Enum for use with getDisplayName
 513      * @stable ICU 2.4
 514      */
 515     enum EDisplayType {
 516         /**
 517          * Selector for short display name
 518          * @stable ICU 2.4
 519          */
 520         SHORT = 1,
 521         /**
 522          * Selector for long display name
 523          * @stable ICU 2.4
 524          */
 525         LONG
 526     };
 527
 528     /**
 529      * Returns a name of this time zone suitable for presentation to the user
 530      * in the default locale.
 531      * This method returns the long name, not including daylight savings.
 532      * If the display name is not available for the locale,
 533      * then this method returns a string in the format
 534      * <code>GMT[+-]hh:mm</code>.
 535      * @param result the human-readable name of this time zone in the default locale.
 536      * @return       A reference to 'result'.
 537      * @stable ICU 2.0
 538      */
 539     UnicodeString& getDisplayName(UnicodeString& result) const;
 540
 541     /**
 542      * Returns a name of this time zone suitable for presentation to the user
 543      * in the specified locale.
 544      * This method returns the long name, not including daylight savings.
 545      * If the display name is not available for the locale,
 546      * then this method returns a string in the format
 547      * <code>GMT[+-]hh:mm</code>.
 548      * @param locale the locale in which to supply the display name.
 549      * @param result the human-readable name of this time zone in the given locale
 550      *               or in the default locale if the given locale is not recognized.
 551      * @return       A reference to 'result'.
 552      * @stable ICU 2.0
 553      */
 554     UnicodeString& getDisplayName(const Locale& locale, UnicodeString& result) const;
 555
 556     /**
 557      * Returns a name of this time zone suitable for presentation to the user
 558      * in the default locale.
 559      * If the display name is not available for the locale,
 560      * then this method returns a string in the format
 561      * <code>GMT[+-]hh:mm</code>.
 562      * @param daylight if true, return the daylight savings name.
 563      * @param style either <code>LONG</code> or <code>SHORT</code>
 564      * @param result the human-readable name of this time zone in the default locale.
 565      * @return       A reference to 'result'.
 566      * @stable ICU 2.0
 567      */
 568     UnicodeString& getDisplayName(UBool daylight, EDisplayType style, UnicodeString& result) const;
 569
 570     /**
 571      * Returns a name of this time zone suitable for presentation to the user
 572      * in the specified locale.
 573      * If the display name is not available for the locale,
 574      * then this method returns a string in the format
 575      * <code>GMT[+-]hh:mm</code>.
 576      * @param daylight if true, return the daylight savings name.
 577      * @param style either <code>LONG</code> or <code>SHORT</code>
 578      * @param locale the locale in which to supply the display name.
 579      * @param result the human-readable name of this time zone in the given locale
 580      *               or in the default locale if the given locale is not recognized.
 581      * @return       A refence to 'result'.
 582      * @stable ICU 2.0
 583      */
 584     UnicodeString& getDisplayName(UBool daylight, EDisplayType style, const Locale& locale, UnicodeString& result) const;
 585
 586     /**
 587      * Queries if this time zone uses daylight savings time.
 588      * @return true if this time zone uses daylight savings time,
 589      * false, otherwise.
 590      * @stable ICU 2.0
 591      */
 592     virtual UBool useDaylightTime(void) const = 0;
 593
 594     /**
 595      * Queries if the given date is in daylight savings time in
 596      * this time zone.
 597      * This method is wasteful since it creates a new GregorianCalendar and
 598      * deletes it each time it is called. This is a deprecated method
 599      * and provided only for Java compatibility.
 600      *
 601      * @param date the given UDate.
 602      * @param status Output param filled in with success/error code.
 603      * @return true if the given date is in daylight savings time,
 604      * false, otherwise.
 605      * @deprecated ICU 2.4. Use Calendar::inDaylightTime() instead.
 606      */
 607     virtual UBool inDaylightTime(UDate date, UErrorCode& status) const = 0;
 608
 609     /**
 610      * Returns true if this zone has the same rule and offset as another zone.
 611      * That is, if this zone differs only in ID, if at all.
 612      * @param other the <code>TimeZone</code> object to be compared with
 613      * @return true if the given zone is the same as this one,
 614      * with the possible exception of the ID
 615      * @stable ICU 2.0
 616      */
 617     virtual UBool hasSameRules(const TimeZone& other) const;
 618
 619     /**
 620      * Clones TimeZone objects polymorphically. Clients are responsible for deleting
 621      * the TimeZone object cloned.
 622      *
 623      * @return   A new copy of this TimeZone object.
 624      * @stable ICU 2.0
 625      */
 626     virtual TimeZone* clone(void) const = 0;
 627
 628     /**
 629      * Return the class ID for this class.  This is useful only for
 630      * comparing to a return value from getDynamicClassID().
 631      * @return The class ID for all objects of this class.
 632      * @stable ICU 2.0
 633      */
 634     static UClassID U_EXPORT2 getStaticClassID(void);
 635
 636     /**
 637      * Returns a unique class ID POLYMORPHICALLY. This method is to
 638      * implement a simple version of RTTI, since not all C++ compilers support genuine
 639      * RTTI. Polymorphic operator==() and clone() methods call this method.
 640      * <P>
 641      * Concrete subclasses of TimeZone must use the UOBJECT_DEFINE_RTTI_IMPLEMENTATION
 642      *  macro from uobject.h in their implementation to provide correct RTTI information.
 643      * @return   The class ID for this object. All objects of a given class have the
 644      *           same class ID. Objects of other classes have different class IDs.
 645      * @stable ICU 2.0
 646      */
 647     virtual UClassID getDynamicClassID(void) const = 0;
 648
 649     /**
 650      * Returns the amount of time to be added to local standard time
 651      * to get local wall clock time.
 652      * <p>
 653      * The default implementation always returns 3600000 milliseconds
 654      * (i.e., one hour) if this time zone observes Daylight Saving
 655      * Time. Otherwise, 0 (zero) is returned.
 656      * <p>
 657      * If an underlying TimeZone implementation subclass supports
 658      * historical Daylight Saving Time changes, this method returns
 659      * the known latest daylight saving value.
 660      *
 661      * @return the amount of saving time in milliseconds
 662      * @stable ICU 3.6
 663      */
 664     virtual int32_t getDSTSavings() const;
 665
 666 protected:
 667
 668     /**
 669      * Default constructor.  ID is initialized to the empty string.
 670      * @stable ICU 2.0
 671      */
 672     TimeZone();
 673
 674     /**
 675      * Construct a timezone with a given ID.
 676      * @param id a system time zone ID
 677      * @stable ICU 2.0
 678      */
 679     TimeZone(const UnicodeString &id);
 680
 681     /**
 682      * Copy constructor.
 683      * @param source the object to be copied.
 684      * @stable ICU 2.0
 685      */
 686     TimeZone(const TimeZone& source);
 687
 688     /**
 689      * Default assignment operator.
 690      * @param right the object to be copied.
 691      * @stable ICU 2.0
 692      */
 693     TimeZone& operator=(const TimeZone& right);
 694
 695     /**
 696      * Utility function. For internally loading rule data.
 697      * @param top Top resource bundle for tz data
 698      * @param ruleid ID of rule to load
 699      * @param oldbundle Old bundle to reuse or NULL
 700      * @param status Status parameter
 701      * @return either a new bundle or *oldbundle
 702      * @internal
 703      */
 704     static UResourceBundle* loadRule(const UResourceBundle* top, const UnicodeString& ruleid, UResourceBundle* oldbundle, UErrorCode&status);
 705
 706 private:
 707     friend class ZoneMeta;
 708
 709
 710     static TimeZone*        createCustomTimeZone(const UnicodeString&); // Creates a time zone based on the string.
 711
 712     /**
 713      * Resolve a link in Olson tzdata.  When the given id is known and it's not a link,
 714      * the id itself is returned.  When the given id is known and it is a link, then
 715      * dereferenced zone id is returned.  When the given id is unknown, then it returns
 716      * empty string.
 717      * @param linkTo Input zone id string
 718      * @param linkFrom Receives the dereferenced zone id string
 719      * @return The reference to the result (linkFrom)
 720      */
 721     static UnicodeString& dereferOlsonLink(const UnicodeString& linkTo, UnicodeString& linkFrom);
 722
 723     /**
 724      * Parses the given custom time zone identifier
 725      * @param id id A string of the form GMT[+-]hh:mm, GMT[+-]hhmm, or
 726      * GMT[+-]hh.
 727      * @param sign Receves parsed sign, 1 for positive, -1 for negative.
 728      * @param hour Receives parsed hour field
 729      * @param minute Receives parsed minute field
 730      * @param second Receives parsed second field
 731      * @return Returns TRUE when the given custom id is valid.
 732      */
 733     static UBool parseCustomID(const UnicodeString& id, int32_t& sign, int32_t& hour,
 734         int32_t& min, int32_t& sec);
 735
 736     /**
 737      * Parse a custom time zone identifier and return the normalized
 738      * custom time zone identifier for the given custom id string.
 739      * @param id a string of the form GMT[+-]hh:mm, GMT[+-]hhmm, or
 740      * GMT[+-]hh.
 741      * @param normalized Receives the normalized custom ID
 742      * @param status Receives the status.  When the input ID string is invalid,
 743      * U_ILLEGAL_ARGUMENT_ERROR is set.
 744      * @return The normalized custom id string.
 745     */
 746     static UnicodeString& getCustomID(const UnicodeString& id, UnicodeString& normalized,
 747         UErrorCode& status);
 748
 749     /**
 750      * Returns the normalized custome timezone ID for the given offset fields.
 751      * @param hour offset hours
 752      * @param min offset minutes
 753      * @param sec offset seconds
 754      * @param netative sign of the offset, TRUE for negative offset.
 755      * @param id Receves the format result (normalized custom ID)
 756      * @return The reference to id
 757      */
 758     static UnicodeString& formatCustomID(int32_t hour, int32_t min, int32_t sec,
 759         UBool negative, UnicodeString& id);
 760
 761     /**
 762      * Responsible for setting up DEFAULT_ZONE.  Uses routines in TPlatformUtilities
 763      * (i.e., platform-specific calls) to get the current system time zone.  Failing
 764      * that, uses the platform-specific default time zone.  Failing that, uses GMT.
 765      */
 766     static void             initDefault(void);
 767
 768     // See source file for documentation
 769     /**
 770      * Lookup the given name in our system zone table.  If found,
 771      * instantiate a new zone of that name and return it.  If not
 772      * found, return 0.
 773      * @param name tthe given name of a system time zone.
 774      * @return the timezone indicated by the 'name'.
 775      */
 776     static TimeZone*        createSystemTimeZone(const UnicodeString& name);
 777
 778     UnicodeString           fID;    // this time zone's ID
 779 };
 780
 781
 782 // -------------------------------------
 783
 784 inline UnicodeString&
 785 TimeZone::getID(UnicodeString& ID) const
 786 {
 787     ID = fID;
 788     return ID;
 789 }
 790
 791 // -------------------------------------
 792
 793 inline void
 794 TimeZone::setID(const UnicodeString& ID)
 795 {
 796     fID = ID;
 797 }
 798 U_NAMESPACE_END
 799
 800 #endif /* #if !UCONFIG_NO_FORMATTING */
 801
 802 #endif //_TIMEZONE
 803 //eof