DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Mercurial (d38398e5144e)

VCS Links

EDisplayType

TimeZone

Macros

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968
// Copyright (C) 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*************************************************************************
* Copyright (c) 1997-2016, International Business Machines Corporation
* and others. All Rights Reserved.
**************************************************************************
*
* File TIMEZONE.H
*
* Modification History:
*
*   Date        Name        Description
*   04/21/97    aliu        Overhauled header.
*   07/09/97    helena      Changed createInstance to createDefault.
*   08/06/97    aliu        Removed dependency on internal header for Hashtable.
*   08/10/98    stephen        Changed getDisplayName() API conventions to match
*   08/19/98    stephen        Changed createTimeZone() to never return 0
*   09/02/98    stephen        Sync to JDK 1.2 8/31
*                            - Added getOffset(... monthlen ...)
*                            - Added hasSameRules()
*   09/15/98    stephen        Added getStaticClassID
*   12/03/99    aliu        Moved data out of static table into icudata.dll.
*                           Hashtable replaced by new static data structures.
*   12/14/99    aliu        Made GMT public.
*   08/15/01    grhoten     Made GMT private and added the getGMT() function
**************************************************************************
*/

#ifndef TIMEZONE_H
#define TIMEZONE_H

#include "unicode/utypes.h"

/**
 * \file 
 * \brief C++ API: TimeZone object
 */

#if !UCONFIG_NO_FORMATTING

#include "unicode/uobject.h"
#include "unicode/unistr.h"
#include "unicode/ures.h"
#include "unicode/ucal.h"

U_NAMESPACE_BEGIN

class StringEnumeration;

/**
 *
 * <code>TimeZone</code> represents a time zone offset, and also figures out daylight
 * savings.
 *
 * <p>
 * Typically, you get a <code>TimeZone</code> using <code>createDefault</code>
 * which creates a <code>TimeZone</code> based on the time zone where the program
 * is running. For example, for a program running in Japan, <code>createDefault</code>
 * creates a <code>TimeZone</code> object based on Japanese Standard Time.
 *
 * <p>
 * You can also get a <code>TimeZone</code> using <code>createTimeZone</code> along
 * with a time zone ID. For instance, the time zone ID for the US Pacific
 * Time zone is "America/Los_Angeles". So, you can get a Pacific Time <code>TimeZone</code> object
 * with:
 * \htmlonly<blockquote>\endhtmlonly
 * <pre>
 * TimeZone *tz = TimeZone::createTimeZone("America/Los_Angeles");
 * </pre>
 * \htmlonly</blockquote>\endhtmlonly
 * You can use the <code>createEnumeration</code> method to iterate through
 * all the supported time zone IDs, or the <code>getCanonicalID</code> method to check
 * if a time zone ID is supported or not.  You can then choose a
 * supported ID to get a <code>TimeZone</code>.
 * If the time zone you want is not represented by one of the
 * supported IDs, then you can create a custom time zone ID with
 * the following syntax:
 *
 * \htmlonly<blockquote>\endhtmlonly
 * <pre>
 * GMT[+|-]hh[[:]mm]
 * </pre>
 * \htmlonly</blockquote>\endhtmlonly
 *
 * For example, you might specify GMT+14:00 as a custom
 * time zone ID.  The <code>TimeZone</code> that is returned
 * when you specify a custom time zone ID uses the specified
 * offset from GMT(=UTC) and does not observe daylight saving
 * time. For example, you might specify GMT+14:00 as a custom
 * time zone ID to create a TimeZone representing 14 hours ahead
 * of GMT (with no daylight saving time). In addition,
 * <code>getCanonicalID</code> can also be used to
 * normalize a custom time zone ID.
 *
 * TimeZone is an abstract class representing a time zone.  A TimeZone is needed for
 * Calendar to produce local time for a particular time zone.  A TimeZone comprises
 * three basic pieces of information:
 * <ul>
 *    <li>A time zone offset; that, is the number of milliseconds to add or subtract
 *      from a time expressed in terms of GMT to convert it to the same time in that
 *      time zone (without taking daylight savings time into account).</li>
 *    <li>Logic necessary to take daylight savings time into account if daylight savings
 *      time is observed in that time zone (e.g., the days and hours on which daylight
 *      savings time begins and ends).</li>
 *    <li>An ID.  This is a text string that uniquely identifies the time zone.</li>
 * </ul>
 *
 * (Only the ID is actually implemented in TimeZone; subclasses of TimeZone may handle
 * daylight savings time and GMT offset in different ways.  Currently we have the following
 * TimeZone subclasses: RuleBasedTimeZone, SimpleTimeZone, and VTimeZone.)
 * <P>
 * The TimeZone class contains a static list containing a TimeZone object for every
 * combination of GMT offset and daylight-savings time rules currently in use in the
 * world, each with a unique ID.  Each ID consists of a region (usually a continent or
 * ocean) and a city in that region, separated by a slash, (for example, US Pacific
 * Time is "America/Los_Angeles.")  Because older versions of this class used
 * three- or four-letter abbreviations instead, there is also a table that maps the older
 * abbreviations to the newer ones (for example, "PST" maps to "America/Los_Angeles").
 * Anywhere the API requires an ID, you can use either form.
 * <P>
 * To create a new TimeZone, you call the factory function TimeZone::createTimeZone()
 * and pass it a time zone ID.  You can use the createEnumeration() function to
 * obtain a list of all the time zone IDs recognized by createTimeZone().
 * <P>
 * You can also use TimeZone::createDefault() to create a TimeZone.  This function uses
 * platform-specific APIs to produce a TimeZone for the time zone corresponding to
 * the client's computer's physical location.  For example, if you're in Japan (assuming
 * your machine is set up correctly), TimeZone::createDefault() will return a TimeZone
 * for Japanese Standard Time ("Asia/Tokyo").
 */
class U_I18N_API TimeZone : public UObject {
public:
    /**
     * @stable ICU 2.0
     */
    virtual ~TimeZone();

    /**
     * Returns the "unknown" time zone.
     * It behaves like the GMT/UTC time zone but has the
     * <code>UCAL_UNKNOWN_ZONE_ID</code> = "Etc/Unknown".
     * createTimeZone() returns a mutable clone of this time zone if the input ID is not recognized.
     *
     * @return the "unknown" time zone.
     * @see UCAL_UNKNOWN_ZONE_ID
     * @see createTimeZone
     * @see getGMT
     * @stable ICU 49
     */
    static const TimeZone& U_EXPORT2 getUnknown();

    /**
     * The GMT (=UTC) time zone has a raw offset of zero and does not use daylight
     * savings time. This is a commonly used time zone.
     *
     * <p>Note: For backward compatibility reason, the ID used by the time
     * zone returned by this method is "GMT", although the ICU's canonical
     * ID for the GMT time zone is "Etc/GMT".
     *
     * @return the GMT/UTC time zone.
     * @see getUnknown
     * @stable ICU 2.0
     */
    static const TimeZone* U_EXPORT2 getGMT(void);

    /**
     * Creates a <code>TimeZone</code> for the given ID.
     * @param ID the ID for a <code>TimeZone</code>, such as "America/Los_Angeles",
     * or a custom ID such as "GMT-8:00".
     * @return the specified <code>TimeZone</code>, or a mutable clone of getUnknown()
     * if the given ID cannot be understood or if the given ID is "Etc/Unknown".
     * The return result is guaranteed to be non-NULL.
     * If you require that the specific zone asked for be returned,
     * compare the result with getUnknown() or check the ID of the return result.
     * @stable ICU 2.0
     */
    static TimeZone* U_EXPORT2 createTimeZone(const UnicodeString& ID);

    /**
     * Returns an enumeration over system time zone IDs with the given
     * filter conditions.
     * @param zoneType      The system time zone type.
     * @param region        The ISO 3166 two-letter country code or UN M.49
     *                      three-digit area code. When NULL, no filtering
     *                      done by region. 
     * @param rawOffset     An offset from GMT in milliseconds, ignoring
     *                      the effect of daylight savings time, if any.
     *                      When NULL, no filtering done by zone offset. 
     * @param ec            Output param to filled in with a success or
     *                      an error.
     * @return an enumeration object, owned by the caller.
     * @stable ICU 4.8
     */
    static StringEnumeration* U_EXPORT2 createTimeZoneIDEnumeration(
        USystemTimeZoneType zoneType,
        const char* region,
        const int32_t* rawOffset,
        UErrorCode& ec);

    /**
     * Returns an enumeration over all recognized time zone IDs. (i.e.,
     * all strings that createTimeZone() accepts)
     *
     * @return an enumeration object, owned by the caller.
     * @stable ICU 2.4
     */
    static StringEnumeration* U_EXPORT2 createEnumeration();

    /**
     * Returns an enumeration over time zone IDs with a given raw
     * offset from GMT.  There may be several times zones with the
     * same GMT offset that differ in the way they handle daylight
     * savings time.  For example, the state of Arizona doesn't
     * observe daylight savings time.  If you ask for the time zone
     * IDs corresponding to GMT-7:00, you'll get back an enumeration
     * over two time zone IDs: "America/Denver," which corresponds to
     * Mountain Standard Time in the winter and Mountain Daylight Time
     * in the summer, and "America/Phoenix", which corresponds to
     * Mountain Standard Time year-round, even in the summer.
     *
     * @param rawOffset an offset from GMT in milliseconds, ignoring
     * the effect of daylight savings time, if any
     * @return an enumeration object, owned by the caller
     * @stable ICU 2.4
     */
    static StringEnumeration* U_EXPORT2 createEnumeration(int32_t rawOffset);

    /**
     * Returns an enumeration over time zone IDs associated with the
     * given country.  Some zones are affiliated with no country
     * (e.g., "UTC"); these may also be retrieved, as a group.
     *
     * @param country The ISO 3166 two-letter country code, or NULL to
     * retrieve zones not affiliated with any country.
     * @return an enumeration object, owned by the caller
     * @stable ICU 2.4
     */
    static StringEnumeration* U_EXPORT2 createEnumeration(const char* country);

    /**
     * Returns the number of IDs in the equivalency group that
     * includes the given ID.  An equivalency group contains zones
     * that have the same GMT offset and rules.
     *
     * <p>The returned count includes the given ID; it is always >= 1.
     * The given ID must be a system time zone.  If it is not, returns
     * zero.
     * @param id a system time zone ID
     * @return the number of zones in the equivalency group containing
     * 'id', or zero if 'id' is not a valid system ID
     * @see #getEquivalentID
     * @stable ICU 2.0
     */
    static int32_t U_EXPORT2 countEquivalentIDs(const UnicodeString& id);

    /**
     * Returns an ID in the equivalency group that
     * includes the given ID.  An equivalency group contains zones
     * that have the same GMT offset and rules.
     *
     * <p>The given index must be in the range 0..n-1, where n is the
     * value returned by <code>countEquivalentIDs(id)</code>.  For
     * some value of 'index', the returned value will be equal to the
     * given id.  If the given id is not a valid system time zone, or
     * if 'index' is out of range, then returns an empty string.
     * @param id a system time zone ID
     * @param index a value from 0 to n-1, where n is the value
     * returned by <code>countEquivalentIDs(id)</code>
     * @return the ID of the index-th zone in the equivalency group
     * containing 'id', or an empty string if 'id' is not a valid
     * system ID or 'index' is out of range
     * @see #countEquivalentIDs
     * @stable ICU 2.0
     */
    static const UnicodeString U_EXPORT2 getEquivalentID(const UnicodeString& id,
                                               int32_t index);

    /**
     * Creates an instance of TimeZone detected from the current host
     * system configuration. Note that ICU4C does not change the default
     * time zone unless TimeZone::adoptDefault(TimeZone*) or
     * TimeZone::setDefault(const TimeZone&) is explicitly called by a
     * user. This method does not update the current ICU's default,
     * and may return a different TimeZone from the one returned by
     * TimeZone::createDefault().
     *
     * @return  A new instance of TimeZone detected from the current host system
     *          configuration.
     * @stable ICU 55
     */
    static TimeZone* U_EXPORT2 detectHostTimeZone();

    /**
     * Creates a new copy of the default TimeZone for this host. Unless the default time
     * zone has already been set using adoptDefault() or setDefault(), the default is
     * determined by querying the system using methods in TPlatformUtilities. If the
     * system routines fail, or if they specify a TimeZone or TimeZone offset which is not
     * recognized, the TimeZone indicated by the ID kLastResortID is instantiated
     * and made the default.
     *
     * @return   A default TimeZone. Clients are responsible for deleting the time zone
     *           object returned.
     * @stable ICU 2.0
     */
    static TimeZone* U_EXPORT2 createDefault(void);

#define ICU_TZ_HAS_RECREATE_DEFAULT
    static void U_EXPORT2 recreateDefault();

    /**
     * Sets the default time zone (i.e., what's returned by createDefault()) to be the
     * specified time zone.  If NULL is specified for the time zone, the default time
     * zone is set to the default host time zone.  This call adopts the TimeZone object
     * passed in; the client is no longer responsible for deleting it.
     *
     * <p>This function is not thread safe. It is an error for multiple threads
     * to concurrently attempt to set the default time zone, or for any thread
     * to attempt to reference the default zone while another thread is setting it.
     *
     * @param zone  A pointer to the new TimeZone object to use as the default.
     * @stable ICU 2.0
     */
    static void U_EXPORT2 adoptDefault(TimeZone* zone);

#ifndef U_HIDE_SYSTEM_API
    /**
     * Same as adoptDefault(), except that the TimeZone object passed in is NOT adopted;
     * the caller remains responsible for deleting it.
     *
     * <p>See the thread safety note under adoptDefault().
     *
     * @param zone  The given timezone.
     * @system
     * @stable ICU 2.0
     */
    static void U_EXPORT2 setDefault(const TimeZone& zone);
#endif  /* U_HIDE_SYSTEM_API */

    /**
     * Returns the timezone data version currently used by ICU.
     * @param status Output param to filled in with a success or an error.
     * @return the version string, such as "2007f"
     * @stable ICU 3.8
     */
    static const char* U_EXPORT2 getTZDataVersion(UErrorCode& status);

    /**
     * Returns the canonical system timezone ID or the normalized
     * custom time zone ID for the given time zone ID.
     * @param id            The input time zone ID to be canonicalized.
     * @param canonicalID   Receives the canonical system time zone ID
     *                      or the custom time zone ID in normalized format.
     * @param status        Receives the status.  When the given time zone ID
     *                      is neither a known system time zone ID nor a
     *                      valid custom time zone ID, U_ILLEGAL_ARGUMENT_ERROR
     *                      is set.
     * @return A reference to the result.
     * @stable ICU 4.0
     */
    static UnicodeString& U_EXPORT2 getCanonicalID(const UnicodeString& id,
        UnicodeString& canonicalID, UErrorCode& status);

    /**
     * Returns the canonical system time zone ID or the normalized
     * custom time zone ID for the given time zone ID.
     * @param id            The input time zone ID to be canonicalized.
     * @param canonicalID   Receives the canonical system time zone ID
     *                      or the custom time zone ID in normalized format.
     * @param isSystemID    Receives if the given ID is a known system
     *                      time zone ID.
     * @param status        Receives the status.  When the given time zone ID
     *                      is neither a known system time zone ID nor a
     *                      valid custom time zone ID, U_ILLEGAL_ARGUMENT_ERROR
     *                      is set.
     * @return A reference to the result.
     * @stable ICU 4.0
     */
    static UnicodeString& U_EXPORT2 getCanonicalID(const UnicodeString& id,
        UnicodeString& canonicalID, UBool& isSystemID, UErrorCode& status);

    /**
    * Converts a system time zone ID to an equivalent Windows time zone ID. For example,
    * Windows time zone ID "Pacific Standard Time" is returned for input "America/Los_Angeles".
    *
    * <p>There are system time zones that cannot be mapped to Windows zones. When the input
    * system time zone ID is unknown or unmappable to a Windows time zone, then the result will be
    * empty, but the operation itself remains successful (no error status set on return).
    *
    * <p>This implementation utilizes <a href="http://unicode.org/cldr/charts/supplemental/zone_tzid.html">
    * Zone-Tzid mapping data</a>. The mapping data is updated time to time. To get the latest changes,
    * please read the ICU user guide section <a href="http://userguide.icu-project.org/datetime/timezone#TOC-Updating-the-Time-Zone-Data">
    * Updating the Time Zone Data</a>.
    *
    * @param id        A system time zone ID.
    * @param winid     Receives a Windows time zone ID. When the input system time zone ID is unknown
    *                  or unmappable to a Windows time zone ID, then an empty string is set on return.
    * @param status    Receives the status.
    * @return          A reference to the result (<code>winid</code>).
    * @see getIDForWindowsID
    *
    * @stable ICU 52
    */
    static UnicodeString& U_EXPORT2 getWindowsID(const UnicodeString& id,
        UnicodeString& winid, UErrorCode& status);

    /**
    * Converts a Windows time zone ID to an equivalent system time zone ID
    * for a region. For example, system time zone ID "America/Los_Angeles" is returned
    * for input Windows ID "Pacific Standard Time" and region "US" (or <code>null</code>),
    * "America/Vancouver" is returned for the same Windows ID "Pacific Standard Time" and
    * region "CA".
    *
    * <p>Not all Windows time zones can be mapped to system time zones. When the input
    * Windows time zone ID is unknown or unmappable to a system time zone, then the result
    * will be empty, but the operation itself remains successful (no error status set on return).
    *
    * <p>This implementation utilizes <a href="http://unicode.org/cldr/charts/supplemental/zone_tzid.html">
    * Zone-Tzid mapping data</a>. The mapping data is updated time to time. To get the latest changes,
    * please read the ICU user guide section <a href="http://userguide.icu-project.org/datetime/timezone#TOC-Updating-the-Time-Zone-Data">
    * Updating the Time Zone Data</a>.
    *
    * @param winid     A Windows time zone ID.
    * @param region    A null-terminated region code, or <code>NULL</code> if no regional preference.
    * @param id        Receives a system time zone ID. When the input Windows time zone ID is unknown
    *                  or unmappable to a system time zone ID, then an empty string is set on return.
    * @param status    Receives the status.
    * @return          A reference to the result (<code>id</code>).
    * @see getWindowsID
    *
    * @stable ICU 52
    */
    static UnicodeString& U_EXPORT2 getIDForWindowsID(const UnicodeString& winid, const char* region,
        UnicodeString& id, UErrorCode& status);

    /**
     * Returns true if the two TimeZones are equal.  (The TimeZone version only compares
     * IDs, but subclasses are expected to also compare the fields they add.)
     *
     * @param that  The TimeZone object to be compared with.
     * @return      True if the given TimeZone is equal to this TimeZone; false
     *              otherwise.
     * @stable ICU 2.0
     */
    virtual UBool operator==(const TimeZone& that) const;

    /**
     * Returns true if the two TimeZones are NOT equal; that is, if operator==() returns
     * false.
     *
     * @param that  The TimeZone object to be compared with.
     * @return      True if the given TimeZone is not equal to this TimeZone; false
     *              otherwise.
     * @stable ICU 2.0
     */
    UBool operator!=(const TimeZone& that) const {return !operator==(that);}

    /**
     * Returns the TimeZone's adjusted GMT offset (i.e., the number of milliseconds to add
     * to GMT to get local time in this time zone, taking daylight savings time into
     * account) as of a particular reference date.  The reference date is used to determine
     * whether daylight savings time is in effect and needs to be figured into the offset
     * that is returned (in other words, what is the adjusted GMT offset in this time zone
     * at this particular date and time?).  For the time zones produced by createTimeZone(),
     * the reference data is specified according to the Gregorian calendar, and the date
     * and time fields are local standard time.
     *
     * <p>Note: Don't call this method. Instead, call the getOffset(UDate...) overload,
     * which returns both the raw and the DST offset for a given time. This method
     * is retained only for backward compatibility.
     *
     * @param era        The reference date's era
     * @param year       The reference date's year
     * @param month      The reference date's month (0-based; 0 is January)
     * @param day        The reference date's day-in-month (1-based)
     * @param dayOfWeek  The reference date's day-of-week (1-based; 1 is Sunday)
     * @param millis     The reference date's milliseconds in day, local standard time
     * @param status     Output param to filled in with a success or an error.
     * @return           The offset in milliseconds to add to GMT to get local time.
     * @stable ICU 2.0
     */
    virtual int32_t getOffset(uint8_t era, int32_t year, int32_t month, int32_t day,
                              uint8_t dayOfWeek, int32_t millis, UErrorCode& status) const = 0;

    /**
     * Gets the time zone offset, for current date, modified in case of
     * daylight savings. This is the offset to add *to* UTC to get local time.
     *
     * <p>Note: Don't call this method. Instead, call the getOffset(UDate...) overload,
     * which returns both the raw and the DST offset for a given time. This method
     * is retained only for backward compatibility.
     *
     * @param era the era of the given date.
     * @param year the year in the given date.
     * @param month the month in the given date.
     * Month is 0-based. e.g., 0 for January.
     * @param day the day-in-month of the given date.
     * @param dayOfWeek the day-of-week of the given date.
     * @param milliseconds the millis in day in <em>standard</em> local time.
     * @param monthLength the length of the given month in days.
     * @param status     Output param to filled in with a success or an error.
     * @return the offset to add *to* GMT to get local time.
     * @stable ICU 2.0
     */
    virtual int32_t getOffset(uint8_t era, int32_t year, int32_t month, int32_t day,
                           uint8_t dayOfWeek, int32_t milliseconds,
                           int32_t monthLength, UErrorCode& status) const = 0;

    /**
     * Returns the time zone raw and GMT offset for the given moment
     * in time.  Upon return, local-millis = GMT-millis + rawOffset +
     * dstOffset.  All computations are performed in the proleptic
     * Gregorian calendar.  The default implementation in the TimeZone
     * class delegates to the 8-argument getOffset().
     *
     * @param date moment in time for which to return offsets, in
     * units of milliseconds from January 1, 1970 0:00 GMT, either GMT
     * time or local wall time, depending on `local'.
     * @param local if true, `date' is local wall time; otherwise it
     * is in GMT time.
     * @param rawOffset output parameter to receive the raw offset, that
     * is, the offset not including DST adjustments
     * @param dstOffset output parameter to receive the DST offset,
     * that is, the offset to be added to `rawOffset' to obtain the
     * total offset between local and GMT time. If DST is not in
     * effect, this value is zero; otherwise it is a positive value,
     * typically one hour.
     * @param ec input-output error code
     *
     * @stable ICU 2.8
     */
    virtual void getOffset(UDate date, UBool local, int32_t& rawOffset,
                           int32_t& dstOffset, UErrorCode& ec) const;

    /**
     * Sets the TimeZone's raw GMT offset (i.e., the number of milliseconds to add
     * to GMT to get local time, before taking daylight savings time into account).
     *
     * @param offsetMillis  The new raw GMT offset for this time zone.
     * @stable ICU 2.0
     */
    virtual void setRawOffset(int32_t offsetMillis) = 0;

    /**
     * Returns the TimeZone's raw GMT offset (i.e., the number of milliseconds to add
     * to GMT to get local time, before taking daylight savings time into account).
     *
     * @return   The TimeZone's raw GMT offset.
     * @stable ICU 2.0
     */
    virtual int32_t getRawOffset(void) const = 0;

    /**
     * Fills in "ID" with the TimeZone's ID.
     *
     * @param ID  Receives this TimeZone's ID.
     * @return    A reference to 'ID'
     * @stable ICU 2.0
     */
    UnicodeString& getID(UnicodeString& ID) const;

    /**
     * Sets the TimeZone's ID to the specified value.  This doesn't affect any other
     * fields (for example, if you say<
     * blockquote><pre>
     * .     TimeZone* foo = TimeZone::createTimeZone("America/New_York");
     * .     foo.setID("America/Los_Angeles");
     * </pre>\htmlonly</blockquote>\endhtmlonly
     * the time zone's GMT offset and daylight-savings rules don't change to those for
     * Los Angeles.  They're still those for New York.  Only the ID has changed.)
     *
     * @param ID  The new time zone ID.
     * @stable ICU 2.0
     */
    void setID(const UnicodeString& ID);

    /**
     * Enum for use with getDisplayName
     * @stable ICU 2.4
     */
    enum EDisplayType {
        /**
         * Selector for short display name
         * @stable ICU 2.4
         */
        SHORT = 1,
        /**
         * Selector for long display name
         * @stable ICU 2.4
         */
        LONG,
        /**
         * Selector for short generic display name
         * @stable ICU 4.4
         */
        SHORT_GENERIC,
        /**
         * Selector for long generic display name
         * @stable ICU 4.4
         */
        LONG_GENERIC,
        /**
         * Selector for short display name derived
         * from time zone offset
         * @stable ICU 4.4
         */
        SHORT_GMT,
        /**
         * Selector for long display name derived
         * from time zone offset
         * @stable ICU 4.4
         */
        LONG_GMT,
        /**
         * Selector for short display name derived
         * from the time zone's fallback name
         * @stable ICU 4.4
         */
        SHORT_COMMONLY_USED,
        /**
         * Selector for long display name derived
         * from the time zone's fallback name
         * @stable ICU 4.4
         */
        GENERIC_LOCATION
    };

    /**
     * Returns a name of this time zone suitable for presentation to the user
     * in the default locale.
     * This method returns the long name, not including daylight savings.
     * If the display name is not available for the locale,
     * then this method returns a string in the localized GMT offset format
     * such as <code>GMT[+-]HH:mm</code>.
     * @param result the human-readable name of this time zone in the default locale.
     * @return       A reference to 'result'.
     * @stable ICU 2.0
     */
    UnicodeString& getDisplayName(UnicodeString& result) const;

    /**
     * Returns a name of this time zone suitable for presentation to the user
     * in the specified locale.
     * This method returns the long name, not including daylight savings.
     * If the display name is not available for the locale,
     * then this method returns a string in the localized GMT offset format
     * such as <code>GMT[+-]HH:mm</code>.
     * @param locale the locale in which to supply the display name.
     * @param result the human-readable name of this time zone in the given locale
     *               or in the default locale if the given locale is not recognized.
     * @return       A reference to 'result'.
     * @stable ICU 2.0
     */
    UnicodeString& getDisplayName(const Locale& locale, UnicodeString& result) const;

    /**
     * Returns a name of this time zone suitable for presentation to the user
     * in the default locale.
     * If the display name is not available for the locale,
     * then this method returns a string in the localized GMT offset format
     * such as <code>GMT[+-]HH:mm</code>.
     * @param daylight if true, return the daylight savings name.
     * @param style
     * @param result the human-readable name of this time zone in the default locale.
     * @return       A reference to 'result'.
     * @stable ICU 2.0
     */
    UnicodeString& getDisplayName(UBool daylight, EDisplayType style, UnicodeString& result) const;

    /**
     * Returns a name of this time zone suitable for presentation to the user
     * in the specified locale.
     * If the display name is not available for the locale,
     * then this method returns a string in the localized GMT offset format
     * such as <code>GMT[+-]HH:mm</code>.
     * @param daylight if true, return the daylight savings name.
     * @param style
     * @param locale the locale in which to supply the display name.
     * @param result the human-readable name of this time zone in the given locale
     *               or in the default locale if the given locale is not recognized.
     * @return       A refence to 'result'.
     * @stable ICU 2.0
     */
    UnicodeString& getDisplayName(UBool daylight, EDisplayType style, const Locale& locale, UnicodeString& result) const;
    
    /**
     * Queries if this time zone uses daylight savings time.
     * @return true if this time zone uses daylight savings time,
     * false, otherwise.
     * <p><strong>Note:</strong>The default implementation of
     * ICU TimeZone uses the tz database, which supports historic
     * rule changes, for system time zones. With the implementation,
     * there are time zones that used daylight savings time in the
     * past, but no longer used currently. For example, Asia/Tokyo has
     * never used daylight savings time since 1951. Most clients would
     * expect that this method to return <code>FALSE</code> for such case.
     * The default implementation of this method returns <code>TRUE</code>
     * when the time zone uses daylight savings time in the current
     * (Gregorian) calendar year.
     * <p>In Java 7, <code>observesDaylightTime()</code> was added in
     * addition to <code>useDaylightTime()</code>. In Java, <code>useDaylightTime()</code>
     * only checks if daylight saving time is observed by the last known
     * rule. This specification might not be what most users would expect
     * if daylight saving time is currently observed, but not scheduled
     * in future. In this case, Java's <code>userDaylightTime()</code> returns
     * <code>false</code>. To resolve the issue, Java 7 added <code>observesDaylightTime()</code>,
     * which takes the current rule into account. The method <code>observesDaylightTime()</code>
     * was added in ICU4J for supporting API signature compatibility with JDK.
     * In general, ICU4C also provides JDK compatible methods, but the current
     * implementation <code>userDaylightTime()</code> serves the purpose
     * (takes the current rule into account), <code>observesDaylightTime()</code>
     * is not added in ICU4C. In addition to <code>useDaylightTime()</code>, ICU4C
     * <code>BasicTimeZone</code> class (Note that <code>TimeZone::createTimeZone(const UnicodeString &ID)</code>
     * always returns a <code>BasicTimeZone</code>) provides a series of methods allowing
     * historic and future time zone rule iteration, so you can check if daylight saving
     * time is observed or not within a given period.
     * 
     * @stable ICU 2.0
     */
    virtual UBool useDaylightTime(void) const = 0;

    /**
     * Queries if the given date is in daylight savings time in
     * this time zone.
     * This method is wasteful since it creates a new GregorianCalendar and
     * deletes it each time it is called. This is a deprecated method
     * and provided only for Java compatibility.
     *
     * @param date the given UDate.
     * @param status Output param filled in with success/error code.
     * @return true if the given date is in daylight savings time,
     * false, otherwise.
     * @deprecated ICU 2.4. Use Calendar::inDaylightTime() instead.
     */
    virtual UBool inDaylightTime(UDate date, UErrorCode& status) const = 0;

    /**
     * Returns true if this zone has the same rule and offset as another zone.
     * That is, if this zone differs only in ID, if at all.
     * @param other the <code>TimeZone</code> object to be compared with
     * @return true if the given zone is the same as this one,
     * with the possible exception of the ID
     * @stable ICU 2.0
     */
    virtual UBool hasSameRules(const TimeZone& other) const;

    /**
     * Clones TimeZone objects polymorphically. Clients are responsible for deleting
     * the TimeZone object cloned.
     *
     * @return   A new copy of this TimeZone object.
     * @stable ICU 2.0
     */
    virtual TimeZone* clone(void) const = 0;

    /**
     * Return the class ID for this class.  This is useful only for
     * comparing to a return value from getDynamicClassID().
     * @return The class ID for all objects of this class.
     * @stable ICU 2.0
     */
    static UClassID U_EXPORT2 getStaticClassID(void);

    /**
     * Returns a unique class ID POLYMORPHICALLY. This method is to
     * implement a simple version of RTTI, since not all C++ compilers support genuine
     * RTTI. Polymorphic operator==() and clone() methods call this method.
     * <P>
     * Concrete subclasses of TimeZone must use the UOBJECT_DEFINE_RTTI_IMPLEMENTATION
     *  macro from uobject.h in their implementation to provide correct RTTI information.
     * @return   The class ID for this object. All objects of a given class have the
     *           same class ID. Objects of other classes have different class IDs.
     * @stable ICU 2.0
     */
    virtual UClassID getDynamicClassID(void) const = 0;
    
    /**
     * Returns the amount of time to be added to local standard time
     * to get local wall clock time.
     * <p>
     * The default implementation always returns 3600000 milliseconds
     * (i.e., one hour) if this time zone observes Daylight Saving
     * Time. Otherwise, 0 (zero) is returned.
     * <p>
     * If an underlying TimeZone implementation subclass supports
     * historical Daylight Saving Time changes, this method returns
     * the known latest daylight saving value.
     *
     * @return the amount of saving time in milliseconds
     * @stable ICU 3.6
     */
    virtual int32_t getDSTSavings() const;

    /**
     * Gets the region code associated with the given
     * system time zone ID. The region code is either ISO 3166
     * 2-letter country code or UN M.49 3-digit area code.
     * When the time zone is not associated with a specific location,
     * for example - "Etc/UTC", "EST5EDT", then this method returns
     * "001" (UN M.49 area code for World).
     * 
     * @param id            The system time zone ID.
     * @param region        Output buffer for receiving the region code.
     * @param capacity      The size of the output buffer.
     * @param status        Receives the status.  When the given time zone ID
     *                      is not a known system time zone ID,
     *                      U_ILLEGAL_ARGUMENT_ERROR is set.
     * @return The length of the output region code.
     * @stable ICU 4.8 
     */ 
    static int32_t U_EXPORT2 getRegion(const UnicodeString& id, 
        char *region, int32_t capacity, UErrorCode& status); 

protected:

    /**
     * Default constructor.  ID is initialized to the empty string.
     * @stable ICU 2.0
     */
    TimeZone();

    /**
     * Construct a TimeZone with a given ID.
     * @param id a system time zone ID
     * @stable ICU 2.0
     */
    TimeZone(const UnicodeString &id);

    /**
     * Copy constructor.
     * @param source the object to be copied.
     * @stable ICU 2.0
     */
    TimeZone(const TimeZone& source);

    /**
     * Default assignment operator.
     * @param right the object to be copied.
     * @stable ICU 2.0
     */
    TimeZone& operator=(const TimeZone& right);

#ifndef U_HIDE_INTERNAL_API
    /**
     * Utility function. For internally loading rule data.
     * @param top Top resource bundle for tz data
     * @param ruleid ID of rule to load
     * @param oldbundle Old bundle to reuse or NULL
     * @param status Status parameter
     * @return either a new bundle or *oldbundle
     * @internal
     */
    static UResourceBundle* loadRule(const UResourceBundle* top, const UnicodeString& ruleid, UResourceBundle* oldbundle, UErrorCode&status);
#endif  /* U_HIDE_INTERNAL_API */

private:
    friend class ZoneMeta;


    static TimeZone*        createCustomTimeZone(const UnicodeString&); // Creates a time zone based on the string.

    /**
     * Finds the given ID in the Olson tzdata. If the given ID is found in the tzdata,
     * returns the pointer to the ID resource. This method is exposed through ZoneMeta class
     * for ICU internal implementation and useful for building hashtable using a time zone
     * ID as a key.
     * @param id zone id string
     * @return the pointer of the ID resource, or NULL.
     */
    static const UChar* findID(const UnicodeString& id);

    /**
     * Resolve a link in Olson tzdata.  When the given id is known and it's not a link,
     * the id itself is returned.  When the given id is known and it is a link, then
     * dereferenced zone id is returned.  When the given id is unknown, then it returns
     * NULL.
     * @param id zone id string
     * @return the dereferenced zone or NULL
     */
    static const UChar* dereferOlsonLink(const UnicodeString& id);

    /**
     * Returns the region code associated with the given zone,
     * or NULL if the zone is not known.
     * @param id zone id string
     * @return the region associated with the given zone
     */
    static const UChar* getRegion(const UnicodeString& id);

  public:
#ifndef U_HIDE_INTERNAL_API
    /**
     * Returns the region code associated with the given zone,
     * or NULL if the zone is not known.
     * @param id zone id string
     * @param status Status parameter
     * @return the region associated with the given zone
     * @internal
     */
    static const UChar* getRegion(const UnicodeString& id, UErrorCode& status);
#endif  /* U_HIDE_INTERNAL_API */

  private:
    /**
     * Parses the given custom time zone identifier
     * @param id id A string of the form GMT[+-]hh:mm, GMT[+-]hhmm, or
     * GMT[+-]hh.
     * @param sign Receves parsed sign, 1 for positive, -1 for negative.
     * @param hour Receives parsed hour field
     * @param minute Receives parsed minute field
     * @param second Receives parsed second field
     * @return Returns TRUE when the given custom id is valid.
     */
    static UBool parseCustomID(const UnicodeString& id, int32_t& sign, int32_t& hour,
        int32_t& minute, int32_t& second);

    /**
     * Parse a custom time zone identifier and return the normalized
     * custom time zone identifier for the given custom id string.
     * @param id a string of the form GMT[+-]hh:mm, GMT[+-]hhmm, or
     * GMT[+-]hh.
     * @param normalized Receives the normalized custom ID
     * @param status Receives the status.  When the input ID string is invalid,
     * U_ILLEGAL_ARGUMENT_ERROR is set.
     * @return The normalized custom id string.
    */
    static UnicodeString& getCustomID(const UnicodeString& id, UnicodeString& normalized,
        UErrorCode& status);

    /**
     * Returns the normalized custome time zone ID for the given offset fields.
     * @param hour offset hours
     * @param min offset minutes
     * @param sec offset seconds
     * @param negative sign of the offset, TRUE for negative offset.
     * @param id Receves the format result (normalized custom ID)
     * @return The reference to id
     */
    static UnicodeString& formatCustomID(int32_t hour, int32_t min, int32_t sec,
        UBool negative, UnicodeString& id);

    UnicodeString           fID;    // this time zone's ID

    friend class TZEnumeration;
};


// -------------------------------------

inline UnicodeString&
TimeZone::getID(UnicodeString& ID) const
{
    ID = fID;
    return ID;
}

// -------------------------------------

inline void
TimeZone::setID(const UnicodeString& ID)
{
    fID = ID;
}
U_NAMESPACE_END

#endif /* #if !UCONFIG_NO_FORMATTING */

#endif //_TIMEZONE
//eof