539 lines
22 KiB
C++
539 lines
22 KiB
C++
/*
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* Copyright © {1997-1999}, International Business Machines Corporation and others. All Rights Reserved.
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********************************************************************************
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*
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* File TIMEZONE.H
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*
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* Modification History:
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*
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* Date Name Description
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* 04/21/97 aliu Overhauled header.
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* 07/09/97 helena Changed createInstance to createDefault.
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* 08/06/97 aliu Removed dependency on internal header for Hashtable.
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* 08/10/98 stephen Changed getDisplayName() API conventions to match
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* 08/19/98 stephen Changed createTimeZone() to never return 0
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* 09/02/98 stephen Sync to JDK 1.2 8/31
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* - Added getOffset(... monthlen ...)
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* - Added hasSameRules()
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* 09/15/98 stephen Added getStaticClassID
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* 12/03/99 aliu Moved data out of static table into icudata.dll.
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* Hashtable replaced by new static data structures.
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* 12/14/99 aliu Made GMT public.
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********************************************************************************
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*/
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#ifndef TIMEZONE_H
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#define TIMEZONE_H
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#include "unicode/unistr.h"
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#include "unicode/locid.h"
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#include "unicode/udata.h"
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class SimpleTimeZone;
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struct TZHeader;
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struct OffsetIndex;
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/**
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* <code>TimeZone</code> represents a time zone offset, and also figures out daylight
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* savings.
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*
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* <p>
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* Typically, you get a <code>TimeZone</code> using <code>createDefault</code>
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* which creates a <code>TimeZone</code> based on the time zone where the program
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* is running. For example, for a program running in Japan, <code>createDefault</code>
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* creates a <code>TimeZone</code> object based on Japanese Standard Time.
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*
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* <p>
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* You can also get a <code>TimeZone</code> using <code>createTimeZone</code> along
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* with a time zone ID. For instance, the time zone ID for the Pacific
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* Standard Time zone is "PST". So, you can get a PST <code>TimeZone</code> object
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* with:
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* <blockquote>
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* <pre>
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* TimeZone *tz = TimeZone::createTimeZone("PST");
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* </pre>
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* </blockquote>
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* You can use <code>getAvailableIDs</code> method to iterate through
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* all the supported time zone IDs. You can then choose a
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* supported ID to get a <code>TimeZone</code>.
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* If the time zone you want is not represented by one of the
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* supported IDs, then you can create a custom time zone ID with
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* the following syntax:
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*
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* <blockquote>
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* <pre>
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* GMT[+|-]hh[[:]mm]
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* </pre>
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* </blockquote>
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*
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* For example, you might specify GMT+14:00 as a custom
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* time zone ID. The <code>TimeZone</code> that is returned
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* when you specify a custom time zone ID does not include
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* daylight savings time.
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*
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* TimeZone is an abstract class representing a time zone. A TimeZone is needed for
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* Calendar to produce local time for a particular time zone. A TimeZone comprises
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* three basic pieces of information:<ul>
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* <li>A time zone offset; that, is the number of milliseconds to add or subtract
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* from a time expressed in terms of GMT to convert it to the same time in that
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* time zone (without taking daylight savings time into account).
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* <li>Logic necessary to take daylight savings time into account if daylight savings
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* time is observed in that time zone (e.g., the days and hours on which daylight
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* savings time begins and ends).
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* <li>An ID. This is a text string that uniquely identifies the time zone.</ul>
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*
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* (Only the ID is actually implemented in TimeZone; subclasses of TimeZone may handle
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* daylight savings time and GMT offset in different ways. Currently we only have one
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* TimeZone subclass: SimpleTimeZone.)
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* <P>
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* The TimeZone class contains a static list containing a TimeZone object for every
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* combination of GMT offset and daylight-savings time rules currently in use in the
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* world, each with a unique ID. Each ID consists of a region (usually a continent or
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* ocean) and a city in that region, separated by a slash, (for example, Pacific
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* Standard Time is "America/Los_Angeles.") Because older versions of this class used
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* three- or four-letter abbreviations instead, there is also a table that maps the older
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* abbreviations to the newer ones (for example, "PST" maps to "America/LosAngeles").
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* Anywhere the API requires an ID, you can use either form.
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* <P>
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* To create a new TimeZone, you call the factory function TimeZone::createTimeZone()
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* and pass it a time zone ID. You can use the createAvailableIDs() function to
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* obtain a list of all the time zone IDs recognized by createTimeZone().
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* <P>
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* You can also use TimeZone::createDefault() to create a TimeZone. This function uses
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* platform-specific APIs to produce a TimeZone for the time zone corresponding to
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* the client's computer's physical location. For example, if you're in Japan (assuming
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* your machine is set up correctly), TimeZone::createDefault() will return a TimeZone
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* for Japanese Standard Time ("Asia/Tokyo").
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*/
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class U_I18N_API TimeZone {
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public:
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virtual ~TimeZone();
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/**
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* The GMT zone has a raw offset of zero and does not use daylight
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* savings time.
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*/
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static const TimeZone* GMT;
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/**
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* Creates a <code>TimeZone</code> for the given ID.
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* @param ID the ID for a <code>TimeZone</code>, either an abbreviation such as
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* "PST", a full name such as "America/Los_Angeles", or a custom ID
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* such as "GMT-8:00".
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* @return the specified <code>TimeZone</code>, or the GMT zone if the given ID
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* cannot be understood. Return result guaranteed to be non-null. If you
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* require that the specific zone asked for be returned, check the ID of the
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* return result.
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*/
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static TimeZone* createTimeZone(const UnicodeString& ID);
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/**
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* Returns a list of time zone IDs, one for each time zone with a given GMT offset.
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* The return value is a list because there may be several times zones with the same
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* GMT offset that differ in the way they handle daylight savings time. For example,
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* the state of Arizona doesn't observe Daylight Savings time. So if you ask for
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* the time zone IDs corresponding to GMT-7:00, you'll get back two time zone IDs:
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* "America/Denver," which corresponds to Mountain Standard Time in the winter and
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* Mountain Daylight Time in the summer, and "America/Phoenix", which corresponds to
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* Mountain Standard Time year-round, even in the summer.
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* <P>
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* The caller owns the list that is returned, but does not own the strings contained
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* in that list. Delete the array, but DON'T delete the elements in the array.
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*
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* @param rawOffset An offset from GMT in milliseconds.
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* @param numIDs Receives the number of items in the array that is returned.
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* @return An array of UnicodeString pointers, where each UnicodeString is
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* a time zone ID for a time zone with the given GMT offset. If
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* there is no timezone that matches the GMT offset
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* specified, NULL is returned.
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*/
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static const UnicodeString** const createAvailableIDs(int32_t rawOffset, int32_t& numIDs);
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/**
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* Returns a list of all time zone IDs supported by the TimeZone class (i.e., all
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* IDs that it's legal to pass to createTimeZone()). The caller owns the list that
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* is returned, but does not own the strings contained in that list. Delete the array,
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* but DON'T delete the elements in the array.
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*
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* @param numIDs Receives the number of zone IDs returned.
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* @return An array of UnicodeString pointers, where each is a time zone ID
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* supported by the TimeZone class.
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*/
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static const UnicodeString** const createAvailableIDs(int32_t& numIDs);
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/**
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* Creates a new copy of the default TimeZone for this host. Unless the default time
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* zone has already been set using adoptDefault() or setDefault(), the default is
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* determined by querying the system using methods in TPlatformUtilities. If the
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* system routines fail, or if they specify a TimeZone or TimeZone offset which is not
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* recognized, the TimeZone indicated by the ID kLastResortID is instantiated
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* and made the default.
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*
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* @return A default TimeZone. Clients are responsible for deleting the time zone
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* object returned.
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*/
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static TimeZone* createDefault(void);
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/**
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* Sets the default time zone (i.e., what's returned by getDefault()) to be the
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* specified time zone. If NULL is specified for the time zone, the default time
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* zone is set to the default host time zone. This call adopts the TimeZone object
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* passed in; the clent is no longer responsible for deleting it.
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*
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* @param zone A pointer to the new TimeZone object to use as the default.
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*/
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static void adoptDefault(TimeZone* zone);
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/**
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* Same as adoptDefault(), except that the TimeZone object passed in is NOT adopted;
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* the caller remains responsible for deleting it.
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*
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* @param zone The given timezone.
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*/
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static void setDefault(const TimeZone& zone);
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/**
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* Returns true if the two TimeZones are equal. (The TimeZone version only compares
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* IDs, but subclasses are expected to also compare the fields they add.)
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*
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* @param that The TimeZone object to be compared with.
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* @return True if the given TimeZone is equal to this TimeZone; false
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* otherwise.
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*/
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virtual bool_t operator==(const TimeZone& that) const;
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/**
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* Returns true if the two TimeZones are NOT equal; that is, if operator==() returns
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* false.
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*
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* @param that The TimeZone object to be compared with.
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* @return True if the given TimeZone is not equal to this TimeZone; false
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* otherwise.
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*/
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bool_t operator!=(const TimeZone& that) const {return !operator==(that);}
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/**
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* Returns the TimeZone's adjusted GMT offset (i.e., the number of milliseconds to add
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* to GMT to get local time in this time zone, taking daylight savings time into
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* account) as of a particular reference date. The reference date is used to determine
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* whether daylight savings time is in effect and needs to be figured into the offset
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* that is returned (in other words, what is the adjusted GMT offset in this time zone
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* at this particular date and time?). For the time zones produced by createTimeZone(),
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* the reference data is specified according to the Gregorian calendar, and the date
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* and time fields are in GMT, NOT local time.
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*
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* @param era The reference date's era
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* @param year The reference date's year
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* @param month The reference date's month (0-based; 0 is January)
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* @param day The reference date's day-in-month (1-based)
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* @param dayOfWeek The reference date's day-of-week (1-based; 1 is Sunday)
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* @param millis The reference date's milliseconds in day, UTT (NOT local time).
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* @return The offset in milliseconds to add to GMT to get local time.
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*/
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virtual int32_t getOffset(uint8_t era, int32_t year, int32_t month, int32_t day,
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uint8_t dayOfWeek, int32_t millis, UErrorCode& status) const = 0;
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// deprecated version
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virtual int32_t getOffset(uint8_t era, int32_t year, int32_t month, int32_t day,
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uint8_t dayOfWeek, int32_t millis) const = 0;
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/**
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* Gets the time zone offset, for current date, modified in case of
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* daylight savings. This is the offset to add *to* UTC to get local time.
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* @param era the era of the given date.
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* @param year the year in the given date.
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* @param month the month in the given date.
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* Month is 0-based. e.g., 0 for January.
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* @param day the day-in-month of the given date.
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* @param dayOfWeek the day-of-week of the given date.
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* @param milliseconds the millis in day in <em>standard</em> local time.
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* @param monthLength the length of the given month in days.
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* @return the offset to add *to* GMT to get local time.
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*/
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virtual int32_t getOffset(uint8_t era, int32_t year, int32_t month, int32_t day,
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uint8_t dayOfWeek, int32_t milliseconds,
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int32_t monthLength, UErrorCode& status) const = 0;
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/**
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* Sets the TimeZone's raw GMT offset (i.e., the number of milliseconds to add
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* to GMT to get local time, before taking daylight savings time into account).
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*
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* @param offsetMillis The new raw GMT offset for this time zone.
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*/
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virtual void setRawOffset(int32_t offsetMillis) = 0;
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/**
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* Returns the TimeZone's raw GMT offset (i.e., the number of milliseconds to add
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* to GMT to get local time, before taking daylight savings time into account).
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*
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* @return The TimeZone's raw GMT offset.
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*/
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virtual int32_t getRawOffset(void) const = 0;
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/**
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* Fills in "ID" with the TimeZone's ID.
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*
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* @param ID Receives this TimeZone's ID.
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* @return "ID"
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*/
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UnicodeString& getID(UnicodeString& ID) const;
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/**
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* Sets the TimeZone's ID to the specified value. This doesn't affect any other
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* fields (for example, if you say<
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* blockquote><pre>
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* . TimeZone* foo = TimeZone::createTimeZone("America/New_York");
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* . foo.setID("America/Los_Angeles");
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* </pre></blockquote>
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* the time zone's GMT offset and daylight-savings rules don't change to those for
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* Los Angeles. They're still those for New York. Only the ID has changed.)
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*
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* @param ID The new timezone ID.
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*/
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void setID(const UnicodeString& ID);
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/**
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* Enum for use with getDisplayName
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*/
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enum EDisplayType {
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SHORT = 1,
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LONG
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};
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/**
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* Returns a name of this time zone suitable for presentation to the user
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* in the default locale.
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* This method returns the long name, not including daylight savings.
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* If the display name is not available for the locale,
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* then this method returns a string in the format
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* <code>GMT[+-]hh:mm</code>.
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* @return the human-readable name of this time zone in the default locale.
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*/
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UnicodeString& getDisplayName(UnicodeString& result) const;
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/**
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* Returns a name of this time zone suitable for presentation to the user
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* in the specified locale.
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* This method returns the long name, not including daylight savings.
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* If the display name is not available for the locale,
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* then this method returns a string in the format
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* <code>GMT[+-]hh:mm</code>.
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* @param locale the locale in which to supply the display name.
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* @return the human-readable name of this time zone in the given locale
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* or in the default locale if the given locale is not recognized.
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*/
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UnicodeString& getDisplayName(const Locale& locale, UnicodeString& result) const;
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/**
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* Returns a name of this time zone suitable for presentation to the user
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* in the default locale.
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* If the display name is not available for the locale,
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* then this method returns a string in the format
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* <code>GMT[+-]hh:mm</code>.
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* @param daylight if true, return the daylight savings name.
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* @param style either <code>LONG</code> or <code>SHORT</code>
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* @return the human-readable name of this time zone in the default locale.
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*/
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UnicodeString& getDisplayName(bool_t daylight, EDisplayType style, UnicodeString& result) const;
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/**
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* Returns a name of this time zone suitable for presentation to the user
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* in the specified locale.
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* If the display name is not available for the locale,
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* then this method returns a string in the format
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* <code>GMT[+-]hh:mm</code>.
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* @param daylight if true, return the daylight savings name.
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* @param style either <code>LONG</code> or <code>SHORT</code>
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* @param locale the locale in which to supply the display name.
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* @return the human-readable name of this time zone in the given locale
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* or in the default locale if the given locale is not recognized.
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*/
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UnicodeString& getDisplayName(bool_t daylight, EDisplayType style, const Locale& locale, UnicodeString& result) const;
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/**
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* Queries if this time zone uses daylight savings time.
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* @return true if this time zone uses daylight savings time,
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* false, otherwise.
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*/
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virtual bool_t useDaylightTime(void) const = 0;
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/**
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* Queries if the given date is in daylight savings time in
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* this time zone.
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* @param date the given UDate.
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* @return true if the given date is in daylight savings time,
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* false, otherwise.
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*/
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virtual bool_t inDaylightTime(UDate date, UErrorCode& status) const = 0;
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/**
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* Returns true if this zone has the same rule and offset as another zone.
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* That is, if this zone differs only in ID, if at all.
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* @param other the <code>TimeZone</code> object to be compared with
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* @return true if the given zone is the same as this one,
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* with the possible exception of the ID
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*/
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virtual bool_t hasSameRules(const TimeZone& other) const;
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/**
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* Clones TimeZone objects polymorphically. Clients are responsible for deleting
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* the TimeZone object cloned.
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*
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* @return A new copy of this TimeZone object.
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*/
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virtual TimeZone* clone(void) const = 0;
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/**
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* Return the class ID for this class. This is useful only for
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* comparing to a return value from getDynamicClassID(). For example:
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* <pre>
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* . Base* polymorphic_pointer = createPolymorphicObject();
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* . if (polymorphic_pointer->getDynamicClassID() ==
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* . Derived::getStaticClassID()) ...
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* </pre>
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* @return The class ID for all objects of this class.
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*/
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static UClassID getStaticClassID(void) { return (UClassID)&fgClassID; }
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/**
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* Returns a unique class ID POLYMORPHICALLY. Pure virtual method. This method is to
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* implement a simple version of RTTI, since not all C++ compilers support genuine
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* RTTI. Polymorphic operator==() and clone() methods call this method.
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* <P>
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* Concrete subclasses of TimeZone must implement getDynamicClassID() and also a
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* static method and data member:
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* <pre>
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* . static UClassID getStaticClassID() { return (UClassID)&fgClassID; }
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* . static char fgClassID;
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* </pre>
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* @return The class ID for this object. All objects of a given class have the
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* same class ID. Objects of other classes have different class IDs.
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*/
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virtual UClassID getDynamicClassID(void) const = 0;
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protected:
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/**
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* Default constructor. ID is initialized to the empty string.
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*/
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TimeZone();
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/**
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* Copy constructor.
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*/
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TimeZone(const TimeZone& source);
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/**
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* Default assignment operator.
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*/
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TimeZone& operator=(const TimeZone& right);
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private:
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static char fgClassID;
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static TimeZone* createCustomTimeZone(const UnicodeString&); // Creates a time zone based on the string.
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static TimeZone* fgDefaultZone; // default time zone (lazy evaluated)
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static const UnicodeString GMT_ID;
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static const int32_t GMT_ID_LENGTH;
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static const UnicodeString CUSTOM_ID;
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////////////////////////////////////////////////////////////////
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// Pointers into memory-mapped icudata. Writing to this memory
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// will segfault! See tzdat.h for more details.
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////////////////////////////////////////////////////////////////
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/**
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* DATA is the start of the memory-mapped zone data, and
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* specifically points to the header object located there.
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* May be zero if loading failed for some reason.
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*/
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static const TZHeader * DATA;
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/**
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* INDEX_BY_ID is an index table in lexicographic order of ID.
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* Each entry is an offset from DATA to the zone object, which
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* will either be a StandardZone or a DSTZone object.
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*/
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static const uint32_t* INDEX_BY_ID;
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/**
|
|
* INDEX_BY_OFFSET is an OffsetIndex table. This table can only
|
|
* be walked through sequentially because the entries are of
|
|
* variable size.
|
|
*/
|
|
static const OffsetIndex* INDEX_BY_OFFSET;
|
|
|
|
////////////////////////////////////////////////////////////////
|
|
// Other system zone data structures
|
|
////////////////////////////////////////////////////////////////
|
|
/**
|
|
* ZONE_IDS is an array of all the system zone ID strings, in
|
|
* lexicographic order. The createAvailableIDs() methods return
|
|
* arrays of pointers into this array.
|
|
*/
|
|
static UnicodeString* ZONE_IDS;
|
|
|
|
/**
|
|
* If DATA_LOADED is true, then an attempt has already been made
|
|
* to load the system zone data, and further attempts will not be
|
|
* made. If DATA_LOADED is true, DATA itself will be zero if
|
|
* loading failed, or non-zero if it succeeded.
|
|
*/
|
|
static bool_t DATA_LOADED;
|
|
|
|
/**
|
|
* The mutex object used to control write access to DATA,
|
|
* INDEX_BY_ID, INDEX_BY_OFFSET, and ZONE_IDS. Also used to
|
|
* control read/write access to fgDefaultZone.
|
|
*/
|
|
static UMTX LOCK;
|
|
|
|
/**
|
|
* Responsible for setting up fgDefaultZone. Uses routines in TPlatformUtilities
|
|
* (i.e., platform-specific calls) to get the current system time zone. Failing
|
|
* that, uses the platform-specific default time zone. Failing that, uses GMT.
|
|
*/
|
|
static void initDefault(void);
|
|
|
|
// See source file for documentation
|
|
static void loadZoneData(void);
|
|
|
|
// See source file for documentation
|
|
static bool_t isDataAcceptable(void *context,
|
|
const char *type, const char *name,
|
|
UDataInfo *pInfo);
|
|
|
|
// See source file for documentation
|
|
static TimeZone* createSystemTimeZone(const UnicodeString& name);
|
|
|
|
UnicodeString fID; // this time zone's ID
|
|
};
|
|
|
|
|
|
// -------------------------------------
|
|
|
|
inline UnicodeString&
|
|
TimeZone::getID(UnicodeString& ID) const
|
|
{
|
|
ID = fID;
|
|
return ID;
|
|
}
|
|
|
|
// -------------------------------------
|
|
|
|
inline void
|
|
TimeZone::setID(const UnicodeString& ID)
|
|
{
|
|
fID = ID;
|
|
}
|
|
|
|
#endif //_TIMEZONE
|
|
//eof
|