BasicTimeZone is an abstract class extending TimeZone. More...

#include <basictz.h>

Inheritance diagram for icu::BasicTimeZone:

Public Types
enum	{ kStandard = 0x01 , kDaylight = 0x03 , kFormer = 0x04 , kLatter = 0x0C }
	The time type option bit flags used by getOffsetFromLocal. More...

Public Types inherited from icu::TimeZone
enum	EDisplayType { SHORT = 1 , LONG , SHORT_GENERIC , LONG_GENERIC , SHORT_GMT , LONG_GMT , SHORT_COMMONLY_USED , GENERIC_LOCATION }
	Enum for use with getDisplayName. More...

Public Member Functions
virtual	~BasicTimeZone ()
	Destructor.

virtual BasicTimeZone *	clone () const override=0
	Clones this object polymorphically.

virtual UBool	getNextTransition (UDate base, UBool inclusive, TimeZoneTransition &result) const =0
	Gets the first time zone transition after the base time.

virtual UBool	getPreviousTransition (UDate base, UBool inclusive, TimeZoneTransition &result) const =0
	Gets the most recent time zone transition before the base time.

virtual UBool	hasEquivalentTransitions (const BasicTimeZone &tz, UDate start, UDate end, UBool ignoreDstAmount, UErrorCode &ec) const
	Checks if the time zone has equivalent transitions in the time range.

virtual int32_t	countTransitionRules (UErrorCode &status) const =0
	Returns the number of `TimeZoneRule`s which represents time transitions, for this time zone, that is, all `TimeZoneRule`s for this time zone except `InitialTimeZoneRule`.

virtual void	getTimeZoneRules (const InitialTimeZoneRule &initial, const TimeZoneRule trsrules[], int32_t &trscount, UErrorCode &status) const =0
	Gets the `InitialTimeZoneRule` and the set of `TimeZoneRule` which represent time transitions for this time zone.

virtual void	getSimpleRulesNear (UDate date, InitialTimeZoneRule &initial, AnnualTimeZoneRule &std, AnnualTimeZoneRule *&dst, UErrorCode &status) const
	Gets the set of time zone rules valid at the specified time.

virtual void	getOffsetFromLocal (UDate date, UTimeZoneLocalOption nonExistingTimeOpt, UTimeZoneLocalOption duplicatedTimeOpt, int32_t &rawOffset, int32_t &dstOffset, UErrorCode &status) const
	Get time zone offsets from local wall time.

void	getOffsetFromLocal (UDate date, int32_t nonExistingTimeOpt, int32_t duplicatedTimeOpt, int32_t &rawOffset, int32_t &dstOffset, UErrorCode &status) const
	Get time zone offsets from local wall time.

Public Member Functions inherited from icu::TimeZone
virtual	~TimeZone ()

virtual bool	operator== (const TimeZone &that) const
	Returns true if the two TimeZones are equal.

bool	operator!= (const TimeZone &that) const
	Returns true if the two TimeZones are NOT equal; that is, if operator==() returns false.

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
	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.

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
	Gets the time zone offset, for current date, modified in case of daylight savings.

virtual void	getOffset (UDate date, UBool local, int32_t &rawOffset, int32_t &dstOffset, UErrorCode &ec) const
	Returns the time zone raw and GMT offset for the given moment in time.

virtual void	setRawOffset (int32_t offsetMillis)=0
	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).

virtual int32_t	getRawOffset () const =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).

UnicodeString &	getID (UnicodeString &ID) const
	Fills in "ID" with the TimeZone's ID.

void	setID (const UnicodeString &ID)
	Sets the TimeZone's ID to the specified value.

UnicodeString &	getDisplayName (UnicodeString &result) const
	Returns a name of this time zone suitable for presentation to the user in the default locale.

UnicodeString &	getDisplayName (const Locale &locale, UnicodeString &result) const
	Returns a name of this time zone suitable for presentation to the user in the specified locale.

UnicodeString &	getDisplayName (UBool inDaylight, EDisplayType style, UnicodeString &result) const
	Returns a name of this time zone suitable for presentation to the user in the default locale.

UnicodeString &	getDisplayName (UBool inDaylight, EDisplayType style, const Locale &locale, UnicodeString &result) const
	Returns a name of this time zone suitable for presentation to the user in the specified locale.

virtual UBool	useDaylightTime () const =0
	Queries if this time zone uses daylight savings time.

virtual UBool	inDaylightTime (UDate date, UErrorCode &status) const =0
	Queries if the given date is in daylight savings time in this time zone.

virtual UBool	hasSameRules (const TimeZone &other) const
	Returns true if this zone has the same rule and offset as another zone.

virtual UClassID	getDynamicClassID () const override=0
	Returns a unique class ID POLYMORPHICALLY.

virtual int32_t	getDSTSavings () const
	Returns the amount of time to be added to local standard time to get local wall clock time.

Public Member Functions inherited from icu::UObject
virtual	~UObject ()
	Destructor.

Protected Member Functions
	BasicTimeZone ()
	Default constructor.

	BasicTimeZone (const UnicodeString &id)
	Construct a timezone with a given ID.

	BasicTimeZone (const BasicTimeZone &source)
	Copy constructor.

BasicTimeZone &	operator= (const BasicTimeZone &)=default
	Copy assignment.

void	getTimeZoneRulesAfter (UDate start, InitialTimeZoneRule &initial, UVector &transitionRules, UErrorCode &status) const
	Gets the set of TimeZoneRule instances applicable to the specified time and after.

Protected Member Functions inherited from icu::TimeZone
	TimeZone ()
	Default constructor.

	TimeZone (const UnicodeString &id)
	Construct a TimeZone with a given ID.

	TimeZone (const TimeZone &source)
	Copy constructor.

TimeZone &	operator= (const TimeZone &right)
	Default assignment operator.

Static Protected Attributes
static constexpr int32_t	kStdDstMask = kDaylight
	A time type option bit mask used by getOffsetFromLocal.

static constexpr int32_t	kFormerLatterMask = kLatter
	A time type option bit mask used by getOffsetFromLocal.

Additional Inherited Members
Static Public Member Functions inherited from icu::TimeZone
static const TimeZone &	getUnknown ()
	Returns the "unknown" time zone.

static const TimeZone *	getGMT ()
	The GMT (=UTC) time zone has a raw offset of zero and does not use daylight savings time.

static TimeZone *	createTimeZone (const UnicodeString &ID)
	Creates a `TimeZone` for the given ID.

static StringEnumeration *	createTimeZoneIDEnumeration (USystemTimeZoneType zoneType, const char region, const int32_t rawOffset, UErrorCode &ec)
	Returns an enumeration over system time zone IDs with the given filter conditions.

static StringEnumeration *	createEnumeration ()
	Returns an enumeration over all recognized time zone IDs.

static StringEnumeration *	createEnumeration (UErrorCode &status)
	Returns an enumeration over all recognized time zone IDs.

static StringEnumeration *	createEnumeration (int32_t rawOffset)
	Returns an enumeration over time zone IDs with a given raw offset from GMT.

static StringEnumeration *	createEnumerationForRawOffset (int32_t rawOffset, UErrorCode &status)
	Returns an enumeration over time zone IDs with a given raw offset from GMT.

static StringEnumeration *	createEnumeration (const char *region)
	Returns an enumeration over time zone IDs associated with the given region.

static StringEnumeration *	createEnumerationForRegion (const char *region, UErrorCode &status)
	Returns an enumeration over time zone IDs associated with the given region.

static int32_t	countEquivalentIDs (const UnicodeString &id)
	Returns the number of IDs in the equivalency group that includes the given ID.

static const UnicodeString	getEquivalentID (const UnicodeString &id, int32_t index)
	Returns an ID in the equivalency group that includes the given ID.

static TimeZone *	detectHostTimeZone ()
	Creates an instance of TimeZone detected from the current host system configuration.

static TimeZone *	createDefault ()
	Creates a new copy of the default TimeZone for this host.

static TimeZone *	forLocaleOrDefault (const Locale &locale)
	If the locale contains the timezone keyword, creates a copy of that TimeZone.

static void	adoptDefault (TimeZone *zone)
	Sets the default time zone (i.e., what's returned by createDefault()) to be the specified time zone.

static void	setDefault (const TimeZone &zone)
	Same as adoptDefault(), except that the TimeZone object passed in is NOT adopted; the caller remains responsible for deleting it.

static const char *	getTZDataVersion (UErrorCode &status)
	Returns the timezone data version currently used by ICU.

static UnicodeString &	getCanonicalID (const UnicodeString &id, UnicodeString &canonicalID, UErrorCode &status)
	Returns the canonical system timezone ID or the normalized custom time zone ID for the given time zone ID.

static UnicodeString &	getCanonicalID (const UnicodeString &id, UnicodeString &canonicalID, UBool &isSystemID, UErrorCode &status)
	Returns the canonical system time zone ID or the normalized custom time zone ID for the given time zone ID.

static UnicodeString &	getIanaID (const UnicodeString &id, UnicodeString &ianaID, UErrorCode &status)
	Returns the preferred time zone ID in the IANA time zone database for the given time zone ID.

static UnicodeString &	getWindowsID (const UnicodeString &id, UnicodeString &winid, UErrorCode &status)
	Converts a system time zone ID to an equivalent Windows time zone ID.

static UnicodeString &	getIDForWindowsID (const UnicodeString &winid, const char *region, UnicodeString &id, UErrorCode &status)
	Converts a Windows time zone ID to an equivalent system time zone ID for a region.

static UClassID	getStaticClassID ()
	Return the class ID for this class.

static int32_t	getRegion (const UnicodeString &id, char *region, int32_t capacity, UErrorCode &status)
	Gets the region code associated with the given system time zone ID.

static const char16_t *	getRegion (const UnicodeString &id, UErrorCode &status)
	Returns the region code associated with the given zone, or nullptr if the zone is not known.

Static Protected Member Functions inherited from icu::TimeZone
static UResourceBundle *	loadRule (const UResourceBundle top, const UnicodeString &ruleid, UResourceBundle oldbundle, UErrorCode &status)
	Utility function.

Detailed Description

BasicTimeZone is an abstract class extending TimeZone.

This class provides some additional methods to access time zone transitions and rules. All ICU TimeZone concrete subclasses extend this class.

Stable:: ICU 3.8

Definition at line 38 of file basictz.h.

Member Enumeration Documentation

◆ anonymous enum

anonymous enum

The time type option bit flags used by getOffsetFromLocal.

Internal:: Do not use. This API is for internal use only.

Definition at line 170 of file basictz.h.

Constructor & Destructor Documentation

◆ ~BasicTimeZone()

virtual icu::BasicTimeZone::~BasicTimeZone ( )

virtual

Destructor.

Stable:: ICU 3.8

◆ BasicTimeZone() [1/3]

icu::BasicTimeZone::BasicTimeZone ( )

protected

Default constructor.

Stable:: ICU 3.8

◆ BasicTimeZone() [2/3]

icu::BasicTimeZone::BasicTimeZone ( const UnicodeString & id )

protected

Construct a timezone with a given ID.

Parameters

id	a system time zone ID

Stable:: ICU 3.8

◆ BasicTimeZone() [3/3]

icu::BasicTimeZone::BasicTimeZone ( const BasicTimeZone & source )

protected

Copy constructor.

Parameters

source the object to be copied.

Stable:: ICU 3.8

Member Function Documentation

◆ clone()

virtual BasicTimeZone * icu::BasicTimeZone::clone ( ) const

overridepure virtual

Clones this object polymorphically.

The caller owns the result and should delete it when done.

Returns: clone, or nullptr if an error occurred

Stable:: ICU 3.8

Implements icu::TimeZone.

Implemented in icu::RuleBasedTimeZone, icu::SimpleTimeZone, and icu::VTimeZone.

◆ countTransitionRules()

virtual int32_t icu::BasicTimeZone::countTransitionRules ( UErrorCode & status ) const

pure virtual

Returns the number of TimeZoneRules which represents time transitions, for this time zone, that is, all TimeZoneRules for this time zone except InitialTimeZoneRule.

The return value range is 0 or any positive value.

Parameters

status Receives error status code.

Returns: The number of TimeZoneRules representing time transitions.

Stable:: ICU 3.8

Implemented in icu::RuleBasedTimeZone, icu::SimpleTimeZone, and icu::VTimeZone.

◆ getNextTransition()

virtual UBool icu::BasicTimeZone::getNextTransition	(	UDate	base,
		UBool	inclusive,
		TimeZoneTransition &	result
	)		const

pure virtual

Gets the first time zone transition after the base time.

Parameters

base	The base time.
inclusive	Whether the base time is inclusive or not.
result	Receives the first transition after the base time.

Returns: true if the transition is found.

Stable:: ICU 3.8

Implemented in icu::RuleBasedTimeZone, icu::SimpleTimeZone, and icu::VTimeZone.

◆ getOffsetFromLocal() [1/2]

void icu::BasicTimeZone::getOffsetFromLocal	(	UDate	date,
		int32_t	nonExistingTimeOpt,
		int32_t	duplicatedTimeOpt,
		int32_t &	rawOffset,
		int32_t &	dstOffset,
		UErrorCode &	status
	)		const

Get time zone offsets from local wall time.

Internal:: Do not use. This API is for internal use only.

◆ getOffsetFromLocal() [2/2]

virtual void icu::BasicTimeZone::getOffsetFromLocal	(	UDate	date,
		UTimeZoneLocalOption	nonExistingTimeOpt,
		UTimeZoneLocalOption	duplicatedTimeOpt,
		int32_t &	rawOffset,
		int32_t &	dstOffset,
		UErrorCode &	status
	)		const

virtual

Get time zone offsets from local wall time.

Stable:: ICU 69

Reimplemented in icu::RuleBasedTimeZone, icu::SimpleTimeZone, and icu::VTimeZone.

◆ getPreviousTransition()

virtual UBool icu::BasicTimeZone::getPreviousTransition	(	UDate	base,
		UBool	inclusive,
		TimeZoneTransition &	result
	)		const

pure virtual

Gets the most recent time zone transition before the base time.

Parameters

base	The base time.
inclusive	Whether the base time is inclusive or not.
result	Receives the most recent transition before the base time.

Returns: true if the transition is found.

Stable:: ICU 3.8

Implemented in icu::RuleBasedTimeZone, icu::SimpleTimeZone, and icu::VTimeZone.

◆ getSimpleRulesNear()

virtual void icu::BasicTimeZone::getSimpleRulesNear	(	UDate	date,
		InitialTimeZoneRule *&	initial,
		AnnualTimeZoneRule *&	std,
		AnnualTimeZoneRule *&	dst,
		UErrorCode &	status
	)		const

virtual

Gets the set of time zone rules valid at the specified time.

Some known external time zone implementations are not capable to handle historic time zone rule changes. Also some implementations can only handle certain type of rule definitions. If this time zone does not use any daylight saving time within about 1 year from the specified time, only the InitialTimeZone is returned. Otherwise, the rule for standard time and daylight saving time transitions are returned in addition to the InitialTimeZoneRule. The standard and daylight saving time transition rules are represented by AnnualTimeZoneRule with DateTimeRule::DOW for its date rule and DateTimeRule::WALL_TIME for its time rule. Because daylight saving time rule is changing time to time in many time zones and also mapping a transition time rule to different type is lossy transformation, the set of rules returned by this method may be valid for short period of time. The time zone rule objects returned by this method is owned by the caller, so the caller is responsible for deleting them after use.

Parameters

date	The date used for extracting time zone rules.
initial	Receives the `InitialTimeZone`, always not nullptr.
std	Receives the `AnnualTimeZoneRule` for standard time transitions. When this time time zone does not observe daylight saving times around the specified date, nullptr is set.
dst	Receives the `AnnualTimeZoneRule` for daylight saving time transitions. When this time zone does not observer daylight saving times around the specified date, nullptr is set.
status	Receives error status code.

Stable:: ICU 3.8

◆ getTimeZoneRules()

virtual void icu::BasicTimeZone::getTimeZoneRules	(	const InitialTimeZoneRule *&	initial,
		const TimeZoneRule *	trsrules[],
		int32_t &	trscount,
		UErrorCode &	status
	)		const

pure virtual

Gets the InitialTimeZoneRule and the set of TimeZoneRule which represent time transitions for this time zone.

On successful return, the argument initial points to non-nullptr InitialTimeZoneRule and the array trsrules is filled with 0 or multiple TimeZoneRule instances up to the size specified by trscount. The results are referencing the rule instance held by this time zone instance. Therefore, after this time zone is destructed, they are no longer available.

Parameters

initial	Receives the initial timezone rule
trsrules	Receives the timezone transition rules
trscount	On input, specify the size of the array 'transitions' receiving the timezone transition rules. On output, actual number of rules filled in the array will be set.
status	Receives error status code.

Stable:: ICU 3.8

Implemented in icu::RuleBasedTimeZone, icu::SimpleTimeZone, and icu::VTimeZone.

◆ getTimeZoneRulesAfter()

void icu::BasicTimeZone::getTimeZoneRulesAfter	(	UDate	start,
		InitialTimeZoneRule *&	initial,
		UVector *&	transitionRules,
		UErrorCode &	status
	)		const

protected

Gets the set of TimeZoneRule instances applicable to the specified time and after.

Parameters

start	The start date used for extracting time zone rules
initial	Output parameter, receives the InitialTimeZone. Always not nullptr (except in case of error)
transitionRules	Output parameter, a UVector of transition rules. May be nullptr, if there are no transition rules. The caller owns the returned vector; the UVector owns the rules.
status	Receives error status code

◆ hasEquivalentTransitions()

virtual UBool icu::BasicTimeZone::hasEquivalentTransitions	(	const BasicTimeZone &	tz,
		UDate	start,
		UDate	end,
		UBool	ignoreDstAmount,
		UErrorCode &	ec
	)		const

virtual

Checks if the time zone has equivalent transitions in the time range.

This method returns true when all of transition times, from/to standard offsets and DST savings used by this time zone match the other in the time range.

Parameters

tz	The `BasicTimeZone` object to be compared with.
start	The start time of the evaluated time range (inclusive)
end	The end time of the evaluated time range (inclusive)
ignoreDstAmount	When true, any transitions with only daylight saving amount changes will be ignored, except either of them is zero. For example, a transition from rawoffset 3:00/dstsavings 1:00 to rawoffset 2:00/dstsavings 2:00 is excluded from the comparison, but a transition from rawoffset 2:00/dstsavings 1:00 to rawoffset 3:00/dstsavings 0:00 is included.
ec	Output param to filled in with a success or an error.

Returns: true if the other time zone has the equivalent transitions in the time range.

Stable:: ICU 3.8

◆ operator=()

BasicTimeZone & icu::BasicTimeZone::operator= ( const BasicTimeZone & )

protecteddefault

Copy assignment.

Stable:: ICU 3.8

Field Documentation

◆ kFormerLatterMask

constexpr int32_t icu::BasicTimeZone::kFormerLatterMask = kLatter

staticconstexprprotected

A time type option bit mask used by getOffsetFromLocal.

Internal:: Do not use. This API is for internal use only.

Definition at line 197 of file basictz.h.

◆ kStdDstMask

constexpr int32_t icu::BasicTimeZone::kStdDstMask = kDaylight

staticconstexprprotected

A time type option bit mask used by getOffsetFromLocal.

Internal:: Do not use. This API is for internal use only.

Definition at line 192 of file basictz.h.

The documentation for this class was generated from the following file:

i18n/unicode/basictz.h

Public Types

Public Member Functions

Protected Member Functions

Static Protected Attributes

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

◆ anonymous enum

Constructor & Destructor Documentation

◆ ~BasicTimeZone()

◆ BasicTimeZone() [1/3]

◆ BasicTimeZone() [2/3]

◆ BasicTimeZone() [3/3]

Member Function Documentation

◆ clone()

◆ countTransitionRules()

◆ getNextTransition()

◆ getOffsetFromLocal() [1/2]

◆ getOffsetFromLocal() [2/2]

◆ getPreviousTransition()

◆ getSimpleRulesNear()

◆ getTimeZoneRules()

◆ getTimeZoneRulesAfter()

◆ hasEquivalentTransitions()

◆ operator=()

Field Documentation

◆ kFormerLatterMask

◆ kStdDstMask