ICU 75.1 75.1
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Public Types | Public Member Functions | Protected Member Functions | Static Protected Attributes
icu::BasicTimeZone Class Referenceabstract

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

#include <basictz.h>

Inheritance diagram for icu::BasicTimeZone:
icu::TimeZone icu::UObject icu::UMemory icu::RuleBasedTimeZone icu::SimpleTimeZone icu::VTimeZone

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 BasicTimeZoneclone () 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 TimeZoneRules which represents time transitions, for this time zone, that is, all TimeZoneRules 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).
 
UnicodeStringgetID (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.
 
UnicodeStringgetDisplayName (UnicodeString &result) const
 Returns a name of this time zone suitable for presentation to the user in the default locale.
 
UnicodeStringgetDisplayName (const Locale &locale, UnicodeString &result) const
 Returns a name of this time zone suitable for presentation to the user in the specified locale.
 
UnicodeStringgetDisplayName (UBool inDaylight, EDisplayType style, UnicodeString &result) const
 Returns a name of this time zone suitable for presentation to the user in the default locale.
 
UnicodeStringgetDisplayName (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.
 
BasicTimeZoneoperator= (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.
 
TimeZoneoperator= (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 TimeZonegetUnknown ()
 Returns the "unknown" time zone.
 
static const TimeZonegetGMT ()
 The GMT (=UTC) time zone has a raw offset of zero and does not use daylight savings time.
 
static TimeZonecreateTimeZone (const UnicodeString &ID)
 Creates a TimeZone for the given ID.
 
static StringEnumerationcreateTimeZoneIDEnumeration (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 StringEnumerationcreateEnumeration ()
 Returns an enumeration over all recognized time zone IDs.
 
static StringEnumerationcreateEnumeration (UErrorCode &status)
 Returns an enumeration over all recognized time zone IDs.
 
static StringEnumerationcreateEnumeration (int32_t rawOffset)
 Returns an enumeration over time zone IDs with a given raw offset from GMT.
 
static StringEnumerationcreateEnumerationForRawOffset (int32_t rawOffset, UErrorCode &status)
 Returns an enumeration over time zone IDs with a given raw offset from GMT.
 
static StringEnumerationcreateEnumeration (const char *region)
 Returns an enumeration over time zone IDs associated with the given region.
 
static StringEnumerationcreateEnumerationForRegion (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 TimeZonedetectHostTimeZone ()
 Creates an instance of TimeZone detected from the current host system configuration.
 
static TimeZonecreateDefault ()
 Creates a new copy of the default TimeZone for this host.
 
static TimeZoneforLocaleOrDefault (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 chargetTZDataVersion (UErrorCode &status)
 Returns the timezone data version currently used by ICU.
 
static UnicodeStringgetCanonicalID (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 UnicodeStringgetCanonicalID (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 UnicodeStringgetIanaID (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 UnicodeStringgetWindowsID (const UnicodeString &id, UnicodeString &winid, UErrorCode &status)
 Converts a system time zone ID to an equivalent Windows time zone ID.
 
static UnicodeStringgetIDForWindowsID (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_tgetRegion (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 UResourceBundleloadRule (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

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
ida system time zone ID
Stable:
ICU 3.8

◆ BasicTimeZone() [3/3]

icu::BasicTimeZone::BasicTimeZone ( const BasicTimeZone source)
protected

Copy constructor.

Parameters
sourcethe 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
statusReceives 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
baseThe base time.
inclusiveWhether the base time is inclusive or not.
resultReceives 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
baseThe base time.
inclusiveWhether the base time is inclusive or not.
resultReceives 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
dateThe date used for extracting time zone rules.
initialReceives the InitialTimeZone, always not nullptr.
stdReceives the AnnualTimeZoneRule for standard time transitions. When this time time zone does not observe daylight saving times around the specified date, nullptr is set.
dstReceives the AnnualTimeZoneRule for daylight saving time transitions. When this time zone does not observer daylight saving times around the specified date, nullptr is set.
statusReceives 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
initialReceives the initial timezone rule
trsrulesReceives the timezone transition rules
trscountOn 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.
statusReceives 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
startThe start date used for extracting time zone rules
initialOutput parameter, receives the InitialTimeZone. Always not nullptr (except in case of error)
transitionRulesOutput 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.
statusReceives 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
tzThe BasicTimeZone object to be compared with.
startThe start time of the evaluated time range (inclusive)
endThe end time of the evaluated time range (inclusive)
ignoreDstAmountWhen 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.
ecOutput 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: