KTimeZone Class Reference

#include <ktimezone.h>

Inheritance diagram for KTimeZone:

Classes
class	LeapSeconds
class	Phase
class	Transition

Public Member Functions
	KTimeZone ()
	KTimeZone (const QString &name)
	KTimeZone (const KTimeZone &tz)
virtual	~KTimeZone ()
QByteArray	abbreviation (const QDateTime &utcDateTime) const
QList< QByteArray >	abbreviations () const
QString	comment () const
QDateTime	convert (const KTimeZone &newZone, const QDateTime &zoneDateTime) const
QString	countryCode () const
int	currentOffset (Qt::TimeSpec basis=Qt::UTC) const
const KTimeZoneData *	data (bool create=false) const
virtual bool	hasTransitions () const
virtual bool	isDst (time_t t) const
virtual bool	isDstAtUtc (const QDateTime &utcDateTime) const
bool	isValid () const
float	latitude () const
QList< LeapSeconds >	leapSecondChanges () const
float	longitude () const
QString	name () const
virtual int	offset (time_t t) const
virtual int	offsetAtUtc (const QDateTime &utcDateTime) const
virtual int	offsetAtZoneTime (const QDateTime &zoneDateTime, int *secondOffset=0) const
bool	operator!= (const KTimeZone &rhs) const
KTimeZone &	operator= (const KTimeZone &tz)
bool	operator== (const KTimeZone &rhs) const
bool	parse () const
QList< Phase >	phases () const
KTimeZoneSource *	source () const
QDateTime	toUtc (const QDateTime &zoneDateTime) const
QDateTime	toZoneTime (const QDateTime &utcDateTime, bool *secondOccurrence=0) const
const KTimeZone::Transition *	transition (const QDateTime &dt, const Transition **secondTransition=0, bool *validTime=0) const
int	transitionIndex (const QDateTime &dt, int *secondIndex=0, bool *validTime=0) const
QList< KTimeZone::Transition >	transitions (const QDateTime &start=QDateTime(), const QDateTime &end=QDateTime()) const
QList< QDateTime >	transitionTimes (const Phase &phase, const QDateTime &start=QDateTime(), const QDateTime &end=QDateTime()) const
QByteArray	type () const
bool	updateBase (const KTimeZone &other)
QList< int >	utcOffsets () const

Static Public Member Functions
static QDateTime	fromTime_t (time_t t)
static time_t	toTime_t (const QDateTime &utcDateTime)
static KTimeZone	utc ()

Static Public Attributes
static const int	InvalidOffset = 0x80000000
static const time_t	InvalidTime_t = 0x80000000
static const float	UNKNOWN = 1000.0

Protected Member Functions
	KTimeZone (KTimeZoneBackend *impl)
void	setData (KTimeZoneData *data, KTimeZoneSource *source=0)

Detailed Description

Base class representing a time zone.

The KTimeZone base class contains general descriptive data about the time zone, and provides an interface for methods to read and parse time zone definitions, and to translate between UTC and local time. Derived classes must implement these methods, and may also hold the actual details of the dates and times of daylight savings changes, offsets from UTC, etc. They should be tailored to deal with the type and format of data held by a particular type of time zone database.

If this base class is instantiated as a valid instance, it always represents the UTC time zone.

KTimeZone is designed to work in partnership with KTimeZoneSource. KTimeZone provides access to individual time zones, while classes derived from KTimeZoneSource read and parse a particular format of time zone definition. Because time zone sources can differ in what information they provide about time zones, the parsed data retured by KTimeZoneSource can vary between different sources, resulting in the need to create different KTimeZone classes to handle the data.

KTimeZone instances are often grouped into KTimeZones collections.

Copying KTimeZone instances is very efficient since the class data is explicitly shared, meaning that only a pointer to the data is actually copied. To achieve this, each class inherited from KTimeZone must have a corresponding backend class derived from KTimeZoneBackend.

Note

Classes derived from KTimeZone should not have their own d-pointer. The d-pointer is instead contained in their backend class (derived from KTimeZoneBackend). This allows KTimeZone's reference-counting of private data to take care of the derived class's data as well, ensuring that instance data is not deleted while any references to the class instance remains. All virtual methods which override KTimeZone virtual methods must be defined in the backend class instead.

Base class representing a time zone

See also

KTimeZoneBackend, KTimeZoneSource, KTimeZoneData

Author

David Jarvie djarv.nosp@m.ie@k.nosp@m.de.or.nosp@m.g.

S.R.Haque srhaq.nosp@m.ue@i.nosp@m.ee.or.nosp@m.g.

Definition at line 416 of file ktimezone.h.

Constructor & Destructor Documentation

KTimeZone::KTimeZone

(

)

Constructs a null time zone.

A null time zone is invalid.

See also

isValid()

Definition at line 600 of file ktimezone.cpp.

KTimeZone::KTimeZone ( const QString &  name )

explicit

Constructs a UTC time zone.

Parameters

name	name of the UTC time zone

Definition at line 604 of file ktimezone.cpp.

KTimeZone::KTimeZone

(

const KTimeZone &

tz

)

Definition at line 608 of file ktimezone.cpp.

KTimeZone::~KTimeZone ( )

virtual

Definition at line 612 of file ktimezone.cpp.

KTimeZone::KTimeZone ( KTimeZoneBackend *  impl )

protected

Definition at line 617 of file ktimezone.cpp.

Member Function Documentation

QByteArray KTimeZone::abbreviation

(

const QDateTime &

utcDateTime

)

const

Returns the time zone abbreviation current at a specified time.

Parameters

utcDateTime

UTC date/time. An error occurs if utcDateTime.timeSpec() is not Qt::UTC.

Returns

time zone abbreviation, or empty string if error

See also

abbreviations()

Definition at line 681 of file ktimezone.cpp.

QList< QByteArray > KTimeZone::abbreviations

(

)

const

Returns the list of time zone abbreviations used by the time zone.

This may include historical ones which are no longer in use or have been superseded.

Returns

list of abbreviations

See also

abbreviation()

Definition at line 674 of file ktimezone.cpp.

QString KTimeZone::comment

(

)

const

Returns any comment for the time zone.

Returns

comment, may be empty

Definition at line 664 of file ktimezone.cpp.

QDateTime KTimeZone::convert	(	const KTimeZone &	newZone,
		const QDateTime &	zoneDateTime
	)		const

Converts a date/time, which is interpreted as being local time in this time zone, into local time in another time zone.

Parameters

newZone	other time zone which the time is to be converted into
zoneDateTime	local date/time. An error occurs if zoneDateTime.timeSpec() is not Qt::LocalTime.

Returns

converted date/time, or invalid date/time if error

See also

toUtc(), toZoneTime()

Definition at line 854 of file ktimezone.cpp.

QString KTimeZone::countryCode

(

)

const

Returns the two-letter country code of the time zone.

Returns

upper case ISO 3166 2-character country code, empty if unknown

Definition at line 649 of file ktimezone.cpp.

int KTimeZone::currentOffset

(

Qt::TimeSpec

basis = Qt::UTC

)

const

Returns the current offset of this time zone to UTC or the local system time zone.

The offset is the number of seconds which you must add to UTC or the local system time to get local time in this time zone.

Take care if you cache the results of this routine; that would break if the result were stored across a daylight savings change.

Parameters

basis

Qt::UTC to return the offset to UTC, Qt::LocalTime to return the offset to local system time

Returns

offset in seconds

See also

offsetAtZoneTime(), offsetAtUtc()

Definition at line 880 of file ktimezone.cpp.

const KTimeZoneData * KTimeZone::data

(

bool

create = false

)

const

Returns the detailed parsed data for the time zone.

This will return null unless either parse() has been called beforehand, or create is true.

Parameters

create

true to parse the zone's data first if not already parsed

Returns

pointer to data, or null if data has not been parsed

Definition at line 754 of file ktimezone.cpp.

QDateTime KTimeZone::fromTime_t ( time_t  t )

static

Converts a UTC time, measured in seconds since 00:00:00 UTC 1st January 1970 (as returned by time(2)), to a UTC QDateTime value.

QDateTime::setTime_t() is limited to handling t >= 0, since its parameter is unsigned. This method takes a parameter of time_t which is signed.

Returns

converted time

See also

toTime_t()

Definition at line 917 of file ktimezone.cpp.

bool KTimeZone::hasTransitions ( ) const

virtual

Return whether daylight saving transitions are available for the time zone.

The base class returns false.

Returns

true if transitions are available, false if not

See also

transitions(), transition()

Definition at line 702 of file ktimezone.cpp.

bool KTimeZone::isDst ( time_t  t ) const

virtual

Returns whether daylight savings time is in operation at a specified UTC time.

Note that time_t has a more limited range than QDateTime, so consider using isDstAtUtc() instead.

Parameters

t	the UTC time, measured in seconds since 00:00:00 UTC 1st January 1970 (as returned by time(2))

Returns

true if daylight savings time is in operation, false otherwise

See also

isDstAtUtc()

Definition at line 906 of file ktimezone.cpp.

bool KTimeZone::isDstAtUtc ( const QDateTime &  utcDateTime ) const

virtual

Returns whether daylight savings time is in operation at the given UTC date/time.

If a derived class needs to work in terms of time_t (as when accessing the system time functions, for example), it should override both this method and isDst() so as to implement its offset calculations in isDst(), and reimplement this method simply as

isDst(toTime_t(utcDateTime));

Parameters

utcDateTime

the UTC date/time. An error occurs if utcDateTime.timeSpec() is not Qt::UTC.

Returns

true if daylight savings time is in operation, false otherwise

See also

isDst()

Definition at line 901 of file ktimezone.cpp.

bool KTimeZone::isValid

(

)

const

Checks whether the instance is valid.

Returns

true if valid, false if invalid

Definition at line 644 of file ktimezone.cpp.

float KTimeZone::latitude

(

)

const

Returns the latitude of the time zone.

Returns

latitude in degrees, UNKNOWN if not known

Definition at line 654 of file ktimezone.cpp.

QList< KTimeZone::LeapSeconds > KTimeZone::leapSecondChanges

(

)

const

Return all leap second adjustments, in time order.

Note that some time zone data sources (such as system time zones accessed via the system libraries) may not provide information on leap second adjustments. In such cases, this method will return an empty list.

Returns

list of adjustments

Definition at line 742 of file ktimezone.cpp.

float KTimeZone::longitude

(

)

const

Returns the latitude of the time zone.

Returns

latitude in degrees, UNKNOWN if not known

Definition at line 659 of file ktimezone.cpp.

QString KTimeZone::name

(

)

const

Returns the name of the time zone.

If it is held in a KTimeZones container, the name is the time zone's unique identifier within that KTimeZones instance.

Returns

name in system-dependent format

Definition at line 669 of file ktimezone.cpp.

int KTimeZone::offset ( time_t  t ) const

virtual

Returns the offset of this time zone to UTC at a specified UTC time.

The offset is the number of seconds which you must add to UTC to get local time in this time zone.

Note that time_t has a more limited range than QDateTime, so consider using offsetAtUtc() instead.

Parameters

t	the UTC time at which the offset is to be calculated, measured in seconds since 00:00:00 UTC 1st January 1970 (as returned by time(2))

Returns

offset in seconds, or 0 if error

See also

offsetAtUtc()

Definition at line 875 of file ktimezone.cpp.

int KTimeZone::offsetAtUtc ( const QDateTime &  utcDateTime ) const

virtual

Returns the offset of this time zone to UTC at the given UTC date/time.

The offset is the number of seconds which you must add to UTC to get local time in this time zone.

If a derived class needs to work in terms of time_t (as when accessing the system time functions, for example), it should override both this method and offset() so as to implement its offset calculations in offset(), and reimplement this method simply as

offset(toTime_t(utcDateTime));

Parameters

utcDateTime

the UTC date/time at which the offset is to be calculated. An error occurs if utcDateTime.timeSpec() is not Qt::UTC.

Returns

offset in seconds, or 0 if error

See also

offset(), offsetAtZoneTime(), currentOffset()

Definition at line 870 of file ktimezone.cpp.

int KTimeZone::offsetAtZoneTime ( const QDateTime &  zoneDateTime, int *  secondOffset = 0  ) const

virtual

Returns the offset of this time zone to UTC at the given local date/time.

Because of daylight savings time shifts, the date/time may occur twice. Optionally, the offsets at both occurrences of dateTime are calculated.

The offset is the number of seconds which you must add to UTC to get local time in this time zone.

Parameters

zoneDateTime	the date/time at which the offset is to be calculated. This is interpreted as a local time in this time zone. An error occurs if zoneDateTime.timeSpec() is not Qt::LocalTime.
secondOffset	if non-null, and the zoneDateTime occurs twice, receives the UTC offset for the second occurrence. Otherwise, it is set the same as the return value.

Returns

offset in seconds. If zoneDateTime occurs twice, it is the offset at the first occurrence which is returned. If zoneDateTime does not exist because of daylight savings time shifts, InvalidOffset is returned. If any other error occurs, 0 is returned.

See also

offsetAtUtc(), currentOffset()

Definition at line 865 of file ktimezone.cpp.

bool KTimeZone::operator!= ( const KTimeZone &  rhs ) const

inline

Definition at line 633 of file ktimezone.h.

KTimeZone & KTimeZone::operator=

(

const KTimeZone &

tz

)

Definition at line 624 of file ktimezone.cpp.

bool KTimeZone::operator==

(

const KTimeZone &

rhs

)

const

Checks whether this is the same instance as another one.

Note that only the pointers to the time zone data are compared, not the contents. So it will only return equality if one instance was copied from the other.

Parameters

rhs	other instance

Returns

true if the same instance, else false

Definition at line 634 of file ktimezone.cpp.

bool KTimeZone::parse

(

)

const

Extracts time zone detail information for this time zone from the source database.

Returns

false if the parse encountered errors, true otherwise

Definition at line 784 of file ktimezone.cpp.

QList< KTimeZone::Phase > KTimeZone::phases

(

)

const

Return all daylight savings time phases for the time zone.

Note that some time zone data sources (such as system time zones accessed via the system libraries) may not allow a list of daylight savings time changes to be compiled easily. In such cases, this method will return an empty list.

Returns

list of phases

Definition at line 695 of file ktimezone.cpp.

void KTimeZone::setData ( KTimeZoneData *  data, KTimeZoneSource *  source = 0  )

protected

Sets the detailed parsed data for the time zone, and optionally a new time zone source object.

Parameters

data	parsed data
source	if non-null, the new source object for the time zone

See also

data()

Definition at line 763 of file ktimezone.cpp.

KTimeZoneSource * KTimeZone::source

(

)

const

Returns the source reader/parser for the time zone's source database.

Returns

reader/parser

Definition at line 749 of file ktimezone.cpp.

time_t KTimeZone::toTime_t ( const QDateTime &  utcDateTime )

static

Converts a UTC QDateTime to a UTC time, measured in seconds since 00:00:00 UTC 1st January 1970 (as returned by time(2)).

QDateTime::toTime_t() returns an unsigned value. This method returns a time_t value, which is signed.

Parameters

utcDateTime

date/time. An error occurs if utcDateTime.timeSpec() is not Qt::UTC.

Returns

converted time, or -1 if the date is out of range for time_t or utcDateTime.timeSpec() is not Qt::UTC

See also

fromTime_t()

Definition at line 934 of file ktimezone.cpp.

QDateTime KTimeZone::toUtc

(

const QDateTime &

zoneDateTime

)

const

Converts a date/time, which is interpreted as local time in this time zone, into UTC.

Because of daylight savings time shifts, the date/time may occur twice. In such cases, this method returns the UTC time for the first occurrence. If you need the UTC time of the second occurrence, use offsetAtZoneTime().

Parameters

zoneDateTime

local date/time. An error occurs if zoneDateTime.timeSpec() is not Qt::LocalTime.

Returns

UTC date/time, or invalid date/time if error

See also

toZoneTime(), convert()

Definition at line 796 of file ktimezone.cpp.

QDateTime KTimeZone::toZoneTime	(	const QDateTime &	utcDateTime,
		bool *	secondOccurrence = 0
	)		const

Converts a UTC date/time into local time in this time zone.

Because of daylight savings time shifts, some local date/time values occur twice. The secondOccurrence parameter may be used to determine whether the time returned is the first or second occurrence of that time.

Parameters

utcDateTime	UTC date/time. An error occurs if utcDateTime.timeSpec() is not Qt::UTC.
secondOccurrence	if non-null, returns true if the return value is the second occurrence of that time, else false

Returns

local date/time, or invalid date/time if error

See also

toUtc(), convert()

Definition at line 808 of file ktimezone.cpp.

const KTimeZone::Transition * KTimeZone::transition	(	const QDateTime &	dt,
		const Transition **	secondTransition = 0,
		bool *	validTime = 0
	)		const

Find the last daylight savings time transition at or before a given UTC or local time.

Because of daylight savings time shifts, a local time may occur twice or may not occur at all. In the former case, the transitions at or before both occurrences of dt may optionally be calculated and returned in secondTransition. The latter case may optionally be detected by use of validTime.

Parameters

dt	date/time. dt.timeSpec() may be set to Qt::UTC or Qt::LocalTime.
secondTransition	if non-null, and the dt occurs twice, receives the transition for the second occurrence. Otherwise, it is set the same as the return value.
validTime	if non-null, is set to false if dt does not occur, or to true otherwise

Returns

time zone transition, or null either if dt is either outside the defined range of the transition data or if dt does not occur

See also

transitionIndex(), hasTransitions(), transitions()

Definition at line 714 of file ktimezone.cpp.

int KTimeZone::transitionIndex	(	const QDateTime &	dt,
		int *	secondIndex = 0,
		bool *	validTime = 0
	)		const

Find the index to the last daylight savings time transition at or before a given UTC or local time.

The return value is the index into the transition list returned by transitions().

Because of daylight savings time shifts, a local time may occur twice or may not occur at all. In the former case, the transitions at or before both occurrences of dt may optionally be calculated and returned in secondIndex. The latter case may optionally be detected by use of validTime.

Parameters

dt	date/time. dt.timeSpec() may be set to Qt::UTC or Qt::LocalTime.
secondIndex	if non-null, and the dt occurs twice, receives the index to the transition for the second occurrence. Otherwise, it is set the same as the return value.
validTime	if non-null, is set to false if dt does not occur, or to true otherwise

Returns

index into the time zone transition list, or -1 either if dt is either outside the defined range of the transition data or if dt does not occur

See also

transition(), transitions(), hasTransitions()

Definition at line 725 of file ktimezone.cpp.

QList< KTimeZone::Transition > KTimeZone::transitions	(	const QDateTime &	start = QDateTime(),
		const QDateTime &	end = QDateTime()
	)		const

Return all daylight saving transitions, in time order.

If desired, the transitions returned may be restricted to a specified time range.

Note that some time zone data sources (such as system time zones accessed via the system libraries) may not allow a list of daylight saving time changes to be compiled easily. In such cases, this method will return an empty list.

Parameters

start	start UTC date/time, or invalid date/time to return all transitions up to end. start.timeSpec() must be Qt::UTC, else start will be considered invalid.
end	end UTC date/time, or invalid date/time for no end. end.timeSpec() must be Qt::UTC, else end will be considered invalid.

Returns

list of transitions, in time order

See also

hasTransitions(), transition(), transitionTimes()

Definition at line 707 of file ktimezone.cpp.

QList< QDateTime > KTimeZone::transitionTimes	(	const Phase &	phase,
		const QDateTime &	start = QDateTime(),
		const QDateTime &	end = QDateTime()
	)		const

Return the times of all daylight saving transitions to a given time zone phase, in time order.

If desired, the times returned may be restricted to a specified time range.

Note that some time zone data sources (such as system time zones accessed via the system libraries) may not allow a list of daylight saving time changes to be compiled easily. In such cases, this method will return an empty list.

Parameters

phase	time zone phase
start	start UTC date/time, or invalid date/time to return all transitions up to end. start.timeSpec() must be Qt::UTC, else start will be considered invalid.
end	end UTC date/time, or invalid date/time for no end. end.timeSpec() must be Qt::UTC, else end will be considered invalid.

Returns

ordered list of transition times

See also

hasTransitions(), transition(), transitions()

Definition at line 735 of file ktimezone.cpp.

QByteArray KTimeZone::type

(

)

const

Returns the class name of the data represented by this instance.

If a derived class object has been assigned to this instance, this method will return the name of that class.

Returns

"KTimeZone" or the class name of a derived class

Definition at line 639 of file ktimezone.cpp.

bool KTimeZone::updateBase

(

const KTimeZone &

other

)

Update the definition of the time zone to be identical to another KTimeZone instance.

A prerequisite is that the two instances must have the same name.

The main purpose of this method is to allow updates of the time zone definition by derived classes without invalidating pointers to the instance (particularly pointers held by KDateTime objects). Note that the KTimeZoneData object and KTimeZoneSource pointer are not updated: the caller class should do this itself by calling setData().

Parameters

other

time zone whose definition is to be used

Returns

true if definition was updated (i.e. names are the same)

See also

setData()

Definition at line 773 of file ktimezone.cpp.

KTimeZone KTimeZone::utc ( )

static

Returns a standard UTC time zone, with name "UTC".

Note

The KTimeZone returned by this method does not belong to any KTimeZones collection. Any KTimeZones instance may contain its own UTC KTimeZone defined by its time zone source data, but that will be a different instance than this KTimeZone.

Returns

UTC time zone

Definition at line 911 of file ktimezone.cpp.

QList< int > KTimeZone::utcOffsets

(

)

const

Returns the complete list of UTC offsets used by the time zone.

This may include historical ones which are no longer in use or have been superseded.

A UTC offset is the number of seconds which you must add to UTC to get local time in this time zone.

If due to the nature of the source data for the time zone, compiling a complete list would require significant processing, an empty list is returned instead.

Returns

sorted list of UTC offsets, or empty list if not readily available.

Definition at line 688 of file ktimezone.cpp.

Member Data Documentation

const int KTimeZone::InvalidOffset = 0x80000000

static

Indicates an invalid UTC offset.

This is returned by offsetAtZoneTime() when the local time does not occur due to a shift to daylight savings time.

Definition at line 1073 of file ktimezone.h.

const time_t KTimeZone::InvalidTime_t = 0x80000000

static

Indicates an invalid time_t value.

Definition at line 1077 of file ktimezone.h.

const float KTimeZone::UNKNOWN = 1000.0

static

A representation for unknown locations; this is a float that does not represent a real latitude or longitude.

Definition at line 1083 of file ktimezone.h.

---

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

• ktimezone.h
• ktimezone.cpp