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KDECore

KTimeZone Class Reference
[Time zone classes]

Base class representing a time zone. More...

#include <ktimezone.h>

Inheritance diagram for KTimeZone:

Inheritance graph
[legend]

List of all members.


Classes

class  LeapSeconds
class  Phase
class  Transition

Public Member Functions

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
 KTimeZone (const KTimeZone &tz)
 KTimeZone (const QString &name)
 KTimeZone ()
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
virtual ~KTimeZone ()

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 <djarvie@kde.org>.

S.R.Haque <srhaque@iee.org>.

Definition at line 415 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 538 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 542 of file ktimezone.cpp.

KTimeZone::KTimeZone ( const KTimeZone &  tz  ) 

Definition at line 546 of file ktimezone.cpp.

KTimeZone::~KTimeZone (  )  [virtual]

Definition at line 550 of file ktimezone.cpp.

KTimeZone::KTimeZone ( KTimeZoneBackend *  impl  )  [protected]

Definition at line 555 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 619 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 612 of file ktimezone.cpp.

QString KTimeZone::comment (  )  const

Returns any comment for the time zone.

Returns:
comment, may be empty

Definition at line 602 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 786 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 587 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 812 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 686 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 849 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 640 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 838 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 833 of file ktimezone.cpp.

bool KTimeZone::isValid (  )  const

Checks whether the instance is valid.

Returns:
true if valid, false if invalid

Definition at line 582 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 592 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 674 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 597 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 607 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 807 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 802 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 797 of file ktimezone.cpp.

bool KTimeZone::operator!= ( const KTimeZone &  rhs  )  const [inline]

Definition at line 628 of file ktimezone.h.

KTimeZone & KTimeZone::operator= ( const KTimeZone &  tz  ) 

Definition at line 562 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 572 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 717 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 633 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 695 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 681 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 865 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 729 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 741 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 652 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 660 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 645 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 667 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 577 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 706 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 843 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 626 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 1068 of file ktimezone.h.

const time_t KTimeZone::InvalidTime_t = 0x80000000 [static]

Indicates an invalid time_t value.

Definition at line 1072 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 1078 of file ktimezone.h.


The documentation for this class was generated from the following files:
  • ktimezone.h
  • ktimezone.cpp

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