RangeIterator represents a sequence of integers between a start and end value. More...

#include <qrangeiterator_p.h>

Inheritance diagram for QPatternist::RangeIterator:

Public Types
enum	Direction { Backward = 0, Forward = 1 }

Public Types inherited from QAbstractXmlForwardIterator< Item >
typedef QList< QExplicitlySharedDataPointer< QAbstractXmlForwardIterator< Item > > >	List
	A QList containing QAbstractXmlForwardIterator::Ptr instances. More...

typedef QExplicitlySharedDataPointer< QAbstractXmlForwardIterator< Item > >	Ptr
	A smart pointer wrapping an instance of a QAbstractXmlForwardIterator subclass. More...

typedef QVector< QExplicitlySharedDataPointer< QAbstractXmlForwardIterator< Item > > >	Vector
	A QVector containing QAbstractXmlForwardIterator::Ptr instances. More...

Public Functions
virtual Item::Iterator::Ptr	copy () const
	Copies this QAbstractXmlForwardIterator and returns the copy. More...

virtual xsInteger	count ()
	Determines the number of items this QAbstractXmlForwardIterator represents. More...

virtual Item	current () const
	Returns the current item in the sequence. More...

virtual Item	next ()
	Returns the next item in the sequence, or a null object if the end has been reached. More...

virtual xsInteger	position () const
	Returns the current position in the sequence represented by this. More...

	RangeIterator (const xsInteger start, const Direction direction, const xsInteger end)

virtual Item::Iterator::Ptr	toReversed ()
	Returns a reverse iterator for the sequence. More...

Public Functions inherited from QAbstractXmlForwardIterator< Item >
virtual bool	isEmpty ()
	Returns true if the sequence is empty. More...

virtual Item	last ()
	Returns the item at the end of this QAbstractXmlForwardIterator. More...

	QAbstractXmlForwardIterator ()
	Default constructor. More...

virtual qint64	sizeHint () const
	Gives a hint to the size of the contained sequence. More...

virtual QList< Item >	toList ()
	Performs a copy of this QAbstractXmlForwardIterator(with copy()), and returns its items in a QList. More...

virtual	~QAbstractXmlForwardIterator ()
	Destructor. More...

Public Functions inherited from QSharedData
	QSharedData ()
	Constructs a QSharedData object with a reference count of 0. More...

	QSharedData (const QSharedData &)
	Constructs a QSharedData object with reference count 0. More...

Properties
xsInteger	m_count

Item	m_current

const Direction	m_direction

xsInteger	m_end

const qint8	m_increment: 2

xsInteger	m_position

xsInteger	m_start

Additional Inherited Members
Public Variables inherited from QSharedData
QAtomicInt	ref

Related Functions inherited from QAbstractXmlForwardIterator< Item >
static QAbstractXmlForwardIterator< TResult >::Ptr	makeSequenceMappingIterator (const TMapper &mapper, const QExplicitlySharedDataPointer< QAbstractXmlForwardIterator< TSource > > &source, const DynamicContext::Ptr &context)
	An object generator for SequenceMappingIterator. More...

bool	qIsForwardIteratorEnd (const Item &unit)
	The Callback QAbstractXmlForwardIterator uses for determining whether unit is the end of a sequence. More...

Detailed Description

RangeIterator represents a sequence of integers between a start and end value.

The RangeIterator contains the evaluation logic for the range expression, N to M, and its behavior is therefore consistent with the definition of that XPath expression. Hence, the detailed behavior of the RangeIterator can be found in the XPath 2.0 specification.

See also: XML Path Language (XPath) 2.0, 3.3 Sequence Expressions, RangeExpr; RangeExpression

Author: Frans Englich frans.nosp@m..eng.nosp@m.lich@.nosp@m.noki.nosp@m.a.com

Definition at line 79 of file qrangeiterator_p.h.

Enumerations

◆ Direction

enum QPatternist::RangeIterator::Direction

RangeIterator can iterate in both directions. This enumerator exist for identifying different directions.

Enumerator
Backward	Signifies that the QAbstractXmlForwardIterator operates in a reverse direction, where the first item returned by the next() function is from the beginning of the source sequence.
Forward	Signifies the forward direction. Iterators do conceptually operate in the forward direction by default.

Definition at line 87 of file qrangeiterator_p.h.

         {
             Backward = 0,
 
             Forward = 1
         };

Constructors and Destructors

◆ RangeIterator()

RangeIterator::RangeIterator	(	const xsInteger	start,
		const Direction	direction,
		const xsInteger	end
	)

Creates an QAbstractXmlForwardIterator that returns integer values from consecutive sequence of integers between start and end, where the step taken between each integer is 1 with polarity as specified in direction.

Note: start must be smaller than end, not larger or equal. This is not checked.

Definition at line 50 of file qrangeiterator.cpp.

Referenced by copy(), and toReversed().

                              : m_start(start),
                                m_end(end),
                                m_position(0),
                                m_count(start),
                                m_direction(direction),
                                m_increment(m_direction == Forward ? 1 : -1)
 {
     Q_ASSERT(m_start < m_end);
     Q_ASSERT(m_direction == Backward || m_direction == Forward);
 
     if(m_direction == Backward)
     {
         qSwap(m_start, m_end);
         m_count = m_start;
     }
 }

Functions

◆ copy()

Item::Iterator::Ptr RangeIterator::copy ( ) const

virtual

Copies this QAbstractXmlForwardIterator and returns the copy.

Warning: This function is not part of the public interface.

A copy and the original instance are completely independent of each other. Because evaluating an QAbstractXmlForwardIterator modifies it, one should always use a copy when an QAbstractXmlForwardIterator needs to be used several times.

Reimplemented from QAbstractXmlForwardIterator< Item >.

Definition at line 118 of file qrangeiterator.cpp.

 {
     if(m_direction == Backward)
         return Item::Iterator::Ptr(new RangeIterator(m_end, Backward, m_start));
     else
         return Item::Iterator::Ptr(new RangeIterator(m_start, Forward, m_end));
 }

◆ count()

xsInteger RangeIterator::count ( )

virtual

Determines the number of items this QAbstractXmlForwardIterator represents.

Warning: This function is not part of the public interface.

Note that this function is not const. It modifies the QAbstractXmlForwardIterator. The reason for this is efficiency. If this QAbstractXmlForwardIterator must not be changed, get a copy() before performing the count.

The default implementation simply calls next() until the end is reached. Hence, it may be of interest to override this function if the sub-class knows a better way of computing its count.

The number of items in the sequence is returned.

Reimplemented from QAbstractXmlForwardIterator< Item >.

Definition at line 90 of file qrangeiterator.cpp.

 {
     /* This complication is for handling that m_start & m_end may be reversed. */
     xsInteger ret;
 
     if(m_start < m_end)
         ret = m_end - m_start;
     else
         ret = m_start - m_end;
 
     return ret + 1;
 }

◆ current()

Item RangeIterator::current ( ) const

virtual

Returns the current item in the sequence.

If this function is called before the first call to next(), a null object is returned. If the end of the sequence has been reached, a null object is returned.

Implements QAbstractXmlForwardIterator< Item >.

Definition at line 108 of file qrangeiterator.cpp.

 {
     return m_current;
 }

◆ next()

Item RangeIterator::next ( )

virtual

Returns the next item in the sequence, or a null object if the end has been reached.

Implements QAbstractXmlForwardIterator< Item >.

Definition at line 70 of file qrangeiterator.cpp.

 {
     if(m_position == -1)
         return Item();
     else if((m_direction == Forward && m_count > m_end) ||
             (m_direction == Backward && m_count < m_end))
     {
         m_position = -1;
         m_current.reset();
         return Item();
     }
     else
     {
         m_current = Integer::fromValue(m_count);
         m_count += m_increment;
         ++m_position;
         return m_current;
     }
 }

◆ position()

xsInteger RangeIterator::position ( ) const

virtual

Returns the current position in the sequence represented by this.

The first position is 1, not 0. If next() hasn't been called, 0 is returned. If this has reached the end, -1 is returned.

Implements QAbstractXmlForwardIterator< Item >.

Definition at line 113 of file qrangeiterator.cpp.

 {
     return m_position;
 }

◆ toReversed()

Item::Iterator::Ptr RangeIterator::toReversed ( )

virtual

Returns a reverse iterator for the sequence.

Warning: This function is not part of the public interface.

This function may modify the iterator, it can be considered a function that evaluates this QAbstractXmlForwardIterator. It is not a getter, but potentially alters the iterator in the same way the next() function does. If this QAbstractXmlForwardIterator must not be modified, such that it can be used for evaluation with next(), use a copy().

Reimplemented from QAbstractXmlForwardIterator< Item >.

Definition at line 103 of file qrangeiterator.cpp.

 {
     return Item::Iterator::Ptr(new RangeIterator(m_start, Backward, m_end));
 }

Properties

◆ m_count

xsInteger QPatternist::RangeIterator::m_count

private

Definition at line 127 of file qrangeiterator_p.h.

Referenced by next(), and RangeIterator().

◆ m_current

Item QPatternist::RangeIterator::m_current

private

Definition at line 125 of file qrangeiterator_p.h.

Referenced by current(), and next().

◆ m_direction

const Direction QPatternist::RangeIterator::m_direction

private

Definition at line 128 of file qrangeiterator_p.h.

Referenced by copy(), next(), and RangeIterator().

◆ m_end

xsInteger QPatternist::RangeIterator::m_end

private

Definition at line 124 of file qrangeiterator_p.h.

Referenced by copy(), count(), next(), RangeIterator(), and toReversed().

◆ m_increment

const qint8 QPatternist::RangeIterator::m_increment

private

We only need to store -1 or 1, so save memory with a bit field.

Definition at line 133 of file qrangeiterator_p.h.

Referenced by next().

◆ m_position

xsInteger QPatternist::RangeIterator::m_position

private

Definition at line 126 of file qrangeiterator_p.h.

Referenced by next(), and position().

◆ m_start

xsInteger QPatternist::RangeIterator::m_start

private

Definition at line 123 of file qrangeiterator_p.h.

Referenced by copy(), count(), RangeIterator(), and toReversed().

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

/src/xmlpatterns/iterators/qrangeiterator_p.h
/src/xmlpatterns/iterators/qrangeiterator.cpp

Public Types

Public Functions

Properties

Additional Inherited Members

Detailed Description

Enumerations

◆ Direction

Constructors and Destructors

◆ RangeIterator()

Functions

◆ copy()

◆ count()

◆ current()

◆ next()

◆ position()

◆ toReversed()

Properties

◆ m_count

◆ m_current

◆ m_direction

◆ m_end

◆ m_increment

◆ m_position

◆ m_start