Picks out a slice from another QAbstractXmlForwardIterator, specified by a start and end position. More...

#include <qsubsequenceiterator_p.h>

Inheritance diagram for QPatternist::SubsequenceIterator:

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

	SubsequenceIterator (const Item::Iterator::Ptr &iterator, const xsInteger start, const xsInteger length)

Public Functions inherited from QAbstractXmlForwardIterator< T >
virtual qint64	count ()
	Determines the number of items this QAbstractXmlForwardIterator represents. More...

virtual bool	isEmpty ()
	Returns true if the sequence is empty. More...

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

virtual QAbstractXmlForwardIterator< T >::Ptr	toReversed ()
	Returns a reverse iterator for the sequence. 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_counter

Item	m_current

const Item::Iterator::Ptr	m_it

const xsInteger	m_len

xsInteger	m_position

const xsInteger	m_start

const xsInteger	m_stop

Additional Inherited Members
Public Types inherited from QAbstractXmlForwardIterator< T >
typedef QList< QExplicitlySharedDataPointer< QAbstractXmlForwardIterator< T > > >	List
	A QList containing QAbstractXmlForwardIterator::Ptr instances. More...

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

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

Public Variables inherited from QSharedData
QAtomicInt	ref

Related Functions inherited from QAbstractXmlForwardIterator< T >
template<typename TResult , typename TSource , typename TMapper >
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 T &unit)
	The Callback QAbstractXmlForwardIterator uses for determining whether unit is the end of a sequence. More...

Detailed Description

Picks out a slice from another QAbstractXmlForwardIterator, specified by a start and end position.

SubsequenceIterator allows a "slice", a subsequence, from an QAbstractXmlForwardIterator to be extracted. The SubsequenceIterator's constructor takes a source QAbstractXmlForwardIterator, a start position, and the length of the subsequence to be extracted.

SubsequenceIterator contains the central business logic to implement the fn:subsequence() function. The detailed behavior, such as how it behaves if the source QAbstractXmlForwardIterator is empty or if the specified subsequence stretches beyond the source QAbstractXmlForwardIterator, is therefore consistent with the definition of the fn:subsequence() function.

See also: XQuery 1.0 and XPath 2.0 Functions and Operators, 15.1.10 fn:subsequence

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

Definition at line 81 of file qsubsequenceiterator_p.h.

Constructors and Destructors

◆ SubsequenceIterator()

SubsequenceIterator::SubsequenceIterator	(	const Item::Iterator::Ptr &	iterator,
		const xsInteger	start,
		const xsInteger	length
	)

Creates a SubsequenceIterator that extracts a subsequence from the sequence in iterator, as specified by the start position and length parameter.

Parameters

iterator	the iterator which the subsequence should be extracted from
start	the start position of extraction. Must be 1 or larger.
length	the length of the subsequence to extract. If it is -1, to the end is returned. The value must be -1 or 1 or larger.

Definition at line 50 of file qsubsequenceiterator.cpp.

Referenced by copy().

                                          : m_position(0),
                                            m_it(iterator),
                                            m_counter(start),
                                            m_start(start),
                                            m_len(len),
                                            m_stop(m_start + m_len)
 {
     Q_ASSERT(iterator);
     Q_ASSERT(start >= 1);
     Q_ASSERT(len == -1 || len >= 1);
 
     /* Note, "The first item of a sequence is located at position 1, not position 0." */
     for(xsInteger i = 1; i != m_start; ++i)
         m_it->next();
 }

Functions

◆ copy()

Item::Iterator::Ptr SubsequenceIterator::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< T >.

Definition at line 105 of file qsubsequenceiterator.cpp.

 {
     return Item::Iterator::Ptr(new SubsequenceIterator(m_it->copy(), m_start, m_len));
 }

◆ current()

Item SubsequenceIterator::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< T >.

Definition at line 95 of file qsubsequenceiterator.cpp.

 {
     return m_current;
 }

◆ next()

Item SubsequenceIterator::next ( )

virtual

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

Implements QAbstractXmlForwardIterator< T >.

Definition at line 69 of file qsubsequenceiterator.cpp.

 {
     if(m_position == -1)
         return Item();
 
     m_current = m_it->next();
     ++m_position;
 
     if(m_len == -1)
     {
         if(!m_current)
             m_position = -1;
 
         return m_current;
     }
 
     ++m_counter;
 
     if(!(m_counter > m_stop) && m_current)
         return m_current;
 
     m_position = -1;
     m_current.reset();
     return Item();
 }

◆ position()

xsInteger SubsequenceIterator::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< T >.

Definition at line 100 of file qsubsequenceiterator.cpp.

 {
     return m_position;
 }

Properties

◆ m_counter

xsInteger QPatternist::SubsequenceIterator::m_counter

private

Definition at line 107 of file qsubsequenceiterator_p.h.

Referenced by next().

◆ m_current

Item QPatternist::SubsequenceIterator::m_current

private

Definition at line 105 of file qsubsequenceiterator_p.h.

Referenced by current(), and next().

◆ m_it

const Item::Iterator::Ptr QPatternist::SubsequenceIterator::m_it

private

Definition at line 106 of file qsubsequenceiterator_p.h.

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

◆ m_len

const xsInteger QPatternist::SubsequenceIterator::m_len

private

Definition at line 109 of file qsubsequenceiterator_p.h.

Referenced by copy(), and next().

◆ m_position

xsInteger QPatternist::SubsequenceIterator::m_position

private

Definition at line 104 of file qsubsequenceiterator_p.h.

Referenced by next(), and position().

◆ m_start

const xsInteger QPatternist::SubsequenceIterator::m_start

private

Definition at line 108 of file qsubsequenceiterator_p.h.

Referenced by copy(), and SubsequenceIterator().

◆ m_stop

const xsInteger QPatternist::SubsequenceIterator::m_stop

private

Definition at line 110 of file qsubsequenceiterator_p.h.

Referenced by next().

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

/src/xmlpatterns/iterators/qsubsequenceiterator_p.h
/src/xmlpatterns/iterators/qsubsequenceiterator.cpp

Public Functions

Properties

Additional Inherited Members

Detailed Description

Constructors and Destructors

◆ SubsequenceIterator()

Functions

◆ copy()

◆ current()

◆ next()

◆ position()

Properties

◆ m_counter

◆ m_current

◆ m_it

◆ m_len

◆ m_position

◆ m_start

◆ m_stop