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Diffstat (limited to 'src/xmlpatterns/iterators/qsingletoniterator_p.h')
| -rw-r--r-- | src/xmlpatterns/iterators/qsingletoniterator_p.h | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/src/xmlpatterns/iterators/qsingletoniterator_p.h b/src/xmlpatterns/iterators/qsingletoniterator_p.h new file mode 100644 index 0000000..d37f057 --- /dev/null +++ b/src/xmlpatterns/iterators/qsingletoniterator_p.h @@ -0,0 +1,177 @@ +/**************************************************************************** +** +** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). +** Contact: Qt Software Information (qt-info@nokia.com) +** +** This file is part of the QtXmlPatterns module of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** No Commercial Usage +** This file contains pre-release code and may not be distributed. +** You may use this file in accordance with the terms and conditions +** contained in the either Technology Preview License Agreement or the +** Beta Release License Agreement. +** +** GNU Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 2.1 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 2.1 requirements +** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. +** +** In addition, as a special exception, Nokia gives you certain +** additional rights. These rights are described in the Nokia Qt LGPL +** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this +** package. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 3.0 as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU General Public License version 3.0 requirements will be +** met: http://www.gnu.org/copyleft/gpl.html. +** +** If you are unsure which license is appropriate for your use, please +** contact the sales department at qt-sales@nokia.com. +** $QT_END_LICENSE$ +** +****************************************************************************/ + +// +// W A R N I N G +// ------------- +// +// This file is not part of the Qt API. It exists purely as an +// implementation detail. This header file may change from version to +// version without notice, or even be removed. +// +// We mean it. + +#ifndef Patternist_SingletonIterator_H +#define Patternist_SingletonIterator_H + +#include <QtXmlPatterns/private/qabstractxmlforwarditerator_p.h> + +#include <QtXmlPatterns/private/qprimitives_p.h> + +QT_BEGIN_HEADER + +QT_BEGIN_NAMESPACE + +namespace QPatternist +{ + /** + * @short An QAbstractXmlForwardIterator over exactly one item. + * + * SingletonIterator's constructor takes one value which is + * the item it forms an QAbstractXmlForwardIterator over. Other QAbstractXmlForwardIterator instances can + * also form an QAbstractXmlForwardIterator with one in length, but by that SingletonIterator + * has this as it only task, it means it is efficient at it. + * + * Having to represent single items in Iterators is relatively common. + * + * @author Frans Englich <fenglich@trolltech.com> + * @ingroup Patternist_iterators + */ + template<typename T> + class SingletonIterator : public QAbstractXmlForwardIterator<T> + { + public: + /** + * Creates an iterator over @p item. + * + * @note item may not be @c null. Use the EmptyIterator for + * the empty sequence + */ + SingletonIterator(const T &item) : m_item(item), + m_position(0) + { + Q_ASSERT(!qIsForwardIteratorEnd(item)); + } + + virtual T next() + { + switch(m_position) + { + case 0: + { + ++m_position; + return m_item; + } + case 1: + { + m_position = -1; + return T(); + } + default: + { + Q_ASSERT(m_position == -1); + return T(); + } + } + } + + virtual T current() const + { + if(m_position == 1) + return m_item; + else + return T(); + } + + virtual xsInteger position() const + { + return m_position; + } + + /** + * @returns a copy of this instance, rewinded to the beginning. + */ + virtual typename QAbstractXmlForwardIterator<T>::Ptr toReversed() + { + return typename QAbstractXmlForwardIterator<T>::Ptr(new SingletonIterator<T>(m_item)); + } + + /** + * @returns always 1 + */ + virtual xsInteger count() + { + return 1; + } + + virtual typename QAbstractXmlForwardIterator<T>::Ptr copy() const + { + return typename QAbstractXmlForwardIterator<T>::Ptr(new SingletonIterator(m_item)); + } + + private: + const T m_item; + qint8 m_position; + }; + + /** + * @short An object generator for SingletonIterator. + * + * makeSingletonIterator() is a convenience function for avoiding specifying + * the full template instantiation for SingletonIterator. Conceptually, it + * is identical to Qt's qMakePair(). + * + * @relates SingletonIterator + */ + template<typename T> + inline + typename SingletonIterator<T>::Ptr + makeSingletonIterator(const T &item) + { + return typename SingletonIterator<T>::Ptr(new SingletonIterator<T>(item)); + } +} + +QT_END_NAMESPACE + +QT_END_HEADER + +#endif |