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Diffstat (limited to 'src/xmlpatterns/iterators/qemptyiterator_p.h')
| -rw-r--r-- | src/xmlpatterns/iterators/qemptyiterator_p.h | 146 |
1 files changed, 146 insertions, 0 deletions
diff --git a/src/xmlpatterns/iterators/qemptyiterator_p.h b/src/xmlpatterns/iterators/qemptyiterator_p.h new file mode 100644 index 0000000..310512e --- /dev/null +++ b/src/xmlpatterns/iterators/qemptyiterator_p.h @@ -0,0 +1,146 @@ +/**************************************************************************** +** +** 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_EmptyIterator_H +#define Patternist_EmptyIterator_H + +#include "qabstractxmlforwarditerator_p.h" +#include "qprimitives_p.h" + +QT_BEGIN_HEADER + +QT_BEGIN_NAMESPACE + +namespace QPatternist +{ + + /** + * @short An QAbstractXmlForwardIterator which always is empty. + * + * EmptyIterator is an QAbstractXmlForwardIterator over the type @c T, which always is empty. Other + * iterators can also be empty(or, at least behave as they are empty), but this + * class is special designed for this purpose and is therefore fast. + * + * EmptyIterator's constructor is protected, instances is retrieved from CommonValues. + * + * @author Frans Englich <fenglich@trolltech.com> + * @ingroup Patternist_iterators + */ + template<typename T> class EmptyIterator : public QAbstractXmlForwardIterator<T> + { + public: + /** + * @returns always a default constructed value, T(). + */ + virtual T next() + { + return T(); + } + + /** + * @returns always a default constructed value, T(). + */ + virtual T current() const + { + return T(); + } + + /** + * @returns always 0. + */ + virtual xsInteger position() const + { + return 0; + } + + /** + * @returns always @c this, the reverse of <tt>()</tt> is <tt>()</tt>. + */ + virtual typename QAbstractXmlForwardIterator<T>::Ptr toReversed() + { + return typename QAbstractXmlForwardIterator<T>::Ptr(const_cast<EmptyIterator<T> *>(this)); + } + + /** + * @returns always 0 + */ + virtual xsInteger count() + { + return 0; + } + + /** + * @returns @c this + */ + virtual typename QAbstractXmlForwardIterator<T>::Ptr copy() const + { + return typename QAbstractXmlForwardIterator<T>::Ptr(const_cast<EmptyIterator *>(this)); + } + + protected: + friend class CommonValues; + }; + + template<typename T> + static inline + typename QAbstractXmlForwardIterator<T>::Ptr + makeEmptyIterator() + { + return typename QAbstractXmlForwardIterator<T>::Ptr(new EmptyIterator<T>()); + } + +} + +QT_END_NAMESPACE + +QT_END_HEADER + +#endif |