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Diffstat (limited to 'src/xmlpatterns/expr/qoperandsiterator_p.h')
| -rw-r--r-- | src/xmlpatterns/expr/qoperandsiterator_p.h | 193 |
1 files changed, 193 insertions, 0 deletions
diff --git a/src/xmlpatterns/expr/qoperandsiterator_p.h b/src/xmlpatterns/expr/qoperandsiterator_p.h new file mode 100644 index 0000000..195c512 --- /dev/null +++ b/src/xmlpatterns/expr/qoperandsiterator_p.h @@ -0,0 +1,193 @@ +/**************************************************************************** +** +** 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_OperandsIterator_H +#define Patternist_OperandsIterator_H + +#include <QPair> +#include <QStack> + +#include "qexpression_p.h" + +QT_BEGIN_HEADER + +QT_BEGIN_NAMESPACE + +namespace QPatternist +{ + /** + * @short A helper class that iterates a tree of Expression instances. It + * is not a sub-class of QAbstractXmlForwardIterator. + * + * The OperandsIterator delivers all Expression instances that are children at any + * depth of the Expression passed in the constructor. + * The order is delivered in a defined way, from left to right and depth + * first. + * + * @author Frans Englich <fenglich@trolltech.com> + */ + class OperandsIterator + { + /** + * The second value, the int, is the current position in the first. + */ + typedef QPair<Expression::List, int> Level; + + public: + enum TreatParent + { + ExcludeParent, + IncludeParent + }; + + /** + * if @p treatParent is @c IncludeParent, @p start is excluded. + * + * @p start must be a valid Expression. + */ + inline OperandsIterator(const Expression::Ptr &start, + const TreatParent treatParent) + { + Q_ASSERT(start); + if(treatParent == IncludeParent) + { + Expression::List l; + l.append(start); + m_exprs.push(qMakePair(l, -1)); + } + + m_exprs.push(qMakePair(start->operands(), -1)); + } + + /** + * @short Returns the current Expression and advances the iterator. + * + * If the end has been reached, a default constructed pointer is + * returned. + * + * We intentionally return by reference. + */ + inline Expression::Ptr next() + { + if(m_exprs.isEmpty()) + return Expression::Ptr(); + + Level &lvl = m_exprs.top(); + ++lvl.second; + + if(lvl.second == lvl.first.size()) + { + /* Resume iteration above us. */ + m_exprs.pop(); + + if(m_exprs.isEmpty()) + return Expression::Ptr(); + + while(true) + { + Level &previous = m_exprs.top(); + ++previous.second; + + if(previous.second < previous.first.count()) + { + const Expression::Ptr &op = previous.first.at(previous.second); + m_exprs.push(qMakePair(op->operands(), -1)); + return op; + } + else + { + // We have already reached the end of this level. + m_exprs.pop(); + if(m_exprs.isEmpty()) + return Expression::Ptr(); + } + } + } + else + { + const Expression::Ptr &op = lvl.first.at(lvl.second); + m_exprs.push(qMakePair(op->operands(), -1)); + return op; + } + } + + /** + * Advances this iterator by the current expression and its operands. + */ + Expression::Ptr skipOperands() + { + if(m_exprs.isEmpty()) + return Expression::Ptr(); + + Level &lvl = m_exprs.top(); + ++lvl.second; + + if(lvl.second == lvl.first.size()) + { + /* We've reached the end of this level, at least. */ + m_exprs.pop(); + } + + return next(); + } + + private: + Q_DISABLE_COPY(OperandsIterator) + + QStack<Level> m_exprs; + }; +} + + +QT_END_NAMESPACE +QT_END_HEADER + +#endif |