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/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** Contact: Nokia Corporation (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 http://qt.nokia.com/contact.
** $QT_END_LICENSE$
**
****************************************************************************/
//
// 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_DistinctIterator_H
#define Patternist_DistinctIterator_H
#include <QList>
#include "qexpression_p.h"
#include "qitem_p.h"
#include "qatomiccomparator_p.h"
#include "qcomparisonplatform_p.h"
#include "qsourcelocationreflection_p.h"
QT_BEGIN_HEADER
QT_BEGIN_NAMESPACE
namespace QPatternist
{
/**
* @short Filters another sequence by removing duplicates such that the items are unique.
*
* DistinctIterator takes an input sequence, and returns a sequence where each
* item is unique. Thus, DistinctIterator removes the duplicates of items
* in a sequence. DistinctIterator is central in the implementation of the
* <tt>fn:distinct-values()</tt> function.
*
* @see <a href="http://www.w3.org/TR/xpath-functions/#func-distinct-values">XQuery 1.0
* and XPath 2.0 Functions and Operators, 15.1.6 fn:distinct-values</a>
* @author Frans Englich <fenglich@trolltech.com>
* @ingroup Patternist_iterators
*/
class DistinctIterator : public Item::Iterator
, public ComparisonPlatform<DistinctIterator, false>
, public SourceLocationReflection
{
public:
/**
* Creates a DistinctIterator.
* @param comp the AtomicComparator to be used for comparing values. This may be @c null,
* meaning the IndexOfIterator iterator will dynamically determine what comparator to use
* @param seq the sequence whose duplicates should be filtered out
* @param context the usual context, used for error reporting and by AtomicComparators.
* @param expression the Expression that this DistinctIterator is
* evaluating for. It is used for error reporting, via
* actualReflection().
*/
DistinctIterator(const Item::Iterator::Ptr &seq,
const AtomicComparator::Ptr &comp,
const Expression::ConstPtr &expression,
const DynamicContext::Ptr &context);
virtual Item next();
virtual Item current() const;
virtual xsInteger position() const;
virtual Item::Iterator::Ptr copy() const;
virtual const SourceLocationReflection *actualReflection() const;
inline AtomicComparator::Operator operatorID() const
{
return AtomicComparator::OperatorEqual;
}
private:
const Item::Iterator::Ptr m_seq;
const DynamicContext::Ptr m_context;
const Expression::ConstPtr m_expr;
Item m_current;
xsInteger m_position;
Item::List m_processed;
};
}
QT_END_NAMESPACE
QT_END_HEADER
#endif
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