src/xmlpatterns/iterators/qdistinctiterator_p.h
changeset 0 1918ee327afb
child 4 3b1da2848fc7
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/xmlpatterns/iterators/qdistinctiterator_p.h	Mon Jan 11 14:00:40 2010 +0000
@@ -0,0 +1,128 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** 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 Technology Preview License Agreement accompanying
+** this package.
+**
+** 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 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@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_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 <frans.englich@nokia.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