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+/****************************************************************************
+**
+** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the QtCore module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial Usage
+** Licensees holding valid Qt Commercial licenses may use this file in
+** accordance with the Qt Commercial License Agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Nokia.
+**
+** 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.
+**
+** 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 have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QTCONCURRENT_MEDIAN_H
+#define QTCONCURRENT_MEDIAN_H
+
+#include <QtCore/qglobal.h>
+
+#ifndef QT_NO_CONCURRENT
+
+#include <QtCore/qvector.h>
+#include <QtCore/qalgorithms.h>
+
+QT_BEGIN_HEADER
+QT_BEGIN_NAMESPACE
+
+QT_MODULE(Core)
+
+#ifndef qdoc
+
+namespace QtConcurrent {
+
+template <typename T>
+class Median
+{
+public:
+ Median(int _bufferSize)
+ : currentMedian(), bufferSize(_bufferSize), currentIndex(0), valid(false), dirty(true)
+ {
+ values.resize(bufferSize);
+ }
+
+ void reset()
+ {
+ values.fill(0);
+ currentIndex = 0;
+ valid = false;
+ dirty = true;
+ }
+
+ void addValue(T value)
+ {
+ currentIndex = ((currentIndex + 1) % bufferSize);
+ if (valid == false && currentIndex % bufferSize == 0)
+ valid = true;
+
+ // Only update the cached median value when we have to, that
+ // is when the new value is on then other side of the median
+ // compared to the current value at the index.
+ const T currentIndexValue = values[currentIndex];
+ if ((currentIndexValue > currentMedian && currentMedian > value)
+ || (currentMedian > currentIndexValue && value > currentMedian)) {
+ dirty = true;
+ }
+
+ values[currentIndex] = value;
+ }
+
+ bool isMedianValid() const
+ {
+ return valid;
+ }
+
+ T median()
+ {
+ if (dirty) {
+ dirty = false;
+ QVector<T> sorted = values;
+ qSort(sorted);
+ currentMedian = sorted.at(bufferSize / 2 + 1);
+ }
+ return currentMedian;
+ }
+private:
+ QVector<T> values;
+ T currentMedian;
+ int bufferSize;
+ int currentIndex;
+ bool valid;
+ bool dirty;
+};
+
+} // namespace QtConcurrent
+
+#endif //qdoc
+
+QT_END_NAMESPACE
+QT_END_HEADER
+
+#endif // QT_NO_CONCURRENT
+
+#endif