| /**************************************************************************** |
| ** |
| ** Copyright (C) 2011 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. |
| ** |
| ** $QT_BEGIN_LICENSE:LGPL$ |
| ** GNU Lesser General Public License Usage |
| ** 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 |
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| ** file. Please review the following information to ensure the GNU Lesser |
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| ** |
| ** 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 |
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| ** |
| ** Other Usage |
| ** Alternatively, this file may be used in accordance with the terms and |
| ** conditions contained in a signed written agreement between you and Nokia. |
| ** |
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| ** $QT_END_LICENSE$ |
| ** |
| ****************************************************************************/ |
| |
| #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 |