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#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