/**************************************************************************** | |
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** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies). | |
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** GNU Lesser General Public License Usage | |
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** rights. These rights are described in the Nokia Qt LGPL Exception | |
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** | |
** GNU General Public License Usage | |
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** file. Please review the following information to ensure the GNU General | |
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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 |