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#include <math.h>

#include <QObject>
#include <QMainWindow>
#include <QIODevice>
#include <QTimer>
#include <QPushButton>
#include <QComboBox>
#include <QByteArray>

#include <QAudioOutput>

class Generator : public QIODevice
{
    Q_OBJECT
public:
    Generator(const QAudioFormat &format, qint64 durationUs, int frequency, QObject *parent);
    ~Generator();

    void start();
    void stop();

    qint64 readData(char *data, qint64 maxlen);
    qint64 writeData(const char *data, qint64 len);
    qint64 bytesAvailable() const;

private:
    void generateData(const QAudioFormat &format, qint64 durationUs, int frequency);

private:
    qint64 m_pos;
    QByteArray m_buffer;
};

class AudioTest : public QMainWindow
{
    Q_OBJECT
public:
    AudioTest();
    ~AudioTest();

private:
    void initializeWindow();
    void initializeAudio();
    void createAudioOutput();

private:
    QTimer*          m_pullTimer;

    // Owned by layout
    QPushButton*     m_modeButton;
    QPushButton*     m_suspendResumeButton;
    QComboBox*       m_deviceBox;

    QAudioDeviceInfo m_device;
    Generator*       m_generator;
    QAudioOutput*    m_audioOutput;
    QIODevice*       m_output; // not owned
    QAudioFormat     m_format;

    bool             m_pullMode;
    QByteArray       m_buffer;

    static const QString PushModeLabel;
    static const QString PullModeLabel;
    static const QString SuspendLabel;
    static const QString ResumeLabel;

private slots:
    void notified();
    void pullTimerExpired();
    void toggleMode();
    void toggleSuspendResume();
    void stateChanged(QAudio::State state);
    void deviceChanged(int index);
};