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#include <QDebug>

#include <QVBoxLayout>

#include <QAudioOutput>

#include <QAudioDeviceInfo>

#include <QtCore/qmath.h>

#include <QtCore/qendian.h>

#include "audiooutput.h"

const QString AudioTest::PushModeLabel(tr("Enable push mode"));

const QString AudioTest::PullModeLabel(tr("Enable pull mode"));

const QString AudioTest::SuspendLabel(tr("Suspend playback"));

const QString AudioTest::ResumeLabel(tr("Resume playback"));

const int DurationSeconds = 1;

const int ToneFrequencyHz = 600;

const int DataFrequencyHz = 44100;

const int BufferSize      = 32768;

Generator::Generator(const QAudioFormat &format,

                     qint64 durationUs,

                     int frequency,

                     QObject *parent)

    :   QIODevice(parent)

    ,   m_pos(0)

{

    generateData(format, durationUs, frequency);

}

Generator::~Generator()

{

}

void Generator::start()

{

    open(QIODevice::ReadOnly);

}

void Generator::stop()

{

    m_pos = 0;

    close();

}

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

{

    const int channelBytes = format.sampleSize() / 8;

    const int sampleBytes = format.channels() * channelBytes;

    qint64 length = (format.frequency() * format.channels() * (format.sampleSize() / 8))

                        * durationUs / 100000;

    Q_ASSERT(length % sampleBytes == 0);

    Q_UNUSED(sampleBytes) // suppress warning in release builds

    m_buffer.resize(length);

    unsigned char *ptr = reinterpret_cast<unsigned char *>(m_buffer.data());

    int sampleIndex = 0;

    while (length) {

        const qreal x = qSin(2 * M_PI * frequency * qreal(sampleIndex % format.frequency()) / format.frequency());

        for (int i=0; i<format.channels(); ++i) {

            if (format.sampleSize() == 8 && format.sampleType() == QAudioFormat::UnSignedInt) {

                const quint8 value = static_cast<quint8>((1.0 + x) / 2 * 255);

                *reinterpret_cast<quint8*>(ptr) = value;

            } else if (format.sampleSize() == 8 && format.sampleType() == QAudioFormat::SignedInt) {

                const qint8 value = static_cast<qint8>(x * 127);

                *reinterpret_cast<quint8*>(ptr) = value;

            } else if (format.sampleSize() == 16 && format.sampleType() == QAudioFormat::UnSignedInt) {

                quint16 value = static_cast<quint16>((1.0 + x) / 2 * 65535);

                if (format.byteOrder() == QAudioFormat::LittleEndian)

                    qToLittleEndian<quint16>(value, ptr);

                else

                    qToBigEndian<quint16>(value, ptr);

            } else if (format.sampleSize() == 16 && format.sampleType() == QAudioFormat::SignedInt) {

                qint16 value = static_cast<qint16>(x * 32767);

                if (format.byteOrder() == QAudioFormat::LittleEndian)

                    qToLittleEndian<qint16>(value, ptr);

                else

                    qToBigEndian<qint16>(value, ptr);

            }

            ptr += channelBytes;

            length -= channelBytes;

        }

        ++sampleIndex;

    }

}

qint64 Generator::readData(char *data, qint64 len)

{

    qint64 total = 0;

    while (len - total) {

        const qint64 chunk = qMin((m_buffer.size() - m_pos), len - total);

        memcpy(data, m_buffer.constData() + m_pos, chunk);

        m_pos = (m_pos + chunk) % m_buffer.size();

        total += chunk;

    }

    return total;

}

qint64 Generator::writeData(const char *data, qint64 len)

{

    Q_UNUSED(data);

    Q_UNUSED(len);

    return 0;

}

qint64 Generator::bytesAvailable() const

{

    return m_buffer.size() + QIODevice::bytesAvailable();

}

AudioTest::AudioTest()

    :   m_pullTimer(new QTimer(this))

    ,   m_modeButton(0)

    ,   m_suspendResumeButton(0)

    ,   m_deviceBox(0)

    ,   m_device(QAudioDeviceInfo::defaultOutputDevice())

    ,   m_generator(0)

    ,   m_audioOutput(0)

    ,   m_output(0)

    ,   m_buffer(BufferSize, 0)

{

    initializeWindow();

    initializeAudio();

}

void AudioTest::initializeWindow()

{

    QScopedPointer<QWidget> window(new QWidget);

    QScopedPointer<QVBoxLayout> layout(new QVBoxLayout);

    m_deviceBox = new QComboBox(this);

    foreach (const QAudioDeviceInfo &deviceInfo, QAudioDeviceInfo::availableDevices(QAudio::AudioOutput))

        m_deviceBox->addItem(deviceInfo.deviceName(), qVariantFromValue(deviceInfo));

    connect(m_deviceBox,SIGNAL(activated(int)),SLOT(deviceChanged(int)));

    layout->addWidget(m_deviceBox);

    m_modeButton = new QPushButton(this);

    m_modeButton->setText(PushModeLabel);

    connect(m_modeButton, SIGNAL(clicked()), SLOT(toggleMode()));

    layout->addWidget(m_modeButton);

    m_suspendResumeButton = new QPushButton(this);

    m_suspendResumeButton->setText(SuspendLabel);

    connect(m_suspendResumeButton, SIGNAL(clicked()), SLOT(toggleSuspendResume()));

    layout->addWidget(m_suspendResumeButton);

    window->setLayout(layout.data());

    layout.take(); // ownership transferred

    setCentralWidget(window.data());

    QWidget *const windowPtr = window.take(); // ownership transferred

    windowPtr->show();

}

void AudioTest::initializeAudio()

{

    connect(m_pullTimer, SIGNAL(timeout()), SLOT(pullTimerExpired()));

    m_pullMode = true;

    m_format.setFrequency(DataFrequencyHz);

    m_format.setChannels(1);

    m_format.setSampleSize(16);

    m_format.setCodec("audio/pcm");

    m_format.setByteOrder(QAudioFormat::LittleEndian);

    m_format.setSampleType(QAudioFormat::SignedInt);

    QAudioDeviceInfo info(QAudioDeviceInfo::defaultOutputDevice());

    if (!info.isFormatSupported(m_format)) {

        qWarning() << "Default format not supported - trying to use nearest";

        m_format = info.nearestFormat(m_format);

    }

    m_generator = new Generator(m_format, DurationSeconds*1000000, ToneFrequencyHz, this);

    createAudioOutput();

}

void AudioTest::createAudioOutput()

{

    delete m_audioOutput;

    m_audioOutput = 0;

    m_audioOutput = new QAudioOutput(m_device, m_format, this);

    connect(m_audioOutput, SIGNAL(notify()), SLOT(notified()));

    connect(m_audioOutput, SIGNAL(stateChanged(QAudio::State)), SLOT(stateChanged(QAudio::State)));

    m_generator->start();

    m_audioOutput->start(m_generator);

}

AudioTest::~AudioTest()

{

}

void AudioTest::deviceChanged(int index)

{

    m_pullTimer->stop();

    m_generator->stop();

    m_audioOutput->stop();

    m_audioOutput->disconnect(this);

    m_device = m_deviceBox->itemData(index).value<QAudioDeviceInfo>();

    createAudioOutput();

}

void AudioTest::notified()

{

    qWarning() << "bytesFree = " << m_audioOutput->bytesFree()

               << ", " << "elapsedUSecs = " << m_audioOutput->elapsedUSecs()

               << ", " << "processedUSecs = " << m_audioOutput->processedUSecs();

}

void AudioTest::pullTimerExpired()

{

    if (m_audioOutput && m_audioOutput->state() != QAudio::StoppedState) {

        int chunks = m_audioOutput->bytesFree()/m_audioOutput->periodSize();

        while (chunks) {

           const qint64 len = m_generator->read(m_buffer.data(), m_audioOutput->periodSize());

           if (len)

               m_output->write(m_buffer.data(), len);

           if (len != m_audioOutput->periodSize())

               break;

           --chunks;

        }

    }

}

void AudioTest::toggleMode()

{

    m_pullTimer->stop();

    m_audioOutput->stop();

    if (m_pullMode) {

        m_modeButton->setText(PullModeLabel);

        m_output = m_audioOutput->start();

        m_pullMode = false;

        m_pullTimer->start(20);

    } else {

        m_modeButton->setText(PushModeLabel);

        m_pullMode = true;

        m_audioOutput->start(m_generator);

    }

    m_suspendResumeButton->setText(SuspendLabel);

}

void AudioTest::toggleSuspendResume()

{

    if (m_audioOutput->state() == QAudio::SuspendedState) {

        qWarning() << "status: Suspended, resume()";

        m_audioOutput->resume();

        m_suspendResumeButton->setText(SuspendLabel);

    } else if (m_audioOutput->state() == QAudio::ActiveState) {

        qWarning() << "status: Active, suspend()";

        m_audioOutput->suspend();

        m_suspendResumeButton->setText(ResumeLabel);

    } else if (m_audioOutput->state() == QAudio::StoppedState) {

        qWarning() << "status: Stopped, resume()";

        m_audioOutput->resume();

        m_suspendResumeButton->setText(SuspendLabel);

    } else if (m_audioOutput->state() == QAudio::IdleState) {

        qWarning() << "status: IdleState";

    }

}

void AudioTest::stateChanged(QAudio::State state)

{

    qWarning() << "state = " << state;

}