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#include "qcoreaudioutils_p.h"
#include <qdebug.h>
#include <mach/mach_time.h>

QT_BEGIN_NAMESPACE

double CoreAudioUtils::sFrequency = 0.0;
bool CoreAudioUtils::sIsInitialized = false;

void CoreAudioUtils::initialize()
{
    struct mach_timebase_info timeBaseInfo;
    mach_timebase_info(&timeBaseInfo);
    sFrequency = static_cast<double>(timeBaseInfo.denom) / static_cast<double>(timeBaseInfo.numer);
    sFrequency *= 1000000000.0;

    sIsInitialized = true;
}


quint64 CoreAudioUtils::currentTime()
{
    return mach_absolute_time();
}

double CoreAudioUtils::frequency()
{
    if (!sIsInitialized)
        initialize();
    return sFrequency;
}

QAudioFormat CoreAudioUtils::toQAudioFormat(AudioStreamBasicDescription const& sf)
{
    QAudioFormat    audioFormat;
    // all Darwin HW is little endian, we ignore those formats
    if ((sf.mFormatFlags & kAudioFormatFlagIsBigEndian) != 0 && QSysInfo::ByteOrder != QSysInfo::LittleEndian)
        return audioFormat;

    // filter out the formats we're interested in
    QAudioFormat::SampleFormat format = QAudioFormat::Unknown;
    switch (sf.mBitsPerChannel) {
    case 8:
        if ((sf.mFormatFlags & kAudioFormatFlagIsSignedInteger) == 0)
            format = QAudioFormat::UInt8;
        break;
    case 16:
        if ((sf.mFormatFlags & kAudioFormatFlagIsSignedInteger) != 0)
            format = QAudioFormat::Int16;
        break;
    case 32:
        if ((sf.mFormatFlags & kAudioFormatFlagIsSignedInteger) != 0)
            format = QAudioFormat::Int32;
        else if ((sf.mFormatFlags & kAudioFormatFlagIsFloat) != 0)
            format = QAudioFormat::Float;
        break;
    default:
        break;
    }

    audioFormat.setSampleFormat(format);
    audioFormat.setSampleRate(sf.mSampleRate);
    audioFormat.setChannelCount(sf.mChannelsPerFrame);

    return audioFormat;
}

AudioStreamBasicDescription CoreAudioUtils::toAudioStreamBasicDescription(QAudioFormat const& audioFormat)
{
    AudioStreamBasicDescription sf;

    sf.mFormatFlags         = kAudioFormatFlagIsPacked;
    sf.mSampleRate          = audioFormat.sampleRate();
    sf.mFramesPerPacket     = 1;
    sf.mChannelsPerFrame    = audioFormat.channelCount();
    sf.mBitsPerChannel      = audioFormat.bytesPerSample() * 8;
    sf.mBytesPerFrame       = audioFormat.bytesPerFrame();
    sf.mBytesPerPacket      = sf.mFramesPerPacket * sf.mBytesPerFrame;
    sf.mFormatID            = kAudioFormatLinearPCM;

    switch (audioFormat.sampleFormat()) {
    case QAudioFormat::Int16:
    case QAudioFormat::Int32:
        sf.mFormatFlags |= kAudioFormatFlagIsSignedInteger;
        break;
    case QAudioFormat::Float:
        sf.mFormatFlags |= kAudioFormatFlagIsFloat;
        break;
    case QAudioFormat::UInt8:
        /* default */
    case QAudioFormat::Unknown:
    case QAudioFormat::NSampleFormats:
        break;
    }

    return sf;
}


static constexpr struct {
    QAudioFormat::AudioChannelPosition pos;
    AudioChannelLabel label;
} channelMap[] =  {
        { QAudioFormat::FrontLeft, kAudioChannelLabel_Left },
        { QAudioFormat::FrontRight, kAudioChannelLabel_Right },
        { QAudioFormat::FrontCenter, kAudioChannelLabel_Center },
        { QAudioFormat::LFE, kAudioChannelLabel_LFEScreen },
        { QAudioFormat::BackLeft, kAudioChannelLabel_LeftSurround },
        { QAudioFormat::BackRight, kAudioChannelLabel_RightSurround },
        { QAudioFormat::FrontLeftOfCenter, kAudioChannelLabel_LeftCenter },
        { QAudioFormat::FrontRightOfCenter, kAudioChannelLabel_RightCenter },
        { QAudioFormat::BackCenter, kAudioChannelLabel_CenterSurround },
        { QAudioFormat::LFE2, kAudioChannelLabel_LFE2 },
        { QAudioFormat::SideLeft, kAudioChannelLabel_LeftSurroundDirect }, // ???
        { QAudioFormat::SideRight, kAudioChannelLabel_RightSurroundDirect }, // ???
        { QAudioFormat::TopFrontLeft, kAudioChannelLabel_VerticalHeightLeft },
        { QAudioFormat::TopFrontRight, kAudioChannelLabel_VerticalHeightRight },
        { QAudioFormat::TopFrontCenter, kAudioChannelLabel_VerticalHeightCenter },
        { QAudioFormat::TopCenter, kAudioChannelLabel_CenterTopMiddle },
        { QAudioFormat::TopBackLeft, kAudioChannelLabel_TopBackLeft },
        { QAudioFormat::TopBackRight, kAudioChannelLabel_TopBackRight },
        { QAudioFormat::TopSideLeft, kAudioChannelLabel_LeftTopMiddle },
        { QAudioFormat::TopSideRight, kAudioChannelLabel_RightTopMiddle },
        { QAudioFormat::TopBackCenter, kAudioChannelLabel_TopBackCenter },
};

std::unique_ptr<AudioChannelLayout> CoreAudioUtils::toAudioChannelLayout(const QAudioFormat &format, UInt32 *size)
{
    auto channelConfig = format.channelConfig();
    if (channelConfig == QAudioFormat::ChannelConfigUnknown)
        channelConfig = QAudioFormat::defaultChannelConfigForChannelCount(format.channelCount());

    *size = sizeof(AudioChannelLayout) + int(QAudioFormat::NChannelPositions)*sizeof(AudioChannelDescription);
    auto *layout = static_cast<AudioChannelLayout *>(malloc(*size));
    memset(layout, 0, *size);
    layout->mChannelLayoutTag = kAudioChannelLayoutTag_UseChannelDescriptions;

    for (const auto &m : channelMap) {
        if (channelConfig & QAudioFormat::channelConfig(m.pos))
            layout->mChannelDescriptions[layout->mNumberChannelDescriptions++].mChannelLabel = m.label;
    }

    if (channelConfig & QAudioFormat::channelConfig(QAudioFormat::BottomFrontCenter)) {
        auto &desc = layout->mChannelDescriptions[layout->mNumberChannelDescriptions++];
        desc.mChannelLabel = kAudioChannelLabel_UseCoordinates;
        desc.mChannelFlags = kAudioChannelFlags_SphericalCoordinates;
        desc.mCoordinates[kAudioChannelCoordinates_Azimuth] = 0.f;
        desc.mCoordinates[kAudioChannelCoordinates_Elevation] = -20.;
        desc.mCoordinates[kAudioChannelCoordinates_Distance] = 1.f;
    }
    if (channelConfig & QAudioFormat::channelConfig(QAudioFormat::BottomFrontLeft)) {
        auto &desc = layout->mChannelDescriptions[layout->mNumberChannelDescriptions++];
        desc.mChannelLabel = kAudioChannelLabel_UseCoordinates;
        desc.mChannelFlags = kAudioChannelFlags_SphericalCoordinates;
        desc.mCoordinates[kAudioChannelCoordinates_Azimuth] = -45.f;
        desc.mCoordinates[kAudioChannelCoordinates_Elevation] = -20.;
        desc.mCoordinates[kAudioChannelCoordinates_Distance] = 1.f;
    }
    if (channelConfig & QAudioFormat::channelConfig(QAudioFormat::BottomFrontRight)) {
        auto &desc = layout->mChannelDescriptions[layout->mNumberChannelDescriptions++];
        desc.mChannelLabel = kAudioChannelLabel_UseCoordinates;
        desc.mChannelFlags = kAudioChannelFlags_SphericalCoordinates;
        desc.mCoordinates[kAudioChannelCoordinates_Azimuth] = 45.f;
        desc.mCoordinates[kAudioChannelCoordinates_Elevation] = -20.;
        desc.mCoordinates[kAudioChannelCoordinates_Distance] = 1.f;
    }

    return std::unique_ptr<AudioChannelLayout>(layout);
}

static constexpr struct {
    AudioChannelLayoutTag tag;
    QAudioFormat::ChannelConfig channelConfig;
} layoutTagMap[] = {
    { kAudioChannelLayoutTag_Mono, QAudioFormat::ChannelConfigMono },
    { kAudioChannelLayoutTag_Stereo, QAudioFormat::ChannelConfigStereo },
    { kAudioChannelLayoutTag_StereoHeadphones, QAudioFormat::ChannelConfigStereo },
    { kAudioChannelLayoutTag_MPEG_1_0, QAudioFormat::ChannelConfigMono },
    { kAudioChannelLayoutTag_MPEG_2_0, QAudioFormat::ChannelConfigStereo },
    { kAudioChannelLayoutTag_MPEG_3_0_A, QAudioFormat::channelConfig(QAudioFormat::FrontLeft,
                                                                     QAudioFormat::FrontRight,
                                                                     QAudioFormat::FrontCenter) },
    { kAudioChannelLayoutTag_MPEG_4_0_A, QAudioFormat::channelConfig(QAudioFormat::FrontLeft,
                                                                     QAudioFormat::FrontRight,
                                                                     QAudioFormat::FrontCenter,
                                                                     QAudioFormat::BackCenter) },
    { kAudioChannelLayoutTag_MPEG_5_0_A, QAudioFormat::ChannelConfigSurround5Dot0 },
    { kAudioChannelLayoutTag_MPEG_5_1_A, QAudioFormat::ChannelConfigSurround5Dot1 },
    { kAudioChannelLayoutTag_MPEG_6_1_A, QAudioFormat::channelConfig(QAudioFormat::FrontLeft,
                                                                     QAudioFormat::FrontRight,
                                                                     QAudioFormat::FrontCenter,
                                                                     QAudioFormat::LFE,
                                                                     QAudioFormat::BackLeft,
                                                                     QAudioFormat::BackRight,
                                                                     QAudioFormat::BackCenter) },
    { kAudioChannelLayoutTag_MPEG_7_1_A, QAudioFormat::ChannelConfigSurround7Dot1 },
    { kAudioChannelLayoutTag_SMPTE_DTV, QAudioFormat::channelConfig(QAudioFormat::FrontLeft,
                                                                    QAudioFormat::FrontRight,
                                                                    QAudioFormat::FrontCenter,
                                                                    QAudioFormat::LFE,
                                                                    QAudioFormat::BackLeft,
                                                                    QAudioFormat::BackRight,
                                                                    QAudioFormat::TopFrontLeft,
                                                                    QAudioFormat::TopFrontRight) },

    { kAudioChannelLayoutTag_ITU_2_1, QAudioFormat::ChannelConfig2Dot1 },
    { kAudioChannelLayoutTag_ITU_2_2, QAudioFormat::channelConfig(QAudioFormat::FrontLeft,
                                                                  QAudioFormat::FrontRight,
                                                                  QAudioFormat::BackLeft,
                                                                  QAudioFormat::BackRight) }
};


QAudioFormat::ChannelConfig CoreAudioUtils::fromAudioChannelLayout(const AudioChannelLayout *layout)
{
    for (const auto &m : layoutTagMap) {
        if (m.tag == layout->mChannelLayoutTag)
            return m.channelConfig;
    }

    quint32 channels = 0;
    if (layout->mChannelLayoutTag == kAudioChannelLayoutTag_UseChannelDescriptions) {
        // special case 1 and 2 channel configs, as they are often reported without proper descriptions
        if (layout->mNumberChannelDescriptions == 1 && layout->mChannelDescriptions[0].mChannelLabel == kAudioChannelLabel_Unknown)
            return QAudioFormat::ChannelConfigMono;
        if (layout->mNumberChannelDescriptions == 2 &&
            layout->mChannelDescriptions[0].mChannelLabel == kAudioChannelLabel_Unknown &&
            layout->mChannelDescriptions[1].mChannelLabel == kAudioChannelLabel_Unknown)
            return QAudioFormat::ChannelConfigStereo;

        for (uint i = 0; i < layout->mNumberChannelDescriptions; ++i) {
            bool found = false;
            for (const auto &m : channelMap) {
                if (layout->mChannelDescriptions[i].mChannelLabel == m.label) {
                    channels |= QAudioFormat::channelConfig(m.pos);
                    found = true;
                    break;
                }
            }
            if (!found)
                qWarning() << "audio device has unknown channel" << layout->mChannelDescriptions[i].mChannelLabel;
        }
    } else {
        qWarning() << "Channel layout uses unimplemented format";
    }
    return QAudioFormat::ChannelConfig(channels);
}

// QAudioRingBuffer
CoreAudioRingBuffer::CoreAudioRingBuffer(int bufferSize):
    m_bufferSize(bufferSize)
{
    m_buffer = new char[m_bufferSize];
    reset();
}

CoreAudioRingBuffer::~CoreAudioRingBuffer()
{
    delete[] m_buffer;
}

CoreAudioRingBuffer::Region CoreAudioRingBuffer::acquireReadRegion(int size)
{
    const int used = m_bufferUsed.fetchAndAddAcquire(0);

    if (used > 0) {
        const int readSize = qMin(size, qMin(m_bufferSize - m_readPos, used));

        return readSize > 0 ? Region(m_buffer + m_readPos, readSize) : Region(0, 0);
    }

    return Region(0, 0);
}

void CoreAudioRingBuffer::releaseReadRegion(const CoreAudioRingBuffer::Region &region)
{
    m_readPos = (m_readPos + region.second) % m_bufferSize;

    m_bufferUsed.fetchAndAddRelease(-region.second);
}

CoreAudioRingBuffer::Region CoreAudioRingBuffer::acquireWriteRegion(int size)
{
    const int free = m_bufferSize - m_bufferUsed.fetchAndAddAcquire(0);

    Region output;

    if (free > 0) {
        const int writeSize = qMin(size, qMin(m_bufferSize - m_writePos, free));
        output =  writeSize > 0 ? Region(m_buffer + m_writePos, writeSize) : Region(0, 0);
    } else {
        output = Region(0, 0);
    }
#ifdef QT_DEBUG_COREAUDIO
    qDebug("acquireWriteRegion(%d) free: %d returning Region(%p, %d)", size, free, output.first, output.second);
#endif
    return output;
}
void CoreAudioRingBuffer::releaseWriteRegion(const CoreAudioRingBuffer::Region &region)
{
    m_writePos = (m_writePos + region.second) % m_bufferSize;

    m_bufferUsed.fetchAndAddRelease(region.second);
#ifdef QT_DEBUG_COREAUDIO
    qDebug("releaseWriteRegion(%p,%d): m_writePos:%d", region.first, region.second, m_writePos);
#endif
}

int CoreAudioRingBuffer::used() const
{
    return m_bufferUsed.loadRelaxed();
}

int CoreAudioRingBuffer::free() const
{
    return m_bufferSize - m_bufferUsed.loadRelaxed();
}

int CoreAudioRingBuffer::size() const
{
    return m_bufferSize;
}

void CoreAudioRingBuffer::reset()
{
    m_readPos = 0;
    m_writePos = 0;
    m_bufferUsed.storeRelaxed(0);
}

QT_END_NAMESPACE