/****************************************************************************
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** GNU Lesser General Public License Usage
** This file may be used under the terms of the GNU Lesser General Public
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** Alternatively, this file may be used under the terms of the GNU General
** Public License version 3.0 as published by the Free Software Foundation
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****************************************************************************/

//
//  W A R N I N G
//  -------------
//
// This file is not part of the Qt API.  It exists for the convenience
// of other Qt classes.  This header file may change from version to
// version without notice, or even be removed.
//
// We mean it.
//


#ifndef QAUDIO_MAC_P_H
#define QAUDIO_MAC_P_H

#include <CoreAudio/CoreAudio.h>

#include <QtCore/qdebug.h>
#include <QtCore/qatomic.h>

#include <qaudioformat.h>

QT_BEGIN_HEADER

QT_BEGIN_NAMESPACE

QT_MODULE(Multimedia)

extern QAudioFormat toQAudioFormat(const AudioStreamBasicDescription& streamFormat);
extern AudioStreamBasicDescription toAudioStreamBasicDescription(QAudioFormat const& audioFormat);

class QAudioRingBuffer
{
public:
    typedef QPair<char*, int> Region;

    QAudioRingBuffer(int bufferSize);
    ~QAudioRingBuffer();

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

        m_bufferUsed.fetchAndAddRelease(-region.second);
    }

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

        if (free > 0) {
            const int writeSize = qMin(size, qMin(m_bufferSize - m_writePos, free));

            return writeSize > 0 ? Region(m_buffer + m_writePos, writeSize) : Region(0, 0);
        }

        return Region(0, 0);
    }

    void releaseWriteRegion(Region const& region)
    {
        m_writePos = (m_writePos + region.second) % m_bufferSize;

        m_bufferUsed.fetchAndAddRelease(region.second);
    }

    int used() const;
    int free() const;
    int size() const;

    void reset();

private:
    int     m_bufferSize;
    int     m_readPos;
    int     m_writePos;
    char*   m_buffer;
    QAtomicInt  m_bufferUsed;
};

QT_END_NAMESPACE

QT_END_HEADER

#endif  // QAUDIO_MAC_P_H