FifoBuffer.h

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/*
 * FifoBuffer.h - FIFO fixed-size buffer
 *
 * Copyright (c) 2007 Javier Serrano Polo <jasp00/at/users.sourceforge.net>
 *
 * This file is part of LMMS - https://lmms.io
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program (see COPYING); if not, write to the
 * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301 USA.
 *
 */
 
#ifndef LMMS_FIFO_BUFFER_H
#define LMMS_FIFO_BUFFER_H
 
#include <QSemaphore>
 
 
namespace lmms
{
 
 
template<typename T>
class FifoBuffer
{
public:
    FifoBuffer(int size) :
        m_readSem(size),
        m_writeSem(size),
        m_readIndex(0),
        m_writeIndex(0),
        m_size(size)
    {
        m_buffer = new T[size];
        m_readSem.acquire(size);
    }
 
    ~FifoBuffer()
    {
        delete[] m_buffer;
        m_readSem.release(m_size);
    }
 
    void write(T element)
    {
        m_writeSem.acquire();
        m_buffer[m_writeIndex++] = element;
        m_writeIndex %= m_size;
        m_readSem.release();
    }
 
    T read()
    {
        m_readSem.acquire();
        T element = m_buffer[m_readIndex++];
        m_readIndex %= m_size;
        m_writeSem.release();
        return element;
    }
 
    void waitUntilRead()
    {
        m_writeSem.acquire(m_size);
        m_writeSem.release(m_size);
    }
 
    bool available()
    {
        return m_readSem.available();
    }
 
 
private:
    QSemaphore m_readSem;
    QSemaphore m_writeSem;
    int m_readIndex;
    int m_writeIndex;
    int m_size;
    T * m_buffer;
} ;
 
 
} // namespace lmms
 
#endif // LMMS_FIFO_BUFFER_H