qequeue.hpp

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//============================================================================
// QP/C++ Real-Time Embedded Framework (RTEF)
// Copyright (C) 2005 Quantum Leaps, LLC. All rights reserved.
//
// SPDX-License-Identifier: GPL-3.0-or-later OR LicenseRef-QL-commercial
//
// This software is dual-licensed under the terms of the open source GNU
// General Public License version 3 (or any later version), or alternatively,
// under the terms of one of the closed source Quantum Leaps commercial
// licenses.
//
// The terms of the open source GNU General Public License version 3
// can be found at: <www.gnu.org/licenses/gpl-3.0>
//
// The terms of the closed source Quantum Leaps commercial licenses
// can be found at: <www.state-machine.com/licensing>
//
// Redistributions in source code must retain this top-level comment block.
// Plagiarizing this software to sidestep the license obligations is illegal.
//
// Contact information:
// <www.state-machine.com>
// <info@state-machine.com>
//============================================================================
 
#ifndef QEQUEUE_HPP
#define QEQUEUE_HPP
 
 
#ifndef QF_EQUEUE_CTR_SIZE
 
    #define QF_EQUEUE_CTR_SIZE 1U
#endif
 
namespace QP {
 
#if (QF_EQUEUE_CTR_SIZE == 1U)
    using QEQueueCtr = std::uint8_t;
#elif (QF_EQUEUE_CTR_SIZE == 2U)
    using QEQueueCtr = std::uint16_t;
#elif (QF_EQUEUE_CTR_SIZE == 4U)
    using QEQueueCtr = std::uint32_t;
#else
    #error "QF_EQUEUE_CTR_SIZE defined incorrectly, expected 1U, 2U, or 4U"
#endif
 
//============================================================================
class QEQueue {
private:
 
    QEvt const * volatile m_frontEvt;
 
    QEvt const **m_ring;
 
    QEQueueCtr m_end;
 
    QEQueueCtr volatile m_head;
 
    QEQueueCtr volatile m_tail;
 
    QEQueueCtr volatile m_nFree;
 
    QEQueueCtr m_nMin;
 
public:
    QEQueue(void) noexcept;
 
    void init(QEvt const *qSto[], std::uint_fast16_t const qLen) noexcept;
 
    bool post(QEvt const * const e, std::uint_fast16_t const margin,
              std::uint_fast8_t const qs_id) noexcept;
 
    void postLIFO(QEvt const * const e,
                  std::uint_fast8_t const qs_id) noexcept;
 
    QEvt const *get(std::uint_fast8_t const qs_id) noexcept;
 
    QEQueueCtr getNFree(void) const noexcept {
        return m_nFree;
    }
 
    QEQueueCtr getNMin(void) const noexcept {
        return m_nMin;
    }
 
    bool isEmpty(void) const noexcept {
        return m_frontEvt == nullptr;
    }
 
private:
    QEQueue(QEQueue const &) = delete;
 
    QEQueue & operator=(QEQueue const &) = delete;
 
    friend class QF;
    friend class QActive;
    friend class QXThread;
    friend class QTicker;
    friend class QS;
};
 
} // namespace QP
 
#endif // QEQUEUE_HPP