atomic_queue.h

/***************************************************************************
 *
 * Project:  OpenCPN
 * Purpose:  General purpose fifo queue.
 * Author:   David Register, Alec Leamas
 *
 ***************************************************************************
 *   Copyright (C) 2022 by David Register, Alec Leamas                     *
 *                                                                         *
 *   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; if not, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,  USA.         *
 **************************************************************************/
 
#include <mutex>
#include <queue>
 
template <typename T>
class atomic_queue {
public:
  size_t size() {
    std::lock_guard<std::mutex> lock(m_mutex);
    return m_queue.size();
  }
 
  bool empty() {
    std::lock_guard<std::mutex> lock(m_mutex);
    return m_queue.empty();
  }
 
  const T& front() {
    std::lock_guard<std::mutex> lock(m_mutex);
    return m_queue.front();
  }
 
  void push(const T& value) {
    std::lock_guard<std::mutex> lock(m_mutex);
    m_queue.push(value);
  }
 
  void pop() {
    std::lock_guard<std::mutex> lock(m_mutex);
    m_queue.pop();
  }
 
private:
  std::queue<T> m_queue;
  mutable std::mutex m_mutex;
};