linear_queue.hpp

/*********************************************************************
 *
 * Linear Arrangement Library - A library that implements a collection
 * algorithms for linear arrangments of graphs.
 *
 * Copyright (C) 2019 - 2023
 *
 * This file is part of Linear Arrangement Library. The full code is available
 * at:
 *      https://github.com/LAL-project/linear-arrangement-library.git
 *
 * Linear Arrangement Library is free software: you can redistribute it
 * and/or modify it under the terms of the GNU Affero General Public License
 * as published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * Linear Arrangement Library 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with Linear Arrangement Library.  If not, see <http://www.gnu.org/licenses/>.
 *
 * Contact:
 *
 *     Lluís Alemany Puig (lalemany@cs.upc.edu)
 *         LARCA (Laboratory for Relational Algorithmics, Complexity and Learning)
 *         CQL (Complexity and Quantitative Linguistics Lab)
 *         Jordi Girona St 1-3, Campus Nord UPC, 08034 Barcelona.   CATALONIA, SPAIN
 *         Webpage: https://cqllab.upc.edu/people/lalemany/
 *
 *     Ramon Ferrer i Cancho (rferrericancho@cs.upc.edu)
 *         LARCA (Laboratory for Relational Algorithmics, Complexity and Learning)
 *         CQL (Complexity and Quantitative Linguistics Lab)
 *         Office S124, Omega building
 *         Jordi Girona St 1-3, Campus Nord UPC, 08034 Barcelona.   CATALONIA, SPAIN
 *         Webpage: https://cqllab.upc.edu/people/rferrericancho/
 *
 ********************************************************************/
 
#pragma once
 
// C++ includes
#if defined DEBUG
#include <cassert>
#endif
 
// lal includes
#include <lal/detail/data_array.hpp>
 
namespace lal {
namespace detail {
 
template <class T>
class linear_queue {
public:
    void init(std::size_t n) noexcept {
        m_queue.resize(n);
        m_left = 0;
        m_right = 0;
    }
 
    void push(const T& v) noexcept {
#if defined DEBUG
        assert(not is_full());
#endif
        m_queue[m_right++] = v;
    }
    void push(T&& v) noexcept {
#if defined DEBUG
        assert(not is_exhausted());
#endif
        m_queue[m_right++] = std::move(v);
    }
    T&& pop() noexcept {
#if defined DEBUG
        assert(m_left < m_queue.size());
#endif
        return std::move(m_queue[m_left++]);
    }
 
    T& front() noexcept {
#if defined DEBUG
        assert(not is_exhausted());
#endif
        return m_queue[m_left];
    }
 
    const T& front() const noexcept {
#if defined DEBUG
        assert(not is_exhausted());
#endif
        return m_queue[m_left];
    }
    std::size_t size() const noexcept {
        return m_right - m_left;
    }
 
    void reset() noexcept {
        m_left = m_right = 0;
    }
 
    bool is_exhausted() const noexcept { return m_left == m_queue.size(); }
 
    bool is_full() const noexcept { return m_right == m_queue.size(); }
 
    T *begin() noexcept { return m_queue.begin() + m_left; }
    const T *begin() const noexcept { return m_queue.begin() + m_left; }
    T *end() noexcept { return m_queue.begin() + m_right; }
    const T *end() const noexcept { return m_queue.begin() + m_right; }
 
private:
    data_array<T> m_queue;
 
    std::size_t m_left;
    std::size_t m_right;
};
 
} // -- namespace detail
} // -- namespace lal