set_array.hpp

/*********************************************************************
 *
 * Linear Arrangement Library - A library that implements a collection
 * algorithms for linear arrangments of graphs.
 *
 * Copyright (C) 2019 - 2024
 *
 * 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 (lluis.alemany.puig@upc.edu)
 *         LQMC (Quantitative, Mathematical, and Computational Linguisitcs)
 *         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)
 *         LQMC (Quantitative, Mathematical, and Computational Linguisitcs)
 *         CQL (Complexity and Quantitative Linguistics Lab)
 *         Office 220, Omega building
 *         Jordi Girona St 1-3, Campus Nord UPC, 08034 Barcelona.   CATALONIA, SPAIN
 *         Webpage: https://cqllab.upc.edu/people/rferrericancho/
 *
 ********************************************************************/
 
#pragma once
 
// lal includes
#include <lal/detail/array.hpp>
 
namespace lal {
namespace detail {
 
template <typename value_t, class indexer_t = value_t>
class set_array {
public:
 
    template <
        typename vt = value_t, typename it = indexer_t,
        std::enable_if_t< std::is_same_v<vt, it>, bool > = true
    >
    void init(const std::size_t max_num_elems, const std::size_t max_index_value) noexcept
    {
        m_size = 0;
        m_values.resize(max_num_elems);
        m_exists.resize(max_index_value, NOT_EXISTS);
        m_position.resize(max_index_value);
    }
 
    template <
        typename vt = value_t, typename it = indexer_t,
        std::enable_if_t< not std::is_same_v<vt, it>, bool > = true
    >
    void init(
        const std::size_t max_num_elems,
        const std::size_t max_index_value,
        indexer_t&& i
    )
    noexcept
    {
        m_I = std::move(i);
        m_size = 0;
        m_values.resize(max_num_elems);
        m_exists.resize(max_index_value, NOT_EXISTS);
        m_position.resize(max_index_value);
    }
 
    [[nodiscard]] const value_t& operator[] (const std::size_t i) const noexcept {
#if defined DEBUG
        assert(i < size());
#endif
        return m_values[i];
    }
 
    [[nodiscard]] std::size_t capacity() const noexcept { return m_exists.size(); }
    [[nodiscard]] std::size_t size() const noexcept { return m_size; }
 
    [[nodiscard]] bool exists(const value_t& v) const noexcept
    { return m_exists[index(v)] == EXISTS; }
 
    [[nodiscard]] std::size_t position(const value_t& v) const noexcept
    { return m_position[index(v)]; }
 
    void add(const value_t& v) noexcept {
        const std::size_t idx_v = index(v);
 
        if (not m_exists[idx_v]) {
            m_exists[idx_v] = EXISTS;
 
#if defined DEBUG
            assert(m_size < m_values.size());
#endif
 
            m_position[idx_v] = m_size;
            m_values[m_size++] = std::move(v);
        }
    }
 
    void add(value_t&& v) noexcept {
        const std::size_t idx_v = index(v);
 
        if (not m_exists[idx_v]) {
            m_exists[idx_v] = EXISTS;
 
#if defined DEBUG
            assert(m_size < m_values.size());
#endif
 
            m_position[idx_v] = m_size;
            m_values[m_size++] = std::move(v);
        }
    }
 
    void remove(const value_t& v) noexcept {
        const std::size_t idx_v = index(v);
        if (m_exists[idx_v]) {
 
            m_exists[idx_v] = NOT_EXISTS;
 
#if defined DEBUG
            assert(m_size > 0);
#endif
 
            const auto pos_v = m_position[idx_v];
            const auto idx_last_value = index(m_values[m_size - 1]);
 
#if defined DEBUG
            assert(m_position[idx_last_value] == m_size - 1);
#endif
 
            std::swap(m_position[idx_v], m_position[idx_last_value]);
            std::swap(m_values[pos_v], m_values[m_size - 1]);
 
            --m_size;
        }
    }
 
    [[nodiscard]] const value_t* begin_values() const noexcept { return m_values.begin(); }
    [[nodiscard]] value_t* begin_values() noexcept { return m_values.begin(); }
    [[nodiscard]] const value_t* end_values() const noexcept { return m_values.end(); }
    [[nodiscard]] value_t* end_values() noexcept { return m_values.end(); }
 
    [[nodiscard]] const value_t* begin_position() const noexcept { return m_position.begin(); }
    [[nodiscard]] value_t* begin_position() noexcept { return m_position.begin(); }
    [[nodiscard]] const value_t* end_position() const noexcept { return m_position.end(); }
    [[nodiscard]] value_t* end_position() noexcept { return m_position.end(); }
 
private:
    static constexpr char EXISTS = 1;
    static constexpr char NOT_EXISTS = 0;
 
private:
    indexer_t m_I;
 
    array<value_t> m_values;
    std::size_t m_size;
 
    array<char> m_exists;
    array<std::size_t> m_position;
 
private:
    [[nodiscard]] std::size_t index(const value_t& v) const noexcept {
        if constexpr (not std::is_same_v<value_t, indexer_t>) {
            return m_I(v);
        }
        else {
            return v;
        }
    }
};
 
 
} // -- namespace detail
} // -- namespace lal