identity_arrangement.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
#include <numeric>
 
// lal includes
#include <lal/linear_arrangement.hpp>
 
namespace lal {
namespace detail {
 
enum class linarr_type {
    identity,
    nonident
};
 
template <linarr_type type>
struct linarr_wrapper {
    linarr_wrapper(const lal::linear_arrangement& arr) noexcept
        : m_arr(arr)
    {
#if defined DEBUG
        if constexpr (type == linarr_type::identity) {
            assert(arr.size() == 0);
        }
        else {
            assert(arr.size() != 0);
        }
#endif
    }
 
    template <typename param_t>
    uint64_t operator[] (const param_t& p) const noexcept {
        static_assert(
            std::is_same_v<param_t,lal::node_t> or
            std::is_same_v<param_t,lal::position_t>
        );
 
        if constexpr (type == linarr_type::identity) {
            return *p;
        }
        else {
            return m_arr[p];
        }
    }
 
    const lal::linear_arrangement& m_arr;
};
 
inline linarr_wrapper<linarr_type::identity> identity_arr(const linear_arrangement& arr)
noexcept
{
    return linarr_wrapper<linarr_type::identity>(arr);
}
 
inline linarr_wrapper<linarr_type::nonident> nonident_arr(const linear_arrangement& arr)
noexcept
{
    return linarr_wrapper<linarr_type::nonident>(arr);
}
 
} // -- namespace detail
} // -- namespace lal