term.hpp

/* Copyright 2009-2017 Francesco Biscani (bluescarni@gmail.com)

This file is part of the Piranha library.

The Piranha library is free software; you can redistribute it and/or modify
it under the terms of either:

  * the GNU Lesser General Public License as published by the Free
    Software Foundation; either version 3 of the License, or (at your
    option) any later version.

or

  * the GNU General Public License as published by the Free Software
    Foundation; either version 3 of the License, or (at your option) any
    later version.

or both in parallel, as here.

The Piranha 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 General Public License
for more details.

You should have received copies of the GNU General Public License and the
GNU Lesser General Public License along with the Piranha library.  If not,
see https://www.gnu.org/licenses/. */

#ifndef PIRANHA_TERM_HPP
#define PIRANHA_TERM_HPP

#include <cstddef>
#include <functional>
#include <type_traits>
#include <utility>

#include <piranha/is_cf.hpp>
#include <piranha/is_key.hpp>
#include <piranha/math.hpp>
#include <piranha/symbol_utils.hpp>
#include <piranha/type_traits.hpp>

namespace piranha
{


template <typename Cf, typename Key>
class term
{
    PIRANHA_TT_CHECK(is_cf, Cf);
    PIRANHA_TT_CHECK(is_key, Key);
    // Enabler for the generic binary ctor.
    template <typename T, typename U>
    using binary_ctor_enabler
        = enable_if_t<conjunction<std::is_constructible<Cf, T &&>, std::is_constructible<Key, U &&>>::value, int>;

public:
    using cf_type = Cf;
    using key_type = Key;

    term() : m_cf(), m_key() {}

    term(const term &) = default;
    term(term &&) = default;

    template <typename T, typename U, binary_ctor_enabler<T, U> = 0>
    explicit term(T &&cf, U &&key) : m_cf(std::forward<T>(cf)), m_key(std::forward<U>(key))
    {
    }
    ~term()
    {
        PIRANHA_TT_CHECK(is_container_element, term);
    }

    term &operator=(const term &other) = default;

    term &operator=(term &&other) noexcept
    {
        m_cf = std::move(other.m_cf);
        m_key = std::move(other.m_key);
        return *this;
    }

    bool operator==(const term &other) const
    {
        return m_key == other.m_key;
    }

    std::size_t hash() const
    {
        return std::hash<key_type>{}(m_key);
    }

    bool is_compatible(const symbol_fset &args) const noexcept
    {
        return m_key.is_compatible(args);
    }

    bool is_zero(const symbol_fset &args) const noexcept
    {
        return math::is_zero(m_cf) || m_key.is_zero(args);
    }
    mutable Cf m_cf;
    Key m_key;
};


template <typename Cf, typename Key>
struct enable_noexcept_checks<term<Cf, Key>> {
private:
    static const bool implementation_defined
        = conjunction<enable_noexcept_checks<Cf>, enable_noexcept_checks<Key>>::value;

public:
    static const bool value = implementation_defined;
};

template <typename Cf, typename Key>
const bool enable_noexcept_checks<term<Cf, Key>>::value;
}

namespace std
{

template <typename Cf, typename Key>
struct hash<piranha::term<Cf, Key>> {
    using result_type = size_t;
    using argument_type = piranha::term<Cf, Key>;

    result_type operator()(const argument_type &a) const
    {
        return a.hash();
    }
};
}

#endif