Variant.hpp

/* Copyright 2017-2021 Fabian Koller, Axel Huebl
 *
 * This file is part of openPMD-api.
 *
 * openPMD-api is free software: you can redistribute it and/or modify
 * it under the terms of of either the GNU General Public License or
 * 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.
 *
 * openPMD-api 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 and the GNU Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU General Public License
 * and the GNU Lesser General Public License along with openPMD-api.
 * If not, see <http://www.gnu.org/licenses/>.
 */
#pragma once
 
#include "VariantSrc.hpp"
 
#include <cstddef>
#include <type_traits>
 
 
namespace openPMD
{
namespace auxiliary
{
template< class T_DTYPES, typename ... T >
class Variant
{
    static_assert(std::is_enum< T_DTYPES >::value, "Datatypes to Variant must be supplied as enum.");
 
public:
    using resource = variantSrc::variant< T ... >;
    Variant(resource r)
            : dtype{static_cast<T_DTYPES>(r.index())},
              m_data{r}
    { }
 
    template< typename U >
    U get() const
    {
        return variantSrc::get< U >(m_data);
    }
 
    resource getResource() const
    {
        return m_data;
    }
 
    constexpr size_t index() const noexcept
    {
        return m_data.index();
    }
 
    T_DTYPES dtype;
 
private:
    resource m_data;
};
} // auxiliary
} // openPMD