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/* This file is part of the OpenLB library
*
* Copyright (C) 2019 Adrian Kummerlaender
* E-mail contact: info@openlb.net
* The most recent release of OpenLB can be downloaded at
* <http://www.openlb.net/>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program 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 a copy of the GNU General Public
* License along with this program; if not, write to the Free
* Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
#ifndef UTILITIES_META_H
#define UTILITIES_META_H
#include <type_traits>
namespace olb {
namespace utilities {
namespace meta {
/// Provide implementation of std::enable_if_t
/**
* Weirdly version 18.0.3 of the Intel C++ compiler doesn't provide this
* useful template alias despite otherwise supporting C++14.
**/
template<bool B, class T = void>
using enable_if_t = typename std::enable_if<B,T>::type;
/// Check whether a given type list contains WANTED
template <
typename WANTED,
typename HEAD = void, // Default argument in case the list is empty
typename... TAIL
>
struct list_contains_item {
using type = typename std::conditional<
std::is_same<WANTED, HEAD>::value,
std::true_type,
typename list_contains_item<WANTED, TAIL...>::type
>::type;
};
template <typename WANTED, typename HEAD>
struct list_contains_item<WANTED, HEAD> {
using type = typename std::is_same<WANTED, HEAD>::type;
};
/// Get first type based on BASE contained in a given type list
/**
* If no such list item exists, type is void.
**/
template <
typename BASE,
typename HEAD = void, // Default argument in case the list is empty
typename... TAIL
>
struct list_item_with_base {
using type = typename std::conditional<
std::is_base_of<BASE, HEAD>::value,
HEAD,
typename list_item_with_base<BASE, TAIL...>::type
>::type;
};
template <typename BASE, typename HEAD>
struct list_item_with_base<BASE, HEAD> {
using type = typename std::conditional<
std::is_base_of<BASE, HEAD>::value,
HEAD,
void
>::type;
};
}
}
}
#endif
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