| /* Copyright (C) 2017-2019 Free Software Foundation, Inc. |
| |
| This file is part of GDB. |
| |
| 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 3 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, see <http://www.gnu.org/licenses/>. */ |
| |
| #ifndef COMMON_TRAITS_H |
| #define COMMON_TRAITS_H |
| |
| #include <type_traits> |
| |
| /* GCC does not understand __has_feature. */ |
| #if !defined(__has_feature) |
| # define __has_feature(x) 0 |
| #endif |
| |
| /* HAVE_IS_TRIVIALLY_COPYABLE is defined as 1 iff |
| std::is_trivially_copyable is available. GCC only implemented it |
| in GCC 5. */ |
| #if (__has_feature(is_trivially_copyable) \ |
| || (defined __GNUC__ && __GNUC__ >= 5)) |
| # define HAVE_IS_TRIVIALLY_COPYABLE 1 |
| #endif |
| |
| /* HAVE_IS_TRIVIALLY_CONSTRUCTIBLE is defined as 1 iff |
| std::is_trivially_constructible is available. GCC only implemented it |
| in GCC 5. */ |
| #if (__has_feature(is_trivially_constructible) \ |
| || (defined __GNUC__ && __GNUC__ >= 5)) |
| # define HAVE_IS_TRIVIALLY_CONSTRUCTIBLE 1 |
| #endif |
| |
| namespace gdb { |
| |
| /* Pre C++14-safe (CWG 1558) version of C++17's std::void_t. See |
| <http://en.cppreference.com/w/cpp/types/void_t>. */ |
| |
| template<typename... Ts> |
| struct make_void { typedef void type; }; |
| |
| template<typename... Ts> |
| using void_t = typename make_void<Ts...>::type; |
| |
| /* A few trait helpers, mainly stolen from libstdc++. Uppercase |
| because "and/or", etc. are reserved keywords. */ |
| |
| template<typename Predicate> |
| struct Not : public std::integral_constant<bool, !Predicate::value> |
| {}; |
| |
| template<typename...> |
| struct Or; |
| |
| template<> |
| struct Or<> : public std::false_type |
| {}; |
| |
| template<typename B1> |
| struct Or<B1> : public B1 |
| {}; |
| |
| template<typename B1, typename B2> |
| struct Or<B1, B2> |
| : public std::conditional<B1::value, B1, B2>::type |
| {}; |
| |
| template<typename B1,typename B2,typename B3, typename... Bn> |
| struct Or<B1, B2, B3, Bn...> |
| : public std::conditional<B1::value, B1, Or<B2, B3, Bn...>>::type |
| {}; |
| |
| template<typename...> |
| struct And; |
| |
| template<> |
| struct And<> : public std::true_type |
| {}; |
| |
| template<typename B1> |
| struct And<B1> : public B1 |
| {}; |
| |
| template<typename B1, typename B2> |
| struct And<B1, B2> |
| : public std::conditional<B1::value, B2, B1>::type |
| {}; |
| |
| template<typename B1, typename B2, typename B3, typename... Bn> |
| struct And<B1, B2, B3, Bn...> |
| : public std::conditional<B1::value, And<B2, B3, Bn...>, B1>::type |
| {}; |
| |
| /* Concepts-light-like helper to make SFINAE logic easier to read. */ |
| template<typename Condition> |
| using Requires = typename std::enable_if<Condition::value, void>::type; |
| } |
| |
| #endif /* COMMON_TRAITS_H */ |