| 1 | /* Copyright (C) 2017 Free Software Foundation, Inc. |
| 2 | |
| 3 | This file is part of GDB. |
| 4 | |
| 5 | This program is free software; you can redistribute it and/or modify |
| 6 | it under the terms of the GNU General Public License as published by |
| 7 | the Free Software Foundation; either version 3 of the License, or |
| 8 | (at your option) any later version. |
| 9 | |
| 10 | This program is distributed in the hope that it will be useful, |
| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | GNU General Public License for more details. |
| 14 | |
| 15 | You should have received a copy of the GNU General Public License |
| 16 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 17 | |
| 18 | #ifndef COMMON_TRAITS_H |
| 19 | #define COMMON_TRAITS_H |
| 20 | |
| 21 | #include <type_traits> |
| 22 | |
| 23 | namespace gdb { |
| 24 | |
| 25 | /* Pre C++14-safe (CWG 1558) version of C++17's std::void_t. See |
| 26 | <http://en.cppreference.com/w/cpp/types/void_t>. */ |
| 27 | |
| 28 | template<typename... Ts> |
| 29 | struct make_void { typedef void type; }; |
| 30 | |
| 31 | template<typename... Ts> |
| 32 | using void_t = typename make_void<Ts...>::type; |
| 33 | |
| 34 | /* A few trait helpers, mainly stolen from libstdc++. Uppercase |
| 35 | because "and" is a keyword. */ |
| 36 | |
| 37 | template<typename...> |
| 38 | struct And; |
| 39 | |
| 40 | template<> |
| 41 | struct And<> : public std::true_type |
| 42 | {}; |
| 43 | |
| 44 | template<typename B1> |
| 45 | struct And<B1> : public B1 |
| 46 | {}; |
| 47 | |
| 48 | template<typename B1, typename B2> |
| 49 | struct And<B1, B2> |
| 50 | : public std::conditional<B1::value, B2, B1>::type |
| 51 | {}; |
| 52 | |
| 53 | template<typename B1, typename B2, typename B3, typename... Bn> |
| 54 | struct And<B1, B2, B3, Bn...> |
| 55 | : public std::conditional<B1::value, And<B2, B3, Bn...>, B1>::type |
| 56 | {}; |
| 57 | |
| 58 | } |
| 59 | |
| 60 | #endif /* COMMON_TRAITS_H */ |