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Diffstat (limited to 'gdbsupport/traits.h')
-rw-r--r-- | gdbsupport/traits.h | 109 |
1 files changed, 109 insertions, 0 deletions
diff --git a/gdbsupport/traits.h b/gdbsupport/traits.h new file mode 100644 index 0000000..2a6f006 --- /dev/null +++ b/gdbsupport/traits.h @@ -0,0 +1,109 @@ +/* Copyright (C) 2017-2020 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 */ |