projects / ceph.git / blame
| Commit | Line | Data |
|---|---|---|
| 7c673cae FG |
1 | /*! |
| 2 | @file | |
| 3 | Defines `boost::hana::detail::any_of`. | |
| 4 | ||
| 5 | @copyright Louis Dionne 2013-2016 | |
| 6 | Distributed under the Boost Software License, Version 1.0. | |
| 7 | (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt) | |
| 8 | */ | |
| 9 | ||
| 10 | #ifndef BOOST_HANA_DETAIL_ANY_OF_HPP | |
| 11 | #define BOOST_HANA_DETAIL_ANY_OF_HPP | |
| 12 | ||
| 13 | #include <boost/hana/config.hpp> | |
| 14 | ||
| 15 | #include <type_traits> | |
| 16 | #include <utility> | |
| 17 | ||
| 18 | ||
| 19 | BOOST_HANA_NAMESPACE_BEGIN namespace detail { | |
| 20 | std::false_type expand(...); | |
| 21 | ||
| 22 | template <template <typename ...> class Predicate, typename ...T> | |
| 23 | decltype(expand( | |
| 24 | typename std::enable_if<!Predicate<T>::value, void*>::type{}... | |
| 25 | )) any_of_impl(int); | |
| 26 | ||
| 27 | template <template <typename ...> class Predicate, typename ...T> | |
| 28 | std::true_type any_of_impl(...); | |
| 29 | ||
| 30 | //! @ingroup group-details | |
| 31 | //! Returns whether the `Predicate` is satisfied by any of the `T...`. | |
| 32 | //! | |
| 33 | //! This metafunction will short-circuit the evaluation at the first | |
| 34 | //! type satisfying the predicate, if such a type exists. | |
| 35 | //! | |
| 36 | //! | |
| 37 | //! @note | |
| 38 | //! The implementation technique used here was originally shown to | |
| 39 | //! me by Eric Fiselier. All credits where due. | |
| 40 | template <template <typename ...> class Predicate, typename ...T> | |
| 41 | struct any_of | |
| 42 | : decltype(any_of_impl<Predicate, T...>(int{})) | |
| 43 | { }; | |
| 44 | } BOOST_HANA_NAMESPACE_END | |
| 45 | ||
| 46 | #endif // !BOOST_HANA_DETAIL_ANY_OF_HPP |