projects / ceph.git / blame
| Commit | Line | Data |
|---|---|---|
| 7c673cae FG |
1 | /*! |
| 2 | @file | |
| 3 | Defines `boost::hana::detail::first_unsatisfied_index`. | |
| 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_FIRST_UNSATISFIED_INDEX_HPP | |
| 11 | #define BOOST_HANA_DETAIL_FIRST_UNSATISFIED_INDEX_HPP | |
| 12 | ||
| 13 | #include <boost/hana/config.hpp> | |
| 14 | #include <boost/hana/integral_constant.hpp> | |
| 15 | #include <boost/hana/value.hpp> | |
| 16 | ||
| 17 | #include <utility> | |
| 18 | ||
| 19 | ||
| 20 | BOOST_HANA_NAMESPACE_BEGIN namespace detail { | |
| 21 | template <bool, typename Pred, typename ...Xs> | |
| 22 | struct find_tail_size; | |
| 23 | ||
| 24 | template <typename Pred, typename X, typename ...Xs> | |
| 25 | struct find_tail_size<true, Pred, X, Xs...> { | |
| 26 | static constexpr int value = find_tail_size< | |
| 27 | static_cast<bool>(hana::value<decltype(std::declval<Pred>()(std::declval<X>()))>()), | |
| 28 | Pred, Xs... | |
| 29 | >::value; | |
| 30 | }; | |
| 31 | ||
| 32 | template <typename Pred> | |
| 33 | struct find_tail_size<true, Pred> { | |
| 34 | static constexpr int value = -1; | |
| 35 | }; | |
| 36 | ||
| 37 | template <typename Pred, typename ...Xs> | |
| 38 | struct find_tail_size<false, Pred, Xs...> { | |
| 39 | static constexpr int value = sizeof...(Xs); | |
| 40 | }; | |
| 41 | ||
| 42 | //! @ingroup group-details | |
| 43 | //! Returns the index of the first element which does not satisfy `Pred`, | |
| 44 | //! or `sizeof...(Xs)` if no such element exists. | |
| 45 | template <typename Pred> | |
| 46 | struct first_unsatisfied_index { | |
| 47 | template <typename ...Xs> | |
| 48 | constexpr auto operator()(Xs&& ...) const { | |
| 49 | return hana::size_c< | |
| 50 | sizeof...(Xs) - 1 - find_tail_size<true, Pred, Xs&&...>::value | |
| 51 | >; | |
| 52 | } | |
| 53 | }; | |
| 54 | } BOOST_HANA_NAMESPACE_END | |
| 55 | ||
| 56 | #endif // !BOOST_HANA_DETAIL_FIRST_UNSATISFIED_INDEX_HPP |