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Diffstat (limited to 'boost/hana/any_of.hpp')
| -rw-r--r-- | boost/hana/any_of.hpp | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/boost/hana/any_of.hpp b/boost/hana/any_of.hpp new file mode 100644 index 0000000000..1dd1cde9be --- /dev/null +++ b/boost/hana/any_of.hpp @@ -0,0 +1,190 @@ +/*! +@file +Defines `boost::hana::any_of`. + +@copyright Louis Dionne 2013-2016 +Distributed under the Boost Software License, Version 1.0. +(See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt) + */ + +#ifndef BOOST_HANA_ANY_OF_HPP +#define BOOST_HANA_ANY_OF_HPP + +#include <boost/hana/fwd/any_of.hpp> + +#include <boost/hana/accessors.hpp> +#include <boost/hana/at.hpp> +#include <boost/hana/bool.hpp> +#include <boost/hana/concept/searchable.hpp> +#include <boost/hana/concept/sequence.hpp> +#include <boost/hana/concept/struct.hpp> +#include <boost/hana/config.hpp> +#include <boost/hana/core/dispatch.hpp> +#include <boost/hana/drop_front.hpp> +#include <boost/hana/first.hpp> +#include <boost/hana/front.hpp> +#include <boost/hana/functional/compose.hpp> +#include <boost/hana/if.hpp> +#include <boost/hana/is_empty.hpp> +#include <boost/hana/length.hpp> + +#include <cstddef> + + +BOOST_HANA_NAMESPACE_BEGIN + //! @cond + template <typename Xs, typename Pred> + constexpr auto any_of_t::operator()(Xs&& xs, Pred&& pred) const { + using S = typename hana::tag_of<Xs>::type; + using AnyOf = BOOST_HANA_DISPATCH_IF(any_of_impl<S>, + hana::Searchable<S>::value + ); + + #ifndef BOOST_HANA_CONFIG_DISABLE_CONCEPT_CHECKS + static_assert(hana::Searchable<S>::value, + "hana::any_of(xs, pred) requires 'xs' to be a Searchable"); + #endif + + return AnyOf::apply(static_cast<Xs&&>(xs), static_cast<Pred&&>(pred)); + } + //! @endcond + + template <typename S, bool condition> + struct any_of_impl<S, when<condition>> : default_ { + template <typename ...Args> + static constexpr auto apply(Args&& ...) = delete; + }; + + template <typename S> + struct any_of_impl<S, when<Sequence<S>::value>> { + //! @cond + template <std::size_t k, std::size_t Len> + struct any_of_helper { + template <typename Xs, typename Pred> + static constexpr auto apply(bool prev_cond, Xs&& xs, Pred&& pred) { + auto cond = hana::if_(pred(hana::at_c<k>(xs)), hana::true_c, + hana::false_c); + return prev_cond ? hana::true_c + : any_of_impl::any_of_helper<k + 1, Len>::apply(cond, + static_cast<Xs&&>(xs), + static_cast<Pred&&>(pred)); + } + + template <typename Xs, typename Pred> + static constexpr auto apply(hana::true_, Xs&&, Pred&&) + { return hana::true_c; } + + template <typename Xs, typename Pred> + static constexpr auto apply(hana::false_, Xs&& xs, Pred&& pred) { + auto cond = hana::if_(pred(hana::at_c<k>(xs)), hana::true_c, + hana::false_c); + return any_of_impl::any_of_helper<k + 1, Len>::apply(cond, + static_cast<Xs&&>(xs), + static_cast<Pred&&>(pred)); + } + }; + + template <std::size_t Len> + struct any_of_helper<Len, Len> { + template <typename Cond, typename Xs, typename Pred> + static constexpr auto apply(Cond cond, Xs&&, Pred&&) + { return cond; } + }; + + template <typename Xs, typename Pred> + static constexpr auto apply(Xs&& xs, Pred&& pred) { + constexpr std::size_t len = decltype(hana::length(xs))::value; + return any_of_impl::any_of_helper<0, len>::apply(hana::false_c, + static_cast<Xs&&>(xs), + static_cast<Pred&&>(pred)); + } + //! @endcond + }; + + template <typename It> + struct any_of_impl<It, when< + hana::Iterable<It>::value && + !Sequence<It>::value + >> { + template <typename Xs, typename Pred> + static constexpr auto lazy_any_of_helper(hana::false_, bool prev_cond, Xs&& xs, Pred&& pred) { + auto cond = hana::if_(pred(hana::front(xs)), hana::true_c, hana::false_c); + decltype(auto) tail = hana::drop_front(static_cast<Xs&&>(xs)); + constexpr bool done = decltype(hana::is_empty(tail))::value; + return prev_cond ? hana::true_c + : lazy_any_of_helper(hana::bool_c<done>, cond, + static_cast<decltype(tail)&&>(tail), + static_cast<Pred&&>(pred)); + } + + template <typename Xs, typename Pred> + static constexpr auto lazy_any_of_helper(hana::false_, hana::true_, Xs&&, Pred&&) + { return hana::true_c; } + + template <typename Xs, typename Pred> + static constexpr auto lazy_any_of_helper(hana::false_, hana::false_, Xs&& xs, Pred&& pred) { + auto cond = hana::if_(pred(hana::front(xs)), hana::true_c, hana::false_c); + constexpr bool done = decltype(hana::is_empty(hana::drop_front(xs)))::value; + return lazy_any_of_helper(hana::bool_c<done>, cond, + hana::drop_front(static_cast<Xs&&>(xs)), + static_cast<Pred&&>(pred)); + } + + template <typename Cond, typename Xs, typename Pred> + static constexpr auto lazy_any_of_helper(hana::true_, Cond cond, Xs&&, Pred&&) + { return cond; } + + template <typename Xs, typename Pred> + static constexpr auto apply(Xs&& xs, Pred&& pred) { + constexpr bool done = decltype(hana::is_empty(xs))::value; + return lazy_any_of_helper(hana::bool_c<done>, hana::false_c, + static_cast<Xs&&>(xs), + static_cast<Pred&&>(pred)); + } + }; + + template <typename T, std::size_t N> + struct any_of_impl<T[N]> { + template <typename Xs, typename Pred> + static constexpr bool any_of_helper(bool cond, Xs&& xs, Pred&& pred) { + if (cond) return true; + for (std::size_t i = 1; i < N; ++i) + if (pred(static_cast<Xs&&>(xs)[i])) + return true; + return false; + } + + // Since an array contains homogeneous data, if the predicate returns + // a compile-time logical at any index, it must do so at every index + // (because the type of the elements won't change)! In this case, we + // then only need to evaluate the predicate on the first element. + template <typename Xs, typename Pred> + static constexpr auto + any_of_helper(hana::true_, Xs&& /*xs*/, Pred&&) + { return hana::true_c; } + + template <typename Xs, typename Pred> + static constexpr auto + any_of_helper(hana::false_, Xs&&, Pred&&) + { return hana::false_c; } + + template <typename Xs, typename Pred> + static constexpr auto apply(Xs&& xs, Pred&& pred) { + auto cond = hana::if_(pred(static_cast<Xs&&>(xs)[0]), hana::true_c, + hana::false_c); + return any_of_helper(cond, static_cast<Xs&&>(xs), + static_cast<Pred&&>(pred)); + } + }; + + template <typename S> + struct any_of_impl<S, when<hana::Struct<S>::value>> { + template <typename X, typename Pred> + static constexpr decltype(auto) apply(X const&, Pred&& pred) { + return hana::any_of(hana::accessors<S>(), + hana::compose(static_cast<Pred&&>(pred), hana::first)); + } + }; +BOOST_HANA_NAMESPACE_END + +#endif // !BOOST_HANA_ANY_OF_HPP |