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