mirror of
https://github.com/ecency/ecency-mobile.git
synced 2024-12-26 06:42:15 +03:00
131 lines
5.1 KiB
C++
131 lines
5.1 KiB
C++
/*!
|
|
@file
|
|
Defines `boost::hana::scan_right`.
|
|
|
|
@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_SCAN_RIGHT_HPP
|
|
#define BOOST_HANA_SCAN_RIGHT_HPP
|
|
|
|
#include <boost/hana/fwd/scan_right.hpp>
|
|
|
|
#include <boost/hana/at.hpp>
|
|
#include <boost/hana/concept/sequence.hpp>
|
|
#include <boost/hana/config.hpp>
|
|
#include <boost/hana/core/dispatch.hpp>
|
|
#include <boost/hana/core/make.hpp>
|
|
#include <boost/hana/empty.hpp>
|
|
#include <boost/hana/front.hpp>
|
|
#include <boost/hana/length.hpp>
|
|
#include <boost/hana/prepend.hpp>
|
|
|
|
#include <cstddef>
|
|
#include <utility>
|
|
|
|
|
|
BOOST_HANA_NAMESPACE_BEGIN
|
|
//! @cond
|
|
template <typename Xs, typename F>
|
|
constexpr auto scan_right_t::operator()(Xs&& xs, F const& f) const {
|
|
using S = typename hana::tag_of<Xs>::type;
|
|
using ScanRight = BOOST_HANA_DISPATCH_IF(scan_right_impl<S>,
|
|
hana::Sequence<S>::value
|
|
);
|
|
|
|
#ifndef BOOST_HANA_CONFIG_DISABLE_CONCEPT_CHECKS
|
|
static_assert(hana::Sequence<S>::value,
|
|
"hana::scan_right(xs, f) requires 'xs' to be a Sequence");
|
|
#endif
|
|
|
|
return ScanRight::apply(static_cast<Xs&&>(xs), f);
|
|
}
|
|
|
|
template <typename Xs, typename State, typename F>
|
|
constexpr auto scan_right_t::operator()(Xs&& xs, State&& state, F const& f) const {
|
|
using S = typename hana::tag_of<Xs>::type;
|
|
using ScanRight = BOOST_HANA_DISPATCH_IF(scan_right_impl<S>,
|
|
hana::Sequence<S>::value
|
|
);
|
|
|
|
#ifndef BOOST_HANA_CONFIG_DISABLE_CONCEPT_CHECKS
|
|
static_assert(hana::Sequence<S>::value,
|
|
"hana::scan_right(xs, state, f) requires 'xs' to be a Sequence");
|
|
#endif
|
|
|
|
return ScanRight::apply(static_cast<Xs&&>(xs),
|
|
static_cast<State&&>(state), f);
|
|
}
|
|
//! @endcond
|
|
|
|
template <typename S, bool condition>
|
|
struct scan_right_impl<S, when<condition>> : default_ {
|
|
// Without initial state
|
|
template <typename Xs, typename F, std::size_t n1, std::size_t n2, std::size_t ...ns>
|
|
static constexpr auto
|
|
apply1_impl(Xs&& xs, F const& f, std::index_sequence<n1, n2, ns...>) {
|
|
auto rest = scan_right_impl::apply1_impl(static_cast<Xs&&>(xs),
|
|
f, std::index_sequence<n2, ns...>{});
|
|
auto element = f(hana::at_c<n1>(static_cast<Xs&&>(xs)), hana::front(rest));
|
|
return hana::prepend(std::move(rest), std::move(element));
|
|
}
|
|
|
|
template <typename Xs, typename F, std::size_t n>
|
|
static constexpr auto apply1_impl(Xs&& xs, F const&, std::index_sequence<n>) {
|
|
return hana::make<S>(hana::at_c<n>(static_cast<Xs&&>(xs)));
|
|
}
|
|
|
|
template <typename Xs, typename F>
|
|
static constexpr auto apply1_impl(Xs&&, F const&, std::index_sequence<>) {
|
|
return hana::empty<S>();
|
|
}
|
|
|
|
template <typename Xs, typename F>
|
|
static constexpr auto apply(Xs&& xs, F const& f) {
|
|
constexpr std::size_t Len = decltype(hana::length(xs))::value;
|
|
return scan_right_impl::apply1_impl(static_cast<Xs&&>(xs),
|
|
f, std::make_index_sequence<Len>{});
|
|
}
|
|
|
|
|
|
// With initial state
|
|
template <typename Xs, typename State, typename F,
|
|
std::size_t n1, std::size_t n2, std::size_t ...ns>
|
|
static constexpr auto
|
|
apply_impl(Xs&& xs, State&& state, F const& f,
|
|
std::index_sequence<n1, n2, ns...>)
|
|
{
|
|
auto rest = scan_right_impl::apply_impl(static_cast<Xs&&>(xs),
|
|
static_cast<State&&>(state),
|
|
f, std::index_sequence<n2, ns...>{});
|
|
auto element = f(hana::at_c<n1>(static_cast<Xs&&>(xs)), hana::front(rest));
|
|
return hana::prepend(std::move(rest), std::move(element));
|
|
}
|
|
|
|
template <typename Xs, typename State, typename F, std::size_t n>
|
|
static constexpr auto
|
|
apply_impl(Xs&& xs, State&& state, F const& f, std::index_sequence<n>) {
|
|
auto element = f(hana::at_c<n>(static_cast<Xs&&>(xs)), state);
|
|
return hana::make<S>(std::move(element), static_cast<State&&>(state));
|
|
}
|
|
|
|
template <typename Xs, typename State, typename F>
|
|
static constexpr auto
|
|
apply_impl(Xs&&, State&& state, F const&, std::index_sequence<>) {
|
|
return hana::make<S>(static_cast<State&&>(state));
|
|
}
|
|
|
|
template <typename Xs, typename State, typename F>
|
|
static constexpr auto apply(Xs&& xs, State&& state, F const& f) {
|
|
constexpr std::size_t Len = decltype(hana::length(xs))::value;
|
|
return scan_right_impl::apply_impl(static_cast<Xs&&>(xs),
|
|
static_cast<State&&>(state),
|
|
f, std::make_index_sequence<Len>{});
|
|
}
|
|
};
|
|
BOOST_HANA_NAMESPACE_END
|
|
|
|
#endif // !BOOST_HANA_SCAN_RIGHT_HPP
|