mirror of
https://github.com/ecency/ecency-mobile.git
synced 2024-12-26 06:42:15 +03:00
87 lines
3.0 KiB
C++
87 lines
3.0 KiB
C++
/*!
|
|
@file
|
|
Defines `boost::hana::remove_at` and `boost::hana::remove_at_c`.
|
|
|
|
@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_REMOVE_AT_HPP
|
|
#define BOOST_HANA_REMOVE_AT_HPP
|
|
|
|
#include <boost/hana/fwd/remove_at.hpp>
|
|
|
|
#include <boost/hana/at.hpp>
|
|
#include <boost/hana/concept/integral_constant.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/integral_constant.hpp>
|
|
#include <boost/hana/length.hpp>
|
|
|
|
#include <cstddef>
|
|
#include <utility>
|
|
|
|
|
|
BOOST_HANA_NAMESPACE_BEGIN
|
|
//! @cond
|
|
template <typename Xs, typename N>
|
|
constexpr auto remove_at_t::operator()(Xs&& xs, N const& n) const {
|
|
using S = typename hana::tag_of<Xs>::type;
|
|
using RemoveAt = BOOST_HANA_DISPATCH_IF(remove_at_impl<S>,
|
|
hana::Sequence<S>::value &&
|
|
hana::IntegralConstant<N>::value
|
|
);
|
|
|
|
#ifndef BOOST_HANA_CONFIG_DISABLE_CONCEPT_CHECKS
|
|
static_assert(hana::Sequence<S>::value,
|
|
"hana::remove_at(xs, n) requires 'xs' to be a Sequence");
|
|
|
|
static_assert(hana::IntegralConstant<N>::value,
|
|
"hana::remove_at(xs, n) requires 'n' to be an IntegralConstant");
|
|
#endif
|
|
|
|
static_assert(N::value >= 0,
|
|
"hana::remove_at(xs, n) requires 'n' to be non-negative");
|
|
|
|
return RemoveAt::apply(static_cast<Xs&&>(xs), n);
|
|
}
|
|
//! @endcond
|
|
|
|
template <typename S, bool condition>
|
|
struct remove_at_impl<S, when<condition>> : default_ {
|
|
template <typename Xs, std::size_t ...before, std::size_t ...after>
|
|
static constexpr auto
|
|
remove_at_helper(Xs&& xs, std::index_sequence<before...>,
|
|
std::index_sequence<after...>)
|
|
{
|
|
return hana::make<S>(
|
|
hana::at_c<before>(static_cast<Xs&&>(xs))...,
|
|
hana::at_c<after + sizeof...(before) + 1>(static_cast<Xs&&>(xs))...
|
|
);
|
|
}
|
|
|
|
template <typename Xs, typename N>
|
|
static constexpr auto apply(Xs&& xs, N const&) {
|
|
constexpr std::size_t n = N::value;
|
|
constexpr std::size_t len = decltype(hana::length(xs))::value;
|
|
static_assert(n < len,
|
|
"hana::remove_at(xs, n) requires 'n' to be in the bounds of the sequence");
|
|
return remove_at_helper(static_cast<Xs&&>(xs),
|
|
std::make_index_sequence<n>{},
|
|
std::make_index_sequence<len - n - 1>{});
|
|
}
|
|
};
|
|
|
|
template <std::size_t n>
|
|
struct remove_at_c_t {
|
|
template <typename Xs>
|
|
constexpr decltype(auto) operator()(Xs&& xs) const
|
|
{ return hana::remove_at(static_cast<Xs&&>(xs), hana::size_c<n>); }
|
|
};
|
|
BOOST_HANA_NAMESPACE_END
|
|
|
|
#endif // !BOOST_HANA_REMOVE_AT_HPP
|