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scylladb/core/apply.hh

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C++

/*
* This file is open source software, licensed to you under the terms
* of the Apache License, Version 2.0 (the "License"). See the NOTICE file
* distributed with this work for additional information regarding copyright
* ownership. You may not use this file except in compliance with the License.
*
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
/*
* Copyright (C) 2014 Cloudius Systems, Ltd.
*/
#ifndef APPLY_HH_
#define APPLY_HH_
#include <tuple>
#include <utility>
template <typename Func, typename Args, typename IndexList>
struct apply_helper;
template <typename Func, typename Tuple, size_t... I>
struct apply_helper<Func, Tuple, std::index_sequence<I...>> {
static auto apply(Func&& func, Tuple args) {
return func(std::get<I>(std::forward<Tuple>(args))...);
}
};
template <typename Func, typename... T>
inline
auto apply(Func&& func, std::tuple<T...>&& args) {
using helper = apply_helper<Func, std::tuple<T...>&&, std::index_sequence_for<T...>>;
return helper::apply(std::forward<Func>(func), std::move(args));
}
template <typename Func, typename... T>
inline
auto apply(Func&& func, std::tuple<T...>& args) {
using helper = apply_helper<Func, std::tuple<T...>&, std::index_sequence_for<T...>>;
return helper::apply(std::forward<Func>(func), args);
}
template <typename Func, typename... T>
inline
auto apply(Func&& func, const std::tuple<T...>& args) {
using helper = apply_helper<Func, const std::tuple<T...>&, std::index_sequence_for<T...>>;
return helper::apply(std::forward<Func>(func), args);
}
#endif /* APPLY_HH_ */