Files
scylladb/core/function_traits.hh
2015-04-08 17:10:51 +03:00

65 lines
1.9 KiB
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 2015 Cloudius Systems
*/
#pragma once
#include <tuple>
template<typename T>
struct function_traits;
template<typename Ret, typename... Args>
struct function_traits<Ret(Args...)>
{
using return_type = Ret;
using args_as_tuple = std::tuple<Args...>;
static constexpr std::size_t arity = sizeof...(Args);
template <std::size_t N>
struct arg
{
static_assert(N < arity, "no such parameter index.");
using type = typename std::tuple_element<N, std::tuple<Args...>>::type;
};
};
template<typename Ret, typename... Args>
struct function_traits<Ret(*)(Args...)> : public function_traits<Ret(Args...)>
{};
template <typename T, typename Ret, typename... Args>
struct function_traits<Ret(T::*)(Args...)> : public function_traits<Ret(Args...)>
{};
template <typename T, typename Ret, typename... Args>
struct function_traits<Ret(T::*)(Args...) const> : public function_traits<Ret(Args...)>
{};
template <typename T>
struct function_traits : public function_traits<decltype(&T::operator())>
{};
template<typename T>
struct function_traits<T&> : public function_traits<std::remove_reference_t<T>>
{};