type_traits.hpp🔗

Namespaces🔗

Name
iox building block to easily create free function for logging in a library context
iox::cxx

Classes🔗

	Name
struct	iox::cxx::add_const_conditionally Conditionally add const to type T if C has the const qualifier.
struct	iox::cxx::add_const_conditionally< T, const C >
struct	iox::cxx::is_invocable Verifies whether the passed Callable type is in fact invocable with the given arguments.
struct	iox::cxx::is_invocable_r Verifies whether the passed Callable type is in fact invocable with the given arguments and the result of the invocation is convertible to ReturnType.
struct	iox::cxx::is_function_pointer Check whether T is a function pointer with arbitrary signature.
struct	*iox::cxx::is_function_pointer< ReturnType()(ArgTypes...)>**

Source code🔗

// Copyright (c) 2020 by Robert Bosch GmbH. All rights reserved.
// Copyright (c) 2021 - 2022 by Apex.AI Inc. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// 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.
//
// SPDX-License-Identifier: Apache-2.0

#ifndef IOX_HOOFS_CXX_TYPE_TRAITS_HPP
#define IOX_HOOFS_CXX_TYPE_TRAITS_HPP

#include <type_traits>

namespace iox
{
namespace cxx
{
template <typename T, typename C>
struct add_const_conditionally
{
    using type = T;
};
template <typename T, typename C>
struct add_const_conditionally<T, const C>
{
    using type = const T;
};
template <typename T, typename C>
using add_const_conditionally_t = typename add_const_conditionally<T, C>::type;

template <typename>
constexpr bool always_false_v = false;

// windows defines __cplusplus as 199711L
#if __cplusplus < 201703L && !defined(_WIN32)
template <typename C, typename... Cargs>
using invoke_result = std::result_of<C(Cargs...)>;
#elif __cplusplus >= 201703L || defined(_WIN32)
template <typename C, typename... Cargs>
using invoke_result = std::invoke_result<C, Cargs...>;
#endif

template <typename Callable, typename... ArgTypes>
struct is_invocable
{
    // This variant is chosen when Callable(ArgTypes) successfully resolves to a valid type, i.e. is invocable.
    template <typename C, typename... As>
    static constexpr std::true_type test(typename cxx::invoke_result<C, As...>::type*) noexcept
    {
        return {};
    }

    // This is chosen if Callable(ArgTypes) does not resolve to a valid type.
    template <typename C, typename... As>
    static constexpr std::false_type test(...) noexcept
    {
        return {};
    }

    // Test with nullptr as this can stand in for a pointer to any type.
    static constexpr bool value = decltype(test<Callable, ArgTypes...>(nullptr))::value;
};

template <typename ReturnType, typename Callable, typename... ArgTypes>
struct is_invocable_r
{
    template <typename C, typename... As>
    static constexpr std::true_type test(
        std::enable_if_t<std::is_convertible<typename cxx::invoke_result<C, As...>::type, ReturnType>::value>*) noexcept
    {
        return {};
    }

    template <typename C, typename... As>
    static constexpr std::false_type test(...) noexcept
    {
        return {};
    }

    // Test with nullptr as this can stand in for a pointer to any type.
    static constexpr bool value = decltype(test<Callable, ArgTypes...>(nullptr))::value;
};

template <typename T>
struct is_function_pointer : std::false_type
{
};
template <typename ReturnType, typename... ArgTypes>
struct is_function_pointer<ReturnType (*)(ArgTypes...)> : std::true_type
{
};

template <typename...>
using void_t = void;
} // namespace cxx
} // namespace iox

#endif // IOX_HOOFS_CXX_TYPE_TRAITS_HPP

Updated on 2 April 2022 at 16:37:47 CEST