inherit_const.hpp

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//===- include/pstore/support/inherit_const.hpp -----------*- mode: C++ -*-===//
//*  _       _               _ _                         _    *
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//* | | '_ \| '_ \ / _ \ '__| | __|  / __/ _ \| '_ \/ __| __| *
//* | | | | | | | |  __/ |  | | |_  | (_| (_) | | | \__ \ |_  *
//* |_|_| |_|_| |_|\___|_|  |_|\__|  \___\___/|_| |_|___/\__| *
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//===----------------------------------------------------------------------===//
//
// Part of the pstore project, under the Apache License v2.0 with LLVM Exceptions.
// See https://github.com/SNSystems/pstore/blob/master/LICENSE.txt for license
// information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#ifndef PSTORE_SUPPORT_INHERIT_CONST_HPP
#define PSTORE_SUPPORT_INHERIT_CONST_HPP

#include <type_traits>

namespace pstore {

    template <typename T, typename R, typename RC = R const>
    struct inherit_const {
        using type =
            typename std::conditional<std::is_const<typename std::remove_reference<T>::type>::value,
                                      RC, R>::type;
    };

} // namespace pstore

static_assert (std::is_same<typename pstore::inherit_const<int, bool>::type, bool>::value,
               "int -> bool");
static_assert (
    std::is_same<typename pstore::inherit_const<int const, bool>::type, bool const>::value,
    "int const -> bool const");
static_assert (std::is_same<typename pstore::inherit_const<int &, bool>::type, bool>::value,
               "int& -> bool");
static_assert (
    std::is_same<typename pstore::inherit_const<int const &, bool>::type, bool const>::value,
    "int const & -> bool const");
static_assert (std::is_same<typename pstore::inherit_const<int &&, bool>::type, bool>::value,
               "int && -> bool");
static_assert (
    std::is_same<typename pstore::inherit_const<int const &&, bool>::type, bool const>::value,
    "int const && -> bool const");

#endif // PSTORE_SUPPORT_INHERIT_CONST_HPP