/**
 *    Copyright (C) 2018-present MongoDB, Inc.
 *
 *    This program is free software: you can redistribute it and/or modify
 *    it under the terms of the Server Side Public License, version 1,
 *    as published by MongoDB, Inc.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    Server Side Public License for more details.
 *
 *    You should have received a copy of the Server Side Public License
 *    along with this program. If not, see
 *    <http://www.mongodb.com/licensing/server-side-public-license>.
 *
 *    As a special exception, the copyright holders give permission to link the
 *    code of portions of this program with the OpenSSL library under certain
 *    conditions as described in each individual source file and distribute
 *    linked combinations including the program with the OpenSSL library. You
 *    must comply with the Server Side Public License in all respects for
 *    all of the code used other than as permitted herein. If you modify file(s)
 *    with this exception, you may extend this exception to your version of the
 *    file(s), but you are not obligated to do so. If you do not wish to do so,
 *    delete this exception statement from your version. If you delete this
 *    exception statement from all source files in the program, then also delete
 *    it in the license file.
 */

#pragma once

#include <type_traits>
#include <utility>

namespace mongo {
namespace stdx {

#if __cplusplus < 201703

template <typename T>
constexpr typename std::add_const<T>::type& as_const(T& t) noexcept {
    return t;
}

template <typename T>
void as_const(T&&) = delete;

#else

using std::as_const;

#endif

/** https://en.cppreference.com/w/cpp/utility/to_underlying */
template <typename E>
constexpr auto to_underlying(E e) noexcept {
    static_assert(std::is_enum_v<E>, "E is not an enumeration");
    return static_cast<std::underlying_type_t<E>>(e);
}

}  // namespace stdx
}  // namespace mongo