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/** @file
 * IPRT / No-CRT - Minimal type_traits C++ header.
 */

/*
 * Copyright (C) 2022 Oracle and/or its affiliates.
 *
 * This file is part of VirtualBox base platform packages, as
 * available from https://www.virtualbox.org.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation, in version 3 of the
 * License.
 *
 * 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 GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see <https://www.gnu.org/licenses>.
 *
 * The contents of this file may alternatively be used under the terms
 * of the Common Development and Distribution License Version 1.0
 * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
 * in the VirtualBox distribution, in which case the provisions of the
 * CDDL are applicable instead of those of the GPL.
 *
 * You may elect to license modified versions of this file under the
 * terms and conditions of either the GPL or the CDDL or both.
 *
 * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
 */

#ifndef VBOX_INCLUDED_SRC_nocrt_type_traits
#define VBOX_INCLUDED_SRC_nocrt_type_traits
#ifndef RT_WITHOUT_PRAGMA_ONCE
# pragma once
#endif

#include <iprt/cdefs.h>

namespace std
{
    /*
     * std::integral_constant
     */
    template<typename a_Type, a_Type a_Value>
    struct integral_constant
    {
        static constexpr a_Type                     value = a_Value;
        typedef a_Type                              value_type;
        typedef integral_constant<a_Type, a_Value>  type;
        constexpr operator value_type() const RT_NOEXCEPT { return value; }
        /** @todo operator()() for 2014+   */
    };
    template<typename a_Type, a_Type a_Value> constexpr a_Type integral_constant<a_Type, a_Value>::value;

    /* Helper: */
    template<bool a_Value> using bool_constant = integral_constant<bool, a_Value>;

    /* Specializations: */
    typedef integral_constant<bool, true>           true_type;
    typedef integral_constant<bool, false>          false_type;


    /*
     * std::is_enum
     */
    template<typename a_Type> struct is_enum
        : integral_constant<bool, __is_enum(a_Type) /* compiler (clan, gcc, msc) builtin */ >
    { };

    /*
     * std::underlying_type
     */
    template<typename a_Type> struct underlying_type
    {
        using type = __underlying_type(a_Type); /* compiler (clan, gcc, msc) builtin */
    };

    template<typename a_Type> using underlying_type_t = typename underlying_type<a_Type>::type;

}

#endif /* !VBOX_INCLUDED_SRC_nocrt_type_traits */