//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// SPDX-FileCopyrightText: Copyright (c) 2025 NVIDIA CORPORATION & AFFILIATES.
//
//===----------------------------------------------------------------------===//

#ifndef _LIBCUDACXX___FUNCTIONAL_UNWRAP_REF_H
#define _LIBCUDACXX___FUNCTIONAL_UNWRAP_REF_H

#include <cuda/std/detail/__config>

#if defined(_CCCL_IMPLICIT_SYSTEM_HEADER_GCC)
#  pragma GCC system_header
#elif defined(_CCCL_IMPLICIT_SYSTEM_HEADER_CLANG)
#  pragma clang system_header
#elif defined(_CCCL_IMPLICIT_SYSTEM_HEADER_MSVC)
#  pragma system_header
#endif // no system header

#include <cuda/std/__fwd/reference_wrapper.h>
#include <cuda/std/__type_traits/decay.h>

#include <cuda/std/__cccl/prologue.h>

_LIBCUDACXX_BEGIN_NAMESPACE_STD

template <class _Tp>
struct unwrap_reference
{
  using type _CCCL_NODEBUG_ALIAS = _Tp;
};

template <class _Tp>
struct unwrap_reference<reference_wrapper<_Tp>>
{
  using type _CCCL_NODEBUG_ALIAS = _Tp&;
};

template <class _Tp>
using unwrap_reference_t = typename unwrap_reference<_Tp>::type;

template <class _Tp>
struct unwrap_ref_decay : unwrap_reference<decay_t<_Tp>>
{};

template <class _Tp>
using unwrap_ref_decay_t = typename unwrap_ref_decay<_Tp>::type;

_LIBCUDACXX_END_NAMESPACE_STD

#include <cuda/std/__cccl/epilogue.h>

#endif // _LIBCUDACXX___FUNCTIONAL_UNWRAP_REF_H