1// -*- C++ -*-
 2//===----------------------------------------------------------------------===//
 3//
 4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 5// See https://llvm.org/LICENSE.txt for license information.
 6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 7//
 8//                        Kokkos v. 4.0
 9//       Copyright (2022) National Technology & Engineering
10//               Solutions of Sandia, LLC (NTESS).
11//
12// Under the terms of Contract DE-NA0003525 with NTESS,
13// the U.S. Government retains certain rights in this software.
14//
15//===---------------------------------------------------------------------===//
16
17#ifndef _LIBCPP___MDSPAN_DEFAULT_ACCESSOR_H
18#define _LIBCPP___MDSPAN_DEFAULT_ACCESSOR_H
19
20#include <__config>
21#include <__cstddef/size_t.h>
22#include <__type_traits/is_abstract.h>
23#include <__type_traits/is_array.h>
24#include <__type_traits/is_convertible.h>
25#include <__type_traits/remove_const.h>
26
27#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
28#  pragma GCC system_header
29#endif
30
31_LIBCPP_PUSH_MACROS
32#include <__undef_macros>
33
34_LIBCPP_BEGIN_NAMESPACE_STD
35
36#if _LIBCPP_STD_VER >= 23
37
38template <class _ElementType>
39struct default_accessor {
40  static_assert(!is_array_v<_ElementType>, "default_accessor: template argument may not be an array type");
41  static_assert(!is_abstract_v<_ElementType>, "default_accessor: template argument may not be an abstract class");
42
43  using offset_policy    = default_accessor;
44  using element_type     = _ElementType;
45  using reference        = _ElementType&;
46  using data_handle_type = _ElementType*;
47
48  _LIBCPP_HIDE_FROM_ABI constexpr default_accessor() noexcept = default;
49  template <class _OtherElementType>
50    requires(is_convertible_v<_OtherElementType (*)[], element_type (*)[]>)
51  _LIBCPP_HIDE_FROM_ABI constexpr default_accessor(default_accessor<_OtherElementType>) noexcept {}
52
53  _LIBCPP_HIDE_FROM_ABI constexpr reference access(data_handle_type __p, size_t __i) const noexcept { return __p[__i]; }
54  _LIBCPP_HIDE_FROM_ABI constexpr data_handle_type offset(data_handle_type __p, size_t __i) const noexcept {
55    return __p + __i;
56  }
57};
58
59#endif // _LIBCPP_STD_VER >= 23
60
61_LIBCPP_END_NAMESPACE_STD
62
63_LIBCPP_POP_MACROS
64
65#endif // _LIBCPP___MDSPAN_DEFAULT_ACCESSOR_H