libcxx/include/__mdspan/default_accessor.h

   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 <__type_traits/is_abstract.h>
  22 #include <__type_traits/is_array.h>
  23 #include <__type_traits/is_convertible.h>
  24 #include <__type_traits/remove_const.h>
  25 #include <cinttypes>
  26 #include <cstddef>
  27
  28 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  29 #  pragma GCC system_header
  30 #endif
  31
  32 _LIBCPP_PUSH_MACROS
  33 #include <__undef_macros>
  34
  35 _LIBCPP_BEGIN_NAMESPACE_STD
  36
  37 #if _LIBCPP_STD_VER >= 23
  38
  39 template <class _ElementType>
  40 struct default_accessor {
  41   static_assert(!is_array_v<_ElementType>, "default_accessor: template argument may not be an array type");
  42   static_assert(!is_abstract_v<_ElementType>, "default_accessor: template argument may not be an abstract class");
  43
  44   using offset_policy    = default_accessor;
  45   using element_type     = _ElementType;
  46   using reference        = _ElementType&;
  47   using data_handle_type = _ElementType*;
  48
  49   _LIBCPP_HIDE_FROM_ABI constexpr default_accessor() noexcept = default;
  50   template <class _OtherElementType>
  51     requires(is_convertible_v<_OtherElementType (*)[], element_type (*)[]>)
  52   _LIBCPP_HIDE_FROM_ABI constexpr default_accessor(default_accessor<_OtherElementType>) noexcept {}
  53
  54   _LIBCPP_HIDE_FROM_ABI constexpr reference access(data_handle_type __p, size_t __i) const noexcept { return __p[__i]; }
  55   _LIBCPP_HIDE_FROM_ABI constexpr data_handle_type offset(data_handle_type __p, size_t __i) const noexcept {
  56     return __p + __i;
  57   }
  58 };
  59
  60 #endif // _LIBCPP_STD_VER >= 23
  61
  62 _LIBCPP_END_NAMESPACE_STD
  63
  64 _LIBCPP_POP_MACROS
  65
  66 #endif // _LIBCPP___MDSPAN_DEFAULT_ACCESSOR_H