cuda_toolkit/include/__mdspan/default_accessor.h

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#ifndef _LIBCUDACXX___MDSPAN_DEFAULT_ACCESSOR_HPP
#define _LIBCUDACXX___MDSPAN_DEFAULT_ACCESSOR_HPP

#ifndef __cuda_std__
#include <__config>
#endif // __cuda_std__

#include "../__mdspan/macros.h"
#include "../__type_traits/is_convertible.h"
#include "../cstddef"

#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

_LIBCUDACXX_BEGIN_NAMESPACE_STD

#if _LIBCUDACXX_STD_VER > 11

template <class _ElementType>
struct default_accessor {

  using offset_policy = default_accessor;
  using element_type = _ElementType;
  using reference = _ElementType&;
  using data_handle_type = _ElementType*;

  __MDSPAN_INLINE_FUNCTION_DEFAULTED constexpr default_accessor() noexcept = default;

  __MDSPAN_TEMPLATE_REQUIRES(
    class _OtherElementType,
    /* requires */ (
      _LIBCUDACXX_TRAIT(is_convertible, _OtherElementType(*)[], element_type(*)[])
    )
  )
  __MDSPAN_INLINE_FUNCTION
  constexpr default_accessor(default_accessor<_OtherElementType>) noexcept {}

  __MDSPAN_INLINE_FUNCTION
  constexpr data_handle_type
  offset(data_handle_type __p, size_t __i) const noexcept {
    return __p + __i;
  }

  __MDSPAN_FORCE_INLINE_FUNCTION
  constexpr reference access(data_handle_type __p, size_t __i) const noexcept {
    return __p[__i];
  }

};

#endif // _LIBCUDACXX_STD_VER > 11

_LIBCUDACXX_END_NAMESPACE_STD

#endif // _LIBCUDACXX___MDSPAN_DEFAULT_ACCESSOR_HPP