default_accessor.hpp

//@HEADER
// ************************************************************************
//
//                        Kokkos v. 4.0
//       Copyright (2022) National Technology & Engineering
//               Solutions of Sandia, LLC (NTESS).
//
// Under the terms of Contract DE-NA0003525 with NTESS,
// the U.S. Government retains certain rights in this software.
//
// Part of Kokkos, under the Apache License v2.0 with LLVM Exceptions.
// See https://kokkos.org/LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//@HEADER
#pragma once

#include "macros.hpp"

#include <cstddef> // size_t

namespace std {
namespace experimental {

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 */ (
      _MDSPAN_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];
  }

};

} // end namespace experimental
} // end namespace std