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_ALIGNED_ACCESSOR_H 18 #define _LIBCPP___MDSPAN_ALIGNED_ACCESSOR_H 19 20 #include <__config> 21 #include <__cstddef/size_t.h> 22 #include <__mdspan/default_accessor.h> 23 #include <__memory/assume_aligned.h> 24 #include <__type_traits/is_abstract.h> 25 #include <__type_traits/is_array.h> 26 #include <__type_traits/is_convertible.h> 27 #include <__type_traits/remove_const.h> 28 29 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 30 # pragma GCC system_header 31 #endif 32 33 _LIBCPP_PUSH_MACROS 34 #include <__undef_macros> 35 36 _LIBCPP_BEGIN_NAMESPACE_STD 37 38 #if _LIBCPP_STD_VER >= 26 39 40 template <class _ElementType, size_t _ByteAlignment> 41 struct aligned_accessor { 42 static_assert(_ByteAlignment != 0 && (_ByteAlignment & (_ByteAlignment - 1)) == 0, 43 "aligned_accessor: byte alignment must be a power of two"); 44 static_assert(_ByteAlignment >= alignof(_ElementType), "aligned_accessor: insufficient byte alignment"); 45 static_assert(!is_array_v<_ElementType>, "aligned_accessor: template argument may not be an array type"); 46 static_assert(!is_abstract_v<_ElementType>, "aligned_accessor: template argument may not be an abstract class"); 47 48 using offset_policy = default_accessor<_ElementType>; 49 using element_type = _ElementType; 50 using reference = _ElementType&; 51 using data_handle_type = _ElementType*; 52 53 static constexpr size_t byte_alignment = _ByteAlignment; 54 55 _LIBCPP_HIDE_FROM_ABI constexpr aligned_accessor() noexcept = default; 56 57 template <class _OtherElementType, size_t _OtherByteAlignment> 58 requires(is_convertible_v<_OtherElementType (*)[], element_type (*)[]> && _OtherByteAlignment >= byte_alignment) aligned_accessoraligned_accessor59 _LIBCPP_HIDE_FROM_ABI constexpr aligned_accessor(aligned_accessor<_OtherElementType, _OtherByteAlignment>) noexcept {} 60 61 template <class _OtherElementType> requiresaligned_accessor62 requires(is_convertible_v<_OtherElementType (*)[], element_type (*)[]>) 63 _LIBCPP_HIDE_FROM_ABI explicit constexpr aligned_accessor(default_accessor<_OtherElementType>) noexcept {} 64 65 template <class _OtherElementType> requiresaligned_accessor66 requires(is_convertible_v<element_type (*)[], _OtherElementType (*)[]>) 67 _LIBCPP_HIDE_FROM_ABI constexpr operator default_accessor<_OtherElementType>() const noexcept { 68 return {}; 69 } 70 accessaligned_accessor71 _LIBCPP_HIDE_FROM_ABI constexpr reference access(data_handle_type __p, size_t __i) const noexcept { 72 return std::assume_aligned<byte_alignment>(__p)[__i]; 73 } 74 75 _LIBCPP_HIDE_FROM_ABI constexpr typename offset_policy::data_handle_type offsetaligned_accessor76 offset(data_handle_type __p, size_t __i) const noexcept { 77 return std::assume_aligned<byte_alignment>(__p) + __i; 78 } 79 }; 80 81 #endif // _LIBCPP_STD_VER >= 26 82 83 _LIBCPP_END_NAMESPACE_STD 84 85 _LIBCPP_POP_MACROS 86 87 #endif // _LIBCPP___MDSPAN_ALIGNED_ACCESSOR_H 88