1//===----------------------------------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#ifndef _LIBCPP___TYPE_TRAITS_RANK_H
10#define _LIBCPP___TYPE_TRAITS_RANK_H
11
12#include <__config>
13#include <__type_traits/integral_constant.h>
14#include <cstddef>
15
16#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
17#  pragma GCC system_header
18#endif
19
20_LIBCPP_BEGIN_NAMESPACE_STD
21
22// TODO: Enable using the builtin __array_rank when https://llvm.org/PR57133 is resolved
23#if __has_builtin(__array_rank) && 0
24
25template <class _Tp>
26struct rank : integral_constant<size_t, __array_rank(_Tp)> {};
27
28#else
29
30template <class _Tp>
31struct _LIBCPP_TEMPLATE_VIS rank : public integral_constant<size_t, 0> {};
32template <class _Tp>
33struct _LIBCPP_TEMPLATE_VIS rank<_Tp[]> : public integral_constant<size_t, rank<_Tp>::value + 1> {};
34template <class _Tp, size_t _Np>
35struct _LIBCPP_TEMPLATE_VIS rank<_Tp[_Np]> : public integral_constant<size_t, rank<_Tp>::value + 1> {};
36
37#endif // __has_builtin(__array_rank)
38
39#if _LIBCPP_STD_VER >= 17
40template <class _Tp>
41inline constexpr size_t rank_v = rank<_Tp>::value;
42#endif
43
44_LIBCPP_END_NAMESPACE_STD
45
46#endif // _LIBCPP___TYPE_TRAITS_RANK_H
47