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 
25 template <class _Tp>
26 struct rank : integral_constant<size_t, __array_rank(_Tp)> {};
27 
28 #else
29 
30 template <class _Tp> struct _LIBCPP_TEMPLATE_VIS rank
31     : public integral_constant<size_t, 0> {};
32 template <class _Tp> struct _LIBCPP_TEMPLATE_VIS rank<_Tp[]>
33     : public integral_constant<size_t, rank<_Tp>::value + 1> {};
34 template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS rank<_Tp[_Np]>
35     : public integral_constant<size_t, rank<_Tp>::value + 1> {};
36 
37 #endif // __has_builtin(__array_rank)
38 
39 #if _LIBCPP_STD_VER > 14
40 template <class _Tp>
41 inline 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