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_EXTENT_H
10 #define _LIBCPP___TYPE_TRAITS_EXTENT_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 #if __has_keyword(__array_extent)
23 
24 template<class _Tp, size_t _Dim = 0>
25 struct _LIBCPP_TEMPLATE_VIS extent
26     : integral_constant<size_t, __array_extent(_Tp, _Dim)> { };
27 
28 #if _LIBCPP_STD_VER > 14
29 template <class _Tp, unsigned _Ip = 0>
30 inline constexpr size_t extent_v = __array_extent(_Tp, _Ip);
31 #endif
32 
33 #else // __has_keyword(__array_extent)
34 
35 template <class _Tp, unsigned _Ip = 0> struct _LIBCPP_TEMPLATE_VIS extent
36     : public integral_constant<size_t, 0> {};
37 template <class _Tp> struct _LIBCPP_TEMPLATE_VIS extent<_Tp[], 0>
38     : public integral_constant<size_t, 0> {};
39 template <class _Tp, unsigned _Ip> struct _LIBCPP_TEMPLATE_VIS extent<_Tp[], _Ip>
40     : public integral_constant<size_t, extent<_Tp, _Ip-1>::value> {};
41 template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS extent<_Tp[_Np], 0>
42     : public integral_constant<size_t, _Np> {};
43 template <class _Tp, size_t _Np, unsigned _Ip> struct _LIBCPP_TEMPLATE_VIS extent<_Tp[_Np], _Ip>
44     : public integral_constant<size_t, extent<_Tp, _Ip-1>::value> {};
45 
46 #if _LIBCPP_STD_VER > 14
47 template <class _Tp, unsigned _Ip = 0>
48 inline constexpr size_t extent_v = extent<_Tp, _Ip>::value;
49 #endif
50 
51 #endif // __has_keyword(__array_extent)
52 
53 _LIBCPP_END_NAMESPACE_STD
54 
55 #endif // _LIBCPP___TYPE_TRAITS_EXTENT_H
56