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___TUPLE_TUPLE_SIZE_H
10 #define _LIBCPP___TUPLE_TUPLE_SIZE_H
11 
12 #include <__config>
13 #include <__fwd/tuple.h>
14 #include <__tuple/tuple_types.h>
15 #include <__type_traits/is_const.h>
16 #include <__type_traits/is_volatile.h>
17 #include <cstddef>
18 
19 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
20 #  pragma GCC system_header
21 #endif
22 
23 _LIBCPP_BEGIN_NAMESPACE_STD
24 
25 template <class _Tp>
26 struct _LIBCPP_TEMPLATE_VIS tuple_size;
27 
28 #if !defined(_LIBCPP_CXX03_LANG)
29 template <class _Tp, class...>
30 using __enable_if_tuple_size_imp = _Tp;
31 
32 template <class _Tp>
33 struct _LIBCPP_TEMPLATE_VIS tuple_size<__enable_if_tuple_size_imp< const _Tp,
34                                                                    __enable_if_t<!is_volatile<_Tp>::value>,
35                                                                    integral_constant<size_t, sizeof(tuple_size<_Tp>)>>>
36     : public integral_constant<size_t, tuple_size<_Tp>::value> {};
37 
38 template <class _Tp>
39 struct _LIBCPP_TEMPLATE_VIS tuple_size<__enable_if_tuple_size_imp< volatile _Tp,
40                                                                    __enable_if_t<!is_const<_Tp>::value>,
41                                                                    integral_constant<size_t, sizeof(tuple_size<_Tp>)>>>
42     : public integral_constant<size_t, tuple_size<_Tp>::value> {};
43 
44 template <class _Tp>
45 struct _LIBCPP_TEMPLATE_VIS
46     tuple_size<__enable_if_tuple_size_imp< const volatile _Tp, integral_constant<size_t, sizeof(tuple_size<_Tp>)>>>
47     : public integral_constant<size_t, tuple_size<_Tp>::value> {};
48 
49 #else
50 template <class _Tp>
51 struct _LIBCPP_TEMPLATE_VIS tuple_size<const _Tp> : public tuple_size<_Tp> {};
52 template <class _Tp>
53 struct _LIBCPP_TEMPLATE_VIS tuple_size<volatile _Tp> : public tuple_size<_Tp> {};
54 template <class _Tp>
55 struct _LIBCPP_TEMPLATE_VIS tuple_size<const volatile _Tp> : public tuple_size<_Tp> {};
56 #endif
57 
58 #ifndef _LIBCPP_CXX03_LANG
59 
60 template <class... _Tp>
61 struct _LIBCPP_TEMPLATE_VIS tuple_size<tuple<_Tp...> > : public integral_constant<size_t, sizeof...(_Tp)> {};
62 
63 template <class... _Tp>
64 struct _LIBCPP_TEMPLATE_VIS tuple_size<__tuple_types<_Tp...> > : public integral_constant<size_t, sizeof...(_Tp)> {};
65 
66 #endif // _LIBCPP_CXX03_LANG
67 
68 _LIBCPP_END_NAMESPACE_STD
69 
70 #endif // _LIBCPP___TUPLE_TUPLE_SIZE_H
71