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