__cxx03/__tuple/tuple_size.h

0001 //===----------------------------------------------------------------------===//
0002 //
0003 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
0004 // See https://llvm.org/LICENSE.txt for license information.
0005 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
0006 //
0007 //===----------------------------------------------------------------------===//
0008
0009 #ifndef _LIBCPP___CXX03___TUPLE_TUPLE_SIZE_H
0010 #define _LIBCPP___CXX03___TUPLE_TUPLE_SIZE_H
0011
0012 #include <__cxx03/__config>
0013 #include <__cxx03/__fwd/tuple.h>
0014 #include <__cxx03/__tuple/tuple_types.h>
0015 #include <__cxx03/__type_traits/is_const.h>
0016 #include <__cxx03/__type_traits/is_volatile.h>
0017 #include <__cxx03/cstddef>
0018
0019 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
0020 #  pragma GCC system_header
0021 #endif
0022
0023 _LIBCPP_BEGIN_NAMESPACE_STD
0024
0025 template <class _Tp>
0026 struct _LIBCPP_TEMPLATE_VIS tuple_size;
0027
0028 #if !defined(_LIBCPP_CXX03_LANG)
0029 template <class _Tp, class...>
0030 using __enable_if_tuple_size_imp = _Tp;
0031
0032 template <class _Tp>
0033 struct _LIBCPP_TEMPLATE_VIS tuple_size<__enable_if_tuple_size_imp< const _Tp,
0034                                                                    __enable_if_t<!is_volatile<_Tp>::value>,
0035                                                                    integral_constant<size_t, sizeof(tuple_size<_Tp>)>>>
0036     : public integral_constant<size_t, tuple_size<_Tp>::value> {};
0037
0038 template <class _Tp>
0039 struct _LIBCPP_TEMPLATE_VIS tuple_size<__enable_if_tuple_size_imp< volatile _Tp,
0040                                                                    __enable_if_t<!is_const<_Tp>::value>,
0041                                                                    integral_constant<size_t, sizeof(tuple_size<_Tp>)>>>
0042     : public integral_constant<size_t, tuple_size<_Tp>::value> {};
0043
0044 template <class _Tp>
0045 struct _LIBCPP_TEMPLATE_VIS
0046 tuple_size<__enable_if_tuple_size_imp<const volatile _Tp, integral_constant<size_t, sizeof(tuple_size<_Tp>)>>>
0047     : public integral_constant<size_t, tuple_size<_Tp>::value> {};
0048
0049 #else
0050 template <class _Tp>
0051 struct _LIBCPP_TEMPLATE_VIS tuple_size<const _Tp> : public tuple_size<_Tp> {};
0052 template <class _Tp>
0053 struct _LIBCPP_TEMPLATE_VIS tuple_size<volatile _Tp> : public tuple_size<_Tp> {};
0054 template <class _Tp>
0055 struct _LIBCPP_TEMPLATE_VIS tuple_size<const volatile _Tp> : public tuple_size<_Tp> {};
0056 #endif
0057
0058 #ifndef _LIBCPP_CXX03_LANG
0059
0060 template <class... _Tp>
0061 struct _LIBCPP_TEMPLATE_VIS tuple_size<tuple<_Tp...> > : public integral_constant<size_t, sizeof...(_Tp)> {};
0062
0063 template <class... _Tp>
0064 struct _LIBCPP_TEMPLATE_VIS tuple_size<__tuple_types<_Tp...> > : public integral_constant<size_t, sizeof...(_Tp)> {};
0065
0066 #  if _LIBCPP_STD_VER >= 17
0067 template <class _Tp>
0068 inline constexpr size_t tuple_size_v = tuple_size<_Tp>::value;
0069 #  endif
0070
0071 #endif // _LIBCPP_CXX03_LANG
0072
0073 _LIBCPP_END_NAMESPACE_STD
0074
0075 #endif // _LIBCPP___CXX03___TUPLE_TUPLE_SIZE_H