xref: /freebsd-src/contrib/llvm-project/libcxx/include/__utility/integer_sequence.h (revision 349cc55c9796c4596a5b9904cd3281af295f878f)
1fe6060f1SDimitry Andric //===----------------------------------------------------------------------===//
2fe6060f1SDimitry Andric //
3fe6060f1SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4fe6060f1SDimitry Andric // See https://llvm.org/LICENSE.txt for license information.
5fe6060f1SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6fe6060f1SDimitry Andric //
7fe6060f1SDimitry Andric //===----------------------------------------------------------------------===//
8fe6060f1SDimitry Andric 
9fe6060f1SDimitry Andric #ifndef _LIBCPP___UTILITY_INTEGER_SEQUENCE_H
10fe6060f1SDimitry Andric #define _LIBCPP___UTILITY_INTEGER_SEQUENCE_H
11fe6060f1SDimitry Andric 
12fe6060f1SDimitry Andric #include <__config>
13fe6060f1SDimitry Andric #include <type_traits>
14fe6060f1SDimitry Andric 
15fe6060f1SDimitry Andric #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
16fe6060f1SDimitry Andric #pragma GCC system_header
17fe6060f1SDimitry Andric #endif
18fe6060f1SDimitry Andric 
19fe6060f1SDimitry Andric _LIBCPP_BEGIN_NAMESPACE_STD
20fe6060f1SDimitry Andric 
21fe6060f1SDimitry Andric #if _LIBCPP_STD_VER > 11
22fe6060f1SDimitry Andric 
23fe6060f1SDimitry Andric template<class _Tp, _Tp... _Ip>
24fe6060f1SDimitry Andric struct _LIBCPP_TEMPLATE_VIS integer_sequence
25fe6060f1SDimitry Andric {
26fe6060f1SDimitry Andric     typedef _Tp value_type;
27fe6060f1SDimitry Andric     static_assert( is_integral<_Tp>::value,
28fe6060f1SDimitry Andric                   "std::integer_sequence can only be instantiated with an integral type" );
29fe6060f1SDimitry Andric     static
30fe6060f1SDimitry Andric     _LIBCPP_INLINE_VISIBILITY
31fe6060f1SDimitry Andric     constexpr
32fe6060f1SDimitry Andric     size_t
33fe6060f1SDimitry Andric     size() noexcept { return sizeof...(_Ip); }
34fe6060f1SDimitry Andric };
35fe6060f1SDimitry Andric 
36fe6060f1SDimitry Andric template<size_t... _Ip>
37fe6060f1SDimitry Andric     using index_sequence = integer_sequence<size_t, _Ip...>;
38fe6060f1SDimitry Andric 
39fe6060f1SDimitry Andric #if __has_builtin(__make_integer_seq) && !defined(_LIBCPP_TESTING_FALLBACK_MAKE_INTEGER_SEQUENCE)
40fe6060f1SDimitry Andric 
41fe6060f1SDimitry Andric template <class _Tp, _Tp _Ep>
42*349cc55cSDimitry Andric using __make_integer_sequence _LIBCPP_NODEBUG = __make_integer_seq<integer_sequence, _Tp, _Ep>;
43fe6060f1SDimitry Andric 
44fe6060f1SDimitry Andric #else
45fe6060f1SDimitry Andric 
46*349cc55cSDimitry Andric template<typename _Tp, _Tp _Np> using __make_integer_sequence_unchecked _LIBCPP_NODEBUG =
47fe6060f1SDimitry Andric   typename __detail::__make<_Np>::type::template __convert<integer_sequence, _Tp>;
48fe6060f1SDimitry Andric 
49fe6060f1SDimitry Andric template <class _Tp, _Tp _Ep>
50fe6060f1SDimitry Andric struct __make_integer_sequence_checked
51fe6060f1SDimitry Andric {
52fe6060f1SDimitry Andric     static_assert(is_integral<_Tp>::value,
53fe6060f1SDimitry Andric                   "std::make_integer_sequence can only be instantiated with an integral type" );
54fe6060f1SDimitry Andric     static_assert(0 <= _Ep, "std::make_integer_sequence must have a non-negative sequence length");
55fe6060f1SDimitry Andric     // Workaround GCC bug by preventing bad installations when 0 <= _Ep
56fe6060f1SDimitry Andric     // https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68929
57*349cc55cSDimitry Andric     typedef _LIBCPP_NODEBUG __make_integer_sequence_unchecked<_Tp, 0 <= _Ep ? _Ep : 0> type;
58fe6060f1SDimitry Andric };
59fe6060f1SDimitry Andric 
60fe6060f1SDimitry Andric template <class _Tp, _Tp _Ep>
61*349cc55cSDimitry Andric using __make_integer_sequence _LIBCPP_NODEBUG = typename __make_integer_sequence_checked<_Tp, _Ep>::type;
62fe6060f1SDimitry Andric 
63fe6060f1SDimitry Andric #endif
64fe6060f1SDimitry Andric 
65fe6060f1SDimitry Andric template<class _Tp, _Tp _Np>
66fe6060f1SDimitry Andric     using make_integer_sequence = __make_integer_sequence<_Tp, _Np>;
67fe6060f1SDimitry Andric 
68fe6060f1SDimitry Andric template<size_t _Np>
69fe6060f1SDimitry Andric     using make_index_sequence = make_integer_sequence<size_t, _Np>;
70fe6060f1SDimitry Andric 
71fe6060f1SDimitry Andric template<class... _Tp>
72fe6060f1SDimitry Andric     using index_sequence_for = make_index_sequence<sizeof...(_Tp)>;
73fe6060f1SDimitry Andric 
74fe6060f1SDimitry Andric #endif // _LIBCPP_STD_VER > 11
75fe6060f1SDimitry Andric 
76fe6060f1SDimitry Andric _LIBCPP_END_NAMESPACE_STD
77fe6060f1SDimitry Andric 
78fe6060f1SDimitry Andric #endif // _LIBCPP___UTILITY_INTEGER_SEQUENCE_H
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