xref: /freebsd-src/contrib/llvm-project/libcxx/include/__utility/integer_sequence.h (revision fe6060f10f634930ff71b7c50291ddc610da2475)
1*fe6060f1SDimitry Andric //===----------------------------------------------------------------------===//
2*fe6060f1SDimitry Andric //
3*fe6060f1SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4*fe6060f1SDimitry Andric // See https://llvm.org/LICENSE.txt for license information.
5*fe6060f1SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6*fe6060f1SDimitry Andric //
7*fe6060f1SDimitry Andric //===----------------------------------------------------------------------===//
8*fe6060f1SDimitry Andric 
9*fe6060f1SDimitry Andric #ifndef _LIBCPP___UTILITY_INTEGER_SEQUENCE_H
10*fe6060f1SDimitry Andric #define _LIBCPP___UTILITY_INTEGER_SEQUENCE_H
11*fe6060f1SDimitry Andric 
12*fe6060f1SDimitry Andric #include <__config>
13*fe6060f1SDimitry Andric #include <type_traits>
14*fe6060f1SDimitry Andric 
15*fe6060f1SDimitry Andric #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
16*fe6060f1SDimitry Andric #pragma GCC system_header
17*fe6060f1SDimitry Andric #endif
18*fe6060f1SDimitry Andric 
19*fe6060f1SDimitry Andric _LIBCPP_PUSH_MACROS
20*fe6060f1SDimitry Andric #include <__undef_macros>
21*fe6060f1SDimitry Andric 
22*fe6060f1SDimitry Andric _LIBCPP_BEGIN_NAMESPACE_STD
23*fe6060f1SDimitry Andric 
24*fe6060f1SDimitry Andric #if _LIBCPP_STD_VER > 11
25*fe6060f1SDimitry Andric 
26*fe6060f1SDimitry Andric template<class _Tp, _Tp... _Ip>
27*fe6060f1SDimitry Andric struct _LIBCPP_TEMPLATE_VIS integer_sequence
28*fe6060f1SDimitry Andric {
29*fe6060f1SDimitry Andric     typedef _Tp value_type;
30*fe6060f1SDimitry Andric     static_assert( is_integral<_Tp>::value,
31*fe6060f1SDimitry Andric                   "std::integer_sequence can only be instantiated with an integral type" );
32*fe6060f1SDimitry Andric     static
33*fe6060f1SDimitry Andric     _LIBCPP_INLINE_VISIBILITY
34*fe6060f1SDimitry Andric     constexpr
35*fe6060f1SDimitry Andric     size_t
36*fe6060f1SDimitry Andric     size() noexcept { return sizeof...(_Ip); }
37*fe6060f1SDimitry Andric };
38*fe6060f1SDimitry Andric 
39*fe6060f1SDimitry Andric template<size_t... _Ip>
40*fe6060f1SDimitry Andric     using index_sequence = integer_sequence<size_t, _Ip...>;
41*fe6060f1SDimitry Andric 
42*fe6060f1SDimitry Andric #if __has_builtin(__make_integer_seq) && !defined(_LIBCPP_TESTING_FALLBACK_MAKE_INTEGER_SEQUENCE)
43*fe6060f1SDimitry Andric 
44*fe6060f1SDimitry Andric template <class _Tp, _Tp _Ep>
45*fe6060f1SDimitry Andric using __make_integer_sequence _LIBCPP_NODEBUG_TYPE = __make_integer_seq<integer_sequence, _Tp, _Ep>;
46*fe6060f1SDimitry Andric 
47*fe6060f1SDimitry Andric #else
48*fe6060f1SDimitry Andric 
49*fe6060f1SDimitry Andric template<typename _Tp, _Tp _Np> using __make_integer_sequence_unchecked _LIBCPP_NODEBUG_TYPE  =
50*fe6060f1SDimitry Andric   typename __detail::__make<_Np>::type::template __convert<integer_sequence, _Tp>;
51*fe6060f1SDimitry Andric 
52*fe6060f1SDimitry Andric template <class _Tp, _Tp _Ep>
53*fe6060f1SDimitry Andric struct __make_integer_sequence_checked
54*fe6060f1SDimitry Andric {
55*fe6060f1SDimitry Andric     static_assert(is_integral<_Tp>::value,
56*fe6060f1SDimitry Andric                   "std::make_integer_sequence can only be instantiated with an integral type" );
57*fe6060f1SDimitry Andric     static_assert(0 <= _Ep, "std::make_integer_sequence must have a non-negative sequence length");
58*fe6060f1SDimitry Andric     // Workaround GCC bug by preventing bad installations when 0 <= _Ep
59*fe6060f1SDimitry Andric     // https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68929
60*fe6060f1SDimitry Andric     typedef _LIBCPP_NODEBUG_TYPE  __make_integer_sequence_unchecked<_Tp, 0 <= _Ep ? _Ep : 0> type;
61*fe6060f1SDimitry Andric };
62*fe6060f1SDimitry Andric 
63*fe6060f1SDimitry Andric template <class _Tp, _Tp _Ep>
64*fe6060f1SDimitry Andric using __make_integer_sequence _LIBCPP_NODEBUG_TYPE = typename __make_integer_sequence_checked<_Tp, _Ep>::type;
65*fe6060f1SDimitry Andric 
66*fe6060f1SDimitry Andric #endif
67*fe6060f1SDimitry Andric 
68*fe6060f1SDimitry Andric template<class _Tp, _Tp _Np>
69*fe6060f1SDimitry Andric     using make_integer_sequence = __make_integer_sequence<_Tp, _Np>;
70*fe6060f1SDimitry Andric 
71*fe6060f1SDimitry Andric template<size_t _Np>
72*fe6060f1SDimitry Andric     using make_index_sequence = make_integer_sequence<size_t, _Np>;
73*fe6060f1SDimitry Andric 
74*fe6060f1SDimitry Andric template<class... _Tp>
75*fe6060f1SDimitry Andric     using index_sequence_for = make_index_sequence<sizeof...(_Tp)>;
76*fe6060f1SDimitry Andric 
77*fe6060f1SDimitry Andric #endif // _LIBCPP_STD_VER > 11
78*fe6060f1SDimitry Andric 
79*fe6060f1SDimitry Andric _LIBCPP_END_NAMESPACE_STD
80*fe6060f1SDimitry Andric 
81*fe6060f1SDimitry Andric _LIBCPP_POP_MACROS
82*fe6060f1SDimitry Andric 
83*fe6060f1SDimitry Andric #endif // _LIBCPP___UTILITY_INTEGER_SEQUENCE_H
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