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___UTILITY_INTEGER_SEQUENCE_H 10 #define _LIBCPP___UTILITY_INTEGER_SEQUENCE_H 11 12 #include <__config> 13 #include <type_traits> 14 15 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 16 #pragma GCC system_header 17 #endif 18 19 _LIBCPP_PUSH_MACROS 20 #include <__undef_macros> 21 22 _LIBCPP_BEGIN_NAMESPACE_STD 23 24 #if _LIBCPP_STD_VER > 11 25 26 template<class _Tp, _Tp... _Ip> 27 struct _LIBCPP_TEMPLATE_VIS integer_sequence 28 { 29 typedef _Tp value_type; 30 static_assert( is_integral<_Tp>::value, 31 "std::integer_sequence can only be instantiated with an integral type" ); 32 static 33 _LIBCPP_INLINE_VISIBILITY 34 constexpr 35 size_t 36 size() noexcept { return sizeof...(_Ip); } 37 }; 38 39 template<size_t... _Ip> 40 using index_sequence = integer_sequence<size_t, _Ip...>; 41 42 #if __has_builtin(__make_integer_seq) && !defined(_LIBCPP_TESTING_FALLBACK_MAKE_INTEGER_SEQUENCE) 43 44 template <class _Tp, _Tp _Ep> 45 using __make_integer_sequence _LIBCPP_NODEBUG_TYPE = __make_integer_seq<integer_sequence, _Tp, _Ep>; 46 47 #else 48 49 template<typename _Tp, _Tp _Np> using __make_integer_sequence_unchecked _LIBCPP_NODEBUG_TYPE = 50 typename __detail::__make<_Np>::type::template __convert<integer_sequence, _Tp>; 51 52 template <class _Tp, _Tp _Ep> 53 struct __make_integer_sequence_checked 54 { 55 static_assert(is_integral<_Tp>::value, 56 "std::make_integer_sequence can only be instantiated with an integral type" ); 57 static_assert(0 <= _Ep, "std::make_integer_sequence must have a non-negative sequence length"); 58 // Workaround GCC bug by preventing bad installations when 0 <= _Ep 59 // https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68929 60 typedef _LIBCPP_NODEBUG_TYPE __make_integer_sequence_unchecked<_Tp, 0 <= _Ep ? _Ep : 0> type; 61 }; 62 63 template <class _Tp, _Tp _Ep> 64 using __make_integer_sequence _LIBCPP_NODEBUG_TYPE = typename __make_integer_sequence_checked<_Tp, _Ep>::type; 65 66 #endif 67 68 template<class _Tp, _Tp _Np> 69 using make_integer_sequence = __make_integer_sequence<_Tp, _Np>; 70 71 template<size_t _Np> 72 using make_index_sequence = make_integer_sequence<size_t, _Np>; 73 74 template<class... _Tp> 75 using index_sequence_for = make_index_sequence<sizeof...(_Tp)>; 76 77 #endif // _LIBCPP_STD_VER > 11 78 79 _LIBCPP_END_NAMESPACE_STD 80 81 _LIBCPP_POP_MACROS 82 83 #endif // _LIBCPP___UTILITY_INTEGER_SEQUENCE_H 84