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90 lines
2.9 KiB
C++
90 lines
2.9 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef _LIBCPP___UTILITY_INTEGER_SEQUENCE_H
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#define _LIBCPP___UTILITY_INTEGER_SEQUENCE_H
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#include <__config>
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#include <__type_traits/is_integral.h>
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#include <cstddef>
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#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
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# pragma GCC system_header
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#endif
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_LIBCPP_BEGIN_NAMESPACE_STD
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template <size_t...>
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struct __tuple_indices;
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template <class _IdxType, _IdxType... _Values>
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struct __integer_sequence {
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template <template <class _OIdxType, _OIdxType...> class _ToIndexSeq, class _ToIndexType>
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using __convert = _ToIndexSeq<_ToIndexType, _Values...>;
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template <size_t _Sp>
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using __to_tuple_indices = __tuple_indices<(_Values + _Sp)...>;
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};
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#if __has_builtin(__make_integer_seq)
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template <size_t _Ep, size_t _Sp>
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using __make_indices_imp =
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typename __make_integer_seq<__integer_sequence, size_t, _Ep - _Sp>::template __to_tuple_indices<_Sp>;
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#elif __has_builtin(__integer_pack)
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template <size_t _Ep, size_t _Sp>
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using __make_indices_imp =
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typename __integer_sequence<size_t, __integer_pack(_Ep - _Sp)...>::template __to_tuple_indices<_Sp>;
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#else
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# error "No known way to get an integer pack from the compiler"
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#endif
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#if _LIBCPP_STD_VER >= 14
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template <class _Tp, _Tp... _Ip>
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struct _LIBCPP_TEMPLATE_VIS integer_sequence {
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typedef _Tp value_type;
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static_assert(is_integral<_Tp>::value, "std::integer_sequence can only be instantiated with an integral type");
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static _LIBCPP_HIDE_FROM_ABI constexpr size_t size() noexcept { return sizeof...(_Ip); }
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};
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template <size_t... _Ip>
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using index_sequence = integer_sequence<size_t, _Ip...>;
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# if __has_builtin(__make_integer_seq)
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template <class _Tp, _Tp _Ep>
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using make_integer_sequence _LIBCPP_NODEBUG = __make_integer_seq<integer_sequence, _Tp, _Ep>;
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# elif __has_builtin(__integer_pack)
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template <class _Tp, _Tp _SequenceSize>
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using make_integer_sequence _LIBCPP_NODEBUG = integer_sequence<_Tp, __integer_pack(_SequenceSize)...>;
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# else
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# error "No known way to get an integer pack from the compiler"
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# endif
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template <size_t _Np>
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using make_index_sequence = make_integer_sequence<size_t, _Np>;
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template <class... _Tp>
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using index_sequence_for = make_index_sequence<sizeof...(_Tp)>;
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# if _LIBCPP_STD_VER >= 20
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// Executes __func for every element in an index_sequence.
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template <size_t... _Index, class _Function>
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_LIBCPP_HIDE_FROM_ABI constexpr void __for_each_index_sequence(index_sequence<_Index...>, _Function __func) {
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(__func.template operator()<_Index>(), ...);
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}
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# endif // _LIBCPP_STD_VER >= 20
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#endif // _LIBCPP_STD_VER >= 14
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_LIBCPP_END_NAMESPACE_STD
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#endif // _LIBCPP___UTILITY_INTEGER_SEQUENCE_H
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