153 lines
6.1 KiB
C++
153 lines
6.1 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) || defined(_LIBCPP_TESTING_FALLBACK_MAKE_INTEGER_SEQUENCE)
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namespace __detail {
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template <typename _Tp, size_t... _Extra>
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struct __repeat;
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template <typename _Tp, _Tp... _Np, size_t... _Extra>
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struct __repeat<__integer_sequence<_Tp, _Np...>, _Extra...> {
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typedef _LIBCPP_NODEBUG __integer_sequence<
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_Tp,
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_Np...,
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sizeof...(_Np) + _Np...,
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2 * sizeof...(_Np) + _Np...,
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3 * sizeof...(_Np) + _Np...,
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4 * sizeof...(_Np) + _Np...,
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5 * sizeof...(_Np) + _Np...,
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6 * sizeof...(_Np) + _Np...,
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7 * sizeof...(_Np) + _Np...,
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_Extra...>
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type;
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};
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template <size_t _Np>
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struct __parity;
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template <size_t _Np>
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struct __make : __parity<_Np % 8>::template __pmake<_Np> {};
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// clang-format off
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template<> struct __make<0> { typedef __integer_sequence<size_t> type; };
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template<> struct __make<1> { typedef __integer_sequence<size_t, 0> type; };
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template<> struct __make<2> { typedef __integer_sequence<size_t, 0, 1> type; };
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template<> struct __make<3> { typedef __integer_sequence<size_t, 0, 1, 2> type; };
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template<> struct __make<4> { typedef __integer_sequence<size_t, 0, 1, 2, 3> type; };
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template<> struct __make<5> { typedef __integer_sequence<size_t, 0, 1, 2, 3, 4> type; };
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template<> struct __make<6> { typedef __integer_sequence<size_t, 0, 1, 2, 3, 4, 5> type; };
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template<> struct __make<7> { typedef __integer_sequence<size_t, 0, 1, 2, 3, 4, 5, 6> type; };
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template<> struct __parity<0> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type> {}; };
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template<> struct __parity<1> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 1> {}; };
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template<> struct __parity<2> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 2, _Np - 1> {}; };
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template<> struct __parity<3> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 3, _Np - 2, _Np - 1> {}; };
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template<> struct __parity<4> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 4, _Np - 3, _Np - 2, _Np - 1> {}; };
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template<> struct __parity<5> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 5, _Np - 4, _Np - 3, _Np - 2, _Np - 1> {}; };
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template<> struct __parity<6> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 6, _Np - 5, _Np - 4, _Np - 3, _Np - 2, _Np - 1> {}; };
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template<> struct __parity<7> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 7, _Np - 6, _Np - 5, _Np - 4, _Np - 3, _Np - 2, _Np - 1> {}; };
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// clang-format on
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} // namespace __detail
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#endif
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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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#else
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template <size_t _Ep, size_t _Sp>
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using __make_indices_imp = typename __detail::__make<_Ep - _Sp>::type::template __to_tuple_indices<_Sp>;
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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) && !defined(_LIBCPP_TESTING_FALLBACK_MAKE_INTEGER_SEQUENCE)
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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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# else
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template <typename _Tp, _Tp _Np>
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using __make_integer_sequence_unchecked _LIBCPP_NODEBUG =
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typename __detail::__make<_Np>::type::template __convert<integer_sequence, _Tp>;
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template <class _Tp, _Tp _Ep>
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struct __make_integer_sequence_checked {
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static_assert(is_integral<_Tp>::value, "std::make_integer_sequence can only be instantiated with an integral type");
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static_assert(0 <= _Ep, "std::make_integer_sequence must have a non-negative sequence length");
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// Workaround GCC bug by preventing bad installations when 0 <= _Ep
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// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68929
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typedef _LIBCPP_NODEBUG __make_integer_sequence_unchecked<_Tp, 0 <= _Ep ? _Ep : 0> type;
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};
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template <class _Tp, _Tp _Ep>
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using __make_integer_sequence _LIBCPP_NODEBUG = typename __make_integer_sequence_checked<_Tp, _Ep>::type;
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# endif
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template <class _Tp, _Tp _Np>
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using make_integer_sequence = __make_integer_sequence<_Tp, _Np>;
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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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