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freebsd
GitHub Repository: freebsd/freebsd-src
 Path: blob/main/contrib/llvm-project/libcxx/include/__utility/integer_sequence.h
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//===----------------------------------------------------------------------===//

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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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