290 lines
10 KiB
C++
290 lines
10 KiB
C++
// -*- C++ -*-
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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___RANGES_SUBRANGE_H
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#define _LIBCPP___RANGES_SUBRANGE_H
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#include <__assert>
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#include <__concepts/constructible.h>
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#include <__concepts/convertible_to.h>
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#include <__concepts/copyable.h>
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#include <__concepts/derived_from.h>
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#include <__concepts/different_from.h>
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#include <__config>
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#include <__iterator/advance.h>
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#include <__iterator/concepts.h>
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#include <__iterator/incrementable_traits.h>
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#include <__iterator/iterator_traits.h>
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#include <__ranges/access.h>
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#include <__ranges/concepts.h>
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#include <__ranges/dangling.h>
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#include <__ranges/enable_borrowed_range.h>
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#include <__ranges/size.h>
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#include <__ranges/view_interface.h>
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#include <__tuple>
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#include <__utility/move.h>
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#include <type_traits>
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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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#if !defined(_LIBCPP_HAS_NO_CONCEPTS) && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
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namespace ranges {
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template<class _From, class _To>
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concept __uses_nonqualification_pointer_conversion =
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is_pointer_v<_From> && is_pointer_v<_To> &&
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!convertible_to<remove_pointer_t<_From>(*)[], remove_pointer_t<_To>(*)[]>;
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template<class _From, class _To>
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concept __convertible_to_non_slicing =
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convertible_to<_From, _To> &&
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!__uses_nonqualification_pointer_conversion<decay_t<_From>, decay_t<_To>>;
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template<class _Tp>
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concept __pair_like =
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!is_reference_v<_Tp> && requires(_Tp __t) {
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typename tuple_size<_Tp>::type; // Ensures `tuple_size<T>` is complete.
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requires derived_from<tuple_size<_Tp>, integral_constant<size_t, 2>>;
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typename tuple_element_t<0, remove_const_t<_Tp>>;
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typename tuple_element_t<1, remove_const_t<_Tp>>;
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{ std::get<0>(__t) } -> convertible_to<const tuple_element_t<0, _Tp>&>;
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{ std::get<1>(__t) } -> convertible_to<const tuple_element_t<1, _Tp>&>;
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};
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template<class _Pair, class _Iter, class _Sent>
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concept __pair_like_convertible_from =
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!range<_Pair> && __pair_like<_Pair> &&
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constructible_from<_Pair, _Iter, _Sent> &&
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__convertible_to_non_slicing<_Iter, tuple_element_t<0, _Pair>> &&
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convertible_to<_Sent, tuple_element_t<1, _Pair>>;
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enum class _LIBCPP_ENUM_VIS subrange_kind : bool { unsized, sized };
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template<input_or_output_iterator _Iter, sentinel_for<_Iter> _Sent = _Iter,
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subrange_kind _Kind = sized_sentinel_for<_Sent, _Iter>
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? subrange_kind::sized
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: subrange_kind::unsized>
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requires (_Kind == subrange_kind::sized || !sized_sentinel_for<_Sent, _Iter>)
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class _LIBCPP_TEMPLATE_VIS subrange
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: public view_interface<subrange<_Iter, _Sent, _Kind>>
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{
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private:
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static constexpr bool _StoreSize = (_Kind == subrange_kind::sized && !sized_sentinel_for<_Sent, _Iter>);
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static constexpr bool _MustProvideSizeAtConstruction = !_StoreSize; // just to improve compiler diagnostics
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struct _Empty { constexpr _Empty(auto) noexcept { } };
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using _Size = conditional_t<_StoreSize, make_unsigned_t<iter_difference_t<_Iter>>, _Empty>;
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_LIBCPP_NO_UNIQUE_ADDRESS _Iter __begin_ = _Iter();
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_LIBCPP_NO_UNIQUE_ADDRESS _Sent __end_ = _Sent();
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_LIBCPP_NO_UNIQUE_ADDRESS _Size __size_ = 0;
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public:
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_LIBCPP_HIDE_FROM_ABI
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subrange() requires default_initializable<_Iter> = default;
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_LIBCPP_HIDE_FROM_ABI
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constexpr subrange(__convertible_to_non_slicing<_Iter> auto __iter, _Sent __sent)
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requires _MustProvideSizeAtConstruction
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: __begin_(std::move(__iter)), __end_(std::move(__sent))
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{ }
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_LIBCPP_HIDE_FROM_ABI
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constexpr subrange(__convertible_to_non_slicing<_Iter> auto __iter, _Sent __sent,
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make_unsigned_t<iter_difference_t<_Iter>> __n)
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requires (_Kind == subrange_kind::sized)
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: __begin_(std::move(__iter)), __end_(std::move(__sent)), __size_(__n)
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{
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if constexpr (sized_sentinel_for<_Sent, _Iter>)
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_LIBCPP_ASSERT((__end_ - __begin_) == static_cast<iter_difference_t<_Iter>>(__n),
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"std::ranges::subrange was passed an invalid size hint");
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}
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template<__different_from<subrange> _Range>
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requires borrowed_range<_Range> &&
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__convertible_to_non_slicing<iterator_t<_Range>, _Iter> &&
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convertible_to<sentinel_t<_Range>, _Sent>
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_LIBCPP_HIDE_FROM_ABI
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constexpr subrange(_Range&& __range)
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requires (!_StoreSize)
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: subrange(ranges::begin(__range), ranges::end(__range))
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{ }
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template<__different_from<subrange> _Range>
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requires borrowed_range<_Range> &&
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__convertible_to_non_slicing<iterator_t<_Range>, _Iter> &&
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convertible_to<sentinel_t<_Range>, _Sent>
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_LIBCPP_HIDE_FROM_ABI
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constexpr subrange(_Range&& __range)
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requires _StoreSize && sized_range<_Range>
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: subrange(__range, ranges::size(__range))
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{ }
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template<borrowed_range _Range>
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requires __convertible_to_non_slicing<iterator_t<_Range>, _Iter> &&
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convertible_to<sentinel_t<_Range>, _Sent>
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_LIBCPP_HIDE_FROM_ABI
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constexpr subrange(_Range&& __range, make_unsigned_t<iter_difference_t<_Iter>> __n)
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requires (_Kind == subrange_kind::sized)
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: subrange(ranges::begin(__range), ranges::end(__range), __n)
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{ }
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template<__different_from<subrange> _Pair>
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requires __pair_like_convertible_from<_Pair, const _Iter&, const _Sent&>
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_LIBCPP_HIDE_FROM_ABI
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constexpr operator _Pair() const {
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return _Pair(__begin_, __end_);
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}
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_LIBCPP_HIDE_FROM_ABI
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constexpr _Iter begin() const requires copyable<_Iter> {
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return __begin_;
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}
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[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Iter begin() requires (!copyable<_Iter>) {
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return std::move(__begin_);
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}
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_LIBCPP_HIDE_FROM_ABI
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constexpr _Sent end() const {
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return __end_;
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}
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[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr bool empty() const {
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return __begin_ == __end_;
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}
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_LIBCPP_HIDE_FROM_ABI
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constexpr make_unsigned_t<iter_difference_t<_Iter>> size() const
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requires (_Kind == subrange_kind::sized)
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{
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if constexpr (_StoreSize)
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return __size_;
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else
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return std::__to_unsigned_like(__end_ - __begin_);
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}
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[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr subrange next(iter_difference_t<_Iter> __n = 1) const&
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requires forward_iterator<_Iter>
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{
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auto __tmp = *this;
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__tmp.advance(__n);
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return __tmp;
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}
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[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr subrange next(iter_difference_t<_Iter> __n = 1) && {
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advance(__n);
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return std::move(*this);
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}
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[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr subrange prev(iter_difference_t<_Iter> __n = 1) const
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requires bidirectional_iterator<_Iter>
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{
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auto __tmp = *this;
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__tmp.advance(-__n);
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return __tmp;
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}
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_LIBCPP_HIDE_FROM_ABI
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constexpr subrange& advance(iter_difference_t<_Iter> __n) {
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if constexpr (bidirectional_iterator<_Iter>) {
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if (__n < 0) {
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ranges::advance(__begin_, __n);
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if constexpr (_StoreSize)
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__size_ += std::__to_unsigned_like(-__n);
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return *this;
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}
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}
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auto __d = __n - ranges::advance(__begin_, __n, __end_);
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if constexpr (_StoreSize)
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__size_ -= std::__to_unsigned_like(__d);
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return *this;
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}
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};
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template<input_or_output_iterator _Iter, sentinel_for<_Iter> _Sent>
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subrange(_Iter, _Sent) -> subrange<_Iter, _Sent>;
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template<input_or_output_iterator _Iter, sentinel_for<_Iter> _Sent>
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subrange(_Iter, _Sent, make_unsigned_t<iter_difference_t<_Iter>>)
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-> subrange<_Iter, _Sent, subrange_kind::sized>;
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template<borrowed_range _Range>
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subrange(_Range&&) -> subrange<iterator_t<_Range>, sentinel_t<_Range>,
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(sized_range<_Range> || sized_sentinel_for<sentinel_t<_Range>, iterator_t<_Range>>)
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? subrange_kind::sized : subrange_kind::unsized>;
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template<borrowed_range _Range>
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subrange(_Range&&, make_unsigned_t<range_difference_t<_Range>>)
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-> subrange<iterator_t<_Range>, sentinel_t<_Range>, subrange_kind::sized>;
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template<size_t _Index, class _Iter, class _Sent, subrange_kind _Kind>
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requires ((_Index == 0 && copyable<_Iter>) || _Index == 1)
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_LIBCPP_HIDE_FROM_ABI
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constexpr auto get(const subrange<_Iter, _Sent, _Kind>& __subrange) {
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if constexpr (_Index == 0)
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return __subrange.begin();
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else
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return __subrange.end();
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}
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template<size_t _Index, class _Iter, class _Sent, subrange_kind _Kind>
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requires (_Index < 2)
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_LIBCPP_HIDE_FROM_ABI
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constexpr auto get(subrange<_Iter, _Sent, _Kind>&& __subrange) {
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if constexpr (_Index == 0)
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return __subrange.begin();
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else
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return __subrange.end();
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}
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template<class _Ip, class _Sp, subrange_kind _Kp>
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inline constexpr bool enable_borrowed_range<subrange<_Ip, _Sp, _Kp>> = true;
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template<range _Rp>
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using borrowed_subrange_t = _If<borrowed_range<_Rp>, subrange<iterator_t<_Rp>>, dangling>;
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} // namespace ranges
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// [range.subrange.general]
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using ranges::get;
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// [ranges.syn]
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template<class _Ip, class _Sp, ranges::subrange_kind _Kp>
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struct tuple_size<ranges::subrange<_Ip, _Sp, _Kp>> : integral_constant<size_t, 2> {};
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template<class _Ip, class _Sp, ranges::subrange_kind _Kp>
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struct tuple_element<0, ranges::subrange<_Ip, _Sp, _Kp>> {
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using type = _Ip;
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};
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template<class _Ip, class _Sp, ranges::subrange_kind _Kp>
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struct tuple_element<1, ranges::subrange<_Ip, _Sp, _Kp>> {
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using type = _Sp;
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};
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template<class _Ip, class _Sp, ranges::subrange_kind _Kp>
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struct tuple_element<0, const ranges::subrange<_Ip, _Sp, _Kp>> {
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using type = _Ip;
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};
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template<class _Ip, class _Sp, ranges::subrange_kind _Kp>
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struct tuple_element<1, const ranges::subrange<_Ip, _Sp, _Kp>> {
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using type = _Sp;
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};
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#endif // !defined(_LIBCPP_HAS_NO_CONCEPTS) && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
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_LIBCPP_END_NAMESPACE_STD
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#endif // _LIBCPP___RANGES_SUBRANGE_H
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