mirror of
https://github.com/jart/cosmopolitan.git
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5660ec4741
This release is an atomic upgrade to GCC 14.1.0 with C23 and C++23
235 lines
8.8 KiB
C++
235 lines
8.8 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_CHUNK_BY_VIEW_H
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#define _LIBCPP___RANGES_CHUNK_BY_VIEW_H
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#include <__algorithm/ranges_adjacent_find.h>
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#include <__assert>
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#include <__concepts/constructible.h>
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#include <__config>
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#include <__functional/bind_back.h>
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#include <__functional/invoke.h>
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#include <__iterator/concepts.h>
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#include <__iterator/default_sentinel.h>
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#include <__iterator/iterator_traits.h>
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#include <__iterator/next.h>
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#include <__iterator/prev.h>
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#include <__memory/addressof.h>
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#include <__ranges/access.h>
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#include <__ranges/all.h>
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#include <__ranges/concepts.h>
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#include <__ranges/movable_box.h>
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#include <__ranges/non_propagating_cache.h>
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#include <__ranges/range_adaptor.h>
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#include <__ranges/reverse_view.h>
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#include <__ranges/subrange.h>
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#include <__ranges/view_interface.h>
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#include <__type_traits/conditional.h>
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#include <__type_traits/decay.h>
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#include <__type_traits/is_nothrow_constructible.h>
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#include <__type_traits/is_object.h>
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#include <__utility/forward.h>
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#include <__utility/in_place.h>
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#include <__utility/move.h>
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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_PUSH_MACROS
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#include <__undef_macros>
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_LIBCPP_BEGIN_NAMESPACE_STD
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#if _LIBCPP_STD_VER >= 23
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namespace ranges {
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template <forward_range _View, indirect_binary_predicate<iterator_t<_View>, iterator_t<_View>> _Pred>
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requires view<_View> && is_object_v<_Pred>
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class _LIBCPP_ABI_LLVM18_NO_UNIQUE_ADDRESS chunk_by_view : public view_interface<chunk_by_view<_View, _Pred>> {
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_LIBCPP_NO_UNIQUE_ADDRESS _View __base_ = _View();
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_LIBCPP_NO_UNIQUE_ADDRESS __movable_box<_Pred> __pred_;
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// We cache the result of begin() to allow providing an amortized O(1).
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using _Cache = __non_propagating_cache<iterator_t<_View>>;
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_Cache __cached_begin_;
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class __iterator;
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_LIBCPP_HIDE_FROM_ABI constexpr iterator_t<_View> __find_next(iterator_t<_View> __current) {
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// Note: this duplicates a check in `optional` but provides a better error message.
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_LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
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__pred_.__has_value(), "Trying to call __find_next() on a chunk_by_view that does not have a valid predicate.");
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auto __reversed_pred = [this]<class _Tp, class _Up>(_Tp&& __x, _Up&& __y) -> bool {
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return !std::invoke(*__pred_, std::forward<_Tp>(__x), std::forward<_Up>(__y));
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};
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return ranges::next(
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ranges::adjacent_find(__current, ranges::end(__base_), __reversed_pred), 1, ranges::end(__base_));
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}
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_LIBCPP_HIDE_FROM_ABI constexpr iterator_t<_View> __find_prev(iterator_t<_View> __current)
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requires bidirectional_range<_View>
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{
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// Attempting to decrement a begin iterator is a no-op (`__find_prev` would return the same argument given to it).
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_LIBCPP_ASSERT_PEDANTIC(__current != ranges::begin(__base_), "Trying to call __find_prev() on a begin iterator.");
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// Note: this duplicates a check in `optional` but provides a better error message.
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_LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
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__pred_.__has_value(), "Trying to call __find_prev() on a chunk_by_view that does not have a valid predicate.");
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auto __first = ranges::begin(__base_);
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reverse_view __reversed{subrange{__first, __current}};
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auto __reversed_pred = [this]<class _Tp, class _Up>(_Tp&& __x, _Up&& __y) -> bool {
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return !std::invoke(*__pred_, std::forward<_Up>(__y), std::forward<_Tp>(__x));
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};
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return ranges::prev(ranges::adjacent_find(__reversed, __reversed_pred).base(), 1, std::move(__first));
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}
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public:
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_LIBCPP_HIDE_FROM_ABI chunk_by_view()
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requires default_initializable<_View> && default_initializable<_Pred>
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= default;
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_LIBCPP_HIDE_FROM_ABI constexpr explicit chunk_by_view(_View __base, _Pred __pred)
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: __base_(std::move(__base)), __pred_(in_place, std::move(__pred)) {}
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_LIBCPP_HIDE_FROM_ABI constexpr _View base() const&
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requires copy_constructible<_View>
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{
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return __base_;
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}
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_LIBCPP_HIDE_FROM_ABI constexpr _View base() && { return std::move(__base_); }
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_LIBCPP_HIDE_FROM_ABI constexpr const _Pred& pred() const { return *__pred_; }
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_LIBCPP_HIDE_FROM_ABI constexpr __iterator begin() {
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// Note: this duplicates a check in `optional` but provides a better error message.
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_LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
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__pred_.__has_value(), "Trying to call begin() on a chunk_by_view that does not have a valid predicate.");
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auto __first = ranges::begin(__base_);
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if (!__cached_begin_.__has_value()) {
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__cached_begin_.__emplace(__find_next(__first));
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}
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return {*this, std::move(__first), *__cached_begin_};
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}
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_LIBCPP_HIDE_FROM_ABI constexpr auto end() {
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if constexpr (common_range<_View>) {
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return __iterator{*this, ranges::end(__base_), ranges::end(__base_)};
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} else {
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return default_sentinel;
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}
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}
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};
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template <class _Range, class _Pred>
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chunk_by_view(_Range&&, _Pred) -> chunk_by_view<views::all_t<_Range>, _Pred>;
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template <forward_range _View, indirect_binary_predicate<iterator_t<_View>, iterator_t<_View>> _Pred>
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requires view<_View> && is_object_v<_Pred>
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class chunk_by_view<_View, _Pred>::__iterator {
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friend chunk_by_view;
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chunk_by_view* __parent_ = nullptr;
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_LIBCPP_NO_UNIQUE_ADDRESS iterator_t<_View> __current_ = iterator_t<_View>();
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_LIBCPP_NO_UNIQUE_ADDRESS iterator_t<_View> __next_ = iterator_t<_View>();
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_LIBCPP_HIDE_FROM_ABI constexpr __iterator(
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chunk_by_view& __parent, iterator_t<_View> __current, iterator_t<_View> __next)
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: __parent_(std::addressof(__parent)), __current_(__current), __next_(__next) {}
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public:
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using value_type = subrange<iterator_t<_View>>;
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using difference_type = range_difference_t<_View>;
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using iterator_category = input_iterator_tag;
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using iterator_concept = conditional_t<bidirectional_range<_View>, bidirectional_iterator_tag, forward_iterator_tag>;
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_LIBCPP_HIDE_FROM_ABI __iterator() = default;
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_LIBCPP_HIDE_FROM_ABI constexpr value_type operator*() const {
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// If the iterator is at end, this would return an empty range which can be checked by the calling code and doesn't
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// necessarily lead to a bad access.
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_LIBCPP_ASSERT_PEDANTIC(__current_ != __next_, "Trying to dereference past-the-end chunk_by_view iterator.");
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return {__current_, __next_};
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}
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_LIBCPP_HIDE_FROM_ABI constexpr __iterator& operator++() {
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// Attempting to increment an end iterator is a no-op (`__find_next` would return the same argument given to it).
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_LIBCPP_ASSERT_PEDANTIC(__current_ != __next_, "Trying to increment past end chunk_by_view iterator.");
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__current_ = __next_;
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__next_ = __parent_->__find_next(__current_);
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return *this;
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}
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_LIBCPP_HIDE_FROM_ABI constexpr __iterator operator++(int) {
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auto __tmp = *this;
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++*this;
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return __tmp;
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}
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_LIBCPP_HIDE_FROM_ABI constexpr __iterator& operator--()
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requires bidirectional_range<_View>
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{
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__next_ = __current_;
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__current_ = __parent_->__find_prev(__next_);
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return *this;
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}
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_LIBCPP_HIDE_FROM_ABI constexpr __iterator operator--(int)
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requires bidirectional_range<_View>
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{
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auto __tmp = *this;
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--*this;
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return __tmp;
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}
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_LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(const __iterator& __x, const __iterator& __y) {
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return __x.__current_ == __y.__current_;
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}
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_LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(const __iterator& __x, default_sentinel_t) {
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return __x.__current_ == __x.__next_;
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}
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};
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namespace views {
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namespace __chunk_by {
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struct __fn {
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template <class _Range, class _Pred>
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[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Range&& __range, _Pred&& __pred) const
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noexcept(noexcept(/**/ chunk_by_view(std::forward<_Range>(__range), std::forward<_Pred>(__pred))))
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-> decltype(/*--*/ chunk_by_view(std::forward<_Range>(__range), std::forward<_Pred>(__pred))) {
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return /*-------------*/ chunk_by_view(std::forward<_Range>(__range), std::forward<_Pred>(__pred));
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}
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template <class _Pred>
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requires constructible_from<decay_t<_Pred>, _Pred>
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[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Pred&& __pred) const
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noexcept(is_nothrow_constructible_v<decay_t<_Pred>, _Pred>) {
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return __range_adaptor_closure_t(std::__bind_back(*this, std::forward<_Pred>(__pred)));
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}
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};
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} // namespace __chunk_by
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inline namespace __cpo {
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inline constexpr auto chunk_by = __chunk_by::__fn{};
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} // namespace __cpo
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} // namespace views
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} // namespace ranges
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#endif // _LIBCPP_STD_VER >= 23
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_LIBCPP_END_NAMESPACE_STD
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_LIBCPP_POP_MACROS
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#endif // _LIBCPP___RANGES_CHUNK_BY_VIEW_H
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