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1//===----------------------------------------------------------------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9#ifndef _LIBCPP___ALGORITHM_RANGES_PARTITION_POINT_H10#define _LIBCPP___ALGORITHM_RANGES_PARTITION_POINT_H11 12#include <__algorithm/half_positive.h>13#include <__config>14#include <__functional/identity.h>15#include <__functional/invoke.h>16#include <__iterator/concepts.h>17#include <__iterator/distance.h>18#include <__iterator/iterator_traits.h>19#include <__iterator/next.h>20#include <__iterator/projected.h>21#include <__ranges/access.h>22#include <__ranges/concepts.h>23#include <__ranges/dangling.h>24#include <__utility/move.h>25 26#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)27# pragma GCC system_header28#endif29 30_LIBCPP_PUSH_MACROS31#include <__undef_macros>32 33#if _LIBCPP_STD_VER >= 2034 35_LIBCPP_BEGIN_NAMESPACE_STD36 37namespace ranges {38struct __partition_point {39 // TODO(ranges): delegate to the classic algorithm.40 template <class _Iter, class _Sent, class _Proj, class _Pred>41 _LIBCPP_HIDE_FROM_ABI constexpr static _Iter42 __partition_point_fn_impl(_Iter&& __first, _Sent&& __last, _Pred& __pred, _Proj& __proj) {43 auto __len = ranges::distance(__first, __last);44 45 while (__len != 0) {46 auto __half_len = std::__half_positive(__len);47 auto __mid = ranges::next(__first, __half_len);48 49 if (std::invoke(__pred, std::invoke(__proj, *__mid))) {50 __first = ++__mid;51 __len -= __half_len + 1;52 53 } else {54 __len = __half_len;55 }56 }57 58 return __first;59 }60 61 template <forward_iterator _Iter,62 sentinel_for<_Iter> _Sent,63 class _Proj = identity,64 indirect_unary_predicate<projected<_Iter, _Proj>> _Pred>65 _LIBCPP_HIDE_FROM_ABI constexpr _Iter operator()(_Iter __first, _Sent __last, _Pred __pred, _Proj __proj = {}) const {66 return __partition_point_fn_impl(std::move(__first), std::move(__last), __pred, __proj);67 }68 69 template <forward_range _Range,70 class _Proj = identity,71 indirect_unary_predicate<projected<iterator_t<_Range>, _Proj>> _Pred>72 _LIBCPP_HIDE_FROM_ABI constexpr borrowed_iterator_t<_Range>73 operator()(_Range&& __range, _Pred __pred, _Proj __proj = {}) const {74 return __partition_point_fn_impl(ranges::begin(__range), ranges::end(__range), __pred, __proj);75 }76};77 78inline namespace __cpo {79inline constexpr auto partition_point = __partition_point{};80} // namespace __cpo81} // namespace ranges82 83_LIBCPP_END_NAMESPACE_STD84 85#endif // _LIBCPP_STD_VER >= 2086 87_LIBCPP_POP_MACROS88 89#endif // _LIBCPP___ALGORITHM_RANGES_PARTITION_POINT_H90