1*4bdff4beSrobert //===----------------------------------------------------------------------===// 2*4bdff4beSrobert // 3*4bdff4beSrobert // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4*4bdff4beSrobert // See https://llvm.org/LICENSE.txt for license information. 5*4bdff4beSrobert // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6*4bdff4beSrobert // 7*4bdff4beSrobert //===----------------------------------------------------------------------===// 8*4bdff4beSrobert 9*4bdff4beSrobert #ifndef _LIBCPP___ALGORITHM_RANGES_PARTITION_POINT_H 10*4bdff4beSrobert #define _LIBCPP___ALGORITHM_RANGES_PARTITION_POINT_H 11*4bdff4beSrobert 12*4bdff4beSrobert #include <__algorithm/half_positive.h> 13*4bdff4beSrobert #include <__config> 14*4bdff4beSrobert #include <__functional/identity.h> 15*4bdff4beSrobert #include <__functional/invoke.h> 16*4bdff4beSrobert #include <__iterator/concepts.h> 17*4bdff4beSrobert #include <__iterator/distance.h> 18*4bdff4beSrobert #include <__iterator/iterator_traits.h> 19*4bdff4beSrobert #include <__iterator/next.h> 20*4bdff4beSrobert #include <__iterator/projected.h> 21*4bdff4beSrobert #include <__ranges/access.h> 22*4bdff4beSrobert #include <__ranges/concepts.h> 23*4bdff4beSrobert #include <__ranges/dangling.h> 24*4bdff4beSrobert #include <__utility/move.h> 25*4bdff4beSrobert 26*4bdff4beSrobert #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 27*4bdff4beSrobert # pragma GCC system_header 28*4bdff4beSrobert #endif 29*4bdff4beSrobert 30*4bdff4beSrobert #if _LIBCPP_STD_VER > 17 31*4bdff4beSrobert 32*4bdff4beSrobert _LIBCPP_BEGIN_NAMESPACE_STD 33*4bdff4beSrobert 34*4bdff4beSrobert namespace ranges { 35*4bdff4beSrobert namespace __partition_point { 36*4bdff4beSrobert 37*4bdff4beSrobert struct __fn { 38*4bdff4beSrobert 39*4bdff4beSrobert // TODO(ranges): delegate to the classic algorithm. 40*4bdff4beSrobert template <class _Iter, class _Sent, class _Proj, class _Pred> 41*4bdff4beSrobert _LIBCPP_HIDE_FROM_ABI constexpr __partition_point_fn_impl__fn42*4bdff4beSrobert static _Iter __partition_point_fn_impl(_Iter&& __first, _Sent&& __last, _Pred& __pred, _Proj& __proj) { 43*4bdff4beSrobert auto __len = ranges::distance(__first, __last); 44*4bdff4beSrobert 45*4bdff4beSrobert while (__len != 0) { 46*4bdff4beSrobert auto __half_len = std::__half_positive(__len); 47*4bdff4beSrobert auto __mid = ranges::next(__first, __half_len); 48*4bdff4beSrobert 49*4bdff4beSrobert if (std::invoke(__pred, std::invoke(__proj, *__mid))) { 50*4bdff4beSrobert __first = ++__mid; 51*4bdff4beSrobert __len -= __half_len + 1; 52*4bdff4beSrobert 53*4bdff4beSrobert } else { 54*4bdff4beSrobert __len = __half_len; 55*4bdff4beSrobert } 56*4bdff4beSrobert } 57*4bdff4beSrobert 58*4bdff4beSrobert return __first; 59*4bdff4beSrobert } 60*4bdff4beSrobert 61*4bdff4beSrobert template <forward_iterator _Iter, sentinel_for<_Iter> _Sent, class _Proj = identity, 62*4bdff4beSrobert indirect_unary_predicate<projected<_Iter, _Proj>> _Pred> 63*4bdff4beSrobert _LIBCPP_HIDE_FROM_ABI constexpr operator__fn64*4bdff4beSrobert _Iter operator()(_Iter __first, _Sent __last, _Pred __pred, _Proj __proj = {}) const { 65*4bdff4beSrobert return __partition_point_fn_impl(std::move(__first), std::move(__last), __pred, __proj); 66*4bdff4beSrobert } 67*4bdff4beSrobert 68*4bdff4beSrobert template <forward_range _Range, class _Proj = identity, 69*4bdff4beSrobert indirect_unary_predicate<projected<iterator_t<_Range>, _Proj>> _Pred> 70*4bdff4beSrobert _LIBCPP_HIDE_FROM_ABI constexpr operator__fn71*4bdff4beSrobert borrowed_iterator_t<_Range> operator()(_Range&& __range, _Pred __pred, _Proj __proj = {}) const { 72*4bdff4beSrobert return __partition_point_fn_impl(ranges::begin(__range), ranges::end(__range), __pred, __proj); 73*4bdff4beSrobert } 74*4bdff4beSrobert 75*4bdff4beSrobert }; 76*4bdff4beSrobert 77*4bdff4beSrobert } // namespace __partition_point 78*4bdff4beSrobert 79*4bdff4beSrobert inline namespace __cpo { 80*4bdff4beSrobert inline constexpr auto partition_point = __partition_point::__fn{}; 81*4bdff4beSrobert } // namespace __cpo 82*4bdff4beSrobert } // namespace ranges 83*4bdff4beSrobert 84*4bdff4beSrobert _LIBCPP_END_NAMESPACE_STD 85*4bdff4beSrobert 86*4bdff4beSrobert #endif // _LIBCPP_STD_VER > 17 87*4bdff4beSrobert 88*4bdff4beSrobert #endif // _LIBCPP___ALGORITHM_RANGES_PARTITION_POINT_H 89