1753f127fSDimitry Andric //===----------------------------------------------------------------------===// 2753f127fSDimitry Andric // 3753f127fSDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4753f127fSDimitry Andric // See https://llvm.org/LICENSE.txt for license information. 5753f127fSDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6753f127fSDimitry Andric // 7753f127fSDimitry Andric //===----------------------------------------------------------------------===// 8753f127fSDimitry Andric 9753f127fSDimitry Andric #ifndef _LIBCPP___ALGORITHM_RANGES_PARTITION_POINT_H 10753f127fSDimitry Andric #define _LIBCPP___ALGORITHM_RANGES_PARTITION_POINT_H 11753f127fSDimitry Andric 12fcaf7f86SDimitry Andric #include <__algorithm/half_positive.h> 13753f127fSDimitry Andric #include <__config> 14753f127fSDimitry Andric #include <__functional/identity.h> 15753f127fSDimitry Andric #include <__functional/invoke.h> 16753f127fSDimitry Andric #include <__iterator/concepts.h> 17fcaf7f86SDimitry Andric #include <__iterator/distance.h> 18753f127fSDimitry Andric #include <__iterator/iterator_traits.h> 19fcaf7f86SDimitry Andric #include <__iterator/next.h> 20753f127fSDimitry Andric #include <__iterator/projected.h> 21753f127fSDimitry Andric #include <__ranges/access.h> 22753f127fSDimitry Andric #include <__ranges/concepts.h> 23753f127fSDimitry Andric #include <__ranges/dangling.h> 24753f127fSDimitry Andric #include <__utility/move.h> 25753f127fSDimitry Andric 26753f127fSDimitry Andric #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 27753f127fSDimitry Andric # pragma GCC system_header 28753f127fSDimitry Andric #endif 29753f127fSDimitry Andric 30*b3edf446SDimitry Andric _LIBCPP_PUSH_MACROS 31*b3edf446SDimitry Andric #include <__undef_macros> 32*b3edf446SDimitry Andric 3306c3fb27SDimitry Andric #if _LIBCPP_STD_VER >= 20 34753f127fSDimitry Andric 35753f127fSDimitry Andric _LIBCPP_BEGIN_NAMESPACE_STD 36753f127fSDimitry Andric 37753f127fSDimitry Andric namespace ranges { 38753f127fSDimitry Andric namespace __partition_point { 39753f127fSDimitry Andric 40753f127fSDimitry Andric struct __fn { 41fcaf7f86SDimitry Andric // TODO(ranges): delegate to the classic algorithm. 42fcaf7f86SDimitry Andric template <class _Iter, class _Sent, class _Proj, class _Pred> 4306c3fb27SDimitry Andric _LIBCPP_HIDE_FROM_ABI constexpr static _Iter __partition_point_fn_impl__fn4406c3fb27SDimitry Andric __partition_point_fn_impl(_Iter&& __first, _Sent&& __last, _Pred& __pred, _Proj& __proj) { 45fcaf7f86SDimitry Andric auto __len = ranges::distance(__first, __last); 46fcaf7f86SDimitry Andric 47fcaf7f86SDimitry Andric while (__len != 0) { 48fcaf7f86SDimitry Andric auto __half_len = std::__half_positive(__len); 49fcaf7f86SDimitry Andric auto __mid = ranges::next(__first, __half_len); 50fcaf7f86SDimitry Andric 51fcaf7f86SDimitry Andric if (std::invoke(__pred, std::invoke(__proj, *__mid))) { 52fcaf7f86SDimitry Andric __first = ++__mid; 53fcaf7f86SDimitry Andric __len -= __half_len + 1; 54fcaf7f86SDimitry Andric 55fcaf7f86SDimitry Andric } else { 56fcaf7f86SDimitry Andric __len = __half_len; 57fcaf7f86SDimitry Andric } 58fcaf7f86SDimitry Andric } 59fcaf7f86SDimitry Andric 60fcaf7f86SDimitry Andric return __first; 61fcaf7f86SDimitry Andric } 62fcaf7f86SDimitry Andric 6306c3fb27SDimitry Andric template <forward_iterator _Iter, 6406c3fb27SDimitry Andric sentinel_for<_Iter> _Sent, 6506c3fb27SDimitry Andric class _Proj = identity, 66753f127fSDimitry Andric indirect_unary_predicate<projected<_Iter, _Proj>> _Pred> operator__fn6706c3fb27SDimitry Andric _LIBCPP_HIDE_FROM_ABI constexpr _Iter operator()(_Iter __first, _Sent __last, _Pred __pred, _Proj __proj = {}) const { 68fcaf7f86SDimitry Andric return __partition_point_fn_impl(std::move(__first), std::move(__last), __pred, __proj); 69753f127fSDimitry Andric } 70753f127fSDimitry Andric 7106c3fb27SDimitry Andric template <forward_range _Range, 7206c3fb27SDimitry Andric class _Proj = identity, 73753f127fSDimitry Andric indirect_unary_predicate<projected<iterator_t<_Range>, _Proj>> _Pred> 7406c3fb27SDimitry Andric _LIBCPP_HIDE_FROM_ABI constexpr borrowed_iterator_t<_Range> operator__fn7506c3fb27SDimitry Andric operator()(_Range&& __range, _Pred __pred, _Proj __proj = {}) const { 76fcaf7f86SDimitry Andric return __partition_point_fn_impl(ranges::begin(__range), ranges::end(__range), __pred, __proj); 77753f127fSDimitry Andric } 78753f127fSDimitry Andric }; 79753f127fSDimitry Andric 80753f127fSDimitry Andric } // namespace __partition_point 81753f127fSDimitry Andric 82753f127fSDimitry Andric inline namespace __cpo { 83753f127fSDimitry Andric inline constexpr auto partition_point = __partition_point::__fn{}; 84753f127fSDimitry Andric } // namespace __cpo 85753f127fSDimitry Andric } // namespace ranges 86753f127fSDimitry Andric 87753f127fSDimitry Andric _LIBCPP_END_NAMESPACE_STD 88753f127fSDimitry Andric 8906c3fb27SDimitry Andric #endif // _LIBCPP_STD_VER >= 20 90753f127fSDimitry Andric 91*b3edf446SDimitry Andric _LIBCPP_POP_MACROS 92*b3edf446SDimitry Andric 93753f127fSDimitry Andric #endif // _LIBCPP___ALGORITHM_RANGES_PARTITION_POINT_H 94