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-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #ifndef _LIBCPP___ALGORITHM_PARTITION_POINT_H 10 #define _LIBCPP___ALGORITHM_PARTITION_POINT_H 11 12 #include <__algorithm/half_positive.h> 13 #include <__config> 14 #include <__iterator/advance.h> 15 #include <__iterator/distance.h> 16 #include <__iterator/iterator_traits.h> 17 18 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 19 # pragma GCC system_header 20 #endif 21 22 _LIBCPP_BEGIN_NAMESPACE_STD 23 24 template <class _ForwardIterator, class _Predicate> 25 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator 26 partition_point(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred) { 27 typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type; 28 difference_type __len = std::distance(__first, __last); 29 while (__len != 0) { 30 difference_type __l2 = std::__half_positive(__len); 31 _ForwardIterator __m = __first; 32 std::advance(__m, __l2); 33 if (__pred(*__m)) { 34 __first = ++__m; 35 __len -= __l2 + 1; 36 } else 37 __len = __l2; 38 } 39 return __first; 40 } 41 42 _LIBCPP_END_NAMESPACE_STD 43 44 #endif // _LIBCPP___ALGORITHM_PARTITION_POINT_H 45