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_LOWER_BOUND_H 10 #define _LIBCPP___ALGORITHM_LOWER_BOUND_H 11 12 #include <__algorithm/comp.h> 13 #include <__algorithm/half_positive.h> 14 #include <__config> 15 #include <iterator> 16 17 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 18 # pragma GCC system_header 19 # pragma clang include_instead(<algorithm>) 20 #endif 21 22 _LIBCPP_BEGIN_NAMESPACE_STD 23 24 template <class _Compare, class _ForwardIterator, class _Tp> 25 _LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator 26 __lower_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp) 27 { 28 typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type; 29 difference_type __len = _VSTD::distance(__first, __last); 30 while (__len != 0) 31 { 32 difference_type __l2 = _VSTD::__half_positive(__len); 33 _ForwardIterator __m = __first; 34 _VSTD::advance(__m, __l2); 35 if (__comp(*__m, __value_)) 36 { 37 __first = ++__m; 38 __len -= __l2 + 1; 39 } 40 else 41 __len = __l2; 42 } 43 return __first; 44 } 45 46 template <class _ForwardIterator, class _Tp, class _Compare> 47 _LIBCPP_NODISCARD_EXT inline 48 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 49 _ForwardIterator 50 lower_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp) 51 { 52 return _VSTD::__lower_bound<_Compare&>(__first, __last, __value_, __comp); 53 } 54 55 template <class _ForwardIterator, class _Tp> 56 _LIBCPP_NODISCARD_EXT inline 57 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 58 _ForwardIterator 59 lower_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_) 60 { 61 return _VSTD::lower_bound(__first, __last, __value_, 62 __less<typename iterator_traits<_ForwardIterator>::value_type, _Tp>()); 63 } 64 65 _LIBCPP_END_NAMESPACE_STD 66 67 #endif // _LIBCPP___ALGORITHM_LOWER_BOUND_H 68