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_EQUAL_RANGE_H 10 #define _LIBCPP___ALGORITHM_EQUAL_RANGE_H 11 12 #include <__algorithm/comp.h> 13 #include <__algorithm/comp_ref_type.h> 14 #include <__algorithm/half_positive.h> 15 #include <__algorithm/lower_bound.h> 16 #include <__algorithm/upper_bound.h> 17 #include <__config> 18 #include <__functional/identity.h> 19 #include <__iterator/advance.h> 20 #include <__iterator/distance.h> 21 #include <__iterator/iterator_traits.h> 22 #include <__utility/pair.h> 23 24 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 25 # pragma GCC system_header 26 #endif 27 28 _LIBCPP_BEGIN_NAMESPACE_STD 29 30 template <class _Compare, class _ForwardIterator, class _Tp> 31 _LIBCPP_CONSTEXPR_AFTER_CXX17 pair<_ForwardIterator, _ForwardIterator> 32 __equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp) 33 { 34 typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type; 35 difference_type __len = _VSTD::distance(__first, __last); 36 while (__len != 0) 37 { 38 difference_type __l2 = _VSTD::__half_positive(__len); 39 _ForwardIterator __m = __first; 40 _VSTD::advance(__m, __l2); 41 if (__comp(*__m, __value_)) 42 { 43 __first = ++__m; 44 __len -= __l2 + 1; 45 } 46 else if (__comp(__value_, *__m)) 47 { 48 __last = __m; 49 __len = __l2; 50 } 51 else 52 { 53 auto __proj = std::__identity(); 54 _ForwardIterator __mp1 = __m; 55 return pair<_ForwardIterator, _ForwardIterator> 56 ( 57 _VSTD::__lower_bound_impl(__first, __m, __value_, __comp, __proj), 58 _VSTD::__upper_bound<_Compare>(++__mp1, __last, __value_, __comp) 59 ); 60 } 61 } 62 return pair<_ForwardIterator, _ForwardIterator>(__first, __first); 63 } 64 65 template <class _ForwardIterator, class _Tp, class _Compare> 66 _LIBCPP_NODISCARD_EXT inline 67 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 68 pair<_ForwardIterator, _ForwardIterator> 69 equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp) 70 { 71 typedef typename __comp_ref_type<_Compare>::type _Comp_ref; 72 return _VSTD::__equal_range<_Comp_ref>(__first, __last, __value_, __comp); 73 } 74 75 template <class _ForwardIterator, class _Tp> 76 _LIBCPP_NODISCARD_EXT inline 77 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 78 pair<_ForwardIterator, _ForwardIterator> 79 equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_) 80 { 81 return _VSTD::equal_range(__first, __last, __value_, 82 __less<typename iterator_traits<_ForwardIterator>::value_type, _Tp>()); 83 } 84 85 _LIBCPP_END_NAMESPACE_STD 86 87 #endif // _LIBCPP___ALGORITHM_EQUAL_RANGE_H 88