1 //===----------------------------------------------------------------------===//
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
7 //===----------------------------------------------------------------------===//
9 #ifndef _LIBCPP___ALGORITHM_EQUAL_RANGE_H
10 #define _LIBCPP___ALGORITHM_EQUAL_RANGE_H
13 #include <__algorithm/comp.h>
14 #include <__algorithm/comp_ref_type.h>
15 #include <__algorithm/half_positive.h>
16 #include <__algorithm/lower_bound.h>
17 #include <__algorithm/upper_bound.h>
20 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
21 #pragma GCC system_header
25 #include <__undef_macros>
27 _LIBCPP_BEGIN_NAMESPACE_STD
29 template <class _Compare, class _ForwardIterator, class _Tp>
30 _LIBCPP_CONSTEXPR_AFTER_CXX17 pair<_ForwardIterator, _ForwardIterator>
31 __equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
33 typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
34 difference_type __len = _VSTD::distance(__first, __last);
37 difference_type __l2 = _VSTD::__half_positive(__len);
38 _ForwardIterator __m = __first;
39 _VSTD::advance(__m, __l2);
40 if (__comp(*__m, __value_))
45 else if (__comp(__value_, *__m))
52 _ForwardIterator __mp1 = __m;
53 return pair<_ForwardIterator, _ForwardIterator>
55 _VSTD::__lower_bound<_Compare>(__first, __m, __value_, __comp),
56 _VSTD::__upper_bound<_Compare>(++__mp1, __last, __value_, __comp)
60 return pair<_ForwardIterator, _ForwardIterator>(__first, __first);
63 template <class _ForwardIterator, class _Tp, class _Compare>
64 _LIBCPP_NODISCARD_EXT inline
65 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
66 pair<_ForwardIterator, _ForwardIterator>
67 equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
69 typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
70 return _VSTD::__equal_range<_Comp_ref>(__first, __last, __value_, __comp);
73 template <class _ForwardIterator, class _Tp>
74 _LIBCPP_NODISCARD_EXT inline
75 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
76 pair<_ForwardIterator, _ForwardIterator>
77 equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
79 return _VSTD::equal_range(__first, __last, __value_,
80 __less<typename iterator_traits<_ForwardIterator>::value_type, _Tp>());
83 _LIBCPP_END_NAMESPACE_STD
87 #endif // _LIBCPP___ALGORITHM_EQUAL_RANGE_H