xref: /llvm-project/libcxx/include/__algorithm/upper_bound.h (revision 5aaefa510ef055e8f044ca89e352d4313f3aba49)
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_UPPER_BOUND_H
10 #define _LIBCPP___ALGORITHM_UPPER_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 __upper_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(__value_, *__m))
36             __len = __l2;
37         else
38         {
39             __first = ++__m;
40             __len -= __l2 + 1;
41         }
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 upper_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
51 {
52     return _VSTD::__upper_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 upper_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
60 {
61     return _VSTD::upper_bound(__first, __last, __value_,
62                              __less<_Tp, typename iterator_traits<_ForwardIterator>::value_type>());
63 }
64 
65 _LIBCPP_END_NAMESPACE_STD
66 
67 #endif // _LIBCPP___ALGORITHM_UPPER_BOUND_H
68