xref: /freebsd/contrib/llvm-project/libcxx/include/__algorithm/upper_bound.h (revision e32fecd0c2c3ee37c47ee100f169e7eb0282a873)
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 <__algorithm/iterator_operations.h>
15 #include <__config>
16 #include <__functional/identity.h>
17 #include <__functional/invoke.h>
18 #include <__iterator/advance.h>
19 #include <__iterator/distance.h>
20 #include <__iterator/iterator_traits.h>
21 #include <__type_traits/is_copy_constructible.h>
22 #include <__utility/move.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 _AlgPolicy, class _Compare, class _Iter, class _Sent, class _Tp, class _Proj>
31 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 _Iter
32 __upper_bound(_Iter __first, _Sent __last, const _Tp& __value, _Compare&& __comp, _Proj&& __proj) {
33   auto __len = _IterOps<_AlgPolicy>::distance(__first, __last);
34   while (__len != 0) {
35     auto __half_len = std::__half_positive(__len);
36     auto __mid      = _IterOps<_AlgPolicy>::next(__first, __half_len);
37     if (std::__invoke(__comp, __value, std::__invoke(__proj, *__mid)))
38       __len = __half_len;
39     else {
40       __first = ++__mid;
41       __len -= __half_len + 1;
42     }
43   }
44   return __first;
45 }
46 
47 template <class _ForwardIterator, class _Tp, class _Compare>
48 _LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator
49 upper_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value, _Compare __comp) {
50   static_assert(is_copy_constructible<_ForwardIterator>::value,
51                 "Iterator has to be copy constructible");
52   return std::__upper_bound<_ClassicAlgPolicy>(
53       std::move(__first), std::move(__last), __value, std::move(__comp), std::__identity());
54 }
55 
56 template <class _ForwardIterator, class _Tp>
57 _LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator
58 upper_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value) {
59   return std::upper_bound(
60       std::move(__first),
61       std::move(__last),
62       __value,
63       __less<_Tp, typename iterator_traits<_ForwardIterator>::value_type>());
64 }
65 
66 _LIBCPP_END_NAMESPACE_STD
67 
68 #endif // _LIBCPP___ALGORITHM_UPPER_BOUND_H
69