xref: /llvm-project/libcxx/include/__algorithm/upper_bound.h (revision 8d151f804ff43aaed1edf810bb2a07607b8bba14)
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_callable.h>
22 #include <__type_traits/is_constructible.h>
23 #include <__utility/move.h>
24 
25 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
26 #  pragma GCC system_header
27 #endif
28 
29 _LIBCPP_PUSH_MACROS
30 #include <__undef_macros>
31 
32 _LIBCPP_BEGIN_NAMESPACE_STD
33 
34 template <class _AlgPolicy, class _Compare, class _Iter, class _Sent, class _Tp, class _Proj>
35 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Iter
36 __upper_bound(_Iter __first, _Sent __last, const _Tp& __value, _Compare&& __comp, _Proj&& __proj) {
37   auto __len = _IterOps<_AlgPolicy>::distance(__first, __last);
38   while (__len != 0) {
39     auto __half_len = std::__half_positive(__len);
40     auto __mid      = _IterOps<_AlgPolicy>::next(__first, __half_len);
41     if (std::__invoke(__comp, __value, std::__invoke(__proj, *__mid)))
42       __len = __half_len;
43     else {
44       __first = ++__mid;
45       __len -= __half_len + 1;
46     }
47   }
48   return __first;
49 }
50 
51 template <class _ForwardIterator, class _Tp, class _Compare>
52 _LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator
53 upper_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value, _Compare __comp) {
54   static_assert(__is_callable<_Compare&, decltype(*__first), const _Tp&>::value, "The comparator has to be callable");
55   static_assert(is_copy_constructible<_ForwardIterator>::value, "Iterator has to be copy constructible");
56   return std::__upper_bound<_ClassicAlgPolicy>(
57       std::move(__first), std::move(__last), __value, std::move(__comp), std::__identity());
58 }
59 
60 template <class _ForwardIterator, class _Tp>
61 _LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator
62 upper_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value) {
63   return std::upper_bound(std::move(__first), std::move(__last), __value, __less<>());
64 }
65 
66 _LIBCPP_END_NAMESPACE_STD
67 
68 _LIBCPP_POP_MACROS
69 
70 #endif // _LIBCPP___ALGORITHM_UPPER_BOUND_H
71