1 // -*- C++ -*-
2 //===----------------------------------------------------------------------===//
3 //
4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5 // See https://llvm.org/LICENSE.txt for license information.
6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #ifndef _LIBCPP___NUMERIC_ADJACENT_DIFFERENCE_H
11 #define _LIBCPP___NUMERIC_ADJACENT_DIFFERENCE_H
12 
13 #include <__config>
14 #include <__iterator/iterator_traits.h>
15 #include <__utility/move.h>
16 
17 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
18 #  pragma GCC system_header
19 #endif
20 
21 _LIBCPP_PUSH_MACROS
22 #include <__undef_macros>
23 
24 _LIBCPP_BEGIN_NAMESPACE_STD
25 
26 template <class _InputIterator, class _OutputIterator>
27 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
28 _OutputIterator
29 adjacent_difference(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
30 {
31     if (__first != __last)
32     {
33         typename iterator_traits<_InputIterator>::value_type __acc(*__first);
34         *__result = __acc;
35         for (++__first, (void) ++__result; __first != __last; ++__first, (void) ++__result)
36         {
37             typename iterator_traits<_InputIterator>::value_type __val(*__first);
38 #if _LIBCPP_STD_VER >= 20
39             *__result = __val - std::move(__acc);
40 #else
41             *__result = __val - __acc;
42 #endif
43             __acc = std::move(__val);
44         }
45     }
46     return __result;
47 }
48 
49 template <class _InputIterator, class _OutputIterator, class _BinaryOperation>
50 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
51 _OutputIterator
52 adjacent_difference(_InputIterator __first, _InputIterator __last, _OutputIterator __result,
53                       _BinaryOperation __binary_op)
54 {
55     if (__first != __last)
56     {
57         typename iterator_traits<_InputIterator>::value_type __acc(*__first);
58         *__result = __acc;
59         for (++__first, (void) ++__result; __first != __last; ++__first, (void) ++__result)
60         {
61             typename iterator_traits<_InputIterator>::value_type __val(*__first);
62 #if _LIBCPP_STD_VER >= 20
63             *__result = __binary_op(__val, std::move(__acc));
64 #else
65             *__result = __binary_op(__val, __acc);
66 #endif
67             __acc = std::move(__val);
68         }
69     }
70     return __result;
71 }
72 
73 _LIBCPP_END_NAMESPACE_STD
74 
75 _LIBCPP_POP_MACROS
76 
77 #endif // _LIBCPP___NUMERIC_ADJACENT_DIFFERENCE_H
78