xref: /freebsd/contrib/llvm-project/libcxx/include/__numeric/adjacent_difference.h (revision 1db9f3b21e39176dd5b67cf8ac378633b172463e)
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 _OutputIterator
28 adjacent_difference(_InputIterator __first, _InputIterator __last, _OutputIterator __result) {
29   if (__first != __last) {
30     typename iterator_traits<_InputIterator>::value_type __acc(*__first);
31     *__result = __acc;
32     for (++__first, (void)++__result; __first != __last; ++__first, (void)++__result) {
33       typename iterator_traits<_InputIterator>::value_type __val(*__first);
34 #if _LIBCPP_STD_VER >= 20
35       *__result = __val - std::move(__acc);
36 #else
37       *__result = __val - __acc;
38 #endif
39       __acc = std::move(__val);
40     }
41   }
42   return __result;
43 }
44 
45 template <class _InputIterator, class _OutputIterator, class _BinaryOperation>
46 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator adjacent_difference(
47     _InputIterator __first, _InputIterator __last, _OutputIterator __result, _BinaryOperation __binary_op) {
48   if (__first != __last) {
49     typename iterator_traits<_InputIterator>::value_type __acc(*__first);
50     *__result = __acc;
51     for (++__first, (void)++__result; __first != __last; ++__first, (void)++__result) {
52       typename iterator_traits<_InputIterator>::value_type __val(*__first);
53 #if _LIBCPP_STD_VER >= 20
54       *__result = __binary_op(__val, std::move(__acc));
55 #else
56       *__result = __binary_op(__val, __acc);
57 #endif
58       __acc = std::move(__val);
59     }
60   }
61   return __result;
62 }
63 
64 _LIBCPP_END_NAMESPACE_STD
65 
66 _LIBCPP_POP_MACROS
67 
68 #endif // _LIBCPP___NUMERIC_ADJACENT_DIFFERENCE_H
69