xref: /freebsd/contrib/llvm-project/libcxx/include/__numeric/exclusive_scan.h (revision c8e7f78a3d28ff6e6223ed136ada8e1e2f34965e)
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_EXCLUSIVE_SCAN_H
11 #define _LIBCPP___NUMERIC_EXCLUSIVE_SCAN_H
12 
13 #include <__config>
14 #include <__functional/operations.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 #if _LIBCPP_STD_VER >= 17
27 
28 template <class _InputIterator, class _OutputIterator, class _Tp, class _BinaryOp>
29 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
30 exclusive_scan(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _Tp __init, _BinaryOp __b) {
31   if (__first != __last) {
32     _Tp __tmp(__b(__init, *__first));
33     while (true) {
34       *__result = _VSTD::move(__init);
35       ++__result;
36       ++__first;
37       if (__first == __last)
38         break;
39       __init = _VSTD::move(__tmp);
40       __tmp = __b(__init, *__first);
41     }
42   }
43   return __result;
44 }
45 
46 template <class _InputIterator, class _OutputIterator, class _Tp>
47 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
48 exclusive_scan(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _Tp __init) {
49   return _VSTD::exclusive_scan(__first, __last, __result, __init, _VSTD::plus<>());
50 }
51 
52 #endif // _LIBCPP_STD_VER >= 17
53 
54 _LIBCPP_END_NAMESPACE_STD
55 
56 _LIBCPP_POP_MACROS
57 
58 #endif // _LIBCPP___NUMERIC_EXCLUSIVE_SCAN_H
59