v1/__numeric/exclusive_scan.h

0001 // -*- C++ -*-
0002 //===----------------------------------------------------------------------===//
0003 //
0004 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
0005 // See https://llvm.org/LICENSE.txt for license information.
0006 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
0007 //
0008 //===----------------------------------------------------------------------===//
0009
0010 #ifndef _LIBCPP___NUMERIC_EXCLUSIVE_SCAN_H
0011 #define _LIBCPP___NUMERIC_EXCLUSIVE_SCAN_H
0012
0013 #include <__config>
0014 #include <__functional/operations.h>
0015 #include <__utility/move.h>
0016
0017 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
0018 #  pragma GCC system_header
0019 #endif
0020
0021 _LIBCPP_PUSH_MACROS
0022 #include <__undef_macros>
0023
0024 _LIBCPP_BEGIN_NAMESPACE_STD
0025
0026 #if _LIBCPP_STD_VER >= 17
0027
0028 template <class _InputIterator, class _OutputIterator, class _Tp, class _BinaryOp>
0029 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
0030 exclusive_scan(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _Tp __init, _BinaryOp __b) {
0031   if (__first != __last) {
0032     _Tp __tmp(__b(__init, *__first));
0033     while (true) {
0034       *__result = std::move(__init);
0035       ++__result;
0036       ++__first;
0037       if (__first == __last)
0038         break;
0039       __init = std::move(__tmp);
0040       __tmp  = __b(__init, *__first);
0041     }
0042   }
0043   return __result;
0044 }
0045
0046 template <class _InputIterator, class _OutputIterator, class _Tp>
0047 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
0048 exclusive_scan(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _Tp __init) {
0049   return std::exclusive_scan(__first, __last, __result, __init, std::plus<>());
0050 }
0051
0052 #endif // _LIBCPP_STD_VER >= 17
0053
0054 _LIBCPP_END_NAMESPACE_STD
0055
0056 _LIBCPP_POP_MACROS
0057
0058 #endif // _LIBCPP___NUMERIC_EXCLUSIVE_SCAN_H