libcxx/include/__numeric/exclusive_scan.h

   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