libcxx/include/__numeric/partial_sum.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_PARTIAL_SUM_H
  11 #define _LIBCPP___NUMERIC_PARTIAL_SUM_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 partial_sum(_InputIterator __first, _InputIterator __last, _OutputIterator __result) {
  29   if (__first != __last) {
  30     typename iterator_traits<_InputIterator>::value_type __t(*__first);
  31     *__result = __t;
  32     for (++__first, (void)++__result; __first != __last; ++__first, (void)++__result) {
  33 #if _LIBCPP_STD_VER >= 20
  34       __t = std::move(__t) + *__first;
  35 #else
  36       __t = __t + *__first;
  37 #endif
  38       *__result = __t;
  39     }
  40   }
  41   return __result;
  42 }
  43
  44 template <class _InputIterator, class _OutputIterator, class _BinaryOperation>
  45 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
  46 partial_sum(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _BinaryOperation __binary_op) {
  47   if (__first != __last) {
  48     typename iterator_traits<_InputIterator>::value_type __t(*__first);
  49     *__result = __t;
  50     for (++__first, (void)++__result; __first != __last; ++__first, (void)++__result) {
  51 #if _LIBCPP_STD_VER >= 20
  52       __t = __binary_op(std::move(__t), *__first);
  53 #else
  54       __t = __binary_op(__t, *__first);
  55 #endif
  56       *__result = __t;
  57     }
  58   }
  59   return __result;
  60 }
  61
  62 _LIBCPP_END_NAMESPACE_STD
  63
  64 _LIBCPP_POP_MACROS
  65
  66 #endif // _LIBCPP___NUMERIC_PARTIAL_SUM_H