libcxx/include/__numeric/inclusive_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_INCLUSIVE_SCAN_H
  11 #define _LIBCPP___NUMERIC_INCLUSIVE_SCAN_H
  12
  13 #include <__config>
  14 #include <__functional/operations.h>
  15 #include <__iterator/iterator_traits.h>
  16 #include <__utility/move.h>
  17
  18 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  19 #  pragma GCC system_header
  20 #endif
  21
  22 _LIBCPP_BEGIN_NAMESPACE_STD
  23
  24 #if _LIBCPP_STD_VER >= 17
  25
  26 template <class _InputIterator, class _OutputIterator, class _Tp, class _BinaryOp>
  27 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
  28 inclusive_scan(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _BinaryOp __b, _Tp __init) {
  29   for (; __first != __last; ++__first, (void)++__result) {
  30     __init    = __b(__init, *__first);
  31     *__result = __init;
  32   }
  33   return __result;
  34 }
  35
  36 template <class _InputIterator, class _OutputIterator, class _BinaryOp>
  37 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
  38 inclusive_scan(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _BinaryOp __b) {
  39   if (__first != __last) {
  40     typename iterator_traits<_InputIterator>::value_type __init = *__first;
  41     *__result++                                                 = __init;
  42     if (++__first != __last)
  43       return std::inclusive_scan(__first, __last, __result, __b, __init);
  44   }
  45
  46   return __result;
  47 }
  48
  49 template <class _InputIterator, class _OutputIterator>
  50 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
  51 inclusive_scan(_InputIterator __first, _InputIterator __last, _OutputIterator __result) {
  52   return std::inclusive_scan(__first, __last, __result, std::plus<>());
  53 }
  54
  55 #endif // _LIBCPP_STD_VER >= 17
  56
  57 _LIBCPP_END_NAMESPACE_STD
  58
  59 #endif // _LIBCPP___NUMERIC_INCLUSIVE_SCAN_H