partial_sum.h 2.0 KB

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  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. #ifndef _LIBCPP___NUMERIC_PARTIAL_SUM_H
  10. #define _LIBCPP___NUMERIC_PARTIAL_SUM_H
  11. #include <__config>
  12. #include <__iterator/iterator_traits.h>
  13. #include <__utility/move.h>
  14. #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  15. # pragma GCC system_header
  16. #endif
  17. _LIBCPP_PUSH_MACROS
  18. #include <__undef_macros>
  19. _LIBCPP_BEGIN_NAMESPACE_STD
  20. template <class _InputIterator, class _OutputIterator>
  21. _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
  22. partial_sum(_InputIterator __first, _InputIterator __last, _OutputIterator __result) {
  23. if (__first != __last) {
  24. typename iterator_traits<_InputIterator>::value_type __t(*__first);
  25. *__result = __t;
  26. for (++__first, (void)++__result; __first != __last; ++__first, (void)++__result) {
  27. #if _LIBCPP_STD_VER >= 20
  28. __t = std::move(__t) + *__first;
  29. #else
  30. __t = __t + *__first;
  31. #endif
  32. *__result = __t;
  33. }
  34. }
  35. return __result;
  36. }
  37. template <class _InputIterator, class _OutputIterator, class _BinaryOperation>
  38. _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
  39. partial_sum(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _BinaryOperation __binary_op) {
  40. if (__first != __last) {
  41. typename iterator_traits<_InputIterator>::value_type __t(*__first);
  42. *__result = __t;
  43. for (++__first, (void)++__result; __first != __last; ++__first, (void)++__result) {
  44. #if _LIBCPP_STD_VER >= 20
  45. __t = __binary_op(std::move(__t), *__first);
  46. #else
  47. __t = __binary_op(__t, *__first);
  48. #endif
  49. *__result = __t;
  50. }
  51. }
  52. return __result;
  53. }
  54. _LIBCPP_END_NAMESPACE_STD
  55. _LIBCPP_POP_MACROS
  56. #endif // _LIBCPP___NUMERIC_PARTIAL_SUM_H