partial_sum.h 2.1 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_BEGIN_NAMESPACE_STD
  18. template <class _InputIterator, class _OutputIterator>
  19. _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
  20. _OutputIterator
  21. partial_sum(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
  22. {
  23. if (__first != __last)
  24. {
  25. typename iterator_traits<_InputIterator>::value_type __t(*__first);
  26. *__result = __t;
  27. for (++__first, (void) ++__result; __first != __last; ++__first, (void) ++__result)
  28. {
  29. #if _LIBCPP_STD_VER > 17
  30. __t = _VSTD::move(__t) + *__first;
  31. #else
  32. __t = __t + *__first;
  33. #endif
  34. *__result = __t;
  35. }
  36. }
  37. return __result;
  38. }
  39. template <class _InputIterator, class _OutputIterator, class _BinaryOperation>
  40. _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
  41. _OutputIterator
  42. partial_sum(_InputIterator __first, _InputIterator __last, _OutputIterator __result,
  43. _BinaryOperation __binary_op)
  44. {
  45. if (__first != __last)
  46. {
  47. typename iterator_traits<_InputIterator>::value_type __t(*__first);
  48. *__result = __t;
  49. for (++__first, (void) ++__result; __first != __last; ++__first, (void) ++__result)
  50. {
  51. #if _LIBCPP_STD_VER > 17
  52. __t = __binary_op(_VSTD::move(__t), *__first);
  53. #else
  54. __t = __binary_op(__t, *__first);
  55. #endif
  56. *__result = __t;
  57. }
  58. }
  59. return __result;
  60. }
  61. _LIBCPP_END_NAMESPACE_STD
  62. #endif // _LIBCPP___NUMERIC_PARTIAL_SUM_H