adjacent_difference.h 2.4 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_ADJACENT_DIFFERENCE_H
  10. #define _LIBCPP___NUMERIC_ADJACENT_DIFFERENCE_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_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
  22. _OutputIterator
  23. adjacent_difference(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
  24. {
  25. if (__first != __last)
  26. {
  27. typename iterator_traits<_InputIterator>::value_type __acc(*__first);
  28. *__result = __acc;
  29. for (++__first, (void) ++__result; __first != __last; ++__first, (void) ++__result)
  30. {
  31. typename iterator_traits<_InputIterator>::value_type __val(*__first);
  32. #if _LIBCPP_STD_VER >= 20
  33. *__result = __val - _VSTD::move(__acc);
  34. #else
  35. *__result = __val - __acc;
  36. #endif
  37. __acc = _VSTD::move(__val);
  38. }
  39. }
  40. return __result;
  41. }
  42. template <class _InputIterator, class _OutputIterator, class _BinaryOperation>
  43. _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
  44. _OutputIterator
  45. adjacent_difference(_InputIterator __first, _InputIterator __last, _OutputIterator __result,
  46. _BinaryOperation __binary_op)
  47. {
  48. if (__first != __last)
  49. {
  50. typename iterator_traits<_InputIterator>::value_type __acc(*__first);
  51. *__result = __acc;
  52. for (++__first, (void) ++__result; __first != __last; ++__first, (void) ++__result)
  53. {
  54. typename iterator_traits<_InputIterator>::value_type __val(*__first);
  55. #if _LIBCPP_STD_VER >= 20
  56. *__result = __binary_op(__val, _VSTD::move(__acc));
  57. #else
  58. *__result = __binary_op(__val, __acc);
  59. #endif
  60. __acc = _VSTD::move(__val);
  61. }
  62. }
  63. return __result;
  64. }
  65. _LIBCPP_END_NAMESPACE_STD
  66. _LIBCPP_POP_MACROS
  67. #endif // _LIBCPP___NUMERIC_ADJACENT_DIFFERENCE_H