adjacent_difference.h 2.2 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_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
  22. adjacent_difference(_InputIterator __first, _InputIterator __last, _OutputIterator __result) {
  23. if (__first != __last) {
  24. typename iterator_traits<_InputIterator>::value_type __acc(*__first);
  25. *__result = __acc;
  26. for (++__first, (void)++__result; __first != __last; ++__first, (void)++__result) {
  27. typename iterator_traits<_InputIterator>::value_type __val(*__first);
  28. #if _LIBCPP_STD_VER >= 20
  29. *__result = __val - std::move(__acc);
  30. #else
  31. *__result = __val - __acc;
  32. #endif
  33. __acc = std::move(__val);
  34. }
  35. }
  36. return __result;
  37. }
  38. template <class _InputIterator, class _OutputIterator, class _BinaryOperation>
  39. _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator adjacent_difference(
  40. _InputIterator __first, _InputIterator __last, _OutputIterator __result, _BinaryOperation __binary_op) {
  41. if (__first != __last) {
  42. typename iterator_traits<_InputIterator>::value_type __acc(*__first);
  43. *__result = __acc;
  44. for (++__first, (void)++__result; __first != __last; ++__first, (void)++__result) {
  45. typename iterator_traits<_InputIterator>::value_type __val(*__first);
  46. #if _LIBCPP_STD_VER >= 20
  47. *__result = __binary_op(__val, std::move(__acc));
  48. #else
  49. *__result = __binary_op(__val, __acc);
  50. #endif
  51. __acc = std::move(__val);
  52. }
  53. }
  54. return __result;
  55. }
  56. _LIBCPP_END_NAMESPACE_STD
  57. _LIBCPP_POP_MACROS
  58. #endif // _LIBCPP___NUMERIC_ADJACENT_DIFFERENCE_H