libcxx/include/__numeric/adjacent_difference.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_ADJACENT_DIFFERENCE_H
  11 #define _LIBCPP___NUMERIC_ADJACENT_DIFFERENCE_H
  12
  13 #include <__config>
  14 #include <__iterator/iterator_traits.h>
  15 #include <__utility/move.h>
  16
  17 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  18 #  pragma GCC system_header
  19 #endif
  20
  21 _LIBCPP_PUSH_MACROS
  22 #include <__undef_macros>
  23
  24 _LIBCPP_BEGIN_NAMESPACE_STD
  25
  26 template <class _InputIterator, class _OutputIterator>
  27 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
  28 _OutputIterator
  29 adjacent_difference(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
  30 {
  31     if (__first != __last)
  32     {
  33         typename iterator_traits<_InputIterator>::value_type __acc(*__first);
  34         *__result = __acc;
  35         for (++__first, (void) ++__result; __first != __last; ++__first, (void) ++__result)
  36         {
  37             typename iterator_traits<_InputIterator>::value_type __val(*__first);
  38 #if _LIBCPP_STD_VER >= 20
  39             *__result = __val - _VSTD::move(__acc);
  40 #else
  41             *__result = __val - __acc;
  42 #endif
  43             __acc = _VSTD::move(__val);
  44         }
  45     }
  46     return __result;
  47 }
  48
  49 template <class _InputIterator, class _OutputIterator, class _BinaryOperation>
  50 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
  51 _OutputIterator
  52 adjacent_difference(_InputIterator __first, _InputIterator __last, _OutputIterator __result,
  53                       _BinaryOperation __binary_op)
  54 {
  55     if (__first != __last)
  56     {
  57         typename iterator_traits<_InputIterator>::value_type __acc(*__first);
  58         *__result = __acc;
  59         for (++__first, (void) ++__result; __first != __last; ++__first, (void) ++__result)
  60         {
  61             typename iterator_traits<_InputIterator>::value_type __val(*__first);
  62 #if _LIBCPP_STD_VER >= 20
  63             *__result = __binary_op(__val, _VSTD::move(__acc));
  64 #else
  65             *__result = __binary_op(__val, __acc);
  66 #endif
  67             __acc = _VSTD::move(__val);
  68         }
  69     }
  70     return __result;
  71 }
  72
  73 _LIBCPP_END_NAMESPACE_STD
  74
  75 _LIBCPP_POP_MACROS
  76
  77 #endif // _LIBCPP___NUMERIC_ADJACENT_DIFFERENCE_H