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