v1/__numeric/adjacent_difference.h

0001 // -*- C++ -*-
0002 //===----------------------------------------------------------------------===//
0003 //
0004 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
0005 // See https://llvm.org/LICENSE.txt for license information.
0006 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
0007 //
0008 //===----------------------------------------------------------------------===//
0009
0010 #ifndef _LIBCPP___NUMERIC_ADJACENT_DIFFERENCE_H
0011 #define _LIBCPP___NUMERIC_ADJACENT_DIFFERENCE_H
0012
0013 #include <__config>
0014 #include <__iterator/iterator_traits.h>
0015 #include <__utility/move.h>
0016
0017 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
0018 #  pragma GCC system_header
0019 #endif
0020
0021 _LIBCPP_PUSH_MACROS
0022 #include <__undef_macros>
0023
0024 _LIBCPP_BEGIN_NAMESPACE_STD
0025
0026 template <class _InputIterator, class _OutputIterator>
0027 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
0028 adjacent_difference(_InputIterator __first, _InputIterator __last, _OutputIterator __result) {
0029   if (__first != __last) {
0030     typename iterator_traits<_InputIterator>::value_type __acc(*__first);
0031     *__result = __acc;
0032     for (++__first, (void)++__result; __first != __last; ++__first, (void)++__result) {
0033       typename iterator_traits<_InputIterator>::value_type __val(*__first);
0034 #if _LIBCPP_STD_VER >= 20
0035       *__result = __val - std::move(__acc);
0036 #else
0037       *__result = __val - __acc;
0038 #endif
0039       __acc = std::move(__val);
0040     }
0041   }
0042   return __result;
0043 }
0044
0045 template <class _InputIterator, class _OutputIterator, class _BinaryOperation>
0046 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator adjacent_difference(
0047     _InputIterator __first, _InputIterator __last, _OutputIterator __result, _BinaryOperation __binary_op) {
0048   if (__first != __last) {
0049     typename iterator_traits<_InputIterator>::value_type __acc(*__first);
0050     *__result = __acc;
0051     for (++__first, (void)++__result; __first != __last; ++__first, (void)++__result) {
0052       typename iterator_traits<_InputIterator>::value_type __val(*__first);
0053 #if _LIBCPP_STD_VER >= 20
0054       *__result = __binary_op(__val, std::move(__acc));
0055 #else
0056       *__result = __binary_op(__val, __acc);
0057 #endif
0058       __acc = std::move(__val);
0059     }
0060   }
0061   return __result;
0062 }
0063
0064 _LIBCPP_END_NAMESPACE_STD
0065
0066 _LIBCPP_POP_MACROS
0067
0068 #endif // _LIBCPP___NUMERIC_ADJACENT_DIFFERENCE_H