libcxx/include/__cxx03/__algorithm/move.h

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #ifndef _LIBCPP___ALGORITHM_MOVE_H
  10 #define _LIBCPP___ALGORITHM_MOVE_H
  11
  12 #include <__cxx03/__algorithm/copy_move_common.h>
  13 #include <__cxx03/__algorithm/for_each_segment.h>
  14 #include <__cxx03/__algorithm/iterator_operations.h>
  15 #include <__cxx03/__algorithm/min.h>
  16 #include <__cxx03/__config>
  17 #include <__cxx03/__iterator/segmented_iterator.h>
  18 #include <__cxx03/__type_traits/common_type.h>
  19 #include <__cxx03/__type_traits/is_constructible.h>
  20 #include <__cxx03/__utility/move.h>
  21 #include <__cxx03/__utility/pair.h>
  22
  23 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  24 #  pragma GCC system_header
  25 #endif
  26
  27 _LIBCPP_PUSH_MACROS
  28 #include <__cxx03/__undef_macros>
  29
  30 _LIBCPP_BEGIN_NAMESPACE_STD
  31
  32 template <class _AlgPolicy, class _InIter, class _Sent, class _OutIter>
  33 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
  34 __move(_InIter __first, _Sent __last, _OutIter __result);
  35
  36 template <class _AlgPolicy>
  37 struct __move_impl {
  38   template <class _InIter, class _Sent, class _OutIter>
  39   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
  40   operator()(_InIter __first, _Sent __last, _OutIter __result) const {
  41     while (__first != __last) {
  42       *__result = _IterOps<_AlgPolicy>::__iter_move(__first);
  43       ++__first;
  44       ++__result;
  45     }
  46     return std::make_pair(std::move(__first), std::move(__result));
  47   }
  48
  49   template <class _InIter, class _OutIter>
  50   struct _MoveSegment {
  51     using _Traits = __segmented_iterator_traits<_InIter>;
  52
  53     _OutIter& __result_;
  54
  55     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit _MoveSegment(_OutIter& __result)
  56         : __result_(__result) {}
  57
  58     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void
  59     operator()(typename _Traits::__local_iterator __lfirst, typename _Traits::__local_iterator __llast) {
  60       __result_ = std::__move<_AlgPolicy>(__lfirst, __llast, std::move(__result_)).second;
  61     }
  62   };
  63
  64   template <class _InIter, class _OutIter, __enable_if_t<__is_segmented_iterator<_InIter>::value, int> = 0>
  65   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
  66   operator()(_InIter __first, _InIter __last, _OutIter __result) const {
  67     std::__for_each_segment(__first, __last, _MoveSegment<_InIter, _OutIter>(__result));
  68     return std::make_pair(__last, std::move(__result));
  69   }
  70
  71   template <class _InIter,
  72             class _OutIter,
  73             __enable_if_t<__has_random_access_iterator_category<_InIter>::value &&
  74                               !__is_segmented_iterator<_InIter>::value && __is_segmented_iterator<_OutIter>::value,
  75                           int> = 0>
  76   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
  77   operator()(_InIter __first, _InIter __last, _OutIter __result) const {
  78     using _Traits = __segmented_iterator_traits<_OutIter>;
  79     using _DiffT  = typename common_type<__iter_diff_t<_InIter>, __iter_diff_t<_OutIter> >::type;
  80
  81     if (__first == __last)
  82       return std::make_pair(std::move(__first), std::move(__result));
  83
  84     auto __local_first      = _Traits::__local(__result);
  85     auto __segment_iterator = _Traits::__segment(__result);
  86     while (true) {
  87       auto __local_last = _Traits::__end(__segment_iterator);
  88       auto __size       = std::min<_DiffT>(__local_last - __local_first, __last - __first);
  89       auto __iters      = std::__move<_AlgPolicy>(__first, __first + __size, __local_first);
  90       __first           = std::move(__iters.first);
  91
  92       if (__first == __last)
  93         return std::make_pair(std::move(__first), _Traits::__compose(__segment_iterator, std::move(__iters.second)));
  94
  95       __local_first = _Traits::__begin(++__segment_iterator);
  96     }
  97   }
  98
  99   // At this point, the iterators have been unwrapped so any `contiguous_iterator` has been unwrapped to a pointer.
 100   template <class _In, class _Out, __enable_if_t<__can_lower_move_assignment_to_memmove<_In, _Out>::value, int> = 0>
 101   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_In*, _Out*>
 102   operator()(_In* __first, _In* __last, _Out* __result) const {
 103     return std::__copy_trivial_impl(__first, __last, __result);
 104   }
 105 };
 106
 107 template <class _AlgPolicy, class _InIter, class _Sent, class _OutIter>
 108 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
 109 __move(_InIter __first, _Sent __last, _OutIter __result) {
 110   return std::__copy_move_unwrap_iters<__move_impl<_AlgPolicy> >(
 111       std::move(__first), std::move(__last), std::move(__result));
 112 }
 113
 114 template <class _InputIterator, class _OutputIterator>
 115 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
 116 move(_InputIterator __first, _InputIterator __last, _OutputIterator __result) {
 117   static_assert(is_copy_constructible<_InputIterator>::value, "Iterators has to be copy constructible.");
 118   static_assert(is_copy_constructible<_OutputIterator>::value, "The output iterator has to be copy constructible.");
 119
 120   return std::__move<_ClassicAlgPolicy>(std::move(__first), std::move(__last), std::move(__result)).second;
 121 }
 122
 123 _LIBCPP_END_NAMESPACE_STD
 124
 125 _LIBCPP_POP_MACROS
 126
 127 #endif // _LIBCPP___ALGORITHM_MOVE_H