libcxx/include/__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 <__algorithm/copy_move_common.h>
  13 #include <__algorithm/for_each_segment.h>
  14 #include <__algorithm/iterator_operations.h>
  15 #include <__algorithm/min.h>
  16 #include <__config>
  17 #include <__iterator/iterator_traits.h>
  18 #include <__iterator/segmented_iterator.h>
  19 #include <__type_traits/common_type.h>
  20 #include <__type_traits/enable_if.h>
  21 #include <__type_traits/is_constructible.h>
  22 #include <__utility/move.h>
  23 #include <__utility/pair.h>
  24
  25 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  26 #  pragma GCC system_header
  27 #endif
  28
  29 _LIBCPP_PUSH_MACROS
  30 #include <__undef_macros>
  31
  32 _LIBCPP_BEGIN_NAMESPACE_STD
  33
  34 template <class _AlgPolicy, class _InIter, class _Sent, class _OutIter>
  35 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
  36 __move(_InIter __first, _Sent __last, _OutIter __result);
  37
  38 template <class _AlgPolicy>
  39 struct __move_impl {
  40   template <class _InIter, class _Sent, class _OutIter>
  41   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
  42   operator()(_InIter __first, _Sent __last, _OutIter __result) const {
  43     while (__first != __last) {
  44       *__result = _IterOps<_AlgPolicy>::__iter_move(__first);
  45       ++__first;
  46       ++__result;
  47     }
  48     return std::make_pair(std::move(__first), std::move(__result));
  49   }
  50
  51   template <class _InIter, class _OutIter>
  52   struct _MoveSegment {
  53     using _Traits = __segmented_iterator_traits<_InIter>;
  54
  55     _OutIter& __result_;
  56
  57     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit _MoveSegment(_OutIter& __result)
  58         : __result_(__result) {}
  59
  60     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void
  61     operator()(typename _Traits::__local_iterator __lfirst, typename _Traits::__local_iterator __llast) {
  62       __result_ = std::__move<_AlgPolicy>(__lfirst, __llast, std::move(__result_)).second;
  63     }
  64   };
  65
  66   template <class _InIter, class _OutIter, __enable_if_t<__is_segmented_iterator<_InIter>::value, int> = 0>
  67   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
  68   operator()(_InIter __first, _InIter __last, _OutIter __result) const {
  69     std::__for_each_segment(__first, __last, _MoveSegment<_InIter, _OutIter>(__result));
  70     return std::make_pair(__last, std::move(__result));
  71   }
  72
  73   template <class _InIter,
  74             class _OutIter,
  75             __enable_if_t<__has_random_access_iterator_category<_InIter>::value &&
  76                               !__is_segmented_iterator<_InIter>::value && __is_segmented_iterator<_OutIter>::value,
  77                           int> = 0>
  78   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
  79   operator()(_InIter __first, _InIter __last, _OutIter __result) const {
  80     using _Traits = __segmented_iterator_traits<_OutIter>;
  81     using _DiffT  = typename common_type<__iter_diff_t<_InIter>, __iter_diff_t<_OutIter> >::type;
  82
  83     if (__first == __last)
  84       return std::make_pair(std::move(__first), std::move(__result));
  85
  86     auto __local_first      = _Traits::__local(__result);
  87     auto __segment_iterator = _Traits::__segment(__result);
  88     while (true) {
  89       auto __local_last = _Traits::__end(__segment_iterator);
  90       auto __size       = std::min<_DiffT>(__local_last - __local_first, __last - __first);
  91       auto __iters      = std::__move<_AlgPolicy>(__first, __first + __size, __local_first);
  92       __first           = std::move(__iters.first);
  93
  94       if (__first == __last)
  95         return std::make_pair(std::move(__first), _Traits::__compose(__segment_iterator, std::move(__iters.second)));
  96
  97       __local_first = _Traits::__begin(++__segment_iterator);
  98     }
  99   }
 100
 101   // At this point, the iterators have been unwrapped so any `contiguous_iterator` has been unwrapped to a pointer.
 102   template <class _In, class _Out, __enable_if_t<__can_lower_move_assignment_to_memmove<_In, _Out>::value, int> = 0>
 103   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_In*, _Out*>
 104   operator()(_In* __first, _In* __last, _Out* __result) const {
 105     return std::__copy_trivial_impl(__first, __last, __result);
 106   }
 107 };
 108
 109 template <class _AlgPolicy, class _InIter, class _Sent, class _OutIter>
 110 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
 111 __move(_InIter __first, _Sent __last, _OutIter __result) {
 112   return std::__copy_move_unwrap_iters<__move_impl<_AlgPolicy> >(
 113       std::move(__first), std::move(__last), std::move(__result));
 114 }
 115
 116 template <class _InputIterator, class _OutputIterator>
 117 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
 118 move(_InputIterator __first, _InputIterator __last, _OutputIterator __result) {
 119   static_assert(is_copy_constructible<_InputIterator>::value, "Iterators has to be copy constructible.");
 120   static_assert(is_copy_constructible<_OutputIterator>::value, "The output iterator has to be copy constructible.");
 121
 122   return std::__move<_ClassicAlgPolicy>(std::move(__first), std::move(__last), std::move(__result)).second;
 123 }
 124
 125 _LIBCPP_END_NAMESPACE_STD
 126
 127 _LIBCPP_POP_MACROS
 128
 129 #endif // _LIBCPP___ALGORITHM_MOVE_H