libcxx/include/__algorithm/copy.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_COPY_H
  10 #define _LIBCPP___ALGORITHM_COPY_H
  11
  12 #include <__algorithm/copy_move_common.h>
  13 #include <__algorithm/for_each_segment.h>
  14 #include <__algorithm/min.h>
  15 #include <__config>
  16 #include <__iterator/iterator_traits.h>
  17 #include <__iterator/segmented_iterator.h>
  18 #include <__type_traits/common_type.h>
  19 #include <__type_traits/enable_if.h>
  20 #include <__utility/move.h>
  21 #include <__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 <__undef_macros>
  29
  30 _LIBCPP_BEGIN_NAMESPACE_STD
  31
  32 template <class _InIter, class _Sent, class _OutIter>
  33 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter> __copy(_InIter, _Sent, _OutIter);
  34
  35 struct __copy_impl {
  36   template <class _InIter, class _Sent, class _OutIter>
  37   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
  38   operator()(_InIter __first, _Sent __last, _OutIter __result) const {
  39     while (__first != __last) {
  40       *__result = *__first;
  41       ++__first;
  42       ++__result;
  43     }
  44
  45     return std::make_pair(std::move(__first), std::move(__result));
  46   }
  47
  48   template <class _InIter, class _OutIter>
  49   struct _CopySegment {
  50     using _Traits = __segmented_iterator_traits<_InIter>;
  51
  52     _OutIter& __result_;
  53
  54     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit _CopySegment(_OutIter& __result)
  55         : __result_(__result) {}
  56
  57     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void
  58     operator()(typename _Traits::__local_iterator __lfirst, typename _Traits::__local_iterator __llast) {
  59       __result_ = std::__copy(__lfirst, __llast, std::move(__result_)).second;
  60     }
  61   };
  62
  63   template <class _InIter, class _OutIter, __enable_if_t<__is_segmented_iterator<_InIter>::value, int> = 0>
  64   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
  65   operator()(_InIter __first, _InIter __last, _OutIter __result) const {
  66     std::__for_each_segment(__first, __last, _CopySegment<_InIter, _OutIter>(__result));
  67     return std::make_pair(__last, std::move(__result));
  68   }
  69
  70   template <class _InIter,
  71             class _OutIter,
  72             __enable_if_t<__has_random_access_iterator_category<_InIter>::value &&
  73                               !__is_segmented_iterator<_InIter>::value && __is_segmented_iterator<_OutIter>::value,
  74                           int> = 0>
  75   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
  76   operator()(_InIter __first, _InIter __last, _OutIter __result) const {
  77     using _Traits = __segmented_iterator_traits<_OutIter>;
  78     using _DiffT  = typename common_type<__iter_diff_t<_InIter>, __iter_diff_t<_OutIter> >::type;
  79
  80     if (__first == __last)
  81       return std::make_pair(std::move(__first), std::move(__result));
  82
  83     auto __local_first      = _Traits::__local(__result);
  84     auto __segment_iterator = _Traits::__segment(__result);
  85     while (true) {
  86       auto __local_last = _Traits::__end(__segment_iterator);
  87       auto __size       = std::min<_DiffT>(__local_last - __local_first, __last - __first);
  88       auto __iters      = std::__copy(__first, __first + __size, __local_first);
  89       __first           = std::move(__iters.first);
  90
  91       if (__first == __last)
  92         return std::make_pair(std::move(__first), _Traits::__compose(__segment_iterator, std::move(__iters.second)));
  93
  94       __local_first = _Traits::__begin(++__segment_iterator);
  95     }
  96   }
  97
  98   // At this point, the iterators have been unwrapped so any `contiguous_iterator` has been unwrapped to a pointer.
  99   template <class _In, class _Out, __enable_if_t<__can_lower_copy_assignment_to_memmove<_In, _Out>::value, int> = 0>
 100   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_In*, _Out*>
 101   operator()(_In* __first, _In* __last, _Out* __result) const {
 102     return std::__copy_trivial_impl(__first, __last, __result);
 103   }
 104 };
 105
 106 template <class _InIter, class _Sent, class _OutIter>
 107 pair<_InIter, _OutIter> inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
 108 __copy(_InIter __first, _Sent __last, _OutIter __result) {
 109   return std::__copy_move_unwrap_iters<__copy_impl>(std::move(__first), std::move(__last), std::move(__result));
 110 }
 111
 112 template <class _InputIterator, class _OutputIterator>
 113 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
 114 copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result) {
 115   return std::__copy(__first, __last, __result).second;
 116 }
 117
 118 _LIBCPP_END_NAMESPACE_STD
 119
 120 _LIBCPP_POP_MACROS
 121
 122 #endif // _LIBCPP___ALGORITHM_COPY_H