libcxx/include/__algorithm/ranges_unique_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_RANGES_UNIQUE_COPY_H
  10 #define _LIBCPP___ALGORITHM_RANGES_UNIQUE_COPY_H
  11
  12 #include <__algorithm/in_out_result.h>
  13 #include <__algorithm/iterator_operations.h>
  14 #include <__algorithm/make_projected.h>
  15 #include <__algorithm/unique_copy.h>
  16 #include <__concepts/same_as.h>
  17 #include <__config>
  18 #include <__functional/identity.h>
  19 #include <__functional/invoke.h>
  20 #include <__functional/ranges_operations.h>
  21 #include <__iterator/concepts.h>
  22 #include <__iterator/iterator_traits.h>
  23 #include <__iterator/projected.h>
  24 #include <__ranges/access.h>
  25 #include <__ranges/concepts.h>
  26 #include <__ranges/dangling.h>
  27 #include <__utility/forward.h>
  28 #include <__utility/move.h>
  29 #include <__utility/pair.h>
  30
  31 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  32 #  pragma GCC system_header
  33 #endif
  34
  35 #if _LIBCPP_STD_VER >= 20
  36
  37 _LIBCPP_BEGIN_NAMESPACE_STD
  38
  39 namespace ranges {
  40
  41 template <class _InIter, class _OutIter>
  42 using unique_copy_result = in_out_result<_InIter, _OutIter>;
  43
  44 namespace __unique_copy {
  45
  46 template <class _InIter, class _OutIter>
  47 concept __can_reread_from_output = (input_iterator<_OutIter> && same_as<iter_value_t<_InIter>, iter_value_t<_OutIter>>);
  48
  49 struct __fn {
  50   template <class _InIter, class _OutIter>
  51   static consteval auto __get_algo_tag() {
  52     if constexpr (forward_iterator<_InIter>) {
  53       return __unique_copy_tags::__reread_from_input_tag{};
  54     } else if constexpr (__can_reread_from_output<_InIter, _OutIter>) {
  55       return __unique_copy_tags::__reread_from_output_tag{};
  56     } else if constexpr (indirectly_copyable_storable<_InIter, _OutIter>) {
  57       return __unique_copy_tags::__read_from_tmp_value_tag{};
  58     }
  59   }
  60
  61   template <class _InIter, class _OutIter>
  62   using __algo_tag_t = decltype(__get_algo_tag<_InIter, _OutIter>());
  63
  64   template <input_iterator _InIter,
  65             sentinel_for<_InIter> _Sent,
  66             weakly_incrementable _OutIter,
  67             class _Proj                                                    = identity,
  68             indirect_equivalence_relation<projected<_InIter, _Proj>> _Comp = ranges::equal_to>
  69     requires indirectly_copyable<_InIter, _OutIter> &&
  70              (forward_iterator<_InIter> ||
  71               (input_iterator<_OutIter> && same_as<iter_value_t<_InIter>, iter_value_t<_OutIter>>) ||
  72               indirectly_copyable_storable<_InIter, _OutIter>)
  73   _LIBCPP_HIDE_FROM_ABI constexpr unique_copy_result<_InIter, _OutIter>
  74   operator()(_InIter __first, _Sent __last, _OutIter __result, _Comp __comp = {}, _Proj __proj = {}) const {
  75     auto __ret = std::__unique_copy<_RangeAlgPolicy>(
  76         std::move(__first),
  77         std::move(__last),
  78         std::move(__result),
  79         std::__make_projected(__comp, __proj),
  80         __algo_tag_t<_InIter, _OutIter>());
  81     return {std::move(__ret.first), std::move(__ret.second)};
  82   }
  83
  84   template <input_range _Range,
  85             weakly_incrementable _OutIter,
  86             class _Proj                                                               = identity,
  87             indirect_equivalence_relation<projected<iterator_t<_Range>, _Proj>> _Comp = ranges::equal_to>
  88     requires indirectly_copyable<iterator_t<_Range>, _OutIter> &&
  89              (forward_iterator<iterator_t<_Range>> ||
  90               (input_iterator<_OutIter> && same_as<range_value_t<_Range>, iter_value_t<_OutIter>>) ||
  91               indirectly_copyable_storable<iterator_t<_Range>, _OutIter>)
  92   _LIBCPP_HIDE_FROM_ABI constexpr unique_copy_result<borrowed_iterator_t<_Range>, _OutIter>
  93   operator()(_Range&& __range, _OutIter __result, _Comp __comp = {}, _Proj __proj = {}) const {
  94     auto __ret = std::__unique_copy<_RangeAlgPolicy>(
  95         ranges::begin(__range),
  96         ranges::end(__range),
  97         std::move(__result),
  98         std::__make_projected(__comp, __proj),
  99         __algo_tag_t<iterator_t<_Range>, _OutIter>());
 100     return {std::move(__ret.first), std::move(__ret.second)};
 101   }
 102 };
 103
 104 } // namespace __unique_copy
 105
 106 inline namespace __cpo {
 107 inline constexpr auto unique_copy = __unique_copy::__fn{};
 108 } // namespace __cpo
 109 } // namespace ranges
 110
 111 _LIBCPP_END_NAMESPACE_STD
 112
 113 #endif // _LIBCPP_STD_VER >= 20
 114
 115 #endif // _LIBCPP___ALGORITHM_RANGES_UNIQUE_COPY_H