libcxx/include/__algorithm/ranges_partition_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_PARTITION_COPY_H
  10 #define _LIBCPP___ALGORITHM_RANGES_PARTITION_COPY_H
  11
  12 #include <__algorithm/in_out_out_result.h>
  13 #include <__config>
  14 #include <__functional/identity.h>
  15 #include <__functional/invoke.h>
  16 #include <__iterator/concepts.h>
  17 #include <__iterator/iterator_traits.h>
  18 #include <__iterator/projected.h>
  19 #include <__ranges/access.h>
  20 #include <__ranges/concepts.h>
  21 #include <__ranges/dangling.h>
  22 #include <__type_traits/remove_cvref.h>
  23 #include <__utility/move.h>
  24
  25 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  26 #  pragma GCC system_header
  27 #endif
  28
  29 #if _LIBCPP_STD_VER >= 20
  30
  31 _LIBCPP_BEGIN_NAMESPACE_STD
  32
  33 namespace ranges {
  34
  35 template <class _InIter, class _OutIter1, class _OutIter2>
  36 using partition_copy_result = in_out_out_result<_InIter, _OutIter1, _OutIter2>;
  37
  38 namespace __partition_copy {
  39
  40 struct __fn {
  41   // TODO(ranges): delegate to the classic algorithm.
  42   template <class _InIter, class _Sent, class _OutIter1, class _OutIter2, class _Proj, class _Pred>
  43   _LIBCPP_HIDE_FROM_ABI constexpr static partition_copy_result<__remove_cvref_t<_InIter>,
  44                                                                __remove_cvref_t<_OutIter1>,
  45                                                                __remove_cvref_t<_OutIter2> >
  46   __partition_copy_fn_impl(
  47       _InIter&& __first,
  48       _Sent&& __last,
  49       _OutIter1&& __out_true,
  50       _OutIter2&& __out_false,
  51       _Pred& __pred,
  52       _Proj& __proj) {
  53     for (; __first != __last; ++__first) {
  54       if (std::invoke(__pred, std::invoke(__proj, *__first))) {
  55         *__out_true = *__first;
  56         ++__out_true;
  57
  58       } else {
  59         *__out_false = *__first;
  60         ++__out_false;
  61       }
  62     }
  63
  64     return {std::move(__first), std::move(__out_true), std::move(__out_false)};
  65   }
  66
  67   template <input_iterator _InIter,
  68             sentinel_for<_InIter> _Sent,
  69             weakly_incrementable _OutIter1,
  70             weakly_incrementable _OutIter2,
  71             class _Proj = identity,
  72             indirect_unary_predicate<projected<_InIter, _Proj>> _Pred>
  73     requires indirectly_copyable<_InIter, _OutIter1> && indirectly_copyable<_InIter, _OutIter2>
  74   _LIBCPP_HIDE_FROM_ABI constexpr partition_copy_result<_InIter, _OutIter1, _OutIter2> operator()(
  75       _InIter __first, _Sent __last, _OutIter1 __out_true, _OutIter2 __out_false, _Pred __pred, _Proj __proj = {})
  76       const {
  77     return __partition_copy_fn_impl(
  78         std::move(__first), std::move(__last), std::move(__out_true), std::move(__out_false), __pred, __proj);
  79   }
  80
  81   template <input_range _Range,
  82             weakly_incrementable _OutIter1,
  83             weakly_incrementable _OutIter2,
  84             class _Proj = identity,
  85             indirect_unary_predicate<projected<iterator_t<_Range>, _Proj>> _Pred>
  86     requires indirectly_copyable<iterator_t<_Range>, _OutIter1> && indirectly_copyable<iterator_t<_Range>, _OutIter2>
  87   _LIBCPP_HIDE_FROM_ABI constexpr partition_copy_result<borrowed_iterator_t<_Range>, _OutIter1, _OutIter2>
  88   operator()(_Range&& __range, _OutIter1 __out_true, _OutIter2 __out_false, _Pred __pred, _Proj __proj = {}) const {
  89     return __partition_copy_fn_impl(
  90         ranges::begin(__range), ranges::end(__range), std::move(__out_true), std::move(__out_false), __pred, __proj);
  91   }
  92 };
  93
  94 } // namespace __partition_copy
  95
  96 inline namespace __cpo {
  97 inline constexpr auto partition_copy = __partition_copy::__fn{};
  98 } // namespace __cpo
  99 } // namespace ranges
 100
 101 _LIBCPP_END_NAMESPACE_STD
 102
 103 #endif // _LIBCPP_STD_VER >= 20
 104
 105 #endif // _LIBCPP___ALGORITHM_RANGES_PARTITION_COPY_H