libcxx/include/__algorithm/ranges_is_partitioned.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_IS_PARTITIONED_H
  10 #define _LIBCPP___ALGORITHM_RANGES_IS_PARTITIONED_H
  11
  12 #include <__config>
  13 #include <__functional/identity.h>
  14 #include <__functional/invoke.h>
  15 #include <__iterator/concepts.h>
  16 #include <__iterator/indirectly_comparable.h>
  17 #include <__iterator/projected.h>
  18 #include <__ranges/access.h>
  19 #include <__ranges/concepts.h>
  20 #include <__utility/move.h>
  21
  22 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  23 #  pragma GCC system_header
  24 #endif
  25
  26 _LIBCPP_PUSH_MACROS
  27 #include <__undef_macros>
  28
  29 #if _LIBCPP_STD_VER >= 20
  30
  31 _LIBCPP_BEGIN_NAMESPACE_STD
  32
  33 namespace ranges {
  34 struct __is_partitioned {
  35   template <class _Iter, class _Sent, class _Proj, class _Pred>
  36   _LIBCPP_HIDE_FROM_ABI constexpr static bool
  37   __is_partitioned_impl(_Iter __first, _Sent __last, _Pred& __pred, _Proj& __proj) {
  38     for (; __first != __last; ++__first) {
  39       if (!std::invoke(__pred, std::invoke(__proj, *__first)))
  40         break;
  41     }
  42
  43     if (__first == __last)
  44       return true;
  45     ++__first;
  46
  47     for (; __first != __last; ++__first) {
  48       if (std::invoke(__pred, std::invoke(__proj, *__first)))
  49         return false;
  50     }
  51
  52     return true;
  53   }
  54
  55   template <input_iterator _Iter,
  56             sentinel_for<_Iter> _Sent,
  57             class _Proj = identity,
  58             indirect_unary_predicate<projected<_Iter, _Proj>> _Pred>
  59   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr bool
  60   operator()(_Iter __first, _Sent __last, _Pred __pred, _Proj __proj = {}) const {
  61     return __is_partitioned_impl(std::move(__first), std::move(__last), __pred, __proj);
  62   }
  63
  64   template <input_range _Range,
  65             class _Proj = identity,
  66             indirect_unary_predicate<projected<iterator_t<_Range>, _Proj>> _Pred>
  67   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr bool
  68   operator()(_Range&& __range, _Pred __pred, _Proj __proj = {}) const {
  69     return __is_partitioned_impl(ranges::begin(__range), ranges::end(__range), __pred, __proj);
  70   }
  71 };
  72
  73 inline namespace __cpo {
  74 inline constexpr auto is_partitioned = __is_partitioned{};
  75 } // namespace __cpo
  76 } // namespace ranges
  77
  78 _LIBCPP_END_NAMESPACE_STD
  79
  80 #endif // _LIBCPP_STD_VER >= 20
  81
  82 _LIBCPP_POP_MACROS
  83
  84 #endif // _LIBCPP___ALGORITHM_RANGES_IS_PARTITIONED_H