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 #if _LIBCPP_STD_VER >= 20
  27
  28 _LIBCPP_BEGIN_NAMESPACE_STD
  29
  30 namespace ranges {
  31 namespace __is_partitioned {
  32 struct __fn {
  33   template <class _Iter, class _Sent, class _Proj, class _Pred>
  34   _LIBCPP_HIDE_FROM_ABI constexpr static bool
  35   __is_partitioned_impl(_Iter __first, _Sent __last, _Pred& __pred, _Proj& __proj) {
  36     for (; __first != __last; ++__first) {
  37       if (!std::invoke(__pred, std::invoke(__proj, *__first)))
  38         break;
  39     }
  40
  41     if (__first == __last)
  42       return true;
  43     ++__first;
  44
  45     for (; __first != __last; ++__first) {
  46       if (std::invoke(__pred, std::invoke(__proj, *__first)))
  47         return false;
  48     }
  49
  50     return true;
  51   }
  52
  53   template <input_iterator _Iter,
  54             sentinel_for<_Iter> _Sent,
  55             class _Proj = identity,
  56             indirect_unary_predicate<projected<_Iter, _Proj>> _Pred>
  57   _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr bool
  58   operator()(_Iter __first, _Sent __last, _Pred __pred, _Proj __proj = {}) const {
  59     return __is_partitioned_impl(std::move(__first), std::move(__last), __pred, __proj);
  60   }
  61
  62   template <input_range _Range,
  63             class _Proj = identity,
  64             indirect_unary_predicate<projected<iterator_t<_Range>, _Proj>> _Pred>
  65   _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr bool
  66   operator()(_Range&& __range, _Pred __pred, _Proj __proj = {}) const {
  67     return __is_partitioned_impl(ranges::begin(__range), ranges::end(__range), __pred, __proj);
  68   }
  69 };
  70 } // namespace __is_partitioned
  71
  72 inline namespace __cpo {
  73 inline constexpr auto is_partitioned = __is_partitioned::__fn{};
  74 } // namespace __cpo
  75 } // namespace ranges
  76
  77 _LIBCPP_END_NAMESPACE_STD
  78
  79 #endif // _LIBCPP_STD_VER >= 20
  80
  81 #endif // _LIBCPP___ALGORITHM_RANGES_IS_PARTITIONED_H