libcxx/include/__cxx03/__algorithm/ranges_adjacent_find.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_ADJACENT_FIND_H
  10 #define _LIBCPP___ALGORITHM_RANGES_ADJACENT_FIND_H
  11
  12 #include <__cxx03/__config>
  13 #include <__cxx03/__functional/identity.h>
  14 #include <__cxx03/__functional/invoke.h>
  15 #include <__cxx03/__functional/ranges_operations.h>
  16 #include <__cxx03/__iterator/concepts.h>
  17 #include <__cxx03/__iterator/projected.h>
  18 #include <__cxx03/__ranges/access.h>
  19 #include <__cxx03/__ranges/concepts.h>
  20 #include <__cxx03/__ranges/dangling.h>
  21 #include <__cxx03/__utility/move.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 <__cxx03/__undef_macros>
  29
  30 #if _LIBCPP_STD_VER >= 20
  31
  32 _LIBCPP_BEGIN_NAMESPACE_STD
  33
  34 namespace ranges {
  35 namespace __adjacent_find {
  36 struct __fn {
  37   template <class _Iter, class _Sent, class _Proj, class _Pred>
  38   _LIBCPP_HIDE_FROM_ABI constexpr static _Iter
  39   __adjacent_find_impl(_Iter __first, _Sent __last, _Pred& __pred, _Proj& __proj) {
  40     if (__first == __last)
  41       return __first;
  42
  43     auto __i = __first;
  44     while (++__i != __last) {
  45       if (std::invoke(__pred, std::invoke(__proj, *__first), std::invoke(__proj, *__i)))
  46         return __first;
  47       __first = __i;
  48     }
  49     return __i;
  50   }
  51
  52   template <forward_iterator _Iter,
  53             sentinel_for<_Iter> _Sent,
  54             class _Proj                                                                       = identity,
  55             indirect_binary_predicate<projected<_Iter, _Proj>, projected<_Iter, _Proj>> _Pred = ranges::equal_to>
  56   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Iter
  57   operator()(_Iter __first, _Sent __last, _Pred __pred = {}, _Proj __proj = {}) const {
  58     return __adjacent_find_impl(std::move(__first), std::move(__last), __pred, __proj);
  59   }
  60
  61   template <forward_range _Range,
  62             class _Proj = identity,
  63             indirect_binary_predicate<projected<iterator_t<_Range>, _Proj>, projected<iterator_t<_Range>, _Proj>>
  64                 _Pred = ranges::equal_to>
  65   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr borrowed_iterator_t<_Range>
  66   operator()(_Range&& __range, _Pred __pred = {}, _Proj __proj = {}) const {
  67     return __adjacent_find_impl(ranges::begin(__range), ranges::end(__range), __pred, __proj);
  68   }
  69 };
  70 } // namespace __adjacent_find
  71
  72 inline namespace __cpo {
  73 inline constexpr auto adjacent_find = __adjacent_find::__fn{};
  74 } // namespace __cpo
  75 } // namespace ranges
  76
  77 _LIBCPP_END_NAMESPACE_STD
  78
  79 #endif // _LIBCPP_STD_VER >= 20
  80
  81 _LIBCPP_POP_MACROS
  82
  83 #endif // _LIBCPP___ALGORITHM_RANGES_ADJACENT_FIND_H