__cxx03/__algorithm/ranges_adjacent_find.h

0001 //===----------------------------------------------------------------------===//
0002 //
0003 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
0004 // See https://llvm.org/LICENSE.txt for license information.
0005 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
0006 //
0007 //===----------------------------------------------------------------------===//
0008
0009 #ifndef _LIBCPP___CXX03___ALGORITHM_RANGES_ADJACENT_FIND_H
0010 #define _LIBCPP___CXX03___ALGORITHM_RANGES_ADJACENT_FIND_H
0011
0012 #include <__cxx03/__config>
0013 #include <__cxx03/__functional/identity.h>
0014 #include <__cxx03/__functional/invoke.h>
0015 #include <__cxx03/__functional/ranges_operations.h>
0016 #include <__cxx03/__iterator/concepts.h>
0017 #include <__cxx03/__iterator/projected.h>
0018 #include <__cxx03/__ranges/access.h>
0019 #include <__cxx03/__ranges/concepts.h>
0020 #include <__cxx03/__ranges/dangling.h>
0021 #include <__cxx03/__utility/move.h>
0022
0023 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
0024 #  pragma GCC system_header
0025 #endif
0026
0027 _LIBCPP_PUSH_MACROS
0028 #include <__cxx03/__undef_macros>
0029
0030 #if _LIBCPP_STD_VER >= 20
0031
0032 _LIBCPP_BEGIN_NAMESPACE_STD
0033
0034 namespace ranges {
0035 namespace __adjacent_find {
0036 struct __fn {
0037   template <class _Iter, class _Sent, class _Proj, class _Pred>
0038   _LIBCPP_HIDE_FROM_ABI constexpr static _Iter
0039   __adjacent_find_impl(_Iter __first, _Sent __last, _Pred& __pred, _Proj& __proj) {
0040     if (__first == __last)
0041       return __first;
0042
0043     auto __i = __first;
0044     while (++__i != __last) {
0045       if (std::invoke(__pred, std::invoke(__proj, *__first), std::invoke(__proj, *__i)))
0046         return __first;
0047       __first = __i;
0048     }
0049     return __i;
0050   }
0051
0052   template <forward_iterator _Iter,
0053             sentinel_for<_Iter> _Sent,
0054             class _Proj                                                                       = identity,
0055             indirect_binary_predicate<projected<_Iter, _Proj>, projected<_Iter, _Proj>> _Pred = ranges::equal_to>
0056   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Iter
0057   operator()(_Iter __first, _Sent __last, _Pred __pred = {}, _Proj __proj = {}) const {
0058     return __adjacent_find_impl(std::move(__first), std::move(__last), __pred, __proj);
0059   }
0060
0061   template <forward_range _Range,
0062             class _Proj = identity,
0063             indirect_binary_predicate<projected<iterator_t<_Range>, _Proj>, projected<iterator_t<_Range>, _Proj>>
0064                 _Pred = ranges::equal_to>
0065   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr borrowed_iterator_t<_Range>
0066   operator()(_Range&& __range, _Pred __pred = {}, _Proj __proj = {}) const {
0067     return __adjacent_find_impl(ranges::begin(__range), ranges::end(__range), __pred, __proj);
0068   }
0069 };
0070 } // namespace __adjacent_find
0071
0072 inline namespace __cpo {
0073 inline constexpr auto adjacent_find = __adjacent_find::__fn{};
0074 } // namespace __cpo
0075 } // namespace ranges
0076
0077 _LIBCPP_END_NAMESPACE_STD
0078
0079 #endif // _LIBCPP_STD_VER >= 20
0080
0081 _LIBCPP_POP_MACROS
0082
0083 #endif // _LIBCPP___CXX03___ALGORITHM_RANGES_ADJACENT_FIND_H