libcxx/include/__algorithm/ranges_find_if.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_FIND_IF_H
  10 #define _LIBCPP___ALGORITHM_RANGES_FIND_IF_H
  11
  12 #include <__config>
  13 #include <__functional/identity.h>
  14 #include <__functional/invoke.h>
  15 #include <__functional/ranges_operations.h>
  16 #include <__iterator/concepts.h>
  17 #include <__iterator/projected.h>
  18 #include <__ranges/access.h>
  19 #include <__ranges/concepts.h>
  20 #include <__ranges/dangling.h>
  21 #include <__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 <__undef_macros>
  29
  30 #if _LIBCPP_STD_VER >= 20
  31
  32 _LIBCPP_BEGIN_NAMESPACE_STD
  33
  34 namespace ranges {
  35
  36 template <class _Ip, class _Sp, class _Pred, class _Proj>
  37 _LIBCPP_HIDE_FROM_ABI constexpr _Ip __find_if_impl(_Ip __first, _Sp __last, _Pred& __pred, _Proj& __proj) {
  38   for (; __first != __last; ++__first) {
  39     if (std::invoke(__pred, std::invoke(__proj, *__first)))
  40       break;
  41   }
  42   return __first;
  43 }
  44
  45 struct __find_if {
  46   template <input_iterator _Ip,
  47             sentinel_for<_Ip> _Sp,
  48             class _Proj = identity,
  49             indirect_unary_predicate<projected<_Ip, _Proj>> _Pred>
  50   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Ip
  51   operator()(_Ip __first, _Sp __last, _Pred __pred, _Proj __proj = {}) const {
  52     return ranges::__find_if_impl(std::move(__first), std::move(__last), __pred, __proj);
  53   }
  54
  55   template <input_range _Rp, class _Proj = identity, indirect_unary_predicate<projected<iterator_t<_Rp>, _Proj>> _Pred>
  56   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr borrowed_iterator_t<_Rp>
  57   operator()(_Rp&& __r, _Pred __pred, _Proj __proj = {}) const {
  58     return ranges::__find_if_impl(ranges::begin(__r), ranges::end(__r), __pred, __proj);
  59   }
  60 };
  61
  62 inline namespace __cpo {
  63 inline constexpr auto find_if = __find_if{};
  64 } // namespace __cpo
  65 } // namespace ranges
  66
  67 _LIBCPP_END_NAMESPACE_STD
  68
  69 #endif // _LIBCPP_STD_VER >= 20
  70
  71 _LIBCPP_POP_MACROS
  72
  73 #endif // _LIBCPP___ALGORITHM_RANGES_FIND_IF_H