libcxx/include/__algorithm/ranges_remove_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_REMOVE_IF_H
  10 #define _LIBCPP___ALGORITHM_RANGES_REMOVE_IF_H
  11 #include <__config>
  12
  13 #include <__algorithm/ranges_find_if.h>
  14 #include <__functional/identity.h>
  15 #include <__functional/invoke.h>
  16 #include <__functional/ranges_operations.h>
  17 #include <__iterator/concepts.h>
  18 #include <__iterator/iter_move.h>
  19 #include <__iterator/permutable.h>
  20 #include <__iterator/projected.h>
  21 #include <__ranges/access.h>
  22 #include <__ranges/concepts.h>
  23 #include <__ranges/subrange.h>
  24 #include <__utility/move.h>
  25
  26 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  27 #  pragma GCC system_header
  28 #endif
  29
  30 #if _LIBCPP_STD_VER >= 20
  31
  32 _LIBCPP_BEGIN_NAMESPACE_STD
  33
  34 namespace ranges {
  35
  36 template <class _Iter, class _Sent, class _Proj, class _Pred>
  37 _LIBCPP_HIDE_FROM_ABI constexpr subrange<_Iter>
  38 __remove_if_impl(_Iter __first, _Sent __last, _Pred& __pred, _Proj& __proj) {
  39   auto __new_end = ranges::__find_if_impl(__first, __last, __pred, __proj);
  40   if (__new_end == __last)
  41     return {__new_end, __new_end};
  42
  43   _Iter __i = __new_end;
  44   while (++__i != __last) {
  45     if (!std::invoke(__pred, std::invoke(__proj, *__i))) {
  46       *__new_end = ranges::iter_move(__i);
  47       ++__new_end;
  48     }
  49   }
  50   return {__new_end, __i};
  51 }
  52
  53 namespace __remove_if {
  54 struct __fn {
  55   template <permutable _Iter,
  56             sentinel_for<_Iter> _Sent,
  57             class _Proj = identity,
  58             indirect_unary_predicate<projected<_Iter, _Proj>> _Pred>
  59   _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr subrange<_Iter>
  60   operator()(_Iter __first, _Sent __last, _Pred __pred, _Proj __proj = {}) const {
  61     return ranges::__remove_if_impl(std::move(__first), std::move(__last), __pred, __proj);
  62   }
  63
  64   template <forward_range _Range,
  65             class _Proj = identity,
  66             indirect_unary_predicate<projected<iterator_t<_Range>, _Proj>> _Pred>
  67     requires permutable<iterator_t<_Range>>
  68   _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr borrowed_subrange_t<_Range>
  69   operator()(_Range&& __range, _Pred __pred, _Proj __proj = {}) const {
  70     return ranges::__remove_if_impl(ranges::begin(__range), ranges::end(__range), __pred, __proj);
  71   }
  72 };
  73 } // namespace __remove_if
  74
  75 inline namespace __cpo {
  76 inline constexpr auto remove_if = __remove_if::__fn{};
  77 } // namespace __cpo
  78 } // namespace ranges
  79
  80 _LIBCPP_END_NAMESPACE_STD
  81
  82 #endif // _LIBCPP_STD_VER >= 20
  83
  84 #endif // _LIBCPP___ALGORITHM_RANGES_REMOVE_IF_H