//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#ifndef _LIBCPP___CXX03___ALGORITHM_RANGES_REMOVE_IF_H
#define _LIBCPP___CXX03___ALGORITHM_RANGES_REMOVE_IF_H
#include <__cxx03/__config>

#include <__cxx03/__algorithm/ranges_find_if.h>
#include <__cxx03/__functional/identity.h>
#include <__cxx03/__functional/invoke.h>
#include <__cxx03/__functional/ranges_operations.h>
#include <__cxx03/__iterator/concepts.h>
#include <__cxx03/__iterator/iter_move.h>
#include <__cxx03/__iterator/permutable.h>
#include <__cxx03/__iterator/projected.h>
#include <__cxx03/__ranges/access.h>
#include <__cxx03/__ranges/concepts.h>
#include <__cxx03/__ranges/subrange.h>
#include <__cxx03/__utility/move.h>

#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#  pragma GCC system_header
#endif

_LIBCPP_PUSH_MACROS
#include <__cxx03/__undef_macros>

#if _LIBCPP_STD_VER >= 20

_LIBCPP_BEGIN_NAMESPACE_STD

namespace ranges {

template <class _Iter, class _Sent, class _Proj, class _Pred>
_LIBCPP_HIDE_FROM_ABI constexpr subrange<_Iter>
__remove_if_impl(_Iter __first, _Sent __last, _Pred& __pred, _Proj& __proj) {
  auto __new_end = ranges::__find_if_impl(__first, __last, __pred, __proj);
  if (__new_end == __last)
    return {__new_end, __new_end};

  _Iter __i = __new_end;
  while (++__i != __last) {
    if (!std::invoke(__pred, std::invoke(__proj, *__i))) {
      *__new_end = ranges::iter_move(__i);
      ++__new_end;
    }
  }
  return {__new_end, __i};
}

namespace __remove_if {
struct __fn {
  template <permutable _Iter,
            sentinel_for<_Iter> _Sent,
            class _Proj = identity,
            indirect_unary_predicate<projected<_Iter, _Proj>> _Pred>
  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr subrange<_Iter>
  operator()(_Iter __first, _Sent __last, _Pred __pred, _Proj __proj = {}) const {
    return ranges::__remove_if_impl(std::move(__first), std::move(__last), __pred, __proj);
  }

  template <forward_range _Range,
            class _Proj = identity,
            indirect_unary_predicate<projected<iterator_t<_Range>, _Proj>> _Pred>
    requires permutable<iterator_t<_Range>>
  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr borrowed_subrange_t<_Range>
  operator()(_Range&& __range, _Pred __pred, _Proj __proj = {}) const {
    return ranges::__remove_if_impl(ranges::begin(__range), ranges::end(__range), __pred, __proj);
  }
};
} // namespace __remove_if

inline namespace __cpo {
inline constexpr auto remove_if = __remove_if::__fn{};
} // namespace __cpo
} // namespace ranges

_LIBCPP_END_NAMESPACE_STD

#endif // _LIBCPP_STD_VER >= 20

_LIBCPP_POP_MACROS

#endif // _LIBCPP___CXX03___ALGORITHM_RANGES_REMOVE_IF_H
