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// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// 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___RANGES_DROP_WHILE_VIEW_H
#define _LIBCPP___RANGES_DROP_WHILE_VIEW_H
#include <__algorithm/ranges_find_if_not.h>
#include <__assert>
#include <__concepts/constructible.h>
#include <__config>
#include <__functional/bind_back.h>
#include <__functional/reference_wrapper.h>
#include <__iterator/concepts.h>
#include <__ranges/access.h>
#include <__ranges/all.h>
#include <__ranges/concepts.h>
#include <__ranges/enable_borrowed_range.h>
#include <__ranges/movable_box.h>
#include <__ranges/non_propagating_cache.h>
#include <__ranges/range_adaptor.h>
#include <__ranges/view_interface.h>
#include <__type_traits/conditional.h>
#include <__type_traits/decay.h>
#include <__type_traits/is_nothrow_constructible.h>
#include <__type_traits/is_object.h>
#include <__utility/forward.h>
#include <__utility/in_place.h>
#include <__utility/move.h>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_PUSH_MACROS
#include <__undef_macros>
_LIBCPP_BEGIN_NAMESPACE_STD
#if _LIBCPP_STD_VER >= 20
namespace ranges {
template <view _View, class _Pred>
requires input_range<_View> && is_object_v<_Pred> && indirect_unary_predicate<const _Pred, iterator_t<_View>>
class _LIBCPP_ABI_LLVM18_NO_UNIQUE_ADDRESS drop_while_view : public view_interface<drop_while_view<_View, _Pred>> {
public:
_LIBCPP_HIDE_FROM_ABI drop_while_view()
requires default_initializable<_View> && default_initializable<_Pred>
= default;
_LIBCPP_HIDE_FROM_ABI constexpr _LIBCPP_EXPLICIT_SINCE_CXX23 drop_while_view(_View __base, _Pred __pred)
: __base_(std::move(__base)), __pred_(std::in_place, std::move(__pred)) {}
_LIBCPP_HIDE_FROM_ABI constexpr _View base() const&
requires copy_constructible<_View>
{
return __base_;
}
_LIBCPP_HIDE_FROM_ABI constexpr _View base() && { return std::move(__base_); }
_LIBCPP_HIDE_FROM_ABI constexpr const _Pred& pred() const { return *__pred_; }
_LIBCPP_HIDE_FROM_ABI constexpr auto begin() {
// Note: this duplicates a check in `optional` but provides a better error message.
_LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
__pred_.__has_value(),
"drop_while_view needs to have a non-empty predicate before calling begin() -- did a previous "
"assignment to this drop_while_view fail?");
if constexpr (_UseCache) {
if (!__cached_begin_.__has_value()) {
__cached_begin_.__emplace(ranges::find_if_not(__base_, std::cref(*__pred_)));
}
return *__cached_begin_;
} else {
return ranges::find_if_not(__base_, std::cref(*__pred_));
}
}
_LIBCPP_HIDE_FROM_ABI constexpr auto end() { return ranges::end(__base_); }
private:
_LIBCPP_NO_UNIQUE_ADDRESS _View __base_ = _View();
_LIBCPP_NO_UNIQUE_ADDRESS __movable_box<_Pred> __pred_;
static constexpr bool _UseCache = forward_range<_View>;
using _Cache = _If<_UseCache, __non_propagating_cache<iterator_t<_View>>, __empty_cache>;
_LIBCPP_NO_UNIQUE_ADDRESS _Cache __cached_begin_ = _Cache();
};
template <class _View, class _Pred>
inline constexpr bool enable_borrowed_range<drop_while_view<_View, _Pred>> = enable_borrowed_range<_View>;
template <class _Range, class _Pred>
drop_while_view(_Range&&, _Pred) -> drop_while_view<views::all_t<_Range>, _Pred>;
namespace views {
namespace __drop_while {
struct __fn {
template <class _Range, class _Pred>
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Range&& __range, _Pred&& __pred) const
noexcept(noexcept(/**/ drop_while_view(std::forward<_Range>(__range), std::forward<_Pred>(__pred))))
-> decltype(/*--*/ drop_while_view(std::forward<_Range>(__range), std::forward<_Pred>(__pred))) {
return /*-------------*/ drop_while_view(std::forward<_Range>(__range), std::forward<_Pred>(__pred));
}
template <class _Pred>
requires constructible_from<decay_t<_Pred>, _Pred>
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Pred&& __pred) const
noexcept(is_nothrow_constructible_v<decay_t<_Pred>, _Pred>) {
return __range_adaptor_closure_t(std::__bind_back(*this, std::forward<_Pred>(__pred)));
}
};
} // namespace __drop_while
inline namespace __cpo {
inline constexpr auto drop_while = __drop_while::__fn{};
} // namespace __cpo
} // namespace views
} // namespace ranges
#endif // _LIBCPP_STD_VER >= 20
_LIBCPP_END_NAMESPACE_STD
_LIBCPP_POP_MACROS
#endif // _LIBCPP___RANGES_DROP_WHILE_VIEW_H