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/// \file
// Range v3 library
//
// Copyright Eric Niebler 2013-present
//
// Use, modification and distribution is subject to the
// Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//
// Project home: https://github.com/ericniebler/range-v3
//
#ifndef RANGES_V3_VIEW_DROP_WHILE_HPP
#define RANGES_V3_VIEW_DROP_WHILE_HPP
#include <utility>
#include <meta/meta.hpp>
#include <range/v3/range_fwd.hpp>
#include <range/v3/algorithm/find_if_not.hpp>
#include <range/v3/functional/bind_back.hpp>
#include <range/v3/functional/compose.hpp>
#include <range/v3/range/concepts.hpp>
#include <range/v3/range/traits.hpp>
#include <range/v3/utility/optional.hpp>
#include <range/v3/utility/semiregular_box.hpp>
#include <range/v3/utility/static_const.hpp>
#include <range/v3/view/all.hpp>
#include <range/v3/view/interface.hpp>
#include <range/v3/view/view.hpp>
#include <range/v3/detail/prologue.hpp>
namespace ranges
{
/// \addtogroup group-views
/// @{
template<typename Rng, typename Pred>
struct drop_while_view
: view_interface<drop_while_view<Rng, Pred>,
is_finite<Rng>::value ? finite : unknown>
{
private:
Rng rng_;
RANGES_NO_UNIQUE_ADDRESS semiregular_box_t<Pred> pred_;
detail::non_propagating_cache<iterator_t<Rng>> begin_;
iterator_t<Rng> get_begin_()
{
if(!begin_)
begin_ = find_if_not(rng_, std::ref(pred_));
return *begin_;
}
public:
drop_while_view() = default;
drop_while_view(Rng rng, Pred pred)
: rng_(std::move(rng))
, pred_(std::move(pred))
{}
iterator_t<Rng> begin()
{
return get_begin_();
}
sentinel_t<Rng> end()
{
return ranges::end(rng_);
}
Rng base() const
{
return rng_;
}
};
// unlike take_while_view, drop_while_view is transparently safe because we only
// need the predicate to find begin()
template<typename Rng, typename Pred>
RANGES_INLINE_VAR constexpr bool enable_borrowed_range<drop_while_view<Rng, Pred>> =
enable_borrowed_range<Rng>;
#if RANGES_CXX_DEDUCTION_GUIDES >= RANGES_CXX_DEDUCTION_GUIDES_17
template(typename Rng, typename Fun)(
requires copy_constructible<Fun>)
drop_while_view(Rng &&, Fun)
-> drop_while_view<views::all_t<Rng>, Fun>;
#endif
template<typename Rng, typename Pred>
RANGES_INLINE_VAR constexpr bool disable_sized_range<drop_while_view<Rng, Pred>> =
true;
namespace views
{
struct drop_while_base_fn
{
template(typename Rng, typename Pred)(
requires viewable_range<Rng> AND input_range<Rng> AND
indirect_unary_predicate<Pred, iterator_t<Rng>>)
auto operator()(Rng && rng, Pred pred) const
-> drop_while_view<all_t<Rng>, Pred>
{
return {all(static_cast<Rng &&>(rng)), std::move(pred)};
}
template(typename Rng, typename Pred, typename Proj)(
requires viewable_range<Rng> AND input_range<Rng> AND
indirect_unary_predicate<composed<Pred, Proj>, iterator_t<Rng>>)
auto operator()(Rng && rng, Pred pred, Proj proj) const
-> drop_while_view<all_t<Rng>, composed<Pred, Proj>>
{
return {all(static_cast<Rng &&>(rng)),
compose(std::move(pred), std::move(proj))};
}
};
struct drop_while_bind_fn
{
template<typename Pred>
constexpr auto operator()(Pred pred) const // TODO: underconstrained
{
return make_view_closure(
bind_back(drop_while_base_fn{}, std::move(pred)));
}
template(typename Pred, typename Proj)(
requires (!range<Pred>)) // TODO: underconstrained
constexpr auto operator()(Pred && pred, Proj proj) const
{
return make_view_closure(bind_back(
drop_while_base_fn{}, static_cast<Pred &&>(pred), std::move(proj)));
}
};
struct RANGES_EMPTY_BASES drop_while_fn
: drop_while_base_fn, drop_while_bind_fn
{
using drop_while_base_fn::operator();
using drop_while_bind_fn::operator();
};
/// \relates drop_while_fn
/// \ingroup group-views
RANGES_INLINE_VARIABLE(drop_while_fn, drop_while)
} // namespace views
namespace cpp20
{
namespace views
{
using ranges::views::drop_while;
}
template(typename Rng, typename Pred)(
requires viewable_range<Rng> AND input_range<Rng> AND
indirect_unary_predicate<Pred, iterator_t<Rng>>)
using drop_while_view = ranges::drop_while_view<Rng, Pred>;
} // namespace cpp20
/// @}
} // namespace ranges
#include <range/v3/detail/epilogue.hpp>
#include <range/v3/detail/satisfy_boost_range.hpp>
RANGES_SATISFY_BOOST_RANGE(::ranges::drop_while_view)
#endif
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