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/// \file
// Range v3 library
//
// Copyright Filip Matzner 2017
//
// 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_EXPERIMENTAL_VIEW_SHARED_HPP
#define RANGES_V3_EXPERIMENTAL_VIEW_SHARED_HPP
#include <memory>
#include <type_traits>
#include <meta/meta.hpp>
#include <range/v3/functional/compose.hpp>
#include <range/v3/range/access.hpp>
#include <range/v3/range/concepts.hpp>
#include <range/v3/range/primitives.hpp>
#include <range/v3/view/all.hpp>
#include <range/v3/detail/prologue.hpp>
namespace ranges
{
/// \addtogroup group-views
/// @{
namespace experimental
{
template<typename Rng>
struct shared_view
: view_interface<shared_view<Rng>, range_cardinality<Rng>::value>
{
private:
// shared storage
std::shared_ptr<Rng> rng_ptr_;
public:
shared_view() = default;
// construct from a range rvalue
explicit shared_view(Rng rng)
: rng_ptr_{std::make_shared<Rng>(std::move(rng))}
{}
// use the stored range's begin and end
iterator_t<Rng> begin() const
{
return ranges::begin(*rng_ptr_);
}
sentinel_t<Rng> end() const
{
return ranges::end(*rng_ptr_);
}
CPP_auto_member
auto CPP_fun(size)()(const
requires sized_range<Rng>)
{
return ranges::size(*rng_ptr_);
}
};
template<typename SharedFn>
struct shared_closure;
struct RANGES_STRUCT_WITH_ADL_BARRIER(shared_closure_base)
{
// Piping requires viewable_ranges.
template(typename Rng, typename SharedFn)(
requires range<Rng> AND (!viewable_range<Rng>) AND
constructible_from<detail::decay_t<Rng>, Rng>)
friend constexpr auto operator|(Rng && rng, shared_closure<SharedFn> vw)
{
return static_cast<SharedFn &&>(vw)(static_cast<Rng &&>(rng));
}
template<typename SharedFn, typename Pipeable>
friend constexpr auto operator|(shared_closure<SharedFn> sh, Pipeable pipe)
-> CPP_broken_friend_ret(shared_closure<composed<Pipeable, SharedFn>>)(
requires (is_pipeable_v<Pipeable>))
{
return shared_closure<composed<Pipeable, SharedFn>>{compose(
static_cast<Pipeable &&>(pipe), static_cast<SharedFn &&>(sh))};
}
};
template<typename SharedFn>
struct shared_closure
: shared_closure_base
, SharedFn
{
shared_closure() = default;
constexpr explicit shared_closure(SharedFn fn)
: SharedFn(static_cast<SharedFn &&>(fn))
{}
};
namespace views
{
struct shared_fn
{
template(typename Rng)(
requires range<Rng> AND (!viewable_range<Rng>)AND
constructible_from<detail::decay_t<Rng>, Rng>)
shared_view<detail::decay_t<Rng>> operator()(Rng && rng) const
{
return shared_view<detail::decay_t<Rng>>{static_cast<Rng &&>(rng)};
}
};
/// \relates shared_fn
/// \ingroup group-views
RANGES_INLINE_VARIABLE(shared_closure<shared_fn>, shared)
} // namespace views
} // namespace experimental
template<typename SharedFn>
RANGES_INLINE_VAR constexpr bool
is_pipeable_v<experimental::shared_closure<SharedFn>> = true;
/// @}
} // namespace ranges
#include <range/v3/detail/epilogue.hpp>
#endif
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