libcxx/include/__ranges/owning_view.h

// -*- 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_OWNING_VIEW_H
#define _LIBCPP___RANGES_OWNING_VIEW_H

#include <__concepts/constructible.h>
#include <__concepts/movable.h>
#include <__config>
#include <__ranges/access.h>
#include <__ranges/concepts.h>
#include <__ranges/data.h>
#include <__ranges/empty.h>
#include <__ranges/enable_borrowed_range.h>
#include <__ranges/size.h>
#include <__ranges/view_interface.h>
#include <__utility/move.h>
#include <type_traits>

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

_LIBCPP_BEGIN_NAMESPACE_STD

#if _LIBCPP_STD_VER > 17

namespace ranges {
  template<range _Rp>
    requires movable<_Rp> && (!__is_std_initializer_list<remove_cvref_t<_Rp>>)
  class owning_view : public view_interface<owning_view<_Rp>> {
    _Rp __r_ = _Rp();

public:
    owning_view() requires default_initializable<_Rp> = default;
    _LIBCPP_HIDE_FROM_ABI constexpr owning_view(_Rp&& __r) : __r_(std::move(__r)) {}

    owning_view(owning_view&&) = default;
    owning_view& operator=(owning_view&&) = default;

    _LIBCPP_HIDE_FROM_ABI constexpr _Rp& base() & noexcept { return __r_; }
    _LIBCPP_HIDE_FROM_ABI constexpr const _Rp& base() const& noexcept { return __r_; }
    _LIBCPP_HIDE_FROM_ABI constexpr _Rp&& base() && noexcept { return std::move(__r_); }
    _LIBCPP_HIDE_FROM_ABI constexpr const _Rp&& base() const&& noexcept { return std::move(__r_); }

    _LIBCPP_HIDE_FROM_ABI constexpr iterator_t<_Rp> begin() { return ranges::begin(__r_); }
    _LIBCPP_HIDE_FROM_ABI constexpr sentinel_t<_Rp> end() { return ranges::end(__r_); }
    _LIBCPP_HIDE_FROM_ABI constexpr auto begin() const requires range<const _Rp> { return ranges::begin(__r_); }
    _LIBCPP_HIDE_FROM_ABI constexpr auto end() const requires range<const _Rp> { return ranges::end(__r_); }

    _LIBCPP_HIDE_FROM_ABI constexpr bool empty() requires requires { ranges::empty(__r_); }
      { return ranges::empty(__r_); }
    _LIBCPP_HIDE_FROM_ABI constexpr bool empty() const requires requires { ranges::empty(__r_); }
      { return ranges::empty(__r_); }

    _LIBCPP_HIDE_FROM_ABI constexpr auto size() requires sized_range<_Rp>
      { return ranges::size(__r_); }
    _LIBCPP_HIDE_FROM_ABI constexpr auto size() const requires sized_range<const _Rp>
      { return ranges::size(__r_); }

    _LIBCPP_HIDE_FROM_ABI constexpr auto data() requires contiguous_range<_Rp>
      { return ranges::data(__r_); }
    _LIBCPP_HIDE_FROM_ABI constexpr auto data() const requires contiguous_range<const _Rp>
      { return ranges::data(__r_); }
  };
  _LIBCPP_CTAD_SUPPORTED_FOR_TYPE(owning_view);

  template<class _Tp>
  inline constexpr bool enable_borrowed_range<owning_view<_Tp>> = enable_borrowed_range<_Tp>;

} // namespace ranges

#endif // _LIBCPP_STD_VER > 17

_LIBCPP_END_NAMESPACE_STD

#endif // _LIBCPP___RANGES_OWNING_VIEW_H