experimental/memory
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// <experimental/memory> -*- C++ -*-
// Copyright (C) 2015-2023 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
/** @file experimental/memory
* This is a TS C++ Library header.
* @ingroup libfund-ts
*/
//
// N4336 Working Draft, C++ Extensions for Library Fundamentals, Version 2
//
#ifndef _GLIBCXX_EXPERIMENTAL_MEMORY
#define _GLIBCXX_EXPERIMENTAL_MEMORY 1
#pragma GCC system_header
#include <bits/requires_hosted.h> // experimental is currently omitted
#if __cplusplus >= 201402L
#include <memory>
#include <type_traits>
#include <experimental/bits/shared_ptr.h>
#include <bits/functional_hash.h>
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
namespace experimental
{
inline namespace fundamentals_v2
{
#define __cpp_lib_experimental_observer_ptr 201411
template <typename _Tp>
class observer_ptr
{
public:
// publish our template parameter and variations thereof
using element_type = _Tp;
using __pointer = add_pointer_t<_Tp>; // exposition-only
using __reference = add_lvalue_reference_t<_Tp>; // exposition-only
// 3.2.2, observer_ptr constructors
// default c'tor
constexpr observer_ptr() noexcept
: __t()
{ }
// pointer-accepting c'tors
constexpr observer_ptr(nullptr_t) noexcept
: __t()
{ }
constexpr explicit observer_ptr(__pointer __p) noexcept
: __t(__p)
{ }
// copying c'tors (in addition to compiler-generated copy c'tor)
template <typename _Up,
typename = typename enable_if<
is_convertible<typename add_pointer<_Up>::type, __pointer
>::value
>::type>
constexpr observer_ptr(observer_ptr<_Up> __p) noexcept
: __t(__p.get())
{
}
// 3.2.3, observer_ptr observers
constexpr __pointer
get() const noexcept
{
return __t;
}
constexpr __reference
operator*() const
{
return *get();
}
constexpr __pointer
operator->() const noexcept
{
return get();
}
constexpr explicit operator bool() const noexcept
{
return get() != nullptr;
}
// 3.2.4, observer_ptr conversions
constexpr explicit operator __pointer() const noexcept
{
return get();
}
// 3.2.5, observer_ptr modifiers
constexpr __pointer
release() noexcept
{
__pointer __tmp = get();
reset();
return __tmp;
}
constexpr void
reset(__pointer __p = nullptr) noexcept
{
__t = __p;
}
constexpr void
swap(observer_ptr& __p) noexcept
{
std::swap(__t, __p.__t);
}
private:
__pointer __t;
}; // observer_ptr<>
template<typename _Tp>
void
swap(observer_ptr<_Tp>& __p1, observer_ptr<_Tp>& __p2) noexcept
{
__p1.swap(__p2);
}
template<typename _Tp>
observer_ptr<_Tp>
make_observer(_Tp* __p) noexcept
{
return observer_ptr<_Tp>(__p);
}
template<typename _Tp, typename _Up>
bool
operator==(observer_ptr<_Tp> __p1, observer_ptr<_Up> __p2)
{
return __p1.get() == __p2.get();
}
template<typename _Tp, typename _Up>
bool
operator!=(observer_ptr<_Tp> __p1, observer_ptr<_Up> __p2)
{
return !(__p1 == __p2);
}
template<typename _Tp>
bool
operator==(observer_ptr<_Tp> __p, nullptr_t) noexcept
{
return !__p;
}
template<typename _Tp>
bool
operator==(nullptr_t, observer_ptr<_Tp> __p) noexcept
{
return !__p;
}
template<typename _Tp>
bool
operator!=(observer_ptr<_Tp> __p, nullptr_t) noexcept
{
return bool(__p);
}
template<typename _Tp>
bool
operator!=(nullptr_t, observer_ptr<_Tp> __p) noexcept
{
return bool(__p);
}
template<typename _Tp, typename _Up>
bool
operator<(observer_ptr<_Tp> __p1, observer_ptr<_Up> __p2)
{
return std::less<typename common_type<typename add_pointer<_Tp>::type,
typename add_pointer<_Up>::type
>::type
>{}(__p1.get(), __p2.get());
}
template<typename _Tp, typename _Up>
bool
operator>(observer_ptr<_Tp> __p1, observer_ptr<_Up> __p2)
{
return __p2 < __p1;
}
template<typename _Tp, typename _Up>
bool
operator<=(observer_ptr<_Tp> __p1, observer_ptr<_Up> __p2)
{
return !(__p2 < __p1);
}
template<typename _Tp, typename _Up>
bool
operator>=(observer_ptr<_Tp> __p1, observer_ptr<_Up> __p2)
{
return !(__p1 < __p2);
}
} // namespace fundamentals_v2
} // namespace experimental
template <typename _Tp>
struct hash<experimental::observer_ptr<_Tp>>
{
using result_type = size_t;
using argument_type = experimental::observer_ptr<_Tp>;
size_t
operator()(const experimental::observer_ptr<_Tp>& __t) const
noexcept(noexcept(hash<typename add_pointer<_Tp>::type> {}(__t.get())))
{
return hash<typename add_pointer<_Tp>::type> {}(__t.get());
}
};
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
#endif // __cplusplus <= 201103L
#endif // _GLIBCXX_EXPERIMENTAL_MEMORY