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// shared_ptr and weak_ptr implementation -*- C++ -*-

// Copyright (C) 2007, 2008, 2009, 2010, 2011 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/>.

// GCC Note: Based on files from version 1.32.0 of the Boost library.

//  shared_count.hpp

//  Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd.

//  shared_ptr.hpp

//  Copyright (C) 1998, 1999 Greg Colvin and Beman Dawes.

//  Copyright (C) 2001, 2002, 2003 Peter Dimov

//  weak_ptr.hpp

//  Copyright (C) 2001, 2002, 2003 Peter Dimov

//  enable_shared_from_this.hpp

//  Copyright (C) 2002 Peter Dimov

// Distributed under 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)

/** @file bits/shared_ptr.h

 *  This is an internal header file, included by other library headers.

 *  Do not attempt to use it directly. @headername{memory}

 */

#ifndef _SHARED_PTR_H

#define _SHARED_PTR_H 1

#include <bits/shared_ptr_base.h>

namespace std _GLIBCXX_VISIBILITY(default)

{

_GLIBCXX_BEGIN_NAMESPACE_VERSION

  /**

   * @addtogroup pointer_abstractions

   * @{

   */

  /// 2.2.3.7 shared_ptr I/O

  template<typename _Ch, typename _Tr, typename _Tp, _Lock_policy _Lp>

    inline std::basic_ostream<_Ch, _Tr>&

    operator<<(std::basic_ostream<_Ch, _Tr>& __os,

               const __shared_ptr<_Tp, _Lp>& __p)

    {

      __os << __p.get();

      return __os;

    }

  /// 2.2.3.10 shared_ptr get_deleter (experimental)

  template<typename _Del, typename _Tp, _Lock_policy _Lp>

    inline _Del*

    get_deleter(const __shared_ptr<_Tp, _Lp>& __p) noexcept

    {

#ifdef __GXX_RTTI

      return static_cast<_Del*>(__p._M_get_deleter(typeid(_Del)));

#else

      return 0;

#endif

    }

  /**

   *  @brief  A smart pointer with reference-counted copy semantics.

   *

   *  The object pointed to is deleted when the last shared_ptr pointing to

   *  it is destroyed or reset.

  */

  template<typename _Tp>

    class shared_ptr : public __shared_ptr<_Tp>

    {

    public:

      /**

       *  @brief  Construct an empty %shared_ptr.

       *  @post   use_count()==0 && get()==0

       */

      constexpr shared_ptr() noexcept

      : __shared_ptr<_Tp>() { }

      shared_ptr(const shared_ptr&) noexcept = default;

      /**

       *  @brief  Construct a %shared_ptr that owns the pointer @a __p.

       *  @param  __p  A pointer that is convertible to element_type*.

       *  @post   use_count() == 1 && get() == __p

       *  @throw  std::bad_alloc, in which case @c delete @a __p is called.

       */

      template<typename _Tp1>

        explicit shared_ptr(_Tp1* __p)

        : __shared_ptr<_Tp>(__p) { }

      /**

       *  @brief  Construct a %shared_ptr that owns the pointer @a __p

       *          and the deleter @a __d.

       *  @param  __p  A pointer.

       *  @param  __d  A deleter.

       *  @post   use_count() == 1 && get() == __p

       *  @throw  std::bad_alloc, in which case @a __d(__p) is called.

       *

       *  Requirements: _Deleter's copy constructor and destructor must

       *  not throw

       *

       *  __shared_ptr will release __p by calling __d(__p)

       */

      template<typename _Tp1, typename _Deleter>

        shared_ptr(_Tp1* __p, _Deleter __d)

        : __shared_ptr<_Tp>(__p, __d) { }

      /**

       *  @brief  Construct a %shared_ptr that owns a null pointer

       *          and the deleter @a __d.

       *  @param  __p  A null pointer constant.

       *  @param  __d  A deleter.

       *  @post   use_count() == 1 && get() == __p

       *  @throw  std::bad_alloc, in which case @a __d(__p) is called.

       *

       *  Requirements: _Deleter's copy constructor and destructor must

       *  not throw

       *

       *  The last owner will call __d(__p)

       */

      template<typename _Deleter>

        shared_ptr(nullptr_t __p, _Deleter __d)

        : __shared_ptr<_Tp>(__p, __d) { }

      /**

       *  @brief  Construct a %shared_ptr that owns the pointer @a __p

       *          and the deleter @a __d.

       *  @param  __p  A pointer.

       *  @param  __d  A deleter.

       *  @param  __a  An allocator.

       *  @post   use_count() == 1 && get() == __p

       *  @throw  std::bad_alloc, in which case @a __d(__p) is called.

       *

       *  Requirements: _Deleter's copy constructor and destructor must

       *  not throw _Alloc's copy constructor and destructor must not

       *  throw.

       *

       *  __shared_ptr will release __p by calling __d(__p)

       */

      template<typename _Tp1, typename _Deleter, typename _Alloc>

        shared_ptr(_Tp1* __p, _Deleter __d, _Alloc __a)

        : __shared_ptr<_Tp>(__p, __d, std::move(__a)) { }

      /**

       *  @brief  Construct a %shared_ptr that owns a null pointer

       *          and the deleter @a __d.

       *  @param  __p  A null pointer constant.

       *  @param  __d  A deleter.

       *  @param  __a  An allocator.

       *  @post   use_count() == 1 && get() == __p

       *  @throw  std::bad_alloc, in which case @a __d(__p) is called.

       *

       *  Requirements: _Deleter's copy constructor and destructor must

       *  not throw _Alloc's copy constructor and destructor must not

       *  throw.

       *

       *  The last owner will call __d(__p)

       */

      template<typename _Deleter, typename _Alloc>

        shared_ptr(nullptr_t __p, _Deleter __d, _Alloc __a)

        : __shared_ptr<_Tp>(__p, __d, std::move(__a)) { }

      // Aliasing constructor

      /**

       *  @brief  Constructs a %shared_ptr instance that stores @a __p

       *          and shares ownership with @a __r.

       *  @param  __r  A %shared_ptr.

       *  @param  __p  A pointer that will remain valid while @a *__r is valid.

       *  @post   get() == __p && use_count() == __r.use_count()

       *

       *  This can be used to construct a @c shared_ptr to a sub-object

       *  of an object managed by an existing @c shared_ptr.

       *

       * @code

       * shared_ptr< pair<int,int> > pii(new pair<int,int>());

       * shared_ptr<int> pi(pii, &pii->first);

       * assert(pii.use_count() == 2);

       * @endcode

       */

      template<typename _Tp1>

        shared_ptr(const shared_ptr<_Tp1>& __r, _Tp* __p) noexcept

        : __shared_ptr<_Tp>(__r, __p) { }

      /**

       *  @brief  If @a __r is empty, constructs an empty %shared_ptr;

       *          otherwise construct a %shared_ptr that shares ownership

       *          with @a __r.

       *  @param  __r  A %shared_ptr.

       *  @post   get() == __r.get() && use_count() == __r.use_count()

       */

      template<typename _Tp1, typename = typename

               std::enable_if<std::is_convertible<_Tp1*, _Tp*>::value>::type>

        shared_ptr(const shared_ptr<_Tp1>& __r) noexcept

        : __shared_ptr<_Tp>(__r) { }

      /**

       *  @brief  Move-constructs a %shared_ptr instance from @a __r.

       *  @param  __r  A %shared_ptr rvalue.

       *  @post   *this contains the old value of @a __r, @a __r is empty.

       */

      shared_ptr(shared_ptr&& __r) noexcept

      : __shared_ptr<_Tp>(std::move(__r)) { }

      /**

       *  @brief  Move-constructs a %shared_ptr instance from @a __r.

       *  @param  __r  A %shared_ptr rvalue.

       *  @post   *this contains the old value of @a __r, @a __r is empty.

       */

      template<typename _Tp1, typename = typename

               std::enable_if<std::is_convertible<_Tp1*, _Tp*>::value>::type>

        shared_ptr(shared_ptr<_Tp1>&& __r) noexcept

        : __shared_ptr<_Tp>(std::move(__r)) { }

      /**

       *  @brief  Constructs a %shared_ptr that shares ownership with @a __r

       *          and stores a copy of the pointer stored in @a __r.

       *  @param  __r  A weak_ptr.

       *  @post   use_count() == __r.use_count()

       *  @throw  bad_weak_ptr when __r.expired(),

       *          in which case the constructor has no effect.

       */

      template<typename _Tp1>

        explicit shared_ptr(const weak_ptr<_Tp1>& __r)

        : __shared_ptr<_Tp>(__r) { }

#if _GLIBCXX_USE_DEPRECATED

      template<typename _Tp1>

        shared_ptr(std::auto_ptr<_Tp1>&& __r)

        : __shared_ptr<_Tp>(std::move(__r)) { }

#endif

      template<typename _Tp1, typename _Del>

        shared_ptr(std::unique_ptr<_Tp1, _Del>&& __r)

        : __shared_ptr<_Tp>(std::move(__r)) { }

      /**

       *  @brief  Construct an empty %shared_ptr.

       *  @param  __p  A null pointer constant.

       *  @post   use_count() == 0 && get() == nullptr

       */

      constexpr shared_ptr(nullptr_t __p) noexcept

      : __shared_ptr<_Tp>(__p) { }

      shared_ptr& operator=(const shared_ptr&) noexcept = default;

      template<typename _Tp1>

        shared_ptr&

        operator=(const shared_ptr<_Tp1>& __r) noexcept

        {

          this->__shared_ptr<_Tp>::operator=(__r);

          return *this;

        }

#if _GLIBCXX_USE_DEPRECATED

      template<typename _Tp1>

        shared_ptr&

        operator=(std::auto_ptr<_Tp1>&& __r)

        {

          this->__shared_ptr<_Tp>::operator=(std::move(__r));

          return *this;

        }

#endif

      shared_ptr&

      operator=(shared_ptr&& __r) noexcept

      {

        this->__shared_ptr<_Tp>::operator=(std::move(__r));

        return *this;

      }

      template<class _Tp1>

        shared_ptr&

        operator=(shared_ptr<_Tp1>&& __r) noexcept

        {

          this->__shared_ptr<_Tp>::operator=(std::move(__r));

          return *this;

        }

      template<typename _Tp1, typename _Del>

        shared_ptr&

        operator=(std::unique_ptr<_Tp1, _Del>&& __r)

        {

          this->__shared_ptr<_Tp>::operator=(std::move(__r));

          return *this;

        }

    private:

      // This constructor is non-standard, it is used by allocate_shared.

      template<typename _Alloc, typename... _Args>

        shared_ptr(_Sp_make_shared_tag __tag, const _Alloc& __a,

                   _Args&&... __args)

        : __shared_ptr<_Tp>(__tag, __a, std::forward<_Args>(__args)...)

        { }

      template<typename _Tp1, typename _Alloc, typename... _Args>

        friend shared_ptr<_Tp1>

        allocate_shared(const _Alloc& __a, _Args&&... __args);

    };

  // 20.8.13.2.7 shared_ptr comparisons

  template<typename _Tp1, typename _Tp2>

    inline bool

    operator==(const shared_ptr<_Tp1>& __a,

               const shared_ptr<_Tp2>& __b) noexcept

    { return __a.get() == __b.get(); }

  template<typename _Tp>

    inline bool

    operator==(const shared_ptr<_Tp>& __a, nullptr_t) noexcept

    { return !__a; }

  template<typename _Tp>

    inline bool

    operator==(nullptr_t, const shared_ptr<_Tp>& __a) noexcept

    { return !__a; }

  template<typename _Tp1, typename _Tp2>

    inline bool

    operator!=(const shared_ptr<_Tp1>& __a,

               const shared_ptr<_Tp2>& __b) noexcept

    { return __a.get() != __b.get(); }

  template<typename _Tp>

    inline bool

    operator!=(const shared_ptr<_Tp>& __a, nullptr_t) noexcept

    { return (bool)__a; }

  template<typename _Tp>

    inline bool

    operator!=(nullptr_t, const shared_ptr<_Tp>& __a) noexcept

    { return (bool)__a; }

  template<typename _Tp1, typename _Tp2>

    inline bool

    operator<(const shared_ptr<_Tp1>& __a,

              const shared_ptr<_Tp2>& __b) noexcept

    {

      typedef typename std::common_type<_Tp1*, _Tp2*>::type _CT;

      return std::less<_CT>()(__a.get(), __b.get());

    }

  template<typename _Tp>

    inline bool

    operator<(const shared_ptr<_Tp>& __a, nullptr_t) noexcept

    { return std::less<_Tp*>()(__a.get(), nullptr); }

  template<typename _Tp>

    inline bool

    operator<(nullptr_t, const shared_ptr<_Tp>& __a) noexcept

    { return std::less<_Tp*>()(nullptr, __a.get()); }

  template<typename _Tp1, typename _Tp2>

    inline bool

    operator<=(const shared_ptr<_Tp1>& __a,

               const shared_ptr<_Tp2>& __b) noexcept

    { return !(__b < __a); }

  template<typename _Tp>

    inline bool

    operator<=(const shared_ptr<_Tp>& __a, nullptr_t) noexcept

    { return !(nullptr < __a); }

  template<typename _Tp>

    inline bool

    operator<=(nullptr_t, const shared_ptr<_Tp>& __a) noexcept

    { return !(__a < nullptr); }

  template<typename _Tp1, typename _Tp2>

    inline bool

    operator>(const shared_ptr<_Tp1>& __a,

              const shared_ptr<_Tp2>& __b) noexcept

    { return (__b < __a); }

  template<typename _Tp>

    inline bool

    operator>(const shared_ptr<_Tp>& __a, nullptr_t) noexcept

    { return std::less<_Tp*>()(nullptr, __a.get()); }

  template<typename _Tp>

    inline bool

    operator>(nullptr_t, const shared_ptr<_Tp>& __a) noexcept

    { return std::less<_Tp*>()(__a.get(), nullptr); }

  template<typename _Tp1, typename _Tp2>

    inline bool

    operator>=(const shared_ptr<_Tp1>& __a,

               const shared_ptr<_Tp2>& __b) noexcept

    { return !(__a < __b); }

  template<typename _Tp>

    inline bool

    operator>=(const shared_ptr<_Tp>& __a, nullptr_t) noexcept

    { return !(__a < nullptr); }

  template<typename _Tp>

    inline bool

    operator>=(nullptr_t, const shared_ptr<_Tp>& __a) noexcept

    { return !(nullptr < __a); }

  template<typename _Tp>

    struct less<shared_ptr<_Tp>> : public _Sp_less<shared_ptr<_Tp>>

    { };

  // 20.8.13.2.9 shared_ptr specialized algorithms.

  template<typename _Tp>

    inline void

    swap(shared_ptr<_Tp>& __a, shared_ptr<_Tp>& __b) noexcept

    { __a.swap(__b); }

  // 20.8.13.2.10 shared_ptr casts.

  template<typename _Tp, typename _Tp1>

    inline shared_ptr<_Tp>

    static_pointer_cast(const shared_ptr<_Tp1>& __r) noexcept

    { return shared_ptr<_Tp>(__r, static_cast<_Tp*>(__r.get())); }

  template<typename _Tp, typename _Tp1>

    inline shared_ptr<_Tp>

    const_pointer_cast(const shared_ptr<_Tp1>& __r) noexcept

    { return shared_ptr<_Tp>(__r, const_cast<_Tp*>(__r.get())); }

  template<typename _Tp, typename _Tp1>

    inline shared_ptr<_Tp>

    dynamic_pointer_cast(const shared_ptr<_Tp1>& __r) noexcept

    {

      if (_Tp* __p = dynamic_cast<_Tp*>(__r.get()))

        return shared_ptr<_Tp>(__r, __p);

      return shared_ptr<_Tp>();

    }

  /**

   *  @brief  A smart pointer with weak semantics.

   *

   *  With forwarding constructors and assignment operators.

   */

  template<typename _Tp>

    class weak_ptr : public __weak_ptr<_Tp>

    {

    public:

      constexpr weak_ptr() noexcept

      : __weak_ptr<_Tp>() { }

      template<typename _Tp1, typename = typename

               std::enable_if<std::is_convertible<_Tp1*, _Tp*>::value>::type>

        weak_ptr(const weak_ptr<_Tp1>& __r) noexcept

        : __weak_ptr<_Tp>(__r) { }

      template<typename _Tp1, typename = typename

               std::enable_if<std::is_convertible<_Tp1*, _Tp*>::value>::type>

        weak_ptr(const shared_ptr<_Tp1>& __r) noexcept

        : __weak_ptr<_Tp>(__r) { }

      template<typename _Tp1>

        weak_ptr&

        operator=(const weak_ptr<_Tp1>& __r) noexcept

        {

          this->__weak_ptr<_Tp>::operator=(__r);

          return *this;

        }

      template<typename _Tp1>

        weak_ptr&

        operator=(const shared_ptr<_Tp1>& __r) noexcept

        {

          this->__weak_ptr<_Tp>::operator=(__r);

          return *this;

        }

      shared_ptr<_Tp>

      lock() const noexcept

      {

#ifdef __GTHREADS

        if (this->expired())

          return shared_ptr<_Tp>();

        __try

          {

            return shared_ptr<_Tp>(*this);

          }

        __catch(const bad_weak_ptr&)

          {

            return shared_ptr<_Tp>();

          }

#else

        return this->expired() ? shared_ptr<_Tp>() : shared_ptr<_Tp>(*this);

#endif

      }

    };

  // 20.8.13.3.7 weak_ptr specialized algorithms.

  template<typename _Tp>

    inline void

    swap(weak_ptr<_Tp>& __a, weak_ptr<_Tp>& __b) noexcept

    { __a.swap(__b); }

  /// Primary template owner_less

  template<typename _Tp>

    struct owner_less;

  /// Partial specialization of owner_less for shared_ptr.

  template<typename _Tp>

    struct owner_less<shared_ptr<_Tp>>

    : public _Sp_owner_less<shared_ptr<_Tp>, weak_ptr<_Tp>>

    { };

  /// Partial specialization of owner_less for weak_ptr.

  template<typename _Tp>

    struct owner_less<weak_ptr<_Tp>>

    : public _Sp_owner_less<weak_ptr<_Tp>, shared_ptr<_Tp>>

    { };

  /**

   *  @brief Base class allowing use of member function shared_from_this.

   */

  template<typename _Tp>

    class enable_shared_from_this

    {

    protected:

      constexpr enable_shared_from_this() noexcept { }

      enable_shared_from_this(const enable_shared_from_this&) noexcept { }

      enable_shared_from_this&

      operator=(const enable_shared_from_this&) noexcept

      { return *this; }

      ~enable_shared_from_this() { }

    public:

      shared_ptr<_Tp>

      shared_from_this()

      { return shared_ptr<_Tp>(this->_M_weak_this); }

      shared_ptr<const _Tp>

      shared_from_this() const

      { return shared_ptr<const _Tp>(this->_M_weak_this); }

    private:

      template<typename _Tp1>

        void

        _M_weak_assign(_Tp1* __p, const __shared_count<>& __n) const noexcept

        { _M_weak_this._M_assign(__p, __n); }

      template<typename _Tp1>

        friend void

        __enable_shared_from_this_helper(const __shared_count<>& __pn,

                                         const enable_shared_from_this* __pe,

                                         const _Tp1* __px) noexcept

        {

          if (__pe != 0)

            __pe->_M_weak_assign(const_cast<_Tp1*>(__px), __pn);

        }

      mutable weak_ptr<_Tp>  _M_weak_this;

    };

  /**

   *  @brief  Create an object that is owned by a shared_ptr.

   *  @param  __a     An allocator.

   *  @param  __args  Arguments for the @a _Tp object's constructor.

   *  @return A shared_ptr that owns the newly created object.

   *  @throw  An exception thrown from @a _Alloc::allocate or from the

   *          constructor of @a _Tp.

   *

   *  A copy of @a __a will be used to allocate memory for the shared_ptr

   *  and the new object.

   */

  template<typename _Tp, typename _Alloc, typename... _Args>

    inline shared_ptr<_Tp>

    allocate_shared(const _Alloc& __a, _Args&&... __args)

    {

      return shared_ptr<_Tp>(_Sp_make_shared_tag(), __a,

                             std::forward<_Args>(__args)...);

    }

  /**

   *  @brief  Create an object that is owned by a shared_ptr.

   *  @param  __args  Arguments for the @a _Tp object's constructor.

   *  @return A shared_ptr that owns the newly created object.

   *  @throw  std::bad_alloc, or an exception thrown from the

   *          constructor of @a _Tp.

   */

  template<typename _Tp, typename... _Args>

    inline shared_ptr<_Tp>

    make_shared(_Args&&... __args)

    {

      typedef typename std::remove_const<_Tp>::type _Tp_nc;

      return std::allocate_shared<_Tp>(std::allocator<_Tp_nc>(),

                                       std::forward<_Args>(__args)...);

    }

  /// std::hash specialization for shared_ptr.

  template<typename _Tp>

    struct hash<shared_ptr<_Tp>>

    : public __hash_base<size_t, shared_ptr<_Tp>>

    {

      size_t

      operator()(const shared_ptr<_Tp>& __s) const noexcept

      { return std::hash<_Tp*>()(__s.get()); }

    };

  // @} group pointer_abstractions

_GLIBCXX_END_NAMESPACE_VERSION

} // namespace

#endif // _SHARED_PTR_H