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// auto_ptr implementation -*- C++ -*-

// Copyright (C) 2007-2012 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 backward/auto_ptr.h

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

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

 */

#ifndef _BACKWARD_AUTO_PTR_H

#define _BACKWARD_AUTO_PTR_H 1

#include <bits/c++config.h>

#include <debug/debug.h>

namespace std _GLIBCXX_VISIBILITY(default)

{

_GLIBCXX_BEGIN_NAMESPACE_VERSION

  /**

   *  A wrapper class to provide auto_ptr with reference semantics.

   *  For example, an auto_ptr can be assigned (or constructed from)

   *  the result of a function which returns an auto_ptr by value.

   *

   *  All the auto_ptr_ref stuff should happen behind the scenes.

   */

  template<typename _Tp1>

    struct auto_ptr_ref

    {

      _Tp1* _M_ptr;

      explicit

      auto_ptr_ref(_Tp1* __p): _M_ptr(__p) { }

    } _GLIBCXX_DEPRECATED;

  /**

   *  @brief  A simple smart pointer providing strict ownership semantics.

   *

   *  The Standard says:

   *  <pre>

   *  An @c auto_ptr owns the object it holds a pointer to.  Copying

   *  an @c auto_ptr copies the pointer and transfers ownership to the

   *  destination.  If more than one @c auto_ptr owns the same object

   *  at the same time the behavior of the program is undefined.

   *

   *  The uses of @c auto_ptr include providing temporary

   *  exception-safety for dynamically allocated memory, passing

   *  ownership of dynamically allocated memory to a function, and

   *  returning dynamically allocated memory from a function.  @c

   *  auto_ptr does not meet the CopyConstructible and Assignable

   *  requirements for Standard Library <a

   *  href="tables.html#65">container</a> elements and thus

   *  instantiating a Standard Library container with an @c auto_ptr

   *  results in undefined behavior.

   *  </pre>

   *  Quoted from [20.4.5]/3.

   *

   *  Good examples of what can and cannot be done with auto_ptr can

   *  be found in the libstdc++ testsuite.

   *

   *  _GLIBCXX_RESOLVE_LIB_DEFECTS

   *  127.  auto_ptr<> conversion issues

   *  These resolutions have all been incorporated.

   */

  template<typename _Tp>

    class auto_ptr

    {

    private:

      _Tp* _M_ptr;

    public:

      /// The pointed-to type.

      typedef _Tp element_type;

      /**

       *  @brief  An %auto_ptr is usually constructed from a raw pointer.

       *  @param  __p  A pointer (defaults to NULL).

       *

       *  This object now @e owns the object pointed to by @a __p.

       */

      explicit

      auto_ptr(element_type* __p = 0) throw() : _M_ptr(__p) { }

      /**

       *  @brief  An %auto_ptr can be constructed from another %auto_ptr.

       *  @param  __a  Another %auto_ptr of the same type.

       *

       *  This object now @e owns the object previously owned by @a __a,

       *  which has given up ownership.

       */

      auto_ptr(auto_ptr& __a) throw() : _M_ptr(__a.release()) { }

      /**

       *  @brief  An %auto_ptr can be constructed from another %auto_ptr.

       *  @param  __a  Another %auto_ptr of a different but related type.

       *

       *  A pointer-to-Tp1 must be convertible to a

       *  pointer-to-Tp/element_type.

       *

       *  This object now @e owns the object previously owned by @a __a,

       *  which has given up ownership.

       */

      template<typename _Tp1>

        auto_ptr(auto_ptr<_Tp1>& __a) throw() : _M_ptr(__a.release()) { }

      /**

       *  @brief  %auto_ptr assignment operator.

       *  @param  __a  Another %auto_ptr of the same type.

       *

       *  This object now @e owns the object previously owned by @a __a,

       *  which has given up ownership.  The object that this one @e

       *  used to own and track has been deleted.

       */

      auto_ptr&

      operator=(auto_ptr& __a) throw()

      {

        reset(__a.release());

        return *this;

      }

      /**

       *  @brief  %auto_ptr assignment operator.

       *  @param  __a  Another %auto_ptr of a different but related type.

       *

       *  A pointer-to-Tp1 must be convertible to a pointer-to-Tp/element_type.

       *

       *  This object now @e owns the object previously owned by @a __a,

       *  which has given up ownership.  The object that this one @e

       *  used to own and track has been deleted.

       */

      template<typename _Tp1>

        auto_ptr&

        operator=(auto_ptr<_Tp1>& __a) throw()

        {

          reset(__a.release());

          return *this;

        }

      /**

       *  When the %auto_ptr goes out of scope, the object it owns is

       *  deleted.  If it no longer owns anything (i.e., @c get() is

       *  @c NULL), then this has no effect.

       *

       *  The C++ standard says there is supposed to be an empty throw

       *  specification here, but omitting it is standard conforming.  Its

       *  presence can be detected only if _Tp::~_Tp() throws, but this is

       *  prohibited.  [17.4.3.6]/2

       */

      ~auto_ptr() { delete _M_ptr; }

      /**

       *  @brief  Smart pointer dereferencing.

       *

       *  If this %auto_ptr no longer owns anything, then this

       *  operation will crash.  (For a smart pointer, <em>no longer owns

       *  anything</em> is the same as being a null pointer, and you know

       *  what happens when you dereference one of those...)

       */

      element_type&

      operator*() const throw()

      {

        _GLIBCXX_DEBUG_ASSERT(_M_ptr != 0);

        return *_M_ptr;

      }

      /**

       *  @brief  Smart pointer dereferencing.

       *

       *  This returns the pointer itself, which the language then will

       *  automatically cause to be dereferenced.

       */

      element_type*

      operator->() const throw()

      {

        _GLIBCXX_DEBUG_ASSERT(_M_ptr != 0);

        return _M_ptr;

      }

      /**

       *  @brief  Bypassing the smart pointer.

       *  @return  The raw pointer being managed.

       *

       *  You can get a copy of the pointer that this object owns, for

       *  situations such as passing to a function which only accepts

       *  a raw pointer.

       *

       *  @note  This %auto_ptr still owns the memory.

       */

      element_type*

      get() const throw() { return _M_ptr; }

      /**

       *  @brief  Bypassing the smart pointer.

       *  @return  The raw pointer being managed.

       *

       *  You can get a copy of the pointer that this object owns, for

       *  situations such as passing to a function which only accepts

       *  a raw pointer.

       *

       *  @note  This %auto_ptr no longer owns the memory.  When this object

       *  goes out of scope, nothing will happen.

       */

      element_type*

      release() throw()

      {

        element_type* __tmp = _M_ptr;

        _M_ptr = 0;

        return __tmp;

      }

      /**

       *  @brief  Forcibly deletes the managed object.

       *  @param  __p  A pointer (defaults to NULL).

       *

       *  This object now @e owns the object pointed to by @a __p.  The

       *  previous object has been deleted.

       */

      void

      reset(element_type* __p = 0) throw()

      {

        if (__p != _M_ptr)

          {

            delete _M_ptr;

            _M_ptr = __p;

          }

      }

      /**

       *  @brief  Automatic conversions

       *

       *  These operations convert an %auto_ptr into and from an auto_ptr_ref

       *  automatically as needed.  This allows constructs such as

       *  @code

       *    auto_ptr<Derived>  func_returning_auto_ptr(.....);

       *    ...

       *    auto_ptr<Base> ptr = func_returning_auto_ptr(.....);

       *  @endcode

       */

      auto_ptr(auto_ptr_ref<element_type> __ref) throw()

      : _M_ptr(__ref._M_ptr) { }

      auto_ptr&

      operator=(auto_ptr_ref<element_type> __ref) throw()

      {

        if (__ref._M_ptr != this->get())

          {

            delete _M_ptr;

            _M_ptr = __ref._M_ptr;

          }

        return *this;

      }

      template<typename _Tp1>

        operator auto_ptr_ref<_Tp1>() throw()

        { return auto_ptr_ref<_Tp1>(this->release()); }

      template<typename _Tp1>

        operator auto_ptr<_Tp1>() throw()

        { return auto_ptr<_Tp1>(this->release()); }

    } _GLIBCXX_DEPRECATED;

  // _GLIBCXX_RESOLVE_LIB_DEFECTS

  // 541. shared_ptr template assignment and void

  template<>

    class auto_ptr<void>

    {

    public:

      typedef void element_type;

    } _GLIBCXX_DEPRECATED;

#if __cplusplus >= 201103L

  template<_Lock_policy _Lp>

  template<typename _Tp>

    inline

    __shared_count<_Lp>::__shared_count(std::auto_ptr<_Tp>&& __r)

    : _M_pi(new _Sp_counted_ptr<_Tp*, _Lp>(__r.get()))

    { __r.release(); }

  template<typename _Tp, _Lock_policy _Lp>

  template<typename _Tp1>

    inline

    __shared_ptr<_Tp, _Lp>::__shared_ptr(std::auto_ptr<_Tp1>&& __r)

    : _M_ptr(__r.get()), _M_refcount()

    {

      __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>)

      static_assert( sizeof(_Tp1) > 0, "incomplete type" );

      _Tp1* __tmp = __r.get();

      _M_refcount = __shared_count<_Lp>(std::move(__r));

      __enable_shared_from_this_helper(_M_refcount, __tmp, __tmp);

    }

  template<typename _Tp>

  template<typename _Tp1>

    inline

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

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

  template<typename _Tp, typename _Dp>

  template<typename _Up, typename>

    inline

    unique_ptr<_Tp, _Dp>::unique_ptr(auto_ptr<_Up>&& __u) noexcept

    : _M_t(__u.release(), deleter_type()) { }

#endif

_GLIBCXX_END_NAMESPACE_VERSION

} // namespace

#endif /* _BACKWARD_AUTO_PTR_H */