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// auto_ptr implementation -*- C++ -*- |
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// Copyright (C) 2007-2015 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. |
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// 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. |
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// 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. |
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// 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/>. |
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/** @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} |
*/ |
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#ifndef _BACKWARD_AUTO_PTR_H |
#define _BACKWARD_AUTO_PTR_H 1 |
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#include <bits/c++config.h> |
#include <debug/debug.h> |
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namespace std _GLIBCXX_VISIBILITY(default) |
{ |
_GLIBCXX_BEGIN_NAMESPACE_VERSION |
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/** |
* 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; |
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explicit |
auto_ptr_ref(_Tp1* __p): _M_ptr(__p) { } |
} _GLIBCXX_DEPRECATED; |
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/** |
* @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; |
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public: |
/// The pointed-to type. |
typedef _Tp element_type; |
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/** |
* @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) { } |
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/** |
* @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()) { } |
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/** |
* @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()) { } |
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/** |
* @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; |
} |
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/** |
* @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; |
} |
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/** |
* 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; } |
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/** |
* @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; |
} |
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/** |
* @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; |
} |
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/** |
* @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; } |
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/** |
* @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; |
} |
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/** |
* @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; |
} |
} |
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/** |
* @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) { } |
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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; |
} |
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template<typename _Tp1> |
operator auto_ptr_ref<_Tp1>() throw() |
{ return auto_ptr_ref<_Tp1>(this->release()); } |
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template<typename _Tp1> |
operator auto_ptr<_Tp1>() throw() |
{ return auto_ptr<_Tp1>(this->release()); } |
} _GLIBCXX_DEPRECATED; |
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// _GLIBCXX_RESOLVE_LIB_DEFECTS |
// 541. shared_ptr template assignment and void |
template<> |
class auto_ptr<void> |
{ |
public: |
typedef void element_type; |
} _GLIBCXX_DEPRECATED; |
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#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(); } |
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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); |
} |
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template<typename _Tp> |
template<typename _Tp1> |
inline |
shared_ptr<_Tp>::shared_ptr(std::auto_ptr<_Tp1>&& __r) |
: __shared_ptr<_Tp>(std::move(__r)) { } |
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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 |
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_GLIBCXX_END_NAMESPACE_VERSION |
} // namespace |
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#endif /* _BACKWARD_AUTO_PTR_H */ |