LTP GCOV extension - code coverage report
Current view: directory - usr/include/c++/4.3/backward - auto_ptr.h
Test: lcov.info
Date: 2008-08-14 Instrumented lines: 15
Code covered: 100.0 % Executed lines: 15

       1                 : // auto_ptr implementation -*- C++ -*-
       2                 : 
       3                 : // Copyright (C) 2007, 2008 Free Software Foundation, Inc.
       4                 : //
       5                 : // This file is part of the GNU ISO C++ Library.  This library is free
       6                 : // software; you can redistribute it and/or modify it under the
       7                 : // terms of the GNU General Public License as published by the
       8                 : // Free Software Foundation; either version 2, or (at your option)
       9                 : // any later version.
      10                 : 
      11                 : // This library is distributed in the hope that it will be useful,
      12                 : // but WITHOUT ANY WARRANTY; without even the implied warranty of
      13                 : // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      14                 : // GNU General Public License for more details.
      15                 : 
      16                 : // You should have received a copy of the GNU General Public License
      17                 : // along with this library; see the file COPYING.  If not, write to
      18                 : // the Free Software Foundation, 51 Franklin Street, Fifth Floor,
      19                 : // Boston, MA 02110-1301, USA.
      20                 : 
      21                 : // As a special exception, you may use this file as part of a free software
      22                 : // library without restriction.  Specifically, if other files instantiate
      23                 : // templates or use macros or inline functions from this file, or you compile
      24                 : // this file and link it with other files to produce an executable, this
      25                 : // file does not by itself cause the resulting executable to be covered by
      26                 : // the GNU General Public License.  This exception does not however
      27                 : // invalidate any other reasons why the executable file might be covered by
      28                 : // the GNU General Public License.
      29                 : 
      30                 : /** @file backward/auto_ptr.h
      31                 :  *  This is an internal header file, included by other library headers.
      32                 :  *  You should not attempt to use it directly.
      33                 :  */
      34                 : 
      35                 : #ifndef _STL_AUTO_PTR_H
      36                 : #define _STL_AUTO_PTR_H 1
      37                 : 
      38                 : #include <bits/c++config.h>
      39                 : #include <debug/debug.h>
      40                 : 
      41                 : _GLIBCXX_BEGIN_NAMESPACE(std)
      42                 : 
      43                 :   /**
      44                 :    *  A wrapper class to provide auto_ptr with reference semantics.
      45                 :    *  For example, an auto_ptr can be assigned (or constructed from)
      46                 :    *  the result of a function which returns an auto_ptr by value.
      47                 :    *
      48                 :    *  All the auto_ptr_ref stuff should happen behind the scenes.
      49                 :    */
      50                 :   template<typename _Tp1>
      51                 :     struct auto_ptr_ref
      52                 :     {
      53                 :       _Tp1* _M_ptr;
      54                 :       
      55                 :       explicit
      56             666 :       auto_ptr_ref(_Tp1* __p): _M_ptr(__p) { }
      57                 :     } _GLIBCXX_DEPRECATED_ATTR;
      58                 : 
      59                 : 
      60                 :   /**
      61                 :    *  @brief  A simple smart pointer providing strict ownership semantics.
      62                 :    *
      63                 :    *  The Standard says:
      64                 :    *  <pre>
      65                 :    *  An @c auto_ptr owns the object it holds a pointer to.  Copying
      66                 :    *  an @c auto_ptr copies the pointer and transfers ownership to the
      67                 :    *  destination.  If more than one @c auto_ptr owns the same object
      68                 :    *  at the same time the behavior of the program is undefined.
      69                 :    *
      70                 :    *  The uses of @c auto_ptr include providing temporary
      71                 :    *  exception-safety for dynamically allocated memory, passing
      72                 :    *  ownership of dynamically allocated memory to a function, and
      73                 :    *  returning dynamically allocated memory from a function.  @c
      74                 :    *  auto_ptr does not meet the CopyConstructible and Assignable
      75                 :    *  requirements for Standard Library <a
      76                 :    *  href="tables.html#65">container</a> elements and thus
      77                 :    *  instantiating a Standard Library container with an @c auto_ptr
      78                 :    *  results in undefined behavior.
      79                 :    *  </pre>
      80                 :    *  Quoted from [20.4.5]/3.
      81                 :    *
      82                 :    *  Good examples of what can and cannot be done with auto_ptr can
      83                 :    *  be found in the libstdc++ testsuite.
      84                 :    *
      85                 :    *  _GLIBCXX_RESOLVE_LIB_DEFECTS
      86                 :    *  127.  auto_ptr<> conversion issues
      87                 :    *  These resolutions have all been incorporated.
      88                 :    */
      89                 :   template<typename _Tp>
      90                 :     class auto_ptr
      91                 :     {
      92                 :     private:
      93                 :       _Tp* _M_ptr;
      94                 :       
      95                 :     public:
      96                 :       /// The pointed-to type.
      97                 :       typedef _Tp element_type;
      98                 :       
      99                 :       /**
     100                 :        *  @brief  An %auto_ptr is usually constructed from a raw pointer.
     101                 :        *  @param  p  A pointer (defaults to NULL).
     102                 :        *
     103                 :        *  This object now @e owns the object pointed to by @a p.
     104                 :        */
     105                 :       explicit
     106             666 :       auto_ptr(element_type* __p = 0) throw() : _M_ptr(__p) { }
     107                 : 
     108                 :       /**
     109                 :        *  @brief  An %auto_ptr can be constructed from another %auto_ptr.
     110                 :        *  @param  a  Another %auto_ptr of the same type.
     111                 :        *
     112                 :        *  This object now @e owns the object previously owned by @a a,
     113                 :        *  which has given up ownership.
     114                 :        */
     115             590 :       auto_ptr(auto_ptr& __a) throw() : _M_ptr(__a.release()) { }
     116                 : 
     117                 :       /**
     118                 :        *  @brief  An %auto_ptr can be constructed from another %auto_ptr.
     119                 :        *  @param  a  Another %auto_ptr of a different but related type.
     120                 :        *
     121                 :        *  A pointer-to-Tp1 must be convertible to a
     122                 :        *  pointer-to-Tp/element_type.
     123                 :        *
     124                 :        *  This object now @e owns the object previously owned by @a a,
     125                 :        *  which has given up ownership.
     126                 :        */
     127                 :       template<typename _Tp1>
     128                 :         auto_ptr(auto_ptr<_Tp1>& __a) throw() : _M_ptr(__a.release()) { }
     129                 : 
     130                 :       /**
     131                 :        *  @brief  %auto_ptr assignment operator.
     132                 :        *  @param  a  Another %auto_ptr of the same type.
     133                 :        *
     134                 :        *  This object now @e owns the object previously owned by @a a,
     135                 :        *  which has given up ownership.  The object that this one @e
     136                 :        *  used to own and track has been deleted.
     137                 :        */
     138                 :       auto_ptr&
     139                 :       operator=(auto_ptr& __a) throw()
     140                 :       {
     141                 :         reset(__a.release());
     142                 :         return *this;
     143                 :       }
     144                 : 
     145                 :       /**
     146                 :        *  @brief  %auto_ptr assignment operator.
     147                 :        *  @param  a  Another %auto_ptr of a different but related type.
     148                 :        *
     149                 :        *  A pointer-to-Tp1 must be convertible to a pointer-to-Tp/element_type.
     150                 :        *
     151                 :        *  This object now @e owns the object previously owned by @a a,
     152                 :        *  which has given up ownership.  The object that this one @e
     153                 :        *  used to own and track has been deleted.
     154                 :        */
     155                 :       template<typename _Tp1>
     156                 :         auto_ptr&
     157                 :         operator=(auto_ptr<_Tp1>& __a) throw()
     158                 :         {
     159                 :           reset(__a.release());
     160                 :           return *this;
     161                 :         }
     162                 : 
     163                 :       /**
     164                 :        *  When the %auto_ptr goes out of scope, the object it owns is
     165                 :        *  deleted.  If it no longer owns anything (i.e., @c get() is
     166                 :        *  @c NULL), then this has no effect.
     167                 :        *
     168                 :        *  The C++ standard says there is supposed to be an empty throw
     169                 :        *  specification here, but omitting it is standard conforming.  Its
     170                 :        *  presence can be detected only if _Tp::~_Tp() throws, but this is
     171                 :        *  prohibited.  [17.4.3.6]/2
     172                 :        */
     173            1922 :       ~auto_ptr() { delete _M_ptr; }
     174                 :       
     175                 :       /**
     176                 :        *  @brief  Smart pointer dereferencing.
     177                 :        *
     178                 :        *  If this %auto_ptr no longer owns anything, then this
     179                 :        *  operation will crash.  (For a smart pointer, "no longer owns
     180                 :        *  anything" is the same as being a null pointer, and you know
     181                 :        *  what happens when you dereference one of those...)
     182                 :        */
     183                 :       element_type&
     184                 :       operator*() const throw() 
     185                 :       {
     186                 :         _GLIBCXX_DEBUG_ASSERT(_M_ptr != 0);
     187                 :         return *_M_ptr; 
     188                 :       }
     189                 :       
     190                 :       /**
     191                 :        *  @brief  Smart pointer dereferencing.
     192                 :        *
     193                 :        *  This returns the pointer itself, which the language then will
     194                 :        *  automatically cause to be dereferenced.
     195                 :        */
     196                 :       element_type*
     197             590 :       operator->() const throw() 
     198                 :       {
     199                 :         _GLIBCXX_DEBUG_ASSERT(_M_ptr != 0);
     200             590 :         return _M_ptr; 
     201                 :       }
     202                 :       
     203                 :       /**
     204                 :        *  @brief  Bypassing the smart pointer.
     205                 :        *  @return  The raw pointer being managed.
     206                 :        *
     207                 :        *  You can get a copy of the pointer that this object owns, for
     208                 :        *  situations such as passing to a function which only accepts
     209                 :        *  a raw pointer.
     210                 :        *
     211                 :        *  @note  This %auto_ptr still owns the memory.
     212                 :        */
     213                 :       element_type*
     214            1256 :       get() const throw() { return _M_ptr; }
     215                 :       
     216                 :       /**
     217                 :        *  @brief  Bypassing the smart pointer.
     218                 :        *  @return  The raw pointer being managed.
     219                 :        *
     220                 :        *  You can get a copy of the pointer that this object owns, for
     221                 :        *  situations such as passing to a function which only accepts
     222                 :        *  a raw pointer.
     223                 :        *
     224                 :        *  @note  This %auto_ptr no longer owns the memory.  When this object
     225                 :        *  goes out of scope, nothing will happen.
     226                 :        */
     227                 :       element_type*
     228            1256 :       release() throw()
     229                 :       {
     230            1256 :         element_type* __tmp = _M_ptr;
     231            1256 :         _M_ptr = 0;
     232            1256 :         return __tmp;
     233                 :       }
     234                 :       
     235                 :       /**
     236                 :        *  @brief  Forcibly deletes the managed object.
     237                 :        *  @param  p  A pointer (defaults to NULL).
     238                 :        *
     239                 :        *  This object now @e owns the object pointed to by @a p.  The
     240                 :        *  previous object has been deleted.
     241                 :        */
     242                 :       void
     243                 :       reset(element_type* __p = 0) throw()
     244                 :       {
     245                 :         if (__p != _M_ptr)
     246                 :           {
     247                 :             delete _M_ptr;
     248                 :             _M_ptr = __p;
     249                 :           }
     250                 :       }
     251                 :       
     252                 :       /** 
     253                 :        *  @brief  Automatic conversions
     254                 :        *
     255                 :        *  These operations convert an %auto_ptr into and from an auto_ptr_ref
     256                 :        *  automatically as needed.  This allows constructs such as
     257                 :        *  @code
     258                 :        *    auto_ptr<Derived>  func_returning_auto_ptr(.....);
     259                 :        *    ...
     260                 :        *    auto_ptr<Base> ptr = func_returning_auto_ptr(.....);
     261                 :        *  @endcode
     262                 :        */
     263             666 :       auto_ptr(auto_ptr_ref<element_type> __ref) throw()
     264             666 :       : _M_ptr(__ref._M_ptr) { }
     265                 :       
     266                 :       auto_ptr&
     267                 :       operator=(auto_ptr_ref<element_type> __ref) throw()
     268                 :       {
     269                 :         if (__ref._M_ptr != this->get())
     270                 :           {
     271                 :             delete _M_ptr;
     272                 :             _M_ptr = __ref._M_ptr;
     273                 :           }
     274                 :         return *this;
     275                 :       }
     276                 :       
     277                 :       template<typename _Tp1>
     278             666 :         operator auto_ptr_ref<_Tp1>() throw()
     279             666 :         { return auto_ptr_ref<_Tp1>(this->release()); }
     280                 : 
     281                 :       template<typename _Tp1>
     282                 :         operator auto_ptr<_Tp1>() throw()
     283                 :         { return auto_ptr<_Tp1>(this->release()); }
     284                 :     } _GLIBCXX_DEPRECATED_ATTR;
     285                 : 
     286                 :   // _GLIBCXX_RESOLVE_LIB_DEFECTS
     287                 :   // 541. shared_ptr template assignment and void
     288                 :   template<>
     289                 :     class auto_ptr<void>
     290                 :     {
     291                 :     public:
     292                 :       typedef void element_type;
     293                 :     } _GLIBCXX_DEPRECATED_ATTR;
     294                 : 
     295                 : _GLIBCXX_END_NAMESPACE
     296                 : 
     297                 : #endif /* _STL_AUTO_PTR_H */

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