src/vsmartptr.h

   1 ///
   2 /// \file       vsmartptr
   3 ///             Variable 'free' smart pointer
   4 ///
   5
   6 /*
   7     Copyright (C) 2006-2009, Net Direct Inc. (http://www.netdirect.ca/)
   8
   9     This program is free software; you can redistribute it and/or modify
  10     it under the terms of the GNU General Public License as published by
  11     the Free Software Foundation; either version 2 of the License, or
  12     (at your option) any later version.
  13
  14     This program is distributed in the hope that it will be useful,
  15     but WITHOUT ANY WARRANTY; without even the implied warranty of
  16     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  17
  18     See the GNU General Public License in the COPYING file at the
  19     root directory of this project for more details.
  20 */
  21
  22 #ifndef __BARRY_VSMARTPTR_H__
  23 #define __BARRY_VSMARTPTR_H__
  24
  25 namespace Barry {
  26
  27 //
  28 // vSmartPtr
  29 //
  30 /// A special smart pointer for variables that have their own
  31 /// special 'free' functions.  Behaves like std::auto_ptr<>
  32 /// in that only one object at a time owns the pointer,
  33 /// and destruction frees it by calling the given FreeFunc.
  34 ///
  35 template <class T, class FT, void (*FreeFunc)(FT *pt)>
  36 class vSmartPtr
  37 {
  38         mutable T *m_pt;
  39
  40 public:
  41         vSmartPtr() : m_pt(0) {}
  42         vSmartPtr(T *pt) : m_pt(pt) {}
  43         vSmartPtr(const vSmartPtr &sp) : m_pt(sp.m_pt)
  44         {
  45                 sp.m_pt = 0;
  46         }
  47         ~vSmartPtr()
  48         {
  49                 if( m_pt )
  50                         FreeFunc(m_pt);
  51         }
  52
  53         vSmartPtr& operator=(T *pt)
  54         {
  55                 Extract();
  56                 m_pt = pt;
  57                 return *this;
  58         }
  59
  60         vSmartPtr& operator=(const vSmartPtr &sp)
  61         {
  62                 Extract();
  63                 m_pt = sp.Extract();
  64                 return *this;
  65         }
  66
  67         T* Extract()
  68         {
  69                 T *rp = m_pt;
  70                 m_pt = 0;
  71                 return rp;
  72         }
  73
  74         T* Get()
  75         {
  76                 return m_pt;
  77         }
  78 };
  79
  80 /*
  81
  82 Example usage:
  83
  84 typedef vSmartPtr<b_VFormatAttribute, b_VFormatAttribute, &b_vformat_attribute_free> vAttrPtr;
  85 typedef vSmartPtr<b_VFormatParam, b_VFormatParam, &b_vformat_attribute_param_free> vParamPtr;
  86 typedef vSmartPtr<char, void, &g_free> gStringPtr;
  87
  88 */
  89
  90 } // namespace Barry
  91
  92 #endif
  93