# gdcmSmartPointer.h

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    00001 /*=========================================================================
    00002
    00003   Program: GDCM (Grassroots DICOM). A DICOM library
    00004   Module:  $URL$
    00005
    00006   Copyright (c) 2006-2010 Mathieu Malaterre
    00007   All rights reserved.
    00008   See Copyright.txt or http://gdcm.sourceforge.net/Copyright.html for details.
    00009
    00010      This software is distributed WITHOUT ANY WARRANTY; without even
    00011      the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
    00012      PURPOSE.  See the above copyright notice for more information.
    00013
    00014 =========================================================================*/
    00015 #ifndef GDCMSMARTPOINTER_H
    00016 #define GDCMSMARTPOINTER_H
    00017
    00018 #include "gdcmObject.h"
    00019
    00020 namespace gdcm
    00021 {
    00039 template<class ObjectType>
    00040 class SmartPointer
    00041 {
    00042 public:
    00043   SmartPointer():Pointer(0) {}
    00044   SmartPointer(const SmartPointer<ObjectType>& p):Pointer(p.Pointer)
    00045     { Register(); }
    00046   SmartPointer(ObjectType* p):Pointer(p)
    00047     { Register(); }
    00048   SmartPointer(ObjectType const & p)
    00049     {
    00050     Pointer = const_cast<ObjectType*>(&p);
    00051     Register();
    00052     }
    00053   ~SmartPointer() {
    00054     UnRegister();
    00055     Pointer = 0;
    00056   }
    00057
    00059   ObjectType *operator -> () const
    00060     { return Pointer; }
    00061
    00062   ObjectType& operator * () const
    00063     { return *Pointer; }
    00064
    00066   operator ObjectType * () const
    00067     { return Pointer; }
    00068
    00070   SmartPointer &operator = (SmartPointer const &r)
    00071     { return operator = (r.Pointer); }
    00072
    00074   SmartPointer &operator = (ObjectType *r)
    00075     {
    00076     // http://www.parashift.com/c++-faq-lite/freestore-mgmt.html#faq-16.22
    00077     // DO NOT CHANGE THE ORDER OF THESE STATEMENTS!
    00078     // (This order properly handles self-assignment)
    00079     // (This order also properly handles recursion, e.g., if a ObjectType contains SmartPointer<ObjectType>s)
    00080     if( Pointer != r )
    00081       {
    00082       ObjectType* old = Pointer;
    00083       Pointer = r;
    00084       Register();
    00085       if ( old ) { old->UnRegister(); }
    00086       }
    00087     return *this;
    00088     }
    00089
    00090   SmartPointer &operator = (ObjectType const &r)
    00091     {
    00092     ObjectType* tmp = const_cast<ObjectType*>(&r);
    00093     return operator = (tmp);
    00094     }
    00095
    00097   ObjectType *GetPointer() const
    00098     { return Pointer; }
    00099
    00100 private:
    00101   void Register()
    00102     {
    00103     if(Pointer) Pointer->Register();
    00104     }
    00105
    00106   void UnRegister()
    00107     {
    00108     if(Pointer) Pointer->UnRegister();
    00109     }
    00110
    00111   ObjectType* Pointer;
    00112 };
    00113
    00114 } // end namespace gdcm
    00115
    00116 #endif //GDCMSMARTPOINTER_H