TReference.hxx

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/*
  This file is part of MURE,
  Copyright (C) 2007-2021 MURE developers.
 
  MURE is free software: you can redistribute it and/or modify
  it under the terms of the GNU Lesser General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.
 
  MURE 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 Lesser General Public License for more details.
 
  You should have received a copy of the GNU Lesser General Public License
  along with MURE.  If not, see <http://www.gnu.org/licenses/>.
*/
 
#ifndef _TREFERENCE_HXX_
#define _TREFERENCE_HXX_
 
 
class TReference
{
  public :
    TReference()
    {
        fNbReferences = 0;   
    }
    virtual ~TReference() = default;        
 
    void AddReference(unsigned n = 1)
    {
        fNbReferences += n;   
    }
    unsigned DelReference(unsigned n = 1)
    {
        fNbReferences -= n;    
        return fNbReferences;
    }
    unsigned Reference()
    {
        return fNbReferences;   
    }
  private :
    unsigned fNbReferences; 
 
};
 
 
template < class T > class Reference_ptr
{
  private:
    T *ptr; 
 
  public:
    explicit Reference_ptr(T *p = nullptr)
    {
        ptr = p;    
        if (ptr) ptr -> AddReference();
    }
    Reference_ptr(const Reference_ptr &r)
    {
        ptr = r.ptr;    
        ptr -> AddReference();
    }
    ~Reference_ptr()
    {
        if(ptr && ptr -> DelReference() == 0) delete ptr;   
    }
    //void Delete_ptr() {if(ptr) {cout<<" TRef delete: "<<ptr<<endl; delete ptr;}} //!< Custom destructor
    T &operator* () const
    {
        return *ptr;   
    }
    T *operator-> () const
    {
        return ptr;   
    }
    T *Get() const
    {
        return ptr;   
    }
 
    Reference_ptr &operator= (const Reference_ptr &r)
    {
        if (ptr != r.ptr)
        {
            if(ptr && ptr -> DelReference() == 0) delete ptr;
            ptr = r.ptr;
            if (ptr) ptr -> AddReference();
        }
        return *this;
    }
 
    Reference_ptr &operator= (T *p) 
    {
        if (ptr != p)
        {
            if(ptr && ptr -> DelReference() == 0) delete ptr;
            ptr = p;
            if (ptr) ptr -> AddReference();
        }
        return *this;
    }
 
    bool operator== (T *p)
    {
        return ptr == p;   
    }
    bool operator!= (T *p)
    {
        return ptr != p;   
    }
};
 
#endif