MnRefCountedPointer.h

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// @(#)root/minuit2:$Id: MnRefCountedPointer.h 20880 2007-11-19 11:23:41Z rdm $
// Authors: M. Winkler, F. James, L. Moneta, A. Zsenei   2003-2005  

/**********************************************************************
 *                                                                    *
 * Copyright (c) 2005 LCG ROOT Math team,  CERN/PH-SFT                *
 *                                                                    *
 **********************************************************************/

#ifndef ROOT_Minuit2_MnRefCountedPointer
#define ROOT_Minuit2_MnRefCountedPointer

#include "MnReferenceCounter.h"

namespace ROOT {

   namespace Minuit2 {


template<class T> class MnRefCountedPointer {

public:

  // Default constructor needed for use inside array, vector, etc.
  MnRefCountedPointer() : fPtr(0), fCounter(0) {}
  
  MnRefCountedPointer(T* pt) : 
    fPtr(pt), fCounter(new MnReferenceCounter()) {AddReference();}

  MnRefCountedPointer(const MnRefCountedPointer<T>& other) : 
    fPtr(other.fPtr), fCounter(other.fCounter) {AddReference();}

  ~MnRefCountedPointer() {
    /*
    if(References() == 0) {
      if(fPtr) delete fPtr; 
      if(fCounter) delete fCounter;
    }
    else RemoveReference();
    */
    if(References() != 0) RemoveReference();
  }
  
  bool IsValid() const {return fPtr != 0;}
  
  MnRefCountedPointer& operator=(const MnRefCountedPointer<T>& other) {
    if(fPtr != other.fPtr) {
      RemoveReference();
      fPtr = other.fPtr;
      fCounter = other.fCounter;
      AddReference();
    }
    return *this;
  }

  MnRefCountedPointer& operator=(T* ptr) {
    if(fPtr != ptr) {
      fPtr = ptr;
      fCounter = new MnReferenceCounter();
    }
    return *this;
  }

  T* Get() const {return fPtr;}

  T* operator->() const {DoCheck(); return fPtr;}
  
  T& operator*() const {DoCheck(); return *fPtr;}
  
  bool operator==(const  T* otherP) const {return fPtr == otherP;}
 
  bool operator<(const  T* otherP) const {return fPtr < otherP;}
 
  unsigned int References() const {return fCounter->References();}

  void AddReference() const {fCounter->AddReference();}

  void RemoveReference() {
    fCounter->RemoveReference();
    if(References() == 0) {
      delete fPtr; fPtr=0; 
      delete fCounter; fCounter=0;
    }
  }
  
private:
  
  T*  fPtr;  
  MnReferenceCounter* fCounter;
 
private:

  void DoCheck() const {assert(IsValid());}  
};

  }  // namespace Minuit2

}  // namespace ROOT

#endif  // ROOT_Minuit2_MnRefCountedPointer

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