TVirtualArray.h

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// @(#)root/io:$Id$
// Author: Philippe Canal July, 2008
 
/*************************************************************************
 * Copyright (C) 1995-2000, Rene Brun and Fons Rademakers.               *
 * All rights reserved.                                                  *
 *                                                                       *
 * For the licensing terms see $ROOTSYS/LICENSE.                         *
 * For the list of contributors see $ROOTSYS/README/CREDITS.             *
  *************************************************************************/
 
#ifndef ROOT_TVirtualArray
#define ROOT_TVirtualArray
 
 
 
/**
\class TVirtualArray
\ingroup IO
Wrapper around an object and giving indirect access to its content
even if the object is not of a class in the Cint/Reflex dictionary.
*/
 
#include "TClass.h"
#include "TClassRef.h"
 
class TVirtualArray {
public:
   using ObjectPtr = TClass::ObjectPtr;
 
   TClassRef  fClass;
   UInt_t     fCapacity;
   UInt_t     fSize;
   ObjectPtr  fArray; ///< fSize elements
 
   TVirtualArray( TClass *cl, UInt_t size ) : fClass(cl), fCapacity(size), fSize(size), fArray( ( cl ? cl->NewObjectArray(size) : ObjectPtr{nullptr, nullptr}) ) {};
   ~TVirtualArray() { if (fClass) fClass->DeleteArray( fArray ); }
 
   TClass *GetClass() { return fClass; }
   char *operator[](UInt_t ind) const { return GetObjectAt(ind); }
   char *GetObjectAt(UInt_t ind) const { return ((char*)fArray.GetPtr())+fClass->Size()*ind; }
 
   void SetSize(UInt_t size) {
      // Set the used size of this array to 'size'.   If size is greater than the existing
      // capacity, reallocate the array BUT no data is preserved.
      fSize = size;
      if (fSize > fCapacity && fClass) {
         fClass->DeleteArray( fArray );
         fArray = fClass->NewObjectArray(fSize);
         fCapacity = fSize;
      }
   }
 
 
};
 
#endif // ROOT_TVirtualArray