FlexPtr.h

#ifndef UTIL_FLEX_PTR_H
#define UTIL_FLEX_PTR_H

/*
* Util Package - C++ Utilities for Scientific Computation
*
* Copyright 2010 - 2017, The Regents of the University of Minnesota
* Distributed under the terms of the GNU General Public License.
*/

#include "isNull.h"
#include <util/global.h>

namespace Util
{

   template <typename T>
   class FlexPtr
   {

   public:

      typedef T element_type;

      FlexPtr()
       : ptr_(0),
         isOwner_(0)
      {}

      ~FlexPtr()
      {
         if (ptr_ != 0 && isOwner_) {  
            delete ptr_; 
         }
      }

      void acquire(T* p)
      {
         if (p == 0) {
            UTIL_THROW("Cannot acquire a null pointer");
         }  
         if (ptr_ != 0 && isOwner_) {
            delete ptr_; 
         }  
         ptr_     = p;
         isOwner_ = 1;
      }

      void copy(T* p)
      {
         if (p == 0) {
            UTIL_THROW("Cannot copy a null pointer");
         }  
         if (ptr_ != 0 && isOwner_) {
            delete ptr_; 
         }  
         ptr_     = p;
         isOwner_ = 0;
      }

      T& operator*() const
      {  return *ptr_; }

      T* operator->() const
      {  return ptr_; }

      T* get() const
      {  return ptr_; }

   private:

      T*  ptr_;

      int isOwner_;

      FlexPtr(const FlexPtr&);

      FlexPtr& operator = (const FlexPtr& );

   };

   template <typename T>
   inline bool isNull(FlexPtr<T> p)
   {  return (p.get() == 0); }

}

#endif