CountedPtr.h

#pragma once

#if defined(CountedPtr_RECURSES)
#error Recursive header files inclusion detected in CountedPtr.h
#else // defined(CountedPtr_RECURSES)

#define CountedPtr_RECURSES

#if !defined CountedPtr_h

#define CountedPtr_h

// Inclusions
#include <iostream>
#include "DGtal/base/Common.h"

namespace DGtal
{

  // template class CountedPtr
  template <typename T>
  class CountedPtr
  {
    // ----------------------- Standard services ------------------------------
  public:

    typedef T element_type;

    explicit CountedPtr(T* p = 0) // allocate a new counter
        : myCounter(0) { if (p) myCounter = new counter(p);}
    ~CountedPtr()
        {release();}
    CountedPtr(const CountedPtr& r) throw()
        {acquire(r.myCounter);}
    CountedPtr& operator=(const CountedPtr& r)
    {
        if (this != &r) {
            release();
            acquire(r.myCounter);
        }
        return *this;
    }

    T& operator*()  const throw()   {return *myCounter->ptr;}
    T* operator->() const throw()   {return myCounter->ptr;}
    T* get()        const throw()   {return myCounter ? myCounter->ptr : 0;}
    bool unique()   const throw()
    {return (myCounter ? myCounter->count == 1 : true);}

    unsigned int count() const      {return myCounter->count;}
private:

    struct counter {
        counter(T* p = 0, unsigned c = 1) : ptr(p), count(c) {}
        T*          ptr;
        unsigned    count;
    }* myCounter;

    void acquire(counter* c) throw()
    { // increment the count
        myCounter = c;
        if (c) ++c->count;
    }

    void release()
    { // decrement the count, delete if it is 0
        if (myCounter) {
            if (--myCounter->count == 0) {
                delete myCounter->ptr;
                delete myCounter;
            }
            myCounter = 0;
        }
    }


    // ----------------------- Interface --------------------------------------
  public:

    void selfDisplay ( std::ostream & out ) const;

    bool isValid() const;

    // ------------------------- Protected Datas ------------------------------
  private:
    // ------------------------- Private Datas --------------------------------
  private:

    // ------------------------- Hidden services ------------------------------
  protected:


    // ------------------------- Internals ------------------------------------
  private:

  }; // end of class CountedPtr


  template <typename T>
  std::ostream&
  operator<< ( std::ostream & out, const CountedPtr<T> & object );

} // namespace DGtal


// Includes inline functions.
#include "DGtal/base/CountedPtr.ih"

//                                                                           //

#endif // !defined CountedPtr_h

#undef CountedPtr_RECURSES
#endif // else defined(CountedPtr_RECURSES)