BorlandTalk.com

Jonathan Benedicto · Guest

I've written a smart pointer class because I didn't like being dependant on
the boost library, but for some reason there must be a bug in it that I
can't see because I keep on gettting problems with it.

It is a shared pointer class, so that makes it more complicated, but I
can't see my bug.

Can anyone point out to me the problem ?

template <class T> class JFSmartPtrData
{
public:
T *Ptr;
int RefCount;

JFSmartPtrData() : Ptr( NULL ), RefCount( 0 ) { }
~JFSmartPtrData() { }
};

template <class T> class JFSmartPtr
{
private:
bool OwnsData;

void ReleaseDataPtr()
{
if( Data->Ptr && --Data->RefCount < 1 )
{
delete Data->Ptr;
Data->Ptr = NULL;
}
}

void ReleaseData()
{
if( OwnsData )
{
delete Data;
Data = NULL;
}
}

public:
JFSmartPtr( T *PPtr = NULL )
: Data( new JFSmartPtrData<T>() ), OwnsData( true )
{
Data->Ptr = PPtr;
Data->RefCount = 1;
}

JFSmartPtr( JFSmartPtr const &PInstance )
: OwnsData( false )
{
Data = PInstance.Data;
++Data->RefCount;
}

~JFSmartPtr()
{
ReleaseDataPtr();
ReleaseData();
}

void Reset( T *PPtr = NULL )
{
ReleaseDataPtr();

Data->Ptr = PPtr;
Data->RefCount = 1;
}

void reset( T *PPtr = NULL )
{
Reset( PPtr );
}

T* GetPtr() const
{
return Data->Ptr;
}

T* get() const
{
return GetPtr();
}

JFSmartPtr& operator =( JFSmartPtr const &PInstance )
{
ReleaseDataPtr();
ReleaseData();

Data = PInstance.Data;
++Data->RefCount;

return *this;
}

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

JFSmartPtrData<T> *Data;
};

Jonathan

Remy Lebeau (TeamB) · Guest

"Jonathan Benedicto" <incorrect (AT) no (DOT) server> wrote

Jonathan Benedicto · Guest

Remy Lebeau (TeamB) wrote:

Alisdair Meredith [TeamB] · Guest

Jonathan Benedicto wrote:

Alan Bellingham · Guest

"Jonathan Benedicto" <incorrect (AT) no (DOT) server> wrote:

Alan Bellingham · Guest

Alan Bellingham <alanb (AT) episys (DOT) com> wrote:

tinyabs · Guest

Personally I have a smart pointer class but it's not widely use by me.
Pointers and auto_ptr is still the main practice.

I understand some of us, including me, is looking or had looked at an ideal
environment where memory management are automatic. In that case, take a look
at D ([url]www.digitalmars.com)[/url]. It was announced in 1999 and currently has a
compiler (DMD) and a few lousy IDEs. The inventor is Walter Bright, a smart
guy who written other C/C++ compiler too. C++ programmers will find it easy
to pick up and it has many glorious language feature. However, it is still
in development stage.

Anyway, this is a good way to learn const correctness and operators in your
class design.

Jonathan Benedicto · Guest

Alisdair Meredith [TeamB] wrote:

Jonathan Benedicto · Guest

Alan Bellingham wrote:

Jonathan Benedicto · Guest

Alan Bellingham wrote:

Jonathan Benedicto · Guest

Tom Widmer wrote:

Jonathan Benedicto · Guest

tinyabs wrote:

Jonathan Benedicto · Guest

New code:

template <class T> class JFSmartPtrData
{
public:
T *Ptr;
int RefCount;

JFSmartPtrData() : Ptr( NULL ), RefCount( 0 ) { }
~JFSmartPtrData()
{
if( Ptr )
delete Ptr;
}
};
//---------------------------------------------------------------------------
template <class T> class JFSmartPtr
{
private:
JFSmartPtrData<T> *Data;

void ReleaseData()
{
if( --Data->RefCount < 1 )
{
delete Data;
Data = NULL;
}
}

public:
JFSmartPtr( T *PPtr = NULL )
: Data( new JFSmartPtrData {
Data->Ptr = PPtr;
Data->RefCount = 1;
}

JFSmartPtr( JFSmartPtr const &PInstance )
{
Data = PInstance.GetData();
++Data->RefCount;
}

~JFSmartPtr()
{
ReleaseData();
}

void Reset( T *PPtr = NULL )
{
ReleaseData();

Data = new JFSmartPtrData<T>();
Data->Ptr = PPtr;
Data->RefCount = 1;
}

void reset( T *PPtr = NULL )
{
Reset( PPtr );
}

T* GetPtr() const
{
return Data->Ptr;
}

T* get() const
{
return GetPtr();
}

JFSmartPtrData<T>* GetData() const
{
return Data;
}

JFSmartPtr& operator =( JFSmartPtr const &PInstance )
{
ReleaseData();

Data = PInstance.GetData();
++Data->RefCount;

return *this;
}

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

Jonathan

Alisdair Meredith [TeamB] · Guest

Jonathan Benedicto wrote:

Thomas Maeder [TeamB] · Guest

"Jonathan Benedicto" <incorrect (AT) no (DOT) server> writes: