Public Member Functions | Private Attributes

SmartPointer< T, P > Class Template Reference
[Memory handling]

List of all members.

Public Member Functions

 SmartPointer ()
template<class Q >
 SmartPointer (const SmartPointer< T, Q > &tt)
 SmartPointer (const SmartPointer< T, P > &tt)
 SmartPointer (T *t, const char *id)
 SmartPointer (T *t)
 ~SmartPointer ()
SmartPointer< T, P > & operator= (T *tt)
template<class Q >
SmartPointer< T, P > & operator= (const SmartPointer< T, Q > &tt)
SmartPointer< T, P > & operator= (const SmartPointer< T, P > &tt)
void clear ()
 operator T * () const
T & operator* () const
T * operator-> () const
template<class Q >
void swap (SmartPointer< T, Q > &tt)
void swap (T *&tt)
std::size_t memory_consumption () const

Private Attributes

T * t
const char *const id

Detailed Description

template<typename T, typename P = void>
class SmartPointer< T, P >

Smart pointers avoid destruction of an object in use. They can be used just like a pointer (i.e. using the * and -> operators and through casting) but make sure that the object pointed to is not deleted in the course of use of the pointer by signalling the pointee its use.

Objects pointed to, that is ,the class T, should inherit Subscriptor or must implement the same functionality. Null pointers are an exception from this rule and are allowed, too.

The second template argument P only serves a single purpose: if a constructor without a debug string is used, then the name of P is used as the debug string.

SmartPointer does NOT implement any memory handling! Especially, deleting a SmartPointer does not delete the object. Writing

 SmartPointer<T,P> dont_do_this = new T;

is a sure way to program a memory leak! The secure version is

 T* p = new T;
 {
   SmartPointer<T,P> t(p);
   ...
 }
 delete p;

Note that a smart pointer can handle constness of an object, i.e. a SmartPointer<const ABC> really behaves as if it were a pointer to a constant object (disallowing write access when dereferenced), while SmartPointer<ABC> is a mutable pointer.

Author:
Guido Kanschat, Wolfgang Bangerth, 1998 - 2009

Definition at line 59 of file smartpointer.h.


Constructor & Destructor Documentation

template<typename T , typename P >
SmartPointer< T, P >::SmartPointer (  ) [inline]

Standard constructor for null pointer. The id of this pointer is set to the name of the class P.

Definition at line 257 of file smartpointer.h.

template<typename T, typename P >
template<class Q >
SmartPointer< T, P >::SmartPointer ( const SmartPointer< T, Q > &  tt ) [inline]

Definition at line 291 of file smartpointer.h.

References SmartPointer< T, P >::t.

template<typename T, typename P>
SmartPointer< T, P >::SmartPointer ( const SmartPointer< T, P > &  tt ) [inline]

Definition at line 303 of file smartpointer.h.

References SmartPointer< T, P >::t.

template<typename T, typename P>
SmartPointer< T, P >::SmartPointer ( T *  t,
const char *  id 
) [inline]

Constructor taking a normal pointer. If possible, i.e. if the pointer is not a null pointer, the constructor subscribes to the given object to lock it, i.e. to prevent its destruction before the end of its use.

The id is used in the call to Subscriptor::subscribe(id) and by ~SmartPointer() in the call to Subscriptor::unsubscribe().

Definition at line 278 of file smartpointer.h.

template<typename T, typename P>
SmartPointer< T, P >::SmartPointer ( T *  t ) [inline]

Constructor taking a normal pointer. If possible, i.e. if the pointer is not a null pointer, the constructor subscribes to the given object to lock it, i.e. to prevent its destruction before the end of its use. The id of this pointer is set to the name of the class P.

Definition at line 266 of file smartpointer.h.

template<typename T , typename P >
SmartPointer< T, P >::~SmartPointer (  ) [inline]

Destructor, removing the subscription.

Definition at line 315 of file smartpointer.h.


Member Function Documentation

template<typename T, typename P >
SmartPointer< T, P > & SmartPointer< T, P >::operator= ( T *  tt ) [inline]

Assignment operator for normal pointers. The pointer subscribes to the new object automatically and unsubscribes to an old one if it exists. It will not try to subscribe to a null-pointer, but still delete the old subscription.

Definition at line 340 of file smartpointer.h.

template<typename T, typename P >
template<class Q >
SmartPointer< T, P > & SmartPointer< T, P >::operator= ( const SmartPointer< T, Q > &  tt ) [inline]

Assignment operator for SmartPointer. The pointer subscribes to the new object automatically and unsubscribes to an old one if it exists.

Definition at line 361 of file smartpointer.h.

References LAPACKSupport::T.

template<typename T, typename P>
SmartPointer< T, P > & SmartPointer< T, P >::operator= ( const SmartPointer< T, P > &  tt ) [inline]

Assignment operator for SmartPointer. The pointer subscribes to the new object automatically and unsubscribes to an old one if it exists.

Definition at line 382 of file smartpointer.h.

References LAPACKSupport::T.

template<typename T , typename P >
void SmartPointer< T, P >::clear (  ) [inline]

Delete the object pointed to and set the pointer to zero.

Definition at line 326 of file smartpointer.h.

template<typename T , typename P >
SmartPointer< T, P >::operator T * (  ) const [inline]

Conversion to normal pointer.

Definition at line 402 of file smartpointer.h.

template<typename T , typename P >
T & SmartPointer< T, P >::operator* (  ) const [inline]

Dereferencing operator. This operator throws an ExcNotInitialized if the pointer is a null pointer.

Definition at line 411 of file smartpointer.h.

References Assert, and StandardExceptions::ExcNotInitialized().

template<typename T , typename P >
T * SmartPointer< T, P >::operator-> (  ) const [inline]

Dereferencing operator. This operator throws an ExcNotInitialized if the pointer is a null pointer.

Definition at line 421 of file smartpointer.h.

References Assert, and StandardExceptions::ExcNotInitialized().

template<typename T, typename P >
template<class Q >
void SmartPointer< T, P >::swap ( SmartPointer< T, Q > &  tt ) [inline]

Exchange the pointers of this object and the argument. Since both the objects to which is pointed are subscribed to before and after, we do not have to change their subscription counters.

Note that this function (with two arguments) and the respective functions where one of the arguments is a pointer and the other one is a C-style pointer are implemented in global namespace.

Definition at line 432 of file smartpointer.h.

References swap(), and SmartPointer< T, P >::t.

Referenced by swap().

template<typename T, typename P >
void SmartPointer< T, P >::swap ( T *&  tt ) [inline]

Swap pointers between this object and the pointer given. As this releases the object pointed to presently, we reduce its subscription count by one, and increase it at the object which we will point to in the future.

Note that we indeed need a reference of a pointer, as we want to change the pointer variable which we are given.

Definition at line 447 of file smartpointer.h.

References swap().

template<typename T , typename P >
std::size_t SmartPointer< T, P >::memory_consumption (  ) const [inline]

Return an estimate of the amount of memory (in bytes) used by this class. Note in particular, that this only includes the amount of memory used by this object, not by the object pointed to.

Definition at line 463 of file smartpointer.h.


Member Data Documentation

template<typename T, typename P = void>
T* SmartPointer< T, P >::t [private]

Pointer to the object we want to subscribt to. Since it is often necessary to follow this pointer when debugging, we have deliberately chosen a short name.

Definition at line 243 of file smartpointer.h.

Referenced by SmartPointer< T, P >::SmartPointer(), and SmartPointer< T, P >::swap().

template<typename T, typename P = void>
const char* const SmartPointer< T, P >::id [private]

The identification for the subscriptor.

Definition at line 248 of file smartpointer.h.


The documentation for this class was generated from the following file:
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deal.II documentation generated on Fri Feb 3 2012 06:04:11 by doxygen 1.7.2