DGtal::CountedPtrOrPtr< T > Class Template Reference

Aim: Smart or simple pointer on T. It can be a smart pointer based on reference counts or a simple pointer on T depending either on a boolean value given at construction or on the constructor used. In the first case, we will call this pointer object smart, otherwise we will call it simple. More...

#include <DGtal/base/CountedPtrOrPtr.h>

Inheritance diagram for DGtal::CountedPtrOrPtr< T >:

Public Types
typedef CountedPtr< T >::Counter	Counter
	The counter is the same as CountedPtr.

Public Member Functions
	CountedPtrOrPtr (T *p=0, bool isCountedPtr=true)
	~CountedPtrOrPtr ()
	CountedPtrOrPtr (const CountedPtr< T > &r) noexcept
	CountedPtrOrPtr (const CountedPtrOrPtr &r) noexcept
CountedPtrOrPtr &	operator= (const CountedPtrOrPtr &r)
CountedPtrOrPtr &	operator= (const CountedPtr< T > &r)
bool	isSmart () const
bool	isSimple () const
bool	operator== (const T *other) const
bool	operator!= (const T *other) const
T &	operator* () const noexcept
T *	operator-> () const noexcept
T *	get () const noexcept
bool	unique () const noexcept
unsigned int	count () const
T *	drop ()
void	selfDisplay (std::ostream &out) const
bool	isValid () const

Private Member Functions
Counter *	counterPtr () const
T *	ptr () const
void	acquire (Counter *c) noexcept
void	release ()

Private Attributes
void *	myAny
bool	myIsCountedPtr
	If true, 'this' pointer object is smart, otherwise it is simple.

Friends
class	CountedConstPtrOrConstPtr< T >

Detailed Description

template<typename T>
class DGtal::CountedPtrOrPtr< T >

Aim: Smart or simple pointer on T. It can be a smart pointer based on reference counts or a simple pointer on T depending either on a boolean value given at construction or on the constructor used. In the first case, we will call this pointer object smart, otherwise we will call it simple.

Description of template class 'CountedPtrOrPtr'

This object is useful when instantiating from an Alias<T> object, letting the user specify if it uses smart pointers or simply pointers. This class should be used as a meta-type for data members, when the programmer wants to hold a reference to some object during some period, but also wants to let the user decides whether the class should keep a smart reference or non-smart reference to the object. How and where to use such smart pointers is explained in User passing an argument to an Alias parameter.

struct B {};
struct A {
  CountedPtrOrPtr<B> myPtrB;
  A( Alias<B> someB ) : myPtrB( B ) {}
};
int main() {
  B b1;
  A a1( b1 ); // a1.myPtrB points to b1, classic pointer
  B* b2 = new B;
  A a2( b2 ); // a2.myPtrB acquires b2 (and will take care of freeing it)
  CountedPtr<B> b3 = CountedPtr<B>( new B ); // smart pointer
  A a3( b3 ); // a3.myPtrB smart points to b3.

Template Parameters

T	any data type.

See also

CountedPtr

Alias

Definition at line 95 of file CountedPtrOrPtr.h.

Member Typedef Documentation

Counter

template<typename T>

typedef CountedPtr<T>::Counter DGtal::CountedPtrOrPtr< T >::Counter

The counter is the same as CountedPtr.

Definition at line 104 of file CountedPtrOrPtr.h.

Constructor & Destructor Documentation

CountedPtrOrPtr() [1/3]

template<typename T>

DGtal::CountedPtrOrPtr< T >::CountedPtrOrPtr ( T * p = 0, bool isCountedPtr = true )

inlineexplicit

Default Constructor and constructor from pointer. The created object is either a simple pointer on p (not acquired) if isCountedPtr is false, or a smart pointer based on reference counts (CountedPtr).

Parameters

p	is a pointer to some object T. If isCountedPtr is true, then pointer p should point to some dynamically allocated object T, and the pointer is acquired. If isCountedPtr is false, then this object holds only the pointer p, without acquiring it.
isCountedPtr	when 'true', stores p as a smart (counted) pointer, otherwise stores p directly.

Definition at line 121 of file CountedPtrOrPtr.h.

      : myAny(0), myIsCountedPtr( isCountedPtr )
    { 
      if ( isCountedPtr ) {
        if (p) myAny = static_cast<void*>( new Counter( p ) );
      }
      else
        myAny = static_cast<void*>( p );
    }

References myAny, and myIsCountedPtr.

Referenced by CountedConstPtrOrConstPtr< T >, CountedPtrOrPtr(), operator=(), and operator=().

~CountedPtrOrPtr()

template<typename T>

DGtal::CountedPtrOrPtr< T >::~CountedPtrOrPtr ( )

inline

Destructor. If this pointer object was smart, the pointed object is released (and possibly freed if the reference count was 1), otherwise, if this pointer object was simple, the destructor does nothing.

Definition at line 137 of file CountedPtrOrPtr.h.

    { 
      if ( myIsCountedPtr ) release(); 
    }

References myIsCountedPtr, and release().

CountedPtrOrPtr() [2/3]

template<typename T>

DGtal::CountedPtrOrPtr< T >::CountedPtrOrPtr ( const CountedPtr< T > & r )

inlinenoexcept

Constructor from smart pointer (CountedPtr) r. In this case, this pointer object is smart and acquire the given smart pointer.

Parameters

r	the smart pointer to acquire.

Definition at line 149 of file CountedPtrOrPtr.h.

      : myIsCountedPtr( true )
    { 
      acquire( r.myCounter ); 
    }

References acquire().

CountedPtrOrPtr() [3/3]

template<typename T>

DGtal::CountedPtrOrPtr< T >::CountedPtrOrPtr ( const CountedPtrOrPtr< T > & r )

inlinenoexcept

Copy constructor. If r is smart, then this pointer object is also smart and acquires r (no duplication). Otherwise, if r is simple, then this pointer object only points at the same place.

Parameters

r	the other pointer to clone, which may be smart or simple.

Definition at line 164 of file CountedPtrOrPtr.h.

      : myIsCountedPtr( r.myIsCountedPtr )
    { 
      if ( myIsCountedPtr )
        acquire( r.counterPtr() ); 
      else
        myAny = r.myAny;
    }

References acquire(), CountedPtrOrPtr(), myAny, and myIsCountedPtr.

Member Function Documentation

acquire()

template<typename T>

void DGtal::CountedPtrOrPtr< T >::acquire ( Counter * c )

inlineprivatenoexcept

Tells this smart pointer that it should reference the counter c. If c is not null, the number of reference counts is incremented.

Parameters

c	any counter (except this.myCounter).

Precondition

'this' pointer object is smart.

Definition at line 382 of file CountedPtrOrPtr.h.

    { // increment the count
      // Travis is too slow in Debug mode with this ASSERT.
      ASSERT( myIsCountedPtr );
      myAny = static_cast<void*>( c );
      if (c) ++c->count;
    }

References myAny, and myIsCountedPtr.

Referenced by CountedPtrOrPtr(), CountedPtrOrPtr(), operator=(), and operator=().

count()

template<typename T>

unsigned int DGtal::CountedPtrOrPtr< T >::count ( ) const

inline

Note

For debug.

Returns

if 'this' object is smart, returns the number of smart pointers pointing to the same object as 'this', or 0 if 'this' object is simple.

Definition at line 314 of file CountedPtrOrPtr.h.

    {
      return myIsCountedPtr ? counterPtr()->count : 0; 
    }

References DGtal::CountedPtr< T >::Counter::count, counterPtr(), and myIsCountedPtr.

Referenced by testCountedConstPtrOrConstPtrMemory(), and testCountedPtrOrPtrMemory().

counterPtr()

template<typename T>

Counter * DGtal::CountedPtrOrPtr< T >::counterPtr ( ) const

inlineprivate

Precondition

'this' pointer object is smart.

Returns

the (possibly shared) counter pointed by myAny.

Definition at line 356 of file CountedPtrOrPtr.h.

    { 
      // Travis is too slow in Debug mode with this ASSERT.
      ASSERT( myIsCountedPtr );
      return static_cast<Counter*>( myAny ); 
    }

References myAny, and myIsCountedPtr.

Referenced by count(), drop(), get(), operator!=(), operator*(), operator->(), DGtal::CountedConstPtrOrConstPtr< T >::operator=(), operator=(), operator==(), release(), and unique().

drop()

template<typename T>

T * DGtal::CountedPtrOrPtr< T >::drop ( )

inline

Gives back the pointer without deleting him. Deletes only the Counter if 'this' was smart.

Returns

the address that was {smartly} or {simply} pointed by 'this' pointer.

Note

Use with care.

Precondition

'isValid()' and, if smart, 'unique()'.

Definition at line 329 of file CountedPtrOrPtr.h.

    { // Gives back the pointer without deleting him. Delete only the counter.
      ASSERT( isValid() );
      if ( myIsCountedPtr ) {
        ASSERT( unique() );
        T* tmp = counterPtr()->ptr;
        delete counterPtr();
        myAny = 0; 
        return tmp;
      } else {
        return ptr();
      }
    }

References counterPtr(), isValid(), myAny, myIsCountedPtr, DGtal::CountedPtr< T >::Counter::ptr, ptr(), and unique().

get()

template<typename T>

T * DGtal::CountedPtrOrPtr< T >::get ( ) const

inlinenoexcept

Secured member access operator.

Returns

a pointer on the object of type T that is smartly or simply pointed by 'this' or 0 if the object is not valid ('isValid()' is false).

Definition at line 290 of file CountedPtrOrPtr.h.

    {
      return myIsCountedPtr ? ( myAny ? counterPtr()->ptr : 0 ) : ptr(); 
    }

References counterPtr(), myAny, myIsCountedPtr, DGtal::CountedPtr< T >::Counter::ptr, and ptr().

Referenced by testCountedConstPtrOrConstPtrMemory(), and testCountedPtrOrPtrMemory().

isSimple()

template<typename T>

bool DGtal::CountedPtrOrPtr< T >::isSimple ( ) const

inline

Returns

'true' iff 'this' pointer object is simple.

Definition at line 225 of file CountedPtrOrPtr.h.

    {
      return ! myIsCountedPtr;
    }

References myIsCountedPtr.

Referenced by testCountedPtrOrPtrMemory().

isSmart()

template<typename T>

bool DGtal::CountedPtrOrPtr< T >::isSmart ( ) const

inline

Returns

'true' iff 'this' pointer object is smart.

Definition at line 217 of file CountedPtrOrPtr.h.

    {
      return myIsCountedPtr;
    }

References myIsCountedPtr.

Referenced by testCountedPtrOrPtrMemory().

isValid()

template<typename T>

bool DGtal::CountedPtrOrPtr< T >::isValid

(

)

const

Checks the validity/consistency of the object.

Returns

'true' if the object is valid, 'false' otherwise.

Referenced by drop(), operator*(), and operator->().

operator!=()

template<typename T>

bool DGtal::CountedPtrOrPtr< T >::operator!= ( const T * other ) const

inline

Inequality operator !=

Parameters

other

any other pointer.

Returns

'true' if 'this' points to a different address than other.

Definition at line 247 of file CountedPtrOrPtr.h.

    {
      return myIsCountedPtr ? ( myAny ? counterPtr()->ptr : 0 ) != other : ptr() != other;
    }

References counterPtr(), myAny, myIsCountedPtr, DGtal::CountedPtr< T >::Counter::ptr, and ptr().

operator*()

template<typename T>

T & DGtal::CountedPtrOrPtr< T >::operator* ( ) const

inlinenoexcept

Dereferencing operator.

Returns

a reference on the object of type T that is smartly or simply pointed by 'this'.

Precondition

'isValid()' is true

Definition at line 260 of file CountedPtrOrPtr.h.

    {
      // Travis is too slow in Debug mode with this ASSERT.
      ASSERT( isValid() );
      return myIsCountedPtr ? ( * counterPtr()->ptr ) : ( * ptr() ); 
    }

References counterPtr(), isValid(), myIsCountedPtr, DGtal::CountedPtr< T >::Counter::ptr, and ptr().

operator->()

template<typename T>

T * DGtal::CountedPtrOrPtr< T >::operator-> ( ) const

inlinenoexcept

Member access operator.

Returns

a pointer on the object of type T that is smartly or simply pointed by 'this' or 0 if the object is not valid ('isValid()' is false).

Precondition

'isValid()' is true

Definition at line 276 of file CountedPtrOrPtr.h.

    {
      // Travis is too slow in Debug mode with this ASSERT.
      ASSERT( isValid() );
      return myIsCountedPtr ? counterPtr()->ptr : ptr(); 
    }

References counterPtr(), isValid(), myIsCountedPtr, DGtal::CountedPtr< T >::Counter::ptr, and ptr().

operator=() [1/2]

template<typename T>

CountedPtrOrPtr & DGtal::CountedPtrOrPtr< T >::operator= ( const CountedPtr< T > & r )

inline

Assignment with smart pointer (CountedPtr). If 'this' was smart, then the shared pointer is released. Then this pointer object becomes also smart and acquires r (no duplication).

Parameters

r	the other smart pointer to clone.

Returns

a reference to 'this'.

Definition at line 206 of file CountedPtrOrPtr.h.

    {
      if ( myIsCountedPtr ) release();
      myIsCountedPtr = true;
      acquire( r.myCounter );
      return *this;
    }

References acquire(), CountedPtrOrPtr(), DGtal::CountedPtr< T >::myCounter, myIsCountedPtr, and release().

operator=() [2/2]

template<typename T>

CountedPtrOrPtr & DGtal::CountedPtrOrPtr< T >::operator= ( const CountedPtrOrPtr< T > & r )

inline

Assignment. If 'this' was smart, then the shared pointer is released. Then, if r is smart, then this pointer object is also smart and acquires r (no duplication). Otherwise, if r is simple, then this pointer object only points at the same place.

Parameters

r	the other pointer to clone, which may be smart or simple.

Returns

a reference to 'this'.

Definition at line 185 of file CountedPtrOrPtr.h.

    {
      if ( this != & r ) {
        if ( myIsCountedPtr ) release();
        myIsCountedPtr = r.myIsCountedPtr;
        if ( r.myIsCountedPtr ) acquire( r.counterPtr() );
        else myAny = r.myAny;
      }
      return *this;
    }

References acquire(), CountedPtrOrPtr(), counterPtr(), myAny, myIsCountedPtr, and release().

operator==()

template<typename T>

bool DGtal::CountedPtrOrPtr< T >::operator== ( const T * other ) const

inline

Equality operator ==

Parameters

other

any other pointer.

Returns

'true' if pointed address is equal to other.

Definition at line 236 of file CountedPtrOrPtr.h.

    {
      return myIsCountedPtr ? ( myAny ? counterPtr()->ptr : 0 ) == other : ptr() == other;
    }

References counterPtr(), myAny, myIsCountedPtr, DGtal::CountedPtr< T >::Counter::ptr, and ptr().

ptr()

template<typename T>

T * DGtal::CountedPtrOrPtr< T >::ptr ( ) const

inlineprivate

Precondition

'this' pointer object is simple.

Returns

the address pointed by myAny.

Definition at line 368 of file CountedPtrOrPtr.h.

    { 
      // Travis is too slow in Debug mode with this ASSERT.
      ASSERT( ! myIsCountedPtr );
      return static_cast<T*>( myAny ); 
    }

References myAny, and myIsCountedPtr.

Referenced by drop(), get(), operator!=(), operator*(), operator->(), and operator==().

release()

template<typename T>

void DGtal::CountedPtrOrPtr< T >::release ( )

inlineprivate

Tells this smart pointer to that it should release its current counter. If this counter was shared then the number of reference counts is decremented, else both the object pointed by the counter and the counter are freed. In all cases, this smart pointer becomes invalid.

Precondition

'this' pointer object is smart.

Definition at line 398 of file CountedPtrOrPtr.h.

    { // decrement the count, delete if it is 0
      // Travis is too slow in Debug mode with this ASSERT.
      ASSERT( myIsCountedPtr );
      if (myAny) {
        Counter * counter = counterPtr();
        if (--counter->count == 0) {
          delete counter->ptr;
          delete counter;
        }
        myAny = 0;
      }
    }

References DGtal::CountedPtr< T >::Counter::count, counterPtr(), myAny, myIsCountedPtr, and DGtal::CountedPtr< T >::Counter::ptr.

Referenced by operator=(), operator=(), and ~CountedPtrOrPtr().

selfDisplay()

template<typename T>

void DGtal::CountedPtrOrPtr< T >::selfDisplay

(

std::ostream &

out

)

const

Writes/Displays the object on an output stream.

Parameters

out	the output stream where the object is written.

unique()

template<typename T>

bool DGtal::CountedPtrOrPtr< T >::unique ( ) const

inlinenoexcept

Returns

'true' iff the smart pointer is the sole one pointing on this object or if the smart pointer is invalid ('isValid()' is false) or if 'this' object is simple.

Definition at line 300 of file CountedPtrOrPtr.h.

    {
      return myIsCountedPtr
        ? ( myAny ? counterPtr()->count == 1 : true )
        : true;
    }

References DGtal::CountedPtr< T >::Counter::count, counterPtr(), myAny, and myIsCountedPtr.

Referenced by drop().

Friends And Related Symbol Documentation

CountedConstPtrOrConstPtr< T >

template<typename T>

friend class CountedConstPtrOrConstPtr< T >

friend

Definition at line 450 of file CountedPtrOrPtr.h.

References CountedPtrOrPtr().

Field Documentation

myAny

template<typename T>

void* DGtal::CountedPtrOrPtr< T >::myAny

private

If smart, the counter object pointed by 'this', or if simple, the address of the object pointed by 'this'.

Definition at line 347 of file CountedPtrOrPtr.h.

Referenced by acquire(), CountedPtrOrPtr(), CountedPtrOrPtr(), counterPtr(), drop(), get(), operator!=(), DGtal::CountedConstPtrOrConstPtr< T >::operator=(), operator=(), operator==(), ptr(), release(), and unique().

myIsCountedPtr

template<typename T>

bool DGtal::CountedPtrOrPtr< T >::myIsCountedPtr

private

If true, 'this' pointer object is smart, otherwise it is simple.

Definition at line 349 of file CountedPtrOrPtr.h.

Referenced by acquire(), count(), CountedPtrOrPtr(), CountedPtrOrPtr(), counterPtr(), drop(), get(), isSimple(), isSmart(), operator!=(), operator*(), operator->(), DGtal::CountedConstPtrOrConstPtr< T >::operator=(), operator=(), operator=(), operator==(), ptr(), release(), unique(), and ~CountedPtrOrPtr().

---

The documentation for this class was generated from the following files:

• CountedPtr.h
• CountedPtrOrPtr.h