eC_TSafeIterator< T > Class Template Reference

An iterator that stays valid even if elements are deleted from the list. More...

#include <eC_TList_Iterators.h>

Inheritance diagram for eC_TSafeIterator< T >:

Public Member Functions
	eC_TSafeIterator ()
	eC_TSafeIterator (const eC_TSafeIterator< T > &kIter)
virtual eC_Bool	IsInsideList () const
eC_Bool	IsNextValid () const
eC_Bool	IsPreviousValid () const
eC_Bool	operator!= (const eC_TSafeIterator &kIter)
eC_TSafeIterator &	operator++ ()
eC_TSafeIterator &	operator-- ()
eC_TSafeIterator &	operator= (const eC_TSafeIterator &kIter)
eC_Bool	operator== (const eC_TSafeIterator &kIter) const
Public Member Functions inherited from eC_TIterator< T >
	eC_TIterator ()
	eC_TIterator (const eC_TIterator< T > &x)
	eC_TIterator (Node *pNode)
virtual	~eC_TIterator ()
	Destructor.
virtual eC_Bool	IsInsideList () const
eC_Bool	IsValid () const
eC_Bool	operator!= (const eC_TIterator &kIter) const
T &	operator* ()
eC_TIterator &	operator++ ()
eC_TIterator	operator++ (int)
eC_TIterator &	operator-- ()
eC_TIterator	operator-- (int)
eC_TIterator &	operator= (const eC_TIterator &kIter)
eC_Bool	operator== (const eC_TIterator &kIter) const
eC_Bool	operator== (const Node *const ptrNode) const

Friends
class	eC_TListDoubleLinked< T >

Additional Inherited Members
Protected Types inherited from eC_TIterator< T >
typedef ListNode< T >	Node
	typedef for node
Protected Member Functions inherited from eC_TIterator< T >
Node *	GetNode () const
Protected Attributes inherited from eC_TIterator< T >
Node *	m_pNode
	this node More...

Detailed Description

template<class T>
class eC_TSafeIterator< T >

An iterator that stays valid even if elements are deleted from the list.

With safe iterators it is possible to remove elements while iterating through a list.

With IsValid() it can be tested if the iterator may be dereferenced. If an item is deleted, the iterator is invalid, but you can still iterate through the list. After the next step (increment or decrement) the iterator is valid again (until you remove another element). After sorting and eC_TListDoubleLinked<T>::RemoveAll() all safe iterators are invalid and have to be set again.

Example:

eC_TListDoubleLinked<listT>::SafeIterator my_SafeIterator();
 
for (my_SafeIterator = m_list.GetBegin(); my_SafeIterator.InsideList(); ++my_SafeIterator)
{
    if (*my_SafeIterator == testValue)
    {
        m_list.Remove(testValue);
    }
 
    if (my_SafeIterator.IsValid())
    {
        // The iterator is still valid and can be used to get a reference to
        // the element.
        cout << *my_SafeIterator << endl;
    }
    else
    {
        // If testValue was removed, the iterator cannot be used to get
        // reference to the element.
        cout << "Value invalid" << endl;
    }
}

If you remove an item and add one at the position of the removed element (in one iteration step) it is possible that the new element is "lost" in that iteration.

Example

3-5-8

5 is deleted 7 is added

3-7-8

In this case 7 will be "lost" if iterator pointed at 5, because iterator is now pointing at 7, and after next iteration step it will be pointing at 8.

Note: This iterator does not have postfix increment/decrement operators because implementing them for the current approach for this safe iterator is not effective.

Constructor & Destructor Documentation

eC_TSafeIterator() [1/2]

template<class T >

eC_TSafeIterator< T >::eC_TSafeIterator ( )

inline

Constructor needs pointer to list, iterator will be used with. This is necessary to register iterator in this list, so that iterators can be updated if list is modified.

eC_TSafeIterator() [2/2]

template<class T >

eC_TSafeIterator< T >::eC_TSafeIterator ( const eC_TSafeIterator< T > &  kIter )

inline

Copy constructor.

Parameters

kIter

Where to copy from

Member Function Documentation

IsInsideList()

template<class T >

virtual eC_Bool eC_TSafeIterator< T >::IsInsideList ( ) const

inlinevirtual

!DO NOT USE WHEN ITERATING BACKWARDS AND DELETING NODES! Use FOR_ALL_BACKWARD_SAFE instead. Used to test if iterator is not pointing beyond list.

Returns

True, if iterator is pointing an element of the list, false if iterator is pointing in front of first or behind last list element.

Reimplemented from eC_TIterator< T >.

IsNextValid()

template<class T >

eC_Bool eC_TSafeIterator< T >::IsNextValid ( ) const

inline

Returns

Returns if a valid node is available behind the current node.

IsPreviousValid()

template<class T >

eC_Bool eC_TSafeIterator< T >::IsPreviousValid ( ) const

inline

Returns

Returns if a valid node is available in front of the current node.

operator!=()

template<class T >

eC_Bool eC_TSafeIterator< T >::operator!= ( const eC_TSafeIterator< T > &  kIter )

inline

Used to compare two Iterators.

Parameters

kIter

What to compare with

Returns

False, if iterators are pointing to the same list element and iterator would behave in the same way in case of iteration, True if not

operator++()

template<class T >

eC_TSafeIterator & eC_TSafeIterator< T >::operator++ ( )

inline

Used to increment Iterator. Prefix version. Iterator is pointing to next list element.

Returns

Unchanged iterator. If current element is beyond the end of the list then an interator will be returned that will evaluate IsInsideList() to false, as before.

operator--()

template<class T >

eC_TSafeIterator & eC_TSafeIterator< T >::operator-- ( )

inline

Used to decrement Iterator. Prefix version. Iterator is pointing to previous list element.

Returns

Unchanged iterator. If current element is beyond the beginning of the list then an interator will be returned that will evaluate IsInsideList() to false, as before.

operator=()

template<class T >

eC_TSafeIterator & eC_TSafeIterator< T >::operator= ( const eC_TSafeIterator< T > &  kIter )

inline

Assignment operator.

Returns

eC_TSafeIterator& to local node after assignment

Parameters

kIter

Where to copy from

operator==()

template<class T >

eC_Bool eC_TSafeIterator< T >::operator== ( const eC_TSafeIterator< T > &  kIter ) const

inline

Used to compare two iterators.

Parameters

kIter

What to compare with

Returns

True, if iterators are pointing to the same list element and iterator would behave in the same way in case of iteration, False if not

---

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

• eC_TList_Iterators.h