Class TDblQueBase

TDblQueBase

Support

Supported from 5.0

Description

A base class that provides implementation for the doubly linked list header. It also encapsulates the offset value of a link object.

The class is abstract and is not intended to be instantiated.

Defined in TDblQueBase:
DoAddFirst(), DoAddLast(), DoAddPriority(), IsEmpty(), Reset(), SetOffset(), TDblQueBase(), TDblQueBase(), TDblQueBase(), __DbgTestEmpty(), iHead, iOffset, operator=()

protected : TDblQueBase();

Description

Default constructor.

It sets:

• iHead to point to this object in both the forwards and backwards direction

• iOffset to zero.

See also:

• iHead
• iOffset

protected : TDblQueBase(TInt anOffset);

Description

Constructor with specified offset.

It sets:

• iHead to point to this object in both the forwards and backwards direction.

• iOffset to the specified value.

Parameters

See also:

• iHead
• iOffset

TBool IsEmpty() const;

Description

Tests whether the doubly linked list is empty, i.e. has no list elements.

Return value

void Reset();

Description

Empties the doubly linked list.

After a call to this function, there are no elements queued from the header; the elements are orphaned. Special care must be taken when list elements are CBase derived objects, i.e. are allocated on the heap.

void SetOffset(TInt anOffset);

Description

Sets the offset of the link object from the start of a doubly linked list element.

Parameters

See also:

• Using TDblQue<class T>
• TDblQue

protected : void DoAddFirst(TAny* aPtr);

Description

Implements the insertion of the specified list element at the front of the doubly linked list.

This function is called by TDblQue::AddFirst().

Parameters

See also:

• TDblQue::AddFirst()

protected : void DoAddLast(TAny* aPtr);

Description

Implements the insertion of the specified list element at the back of the doubly linked list.

This function is called by TDblQue::AddLast().

Parameters

See also:

• TDblQue::AddLast()

protected : void DoAddPriority(TAny* aPtr);

Description

Implements the insertion of the specified list element in priority order.

This function is called by TPriQue::Add().

Parameters

See also:

• TPriQue::Add()

protected : void __DbgTestEmpty() const;

Description

Tests whether the queue is empty.

The function is implemented as an __ASSERT_DEBUG. If the assertion fails, a USER 79 panic is raised.

protected : TDblQueLink iHead;

Description

The head, or anchor point of the queue.

protected : TInt iOffset;

Description

The offset of a component link object within elements that form the list.

TDblQueBase(const TDblQueBase& aQue);
    

Description

This is internal and not intended for use.

TDblQueBase& operator=(const TDblQueBase& aQue);

Description

This is internal and not intended for use.