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PAbstractSortedList Class Reference

This class is a collection of objects which are descendents of the PObject class. More...

#include <lists.h>

Inheritance diagram for PAbstractSortedList:
Collaboration diagram for PAbstractSortedList:

Public Member Functions

Construction
 PAbstractSortedList ()
 Create a new, empty, sorted list. More...
 
Overrides from class PObject
virtual Comparison Compare (const PObject &obj) const
 Get the relative rank of the two lists. More...
 
Overrides from class PContainer
virtual PBoolean SetSize (PINDEX newSize)
 This function is meaningless for lists. More...
 
Overrides from class PCollection
virtual PINDEX Append (PObject *obj)
 Add a new object to the collection. More...
 
virtual PINDEX Insert (const PObject &before, PObject *obj)
 Add a new object to the collection. More...
 
virtual PINDEX InsertAt (PINDEX index, PObject *obj)
 Add a new object to the collection. More...
 
virtual PBoolean Remove (const PObject *obj)
 Remove the object from the collection. More...
 
virtual PObjectRemoveAt (PINDEX index)
 Remove the object at the specified ordinal index from the collection. More...
 
virtual void RemoveAll ()
 Remove all of the elements in the collection. More...
 
virtual PBoolean SetAt (PINDEX index, PObject *val)
 This method simply returns false as the list order is mantained by the class. More...
 
virtual PObjectGetAt (PINDEX index) const
 Get the object at the specified ordinal position. More...
 
virtual PINDEX GetObjectsIndex (const PObject *obj) const
 Search the collection for the specific instance of the object. More...
 
virtual PINDEX GetValuesIndex (const PObject &obj) const
 Search the collection for the specified value of the object. More...
 
- Public Member Functions inherited from PCollection
 PCollection (PINDEX initialSize=0)
 Create a new collection. More...
 
virtual void PrintOn (ostream &strm) const
 Print the collection on the stream. More...
 
__inline void remove (const PObject *obj)
 
__inline void clear ()
 
PINLINE void AllowDeleteObjects (PBoolean yes=true)
 Allow or disallow the deletion of the objects contained in the collection. More...
 
void DisallowDeleteObjects ()
 Disallow the deletion of the objects contained in the collection. More...
 
- Public Member Functions inherited from PContainer
 PContainer (PINDEX initialSize=0)
 Create a new unique container. More...
 
 PContainer (const PContainer &cont)
 Create a new refernce to container. More...
 
PContaineroperator= (const PContainer &cont)
 Assign one container reference to another. More...
 
virtual ~PContainer ()
 Destroy the container class. More...
 
virtual PINDEX GetSize () const
 Get the current size of the container. More...
 
__inline size_t size () const
 
PBoolean SetMinSize (PINDEX minSize)
 Set the minimum size of container. More...
 
virtual PBoolean IsEmpty () const
 Determine if the container is empty. More...
 
__inline bool empty () const
 
PBoolean IsUnique () const
 Determine if container is unique reference. More...
 
virtual PBoolean MakeUnique ()
 Make this instance to be the one and only reference to the container contents. More...
 
- Public Member Functions inherited from PObject
__inline unsigned GetTraceContextIdentifier () const
 Get PTRACE context identifier. More...
 
__inline void SetTraceContextIdentifier (unsigned id)
 
__inline void SetTraceContextIdentifier (const PObject &obj)
 
__inline void SetTraceContextIdentifier (const PObject *obj)
 
__inline void CopyTraceContextIdentifier (PObject &obj) const
 
__inline void CopyTraceContextIdentifier (PObject *obj) const
 
virtual ~PObject ()
 
__inline const char * GetClass () const
 
__inline bool IsClass (const char *name) const
 
__inline const PObjectPTraceObjectInstance () const
 
virtual PObjectClone () const
 Create a copy of the class on the heap. More...
 
template<class CLS >
CLS * CloneAs () const
 As for Clone() but converts to specified type. More...
 
virtual PINDEX HashFunction () const
 This function yields a hash value required by the PDictionary class. More...
 
virtual Comparison CompareObjectMemoryDirect (const PObject &obj) const
 Determine the byte wise comparison of two objects. More...
 
bool operator== (const PObject &obj) const
 Compare the two objects. More...
 
bool operator!= (const PObject &obj) const
 Compare the two objects. More...
 
bool operator< (const PObject &obj) const
 Compare the two objects. More...
 
bool operator> (const PObject &obj) const
 Compare the two objects. More...
 
bool operator<= (const PObject &obj) const
 Compare the two objects. More...
 
bool operator>= (const PObject &obj) const
 Compare the two objects. More...
 
virtual void ReadFrom (istream &strm)
 Input the contents of the object from the stream. More...
 

Protected Member Functions

void RemoveElement (PSortedListElement *node)
 
void LeftRotate (PSortedListElement *node)
 
void RightRotate (PSortedListElement *node)
 
void DeleteSubTrees (PSortedListElement *node, bool deleteObject)
 
PSortedListElementFindElement (const PObject &obj, PINDEX *index) const
 
PSortedListElementFindElement (const PObject *obj, PINDEX *index) const
 
- Protected Member Functions inherited from PCollection
PINLINE PCollection (int dummy, const PCollection *coll)
 Constructor used in support of the Clone() function. More...
 
- Protected Member Functions inherited from PContainer
 PContainer (int dummy, const PContainer *cont)
 Constructor used in support of the Clone() function. More...
 
 PContainer (PContainerReference &reference)
 Construct using static PContainerReference. More...
 
virtual void DestroyContents ()=0
 Destroy the container contents. More...
 
virtual void AssignContents (const PContainer &c)
 Copy the container contents. More...
 
void CopyContents (const PContainer &c)
 Copy the container contents. More...
 
void CloneContents (const PContainer *src)
 Create a duplicate of the container contents. More...
 
void Destruct ()
 Internal function called from container destructors. More...
 
virtual void DestroyReference ()
 Destroy the PContainerReference instance. More...
 
- Protected Member Functions inherited from PObject
 PObject ()
 Constructor for PObject, made protected so cannot ever create one on its own. More...
 

Protected Attributes

PSortedListInfom_info
 
- Protected Attributes inherited from PContainer
PContainerReferencereference
 
- Protected Attributes inherited from PObject
unsigned m_traceContextIdentifier
 

Additional Inherited Members

- Public Types inherited from PObject
enum  Comparison { LessThan = -1, EqualTo = 0, GreaterThan = 1 }
 Result of the comparison operation performed by the Compare() function. More...
 
- Static Public Member Functions inherited from PObject
static __inline void CopyTraceContextIdentifier (PObject &to, const PObject &from)
 
static __inline void CopyTraceContextIdentifier (PObject &to, const PObject *from)
 
static __inline void CopyTraceContextIdentifier (PObject *to, const PObject &from)
 
static __inline void CopyTraceContextIdentifier (PObject *to, const PObject *from)
 
static __inline const char * Class ()
 
static __inline const PObjectPTraceObjectInstance (const char *)
 
static __inline const PObjectPTraceObjectInstance (const PObject *obj)
 
template<typename T >
static Comparison Compare2 (T v1, T v2)
 Compare two types, returning Comparison type. More...
 
static Comparison InternalCompareObjectMemoryDirect (const PObject *obj1, const PObject *obj2, PINDEX size)
 Internal function caled from CompareObjectMemoryDirect() More...
 

Detailed Description

This class is a collection of objects which are descendents of the PObject class.

It is implemeted as a Red-Black binary tree to maintain the objects in rank order. Note that this requires that the PObject::Compare() function be fully implemented oin objects contained in the collection.

The implementation of a sorted list allows fast inserting and deleting as well as random access of objects in the collection. As the objects are being kept sorted, "fast" is a relative term. All operations take o(lg n) unless a particular object is repeatedly accessed.

The class remembers the last accessed element. This state information is used to optimise access by the "virtual array" model of collections. If repeated access via ordinal index is made there is little overhead. All other access incurs a minimum overhead, but not insignificant.

The PAbstractSortedList class would very rarely be descended from directly by the user. The PDECLARE_LIST and PLIST macros would normally be used to create descendent classes. They will instantiate the template based on PSortedList or directly declare and define the class (using inline functions) if templates are not being used.

The PSortedList class or PDECLARE_SORTED_LIST macro will define the correctly typed operators for subscript access (operator[]).

Constructor & Destructor Documentation

PAbstractSortedList::PAbstractSortedList ( )

Create a new, empty, sorted list.

Note that by default, objects placed into the list will be deleted when removed or when all references to the list are destroyed.

Member Function Documentation

virtual PINDEX PAbstractSortedList::Append ( PObject obj)
virtual

Add a new object to the collection.

The object is always placed in the correct ordinal position in the list. It is not placed at the "end".

Returns
index of the newly added object.

Implements PCollection.

Referenced by PSortedList< PString >::insert().

virtual Comparison PAbstractSortedList::Compare ( const PObject obj) const
virtual

Get the relative rank of the two lists.

The following algorithm is employed for the comparison:

  • EqualTo if the two lists are identical in length and each objects values, not pointer, are equal.
  • LessThan if the instances object value at an ordinal position is less than the corresponding objects value in the obj parameters list.

This is also returned if all objects are equal and the instances list length is less than the obj parameters list length.

  • GreaterThan if the instances object value at an ordinal position is greater than the corresponding objects value in the obj parameters list.

This is also returned if all objects are equal and the instances list length is greater than the obj parameters list length.

Returns
comparison of the two objects, EqualTo for same, LessThan for obj logically less than the object and GreaterThan for obj logically greater than the object.

Reimplemented from PObject.

void PAbstractSortedList::DeleteSubTrees ( PSortedListElement node,
bool  deleteObject 
)
protected
PSortedListElement* PAbstractSortedList::FindElement ( const PObject obj,
PINDEX *  index 
) const
protected
PSortedListElement* PAbstractSortedList::FindElement ( const PObject obj,
PINDEX *  index 
) const
protected
virtual PObject* PAbstractSortedList::GetAt ( PINDEX  index) const
virtual

Get the object at the specified ordinal position.

If the index was greater than the size of the collection then NULL is returned.

Returns
pointer to object at the specified index.

Implements PCollection.

Referenced by PSortedList< PString >::operator[]().

virtual PINDEX PAbstractSortedList::GetObjectsIndex ( const PObject obj) const
virtual

Search the collection for the specific instance of the object.

The object pointers are compared, not the values. A binary search is employed to locate the entry.

Note that that will require value comparisons to be made to find the equivalent entry and then a final check is made with the pointers to see if they are the same instance.

Returns
ordinal index position of the object, or P_MAX_INDEX.

Implements PCollection.

virtual PINDEX PAbstractSortedList::GetValuesIndex ( const PObject obj) const
virtual

Search the collection for the specified value of the object.

The object values are compared, not the pointers. So the objects in the collection must correctly implement the PObject::Compare() function. A binary search is employed to locate the entry.

Returns
ordinal index position of the object, or P_MAX_INDEX.

Implements PCollection.

virtual PINDEX PAbstractSortedList::Insert ( const PObject before,
PObject obj 
)
virtual

Add a new object to the collection.

The object is always placed in the correct ordinal position in the list. It is not placed at the specified position. The before parameter is ignored.

Returns
index of the newly inserted object.

Implements PCollection.

virtual PINDEX PAbstractSortedList::InsertAt ( PINDEX  index,
PObject obj 
)
virtual

Add a new object to the collection.

The object is always placed in the correct ordinal position in the list. It is not placed at the specified position. The index parameter is ignored.

Returns
index of the newly inserted object.

Implements PCollection.

void PAbstractSortedList::LeftRotate ( PSortedListElement node)
protected
virtual PBoolean PAbstractSortedList::Remove ( const PObject obj)
virtual

Remove the object from the collection.

If the AllowDeleteObjects option is set then the object is also deleted.

Note that the comparison for searching for the object in collection is made by pointer, not by value. Thus the parameter must point to the same instance of the object that is in the collection.

Returns
true if the object was in the collection.

Implements PCollection.

virtual void PAbstractSortedList::RemoveAll ( )
virtual

Remove all of the elements in the collection.

This operates by continually calling RemoveAt() until there are no objects left.

The objects are removed from the last, at index (GetSize()-1) toward the first at index zero.

Reimplemented from PCollection.

virtual PObject* PAbstractSortedList::RemoveAt ( PINDEX  index)
virtual

Remove the object at the specified ordinal index from the collection.

If the AllowDeleteObjects option is set then the object is also deleted.

Note if the index is beyond the size of the collection then the function will assert.

Returns
pointer to the object being removed, or NULL if it was deleted.

Implements PCollection.

void PAbstractSortedList::RemoveElement ( PSortedListElement node)
protected
void PAbstractSortedList::RightRotate ( PSortedListElement node)
protected
virtual PBoolean PAbstractSortedList::SetAt ( PINDEX  index,
PObject val 
)
virtual

This method simply returns false as the list order is mantained by the class.

Kept to mimic PAbstractList interface.

Returns
false allways

Implements PCollection.

virtual PBoolean PAbstractSortedList::SetSize ( PINDEX  newSize)
virtual

This function is meaningless for lists.

The size of the collection is determined by the addition and removal of objects. The size cannot be set in any other way.

Returns
Always true.

Implements PContainer.

Member Data Documentation

PSortedListInfo* PAbstractSortedList::m_info
protected

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