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PAbstractSortedList Class Reference

#include <lists.h>

Inheritance diagram for PAbstractSortedList:

PCollection PContainer PObject List of all members.

Public Member Functions

Construction
 PAbstractSortedList ()
Overrides from class PObject
virtual Comparison Compare (const PObject &obj) const
Overrides from class PContainer
virtual BOOL SetSize (PINDEX newSize)
Overrides from class PCollection
virtual PINDEX Append (PObject *obj)
virtual PINDEX Insert (const PObject &before, PObject *obj)
virtual PINDEX InsertAt (PINDEX index, PObject *obj)
virtual BOOL Remove (const PObject *obj)
virtual PObjectRemoveAt (PINDEX index)
virtual void RemoveAll ()
virtual BOOL SetAt (PINDEX index, PObject *val)
virtual PObjectGetAt (PINDEX index) const
virtual PINDEX GetObjectsIndex (const PObject *obj) const
virtual PINDEX GetValuesIndex (const PObject &obj) const

Protected Member Functions

void RemoveElement (Element *node)
void LeftRotate (Element *node)
void RightRotate (Element *node)
void DeleteSubTrees (Element *node, BOOL deleteObject)
PINDEX ValueSelect (const Element *node, const PObject &obj, const Element **lastElement) const

Protected Attributes

PAbstractSortedList::Infoinfo

Classes

struct  Element
struct  Info

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.

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: {descriptions} [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. {descriptions}

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 Element node,
BOOL  deleteObject
[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.

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 Element node  )  [protected]
 

virtual BOOL 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 Element node  )  [protected]
 

void PAbstractSortedList::RightRotate Element node  )  [protected]
 

virtual BOOL 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 BOOL 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.

PINDEX PAbstractSortedList::ValueSelect const Element node,
const PObject obj,
const Element **  lastElement
const [protected]
 


Member Data Documentation

struct PAbstractSortedList::Info * PAbstractSortedList::info [protected]
 


The documentation for this class was generated from the following file:
Generated on Sat Dec 22 16:46:52 2007 for PWLib by  doxygen 1.4.2