# ACE_Double_Linked_List< T > Class Template Reference

A double-linked list implementation. More...

`#include <Containers_T.h>`

Collaboration diagram for ACE_Double_Linked_List< T >:

[legend]
List of all members.

## Public Types

typedef ACE_Double_Linked_List_Iterator< T > | ITERATOR
typedef ACE_Double_Linked_List_Reverse_Iterator< T > | REVERSE_ITERATOR

## Public Member Functions

| ACE_Double_Linked_List (ACE_Allocator *the_allocator=0)
| ACE_Double_Linked_List (const ACE_Double_Linked_List< T > &)
| Copy constructor.
void | operator= (const ACE_Double_Linked_List< T > &)
| Assignment operator.
| ~ACE_Double_Linked_List (void)
| Destructor.
int | is_empty (void) const
| Returns 1 if the container is empty, 0 otherwise.
int | is_full (void) const
| The list is unbounded, so this always returns 0.
T * | insert_tail (T *new_item)
T * | insert_head (T *new_item)
T * | delete_head (void)
| Removes the head of the list and returns a pointer to that item.
T * | delete_tail (void)
| Removes the tail of the list and returns a pointer to that item.
void | reset (void)
| Empty the list.
int | get (T *&item, size_t slot=0)
size_t | size (void) const
| The number of items in the queue.
void | dump (void) const
| Dump the state of an object.
int | remove (T *n)
| Use DNode address directly.

## Public Attributes

| ACE_ALLOC_HOOK_DECLARE
| Declare the dynamic allocation hooks.

## Protected Member Functions

void | delete_nodes (void)
| Delete all the nodes in the list.
void | copy_nodes (const ACE_Double_Linked_List< T > &rhs)
| Copy nodes from {rhs} into this list.
void | init_head (void)
| Setup header pointer. Called after we create the head node in ctor.
int | insert_element (T *new_item, int before=0, T *old_item=0)
| Constant time insert a new item into the list structure.
int | remove_element (T *item)
| Constant time delete an item from the list structure.

## Protected Attributes

T * | head_
| Head of the circular double-linked list.
size_t | size_
| Size of this list.
ACE_Allocator * | allocator_
| Allocation Strategy of the queue.

## Friends

class | ACE_Double_Linked_List_Iterator_Base<T>
class | ACE_Double_Linked_List_Iterator<T>
class | ACE_Double_Linked_List_Reverse_Iterator<T>

## Detailed Description

### template<class T>
class ACE_Double_Linked_List< T >

A double-linked list implementation.

This implementation of an unbounded double-linked list uses a circular linked list with a dummy node. It is pretty much like the {ACE_Unbounded_Queue} except that it allows removing of a specific element from a specific location. Notice that this class is an implementation of a very simple data structure. This is *NOT* a container class. You can use the class to implement other contains classes but it is *NOT* a general purpose container class. The parameter class *MUST* have members T* prev and T* next and users of this class are responsible to follow the general rules of using double-linked lists to maintaining the list integrity. If you need a double linked container class, use the DLList class which is a container but delegates to the Double_Linked_List class.

Requirements and Performance Characteristics

- Internal Structure Double Linked List
- Duplicates allowed? Yes
- Random access allowed? No
- Search speed N/A
- Insert/replace speed Linear
- Iterator still valid after change to container? Yes
- Frees memory for removed elements? No
- Items inserted by Value
- Requirements for contained type
  1. Default constructor
  2. Copy constructor
  3. operator=

## Member Typedef Documentation

template<class T>
typedef ACE_Double_Linked_List_Iterator<T> ACE_Double_Linked_List< T >::ITERATOR

template<class T>
typedef ACE_Double_Linked_List_Reverse_Iterator<T> ACE_Double_Linked_List< T >::REVERSE_ITERATOR

## Constructor & Destructor Documentation

template<class T>
ACE_Double_Linked_List< T >::ACE_Double_Linked_List | ( | ACE_Allocator * | the_allocator = `0` | ) |

| Initialize an empy list using the allocation strategy specified by the user. If none is specified, then use default allocation strategy.

template<class T>
ACE_Double_Linked_List< T >::ACE_Double_Linked_List | ( | const ACE_Double_Linked_List< T > & |  | ) |

| Copy constructor. Create a double linked list that is a copy of the provided parameter.

template<class T>
ACE_Double_Linked_List< T >::~ACE_Double_Linked_List | ( | void |  | ) |

| Destructor. Clean up the memory allocated for the nodes of the list.

## Member Function Documentation

template<class T>
void ACE_Double_Linked_List< T >::copy_nodes | ( | const ACE_Double_Linked_List< T > & | rhs | ) | `[protected]`

| Copy nodes from {rhs} into this list. Copy the elements of the provided list by allocated new nodes and assigning them with the proper data.

template<class T>
T * ACE_Double_Linked_List< T >::delete_head | ( | void |  | ) |

| Removes the head of the list and returns a pointer to that item. Removes and returns the first {item} in the list. Returns internal node's address on success, 0 if the queue was empty. This method will *not* free the internal node. Reimplemented in ACE_DLList< T >.

template<class T>
void ACE_Double_Linked_List< T >::delete_nodes | ( | void |  | ) | `[protected]`

| Delete all the nodes in the list. Removes and deallocates memory for all of the list nodes.

template<class T>
T * ACE_Double_Linked_List< T >::delete_tail | ( | void |  | ) |

| Removes the tail of the list and returns a pointer to that item. Removes and returns the last {item} in the list. Returns internal nodes's address on success, 0 if the queue was empty. This method will *not* free the internal node. Reimplemented in ACE_DLList< T >.

template<class T>
void ACE_Double_Linked_List< T >::dump | ( | void |  | ) | const

| Dump the state of an object. Reimplemented in ACE_DLList< T >.

template<class T>
int ACE_Double_Linked_List< T >::get | ( | T *& | item,
|  | size_t | slot = `0`
| ) |

| Iterates through the list to the desired index and assigns the provides pointer with the address of the node occupying that index.

template<class T>
void ACE_Double_Linked_List< T >::init_head | ( | void |  | ) | `[protected]`

| Setup header pointer. Called after we create the head node in ctor. Initialize the head pointer so that the list has a dummy node.

template<class T>
int ACE_Double_Linked_List< T >::insert_element | ( | T * | new_item,
|  | int | before = `0`,
|  | T * | old_item = `0`
| ) | `[protected]`

| Constant time insert a new item into the list structure. Insert a new_item into the list. It will be added before or after old_item. Default is to insert the new item *after* {head_}. Return 0 if succeed, -1 if error occured.

template<class T>
T * ACE_Double_Linked_List< T >::insert_head | ( | T * | new_item | ) |

| Provides constant time insertion at the head of the list.

template<class T>
T * ACE_Double_Linked_List< T >::insert_tail | ( | T * | new_item | ) |

| Provides constant time insertion at the end of the list structure.

template<class T>
int ACE_Double_Linked_List< T >::is_empty | ( | void |  | ) | const

| Returns 1 if the container is empty, 0 otherwise. Performs constant time check to determine if the list is empty.

template<class T>
int ACE_Double_Linked_List< T >::is_full | ( | void |  | ) | const

| The list is unbounded, so this always returns 0. Since the list is unbounded, the method simply returns 0.

template<class T>
void ACE_Double_Linked_List< T >::operator= | ( | const ACE_Double_Linked_List< T > & |  | ) |

| Assignment operator. Perform a deep copy of the provided list by first deleting the nodes of the lhs and then copying the nodes of the rhs.

template<class T>
int ACE_Double_Linked_List< T >::remove | ( | T * | n | ) |

| Use DNode address directly. Constant time removal of an item from the list using it's address. Reimplemented in ACE_DLList< T >.

template<class T>
int ACE_Double_Linked_List< T >::remove_element | ( | T * | item | ) | `[protected]`

| Constant time delete an item from the list structure. Remove item from the list. Return 0 if succeed, -1 otherwise. Notice that this function checks if item is {head_} and either its {next_} or {prev_} is NULL. The function resets item's {next_} and {prev_} to 0 to prevent clobbering the double-linked list if a user tries to remove the same node again.

template<class T>
void ACE_Double_Linked_List< T >::reset | ( | void |  | ) |

| Empty the list. Reset the {ACE_Double_Linked_List} to be empty. Notice that since no one is interested in the items within, This operation will delete all items.

template<class T>
size_t ACE_Double_Linked_List< T >::size | ( | void |  | ) | const

| The number of items in the queue. Constant time call to return the current size of the list.

## Friends And Related Function Documentation

template<class T>
friend class ACE_Double_Linked_List_Iterator<T>`[friend]`

| Reimplemented in ACE_DLList< T >.

template<class T>
friend class ACE_Double_Linked_List_Iterator_Base<T>`[friend]`

template<class T>
friend class ACE_Double_Linked_List_Reverse_Iterator<T>`[friend]`

## Member Data Documentation

template<class T>
ACE_Double_Linked_List< T >::ACE_ALLOC_HOOK_DECLARE

| Declare the dynamic allocation hooks.

template<class T>
ACE_Allocator* ACE_Double_Linked_List< T >::allocator_ `[protected]`

| Allocation Strategy of the queue.

template<class T>
T* ACE_Double_Linked_List< T >::head_ `[protected]`

| Head of the circular double-linked list.

template<class T>
size_t ACE_Double_Linked_List< T >::size_ `[protected]`

| Size of this list.

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

- Containers_T.h
- Containers_T.cpp