utils-lists 4.0.2
The µOS++ Intrusive Lists
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micro_os_plus::utils::double_list< T, L > Class Template Reference

A class template for a doubly linked list of nodes. More...

#include <micro-os-plus/utils/lists.h>

Public Types

using is_statically_allocated
 Type indicating if the links node is statically allocated.
 
using iterator = double_list_iterator<value_type>
 Type of iterator over the values.
 
using iterator_pointer = value_type*
 Type of reference to the iterator internal pointer.
 
using links_type = L
 Type of the links node object where the pointers to the list head and tail are stored.
 
using pointer = value_type*
 Type of pointer to object pointed to by the iterator.
 
using reference = value_type&
 Type of reference to object pointed to by the iterator.
 
using value_type = T
 Type of value pointed to by the iterator.
 

Public Member Functions

 double_list ()
 Construct a doubly linked list.
 
 double_list (const double_list &)=delete
 Deleted copy constructor.
 
 double_list (double_list &&)=delete
 Deleted move constructor.
 
constexpr ~double_list ()
 Destruct the list.
 
iterator begin () const
 Iterator begin.
 
void clear (void)
 Clear the list.
 
bool empty (void) const
 Check if the list is empty.
 
iterator end () const
 Iterator end.
 
constexpr pointer head (void) const
 Get the list head.
 
void initialize_once (void)
 Initialize the list only at first run.
 
void link_head (reference node)
 Add a node to the head of the list.
 
void link_tail (reference node)
 Add a node to the tail of the list.
 
constexpr const links_typelinks_pointer (void) const
 Get the address of the node storing the list links.
 
double_listoperator= (const double_list &)=delete
 Deleted copy assignment operator.
 
double_listoperator= (double_list &&)=delete
 Deleted move assignment operator.
 
constexpr pointer tail (void) const
 Get the list tail.
 
bool uninitialized (void) const
 Check if the list is uninitialised (only statically allocated lists can be uninitialised).
 

Protected Attributes

links_type links_
 The list top node used to point to head and tail nodes.
 

Detailed Description

template<class T, class L = double_list_links>
class micro_os_plus::utils::double_list< T, L >

A class template for a doubly linked list of nodes.

Template Parameters
TType of the elements linked into the list, derived from class double_list_links_base.
LType of the links node (either double_list_links or static_double_list_links).

This class implements a generic doubly linked list, maintaining a pair of head and tail pointers to allow efficient iteration and manipulation of nodes. The list elements (of type T) must be derived from double_list_links_base (typically from double_list_links) and extended with the required payload, which may be the actual content or a pointer to it.

The class uses composition for the links node, rather than inheritance, to avoid inheriting unwanted methods. Iterators return pointers to the list elements, enabling traversal of the list in a manner similar to standard containers.

Note
Only forward iterators are provided by default, but reverse iterators can be added if required.

Definition at line 674 of file lists.h.

Member Typedef Documentation

◆ is_statically_allocated

template<class T, class L = double_list_links>
using micro_os_plus::utils::double_list< T, L >::is_statically_allocated
Initial value:
typename links_type::is_statically_allocated

Type indicating if the links node is statically allocated.

Definition at line 716 of file lists.h.

◆ iterator

template<class T, class L = double_list_links>
using micro_os_plus::utils::double_list< T, L >::iterator = double_list_iterator<value_type>

Type of iterator over the values.

Definition at line 706 of file lists.h.

◆ iterator_pointer

template<class T, class L = double_list_links>
using micro_os_plus::utils::double_list< T, L >::iterator_pointer = value_type*

Type of reference to the iterator internal pointer.

Definition at line 711 of file lists.h.

◆ links_type

template<class T, class L = double_list_links>
using micro_os_plus::utils::double_list< T, L >::links_type = L

Type of the links node object where the pointers to the list head and tail are stored.

Definition at line 686 of file lists.h.

◆ pointer

template<class T, class L = double_list_links>
using micro_os_plus::utils::double_list< T, L >::pointer = value_type*

Type of pointer to object pointed to by the iterator.

Definition at line 696 of file lists.h.

◆ reference

template<class T, class L = double_list_links>
using micro_os_plus::utils::double_list< T, L >::reference = value_type&

Type of reference to object pointed to by the iterator.

Definition at line 701 of file lists.h.

◆ value_type

template<class T, class L = double_list_links>
using micro_os_plus::utils::double_list< T, L >::value_type = T

Type of value pointed to by the iterator.

Definition at line 691 of file lists.h.

Constructor & Destructor Documentation

◆ double_list() [1/3]

template<class T, class L>
micro_os_plus::utils::double_list< T, L >::double_list ( )

Construct a doubly linked list.

For non-statically allocated lists, the initial list status is empty after construction, meaning the list is ready for use and contains no nodes.

For statically allocated lists, the list remains uninitialised after construction, with its internal pointers set to nullptr. Such lists require explicit initialisation (typically via initialize_once()) before use.

This constructor does not clear or modify the internal pointers for statically allocated lists, relying on zero-initialisation by the runtime. For dynamically allocated lists, it calls clear() to ensure the list is in a valid empty state.

The rule of five
The copy constructor, move constructor, copy assignment operator, and move assignment operator are explicitly deleted to prevent accidental copying or moving of intrusive_list objects. This ensures the integrity of the list structure, as duplicating or moving lists could result in invalid or inconsistent links within the list.

Definition at line 486 of file lists-inlines.h.

◆ double_list() [2/3]

template<class T, class L = double_list_links>
micro_os_plus::utils::double_list< T, L >::double_list ( const double_list< T, L > & )
delete

Deleted copy constructor.

Copying of double_list instances is explicitly disallowed to prevent accidental duplication, which could compromise the integrity of the list structure.

◆ double_list() [3/3]

template<class T, class L = double_list_links>
micro_os_plus::utils::double_list< T, L >::double_list ( double_list< T, L > && )
delete

Deleted move constructor.

Moving of double_list instances is explicitly disallowed to avoid invalid or inconsistent links within the list that could result from moving lists.

◆ ~double_list()

template<class T, class L>
micro_os_plus::utils::double_list< T, L >::~double_list ( )
constexpr

Destruct the list.

Normally at this point there must be no nodes in the list. However, for statically allocated lists, this might not be always true due to their lifetime and initialization patterns.

Note
In debug mode, the destructor emits a warning if the list is not empty when destroyed, helping to catch potential resource leaks or logic errors in list management.

Definition at line 516 of file lists-inlines.h.

Member Function Documentation

◆ begin()

template<class T, class L>
double_list< T, L >::iterator micro_os_plus::utils::double_list< T, L >::begin ( ) const

Iterator begin.

Returns
An iterator to the first element.

Returns an iterator to the first element in the list. For statically allocated lists, asserts that the list is already initialised. The iterator will point to the node after the internal links node (the head). If the list is empty, the iterator will compare equal to end().

Definition at line 691 of file lists-inlines.h.

◆ clear()

template<class T, class L>
void micro_os_plus::utils::double_list< T, L >::clear ( void )

Clear the list.

Parameters
None.
Returns
Nothing.

The clear() method initialises the mandatory internal links node so that both its previous_ and next_ pointers refer to itself. This marks the list as empty and ensures it is in a safe, known state, ready for new insertions. This operation is typically used to reset the list, removing all elements and breaking any existing links.

Definition at line 601 of file lists-inlines.h.

◆ empty()

template<class T, class L>
bool micro_os_plus::utils::double_list< T, L >::empty ( void ) const

Check if the list is empty.

Parameters
None.
Return values
trueThe list has no nodes.
falseThe list has at least one node.

Checks whether the list contains any nodes. The list is considered empty if the internal links node is not linked to any other nodes. This method provides a fast way to determine if the list has elements or is currently empty.

Definition at line 585 of file lists-inlines.h.

◆ end()

template<class T, class L>
double_list< T, L >::iterator micro_os_plus::utils::double_list< T, L >::end ( ) const

Iterator end.

Returns
An iterator positioned after the last element.

Returns an iterator to the position after the last element in the list (the end iterator). This iterator points to the internal links node, which acts as a sentinel. It is used as the past-the-end marker in iteration and comparison operations. The end iterator does not reference any valid list element.

Definition at line 711 of file lists-inlines.h.

◆ head()

template<class T, class L>
double_list< T, L >::pointer micro_os_plus::utils::double_list< T, L >::head ( void ) const
constexpr

Get the list head.

Parameters
None.
Returns
Pointer to the head node.

Returns a pointer to the first node in the list. If the list is empty, this will point to the internal links node itself, which can be used to detect the end of the list during iteration. The returned pointer should be checked against end() or the sentinel node to determine if the list contains any elements.

Definition at line 619 of file lists-inlines.h.

◆ initialize_once()

template<class T, class L>
void micro_os_plus::utils::double_list< T, L >::initialize_once ( void )

Initialize the list only at first run.

Parameters
None.
Returns
Nothing.

If the statically allocated list is still in the initial uninitialised state (with both pointers null), this method initialises the list to the empty state, with both pointers pointing to itself. For non-statically initialised lists, this method has no effect.

Note
Must be manually called for statically allocated lists before inserting elements or performing any other operations.

Definition at line 568 of file lists-inlines.h.

◆ link_head()

template<class T, class L>
void micro_os_plus::utils::double_list< T, L >::link_head ( reference node)

Add a node to the head of the list.

Parameters
[in]nodeReference to the node to add.
Returns
Nothing.

Adds a new node to the beginning (head) of the list. For statically allocated lists, asserts that the list is already initialised. The new node is linked before the current head node, updating the list structure accordingly. This operation does not check for duplicate nodes or whether the node is already linked elsewhere.

Definition at line 670 of file lists-inlines.h.

◆ link_tail()

template<class T, class L>
void micro_os_plus::utils::double_list< T, L >::link_tail ( reference node)

Add a node to the tail of the list.

Parameters
[in]nodeReference to the node to add.
Returns
Nothing.

Adds a new node to the end (tail) of the list. For statically allocated lists, asserts that the list is already initialised. The new node is linked after the current tail node, updating the list structure accordingly. This operation does not check for duplicate nodes or whether the node is already linked elsewhere.

Definition at line 649 of file lists-inlines.h.

◆ links_pointer()

template<class T, class L = double_list_links>
const links_type * micro_os_plus::utils::double_list< T, L >::links_pointer ( void ) const
inlineconstexpr

Get the address of the node storing the list links.

Parameters
None.
Returns
A pointer to the list head object.

Definition at line 886 of file lists.h.

◆ operator=() [1/2]

template<class T, class L = double_list_links>
double_list & micro_os_plus::utils::double_list< T, L >::operator= ( const double_list< T, L > & )
delete

Deleted copy assignment operator.

Copy assignment is explicitly disallowed to prevent accidental overwriting of list objects, which could lead to corruption of the list structure.

◆ operator=() [2/2]

template<class T, class L = double_list_links>
double_list & micro_os_plus::utils::double_list< T, L >::operator= ( double_list< T, L > && )
delete

Deleted move assignment operator.

Move assignment is explicitly disallowed to avoid invalid or inconsistent links within the list that could result from moving lists.

◆ tail()

template<class T, class L>
double_list< T, L >::pointer micro_os_plus::utils::double_list< T, L >::tail ( void ) const
constexpr

Get the list tail.

Parameters
None.
Returns
Pointer to the tail node.

Returns a pointer to the last node in the list. If the list is empty, this will point to the internal links node itself, which can be used to detect the end of the list during reverse iteration. The returned pointer should be checked against the sentinel node to determine if the list contains any elements.

Definition at line 634 of file lists-inlines.h.

◆ uninitialized()

template<class T, class L>
bool micro_os_plus::utils::double_list< T, L >::uninitialized ( void ) const

Check if the list is uninitialised (only statically allocated lists can be uninitialised).

Parameters
None.
Return values
trueThe list was not initialised.
falseThe list was initialised.

An uninitialized node is a node with any of the pointers set to nullptr. Only statically allocated nodes in the initial state are considered uninitialized. For dynamically allocated lists, this method always returns false since their nodes are explicitly initialized during construction.

Definition at line 542 of file lists-inlines.h.

Member Data Documentation

◆ links_

template<class T, class L = double_list_links>
links_type micro_os_plus::utils::double_list< T, L >::links_
protected

The list top node used to point to head and tail nodes.

This member stores the internal links node for the list. The next pointer of this node points to the head of the list, and the previous pointer points to the tail. For an empty list, both pointers refer to the node itself, simplifying list management and boundary checks.

Definition at line 904 of file lists.h.


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