Inline List

---

These functions provide inline list management.

Inline lists mean its nodes pointers are part of same memory as data. This has the benefit of fragmenting memory less and avoiding node->data indirection, but has the drawback of higher cost for some common operations like count and sort.

It is possible to have inlist nodes to be part of regular lists, created with eina_list_append() or eina_list_prepend(). It's also possible to have a structure with two inlist pointers, thus be part of two different inlists at the same time, but the current convenience macros provided won't work for both of them. Consult Advanced Usage for more info.

Inline lists have their purposes, but if you don't know what those purposes are, go with regular lists instead.

Tip: When using inlists in more than one place (that is, passing them around functions or keeping a pointer to them in a structure) it's more correct to keep a pointer to the first container, and not a pointer to the first inlist item (mostly they are the same, but that's not always correct). This lets the compiler to do type checking and let the programmer know exactly what type this list is.

A simple example demonstrating the basic usage of an inlist can be found here: Eina_Inlist basic usage

Algorithm

The basic structure can be represented by the following picture:

One data structure will also have the node information, with three pointers: prev, next and last. The last pointer is just valid for the first element (the list head), otherwise each insertion in the list would have to be done updating every node with the correct pointer. This means that it's always very important to keep a pointer to the first element of the list, since it is the only one that has the correct information to allow a proper O(1) append to the list.

Performance

Due to the nature of the inlist, there's no accounting information, and no easy access to the last element from each list node. This means that eina_inlist_count() is order-N, while eina_list_count() is order-1 (constant time).

Advanced Usage

The basic usage considers a struct that will have the user data, and also have an inlist node information (prev, next and last pointers) created with EINA_INLIST during the struct declaration. This allows one to use the convenience macros EINA_INLIST_GET(), EINA_INLIST_CONTAINER_GET(), EINA_INLIST_FOREACH() and so. This happens because the EINA_INLIST macro declares a struct member with the name __inlist, and all the other macros assume that this struct member has this name.

It may be the case that someone needs to have some inlist nodes added to a Eina_List too. If this happens, the inlist nodes can be added to the Eina_List without any problems. This example demonstrates this case: Eina_Inlist advanced usage - lists and inlists

It's also possible to have some data that is part of two different inlists. If this is the case, then it won't be possible to use the convenience macros to both of the lists. It will be necessary to create a new set of macros that will allow access to the second list node info. An example for this usage can be found here: Eina_Inlist advanced usage - multi-inlists

List of examples:

• Eina_Inlist basic usage
• Eina_Inlist advanced usage - lists and inlists
• Eina_Inlist advanced usage - multi-inlists

Functions
Eina_Inlist *	eina_inlist_append (Eina_Inlist *in_list, Eina_Inlist *in_item)
	Adds a new node to end of a list.
Eina_Inlist *	eina_inlist_prepend (Eina_Inlist *in_list, Eina_Inlist *in_item)
	Adds a new node to beginning of list.
Eina_Inlist *	eina_inlist_append_relative (Eina_Inlist *in_list, Eina_Inlist *in_item, Eina_Inlist *in_relative)
	Adds a new node after the given relative item in list.
Eina_Inlist *	eina_inlist_prepend_relative (Eina_Inlist *in_list, Eina_Inlist *in_item, Eina_Inlist *in_relative)
	Adds a new node before the given relative item in list.
Eina_Inlist *	eina_inlist_remove (Eina_Inlist *in_list, Eina_Inlist *in_item) 2)
	Removes node from list.
Eina_Inlist *	eina_inlist_find (Eina_Inlist *in_list, Eina_Inlist *in_item)
	Finds given node in list, returns itself if found, NULL if not.
Eina_Inlist *	eina_inlist_promote (Eina_Inlist *list, Eina_Inlist *item) 2)
	Moves existing node to beginning of list.
Eina_Inlist *	eina_inlist_demote (Eina_Inlist *list, Eina_Inlist *item) 2)
	Moves existing node to end of list.
static Eina_Inlist *	eina_inlist_first (const Eina_Inlist *list)
	Gets the first list node in the list.
static Eina_Inlist *	eina_inlist_last (const Eina_Inlist *list)
	Gets the last list node in the list.
unsigned int	eina_inlist_count (const Eina_Inlist *list)
	Gets the count of the number of items in a list.
Eina_Iterator *	eina_inlist_iterator_new (const Eina_Inlist *in_list)
	Returns a new iterator associated to list.
Eina_Accessor *	eina_inlist_accessor_new (const Eina_Inlist *in_list)
	Returns a new accessor associated to a list.
Eina_Inlist *	eina_inlist_sorted_insert (Eina_Inlist *list, Eina_Inlist *item, Eina_Compare_Cb func) 3)
	Inserts a new node into a sorted list.
Eina_Inlist_Sorted_State *	eina_inlist_sorted_state_new (void)
	Creates state with valid data in it.
int	eina_inlist_sorted_state_init (Eina_Inlist_Sorted_State *state, Eina_Inlist *list)
	Forces an Eina_Inlist_Sorted_State to match the content of a list.
void	eina_inlist_sorted_state_free (Eina_Inlist_Sorted_State *state)
	Frees an Eina_Inlist_Sorted_State.
Eina_Inlist *	eina_inlist_sorted_state_insert (Eina_Inlist *list, Eina_Inlist *item, Eina_Compare_Cb func, Eina_Inlist_Sorted_State *state)
	Inserts a new node into a sorted list.
Eina_Inlist *	eina_inlist_sort (Eina_Inlist *head, Eina_Compare_Cb func)
	Sorts a list according to the ordering func will return.
Typedefs
typedef struct _Eina_Inlist	Eina_Inlist
typedef struct _Eina_Inlist_Sorted_State	Eina_Inlist_Sorted_State
Defines
#define	EINA_INLIST   Eina_Inlist __in_list
#define	EINA_INLIST_GET(Inlist)   (& ((Inlist)->__in_list))
#define	EINA_INLIST_CONTAINER_GET(ptr,type)
#define	_EINA_INLIST_OFFSET(ref)   ((char *)&(ref)->__in_list - (char *)(ref))
#define	_EINA_INLIST_CONTAINER(ref, ptr)
#define	EINA_INLIST_FOREACH(list, it)
#define	EINA_INLIST_FOREACH_SAFE(list, list2, it)
#define	EINA_INLIST_REVERSE_FOREACH(list, it)
#define	EINA_INLIST_REVERSE_FOREACH_FROM(list, it)
#define	EINA_INLIST_FREE(list, it)   for (it = (__typeof__(it)) list; list; it = (__typeof__(it)) list)

---

Define Documentation

#define _EINA_INLIST_CONTAINER	(		ref,
			ptr
	)

Value:

(void *)((char *)(ptr) - \
                                                  _EINA_INLIST_OFFSET(ref))

Parameters:

ref	The reference to be used.
ptr	The pointer to be used.

#define _EINA_INLIST_OFFSET

(

ref

)

((char *)&(ref)->__in_list - (char *)(ref))

Parameters:

ref	The reference to be used.

#define EINA_INLIST   Eina_Inlist __in_list

Used for declaring an inlist member in a struct

Examples:

eina_inlist_01.c, eina_inlist_02.c, and eina_inlist_03.c.

#define EINA_INLIST_CONTAINER_GET	(		ptr,
			type
	)

Value:

((type *)((char *)ptr - \
                                                  offsetof(type, __in_list)))

Utility macro to get the container object of an inlist

Examples:

eina_inlist_01.c, eina_inlist_02.c, and eina_inlist_03.c.

#define EINA_INLIST_FOREACH	(		list,
			it
	)

Value:

for (it = NULL, it = (list ? _EINA_INLIST_CONTAINER(it, list) : NULL); it; \
       it = (EINA_INLIST_GET(it)->next ? _EINA_INLIST_CONTAINER(it, EINA_INLIST_GET(it)->next) : NULL))

Parameters:

list	The list to iterate on.
it	The pointer to the list item, i.e. a pointer to each item that is part of the list.

Examples:

eina_inlist_01.c, eina_inlist_02.c, and eina_inlist_03.c.

#define EINA_INLIST_FOREACH_SAFE	(		list,
			list2,
			it
	)

Value:

for (it = NULL, it = (list ? _EINA_INLIST_CONTAINER(it, list) : NULL), list2 = it ? EINA_INLIST_GET(it)->next : NULL; \
        it; \
        it = NULL, it = list2 ? _EINA_INLIST_CONTAINER(it, list2) : NULL, list2 = list2 ? list2->next : NULL)

Parameters:

list	The list to iterate on.
list2	Auxiliary Eina_Inlist variable so we can save the pointer to the next element, allowing us to free/remove the current one. Note that this macro is only safe if the next element is not removed. Only the current one is allowed to be removed.
it	The pointer to the list item, i.e. a pointer to each item that is part of the list.

#define EINA_INLIST_FREE	(		list,
			it
	)		for (it = (__typeof__(it)) list; list; it = (__typeof__(it)) list)

Parameters:

list	The list to free.
it	The pointer to the list item, i.e. a pointer to each item that is part of the list.

NOTE: it is the duty of the body loop to properly remove the item from the inlist and free it. This function will turn into a infinite loop if you don't remove all items from the list.

Since (EFL) :

1.8

#define EINA_INLIST_GET

(

Inlist

)

(& ((Inlist)->__in_list))

Utility macro to get the inlist object of a struct

Examples:

eina_inlist_01.c, eina_inlist_02.c, and eina_inlist_03.c.

#define EINA_INLIST_REVERSE_FOREACH	(		list,
			it
	)

Value:

for (it = NULL, it = (list ? _EINA_INLIST_CONTAINER(it, list->last) : NULL); \
       it; it = (EINA_INLIST_GET(it)->prev ? _EINA_INLIST_CONTAINER(it, EINA_INLIST_GET(it)->prev) : NULL))

Parameters:

list	The list to traversed in reverse order.
it	The pointer to the list item, i.e. a pointer to each item that is part of the list.

#define EINA_INLIST_REVERSE_FOREACH_FROM	(		list,
			it
	)

Value:

for (it = NULL, it = (list ? _EINA_INLIST_CONTAINER(it, list) : NULL); \
       it; it = (EINA_INLIST_GET(it)->prev ? _EINA_INLIST_CONTAINER(it, EINA_INLIST_GET(it)->prev) : NULL))

Parameters:

list	The last list to traversed in reverse order.
it	The pointer to the list item, i.e. a pointer to each item that is part of the list.

See also:

EINA_INLIST_REVERSE_FOREACH()

Since (EFL) :

1.8

EINA_INLIST_REVERSE_FOREACH() starts from last list of the given list. This starts from given list, not the last one.

---

Typedef Documentation

Eina_Inlist

Inlined list type.

Eina_Inlist_Sorted_State

Since (EFL) :

1.1.0 State of sorted Eina_Inlist

---

Function Documentation

Eina_Accessor* eina_inlist_accessor_new

(

const Eina_Inlist *

in_list

)

Returns a new accessor associated to a list.

Parameters:

in_list

The list.

Returns:

A new accessor.

This function returns a newly allocated accessor associated to in_list. If in_list is NULL or the count member of in_list is less or equal than 0, this function returns NULL. If the memory can not be allocated, NULL is returned and Otherwise, a valid accessor is returned.

Since :

2.3

Eina_Inlist* eina_inlist_append	(	Eina_Inlist *	in_list,
		Eina_Inlist *	in_item
	)

Adds a new node to end of a list.

Note:

This code is meant to be fast: appends are O(1) and do not walk in_list.

in_item is considered to be in no list. If it was in another list before, eina_inlist_remove() it before adding. No check of new_l prev and next pointers is done, so it's safe to have them uninitialized.

Parameters:

in_list	Existing list head or NULL to create a new list.
in_item	New list node, must not be NULL.

Returns:

The new list head. Use it and not in_list anymore.

Since :

2.3

Examples:

eina_inlist_01.c, eina_inlist_02.c, and eina_inlist_03.c.

Eina_Inlist* eina_inlist_append_relative	(	Eina_Inlist *	in_list,
		Eina_Inlist *	in_item,
		Eina_Inlist *	in_relative
	)

Adds a new node after the given relative item in list.

Note:

This code is meant to be fast: appends are O(1) and do not walk in_list.

in_item_l is considered to be in no list. If it was in another list before, eina_inlist_remove() it before adding. No check of in_item prev and next pointers is done, so it's safe to have them uninitialized.

in_relative is considered to be inside in_list, no checks are done to confirm that and giving nodes from different lists will lead to problems. Giving NULL in_relative is the same as eina_list_append().

Parameters:

in_list	Existing list head or NULL to create a new list.
in_item	New list node, must not be NULL.
in_relative	Reference node, in_item will be added after it.

Returns:

The new list head. Use it and not list anymore.

Since :

2.3

Examples:

eina_inlist_01.c.

unsigned int eina_inlist_count

(

const Eina_Inlist *

list

)

Gets the count of the number of items in a list.

Parameters:

list	The list whose count to return.

Returns:

The number of members in the list.

This function returns how many members list contains. If the list is NULL, 0 is returned.

Warning:

This is an order-N operation and so the time will depend on the number of elements on the list, so, it might become slow for big lists!

Since :

2.3

Examples:

eina_inlist_02.c, and eina_inlist_03.c.

Eina_Inlist* eina_inlist_demote	(	Eina_Inlist *	list,
		Eina_Inlist *	item
	)

Moves existing node to end of list.

Note:

This code is meant to be fast: appends are O(1) and do not walk list.

item is considered to be inside list. No checks are done to confirm this, and giving nodes from different lists will lead to problems.

Parameters:

list	Existing list head or NULL to create a new list.
item	List node to move to end (tail), must not be NULL.

Returns:

The new list head. Use it and not list anymore.

Since :

2.3

Examples:

eina_inlist_01.c.

Eina_Inlist* eina_inlist_find	(	Eina_Inlist *	in_list,
		Eina_Inlist *	in_item
	)

Finds given node in list, returns itself if found, NULL if not.

Warning:

This is an expensive call and has O(n) cost, possibly walking the whole list.

Parameters:

in_list	Existing list to search in_item in, must not be NULL.
in_item	What to search for, must not be NULL.

Returns:

in_item if found, NULL if not.

Since :

2.3

Examples:

eina_inlist_01.c.

static Eina_Inlist* eina_inlist_first

(

const Eina_Inlist *

list

)

[static]

Gets the first list node in the list.

Parameters:

list	The list to get the first list node from.

Returns:

The first list node in the list.

This function returns the first list node in the list list. If list is NULL, NULL is returned.

This is a O(N) operation (it takes time proportional to the length of the list).

Since (EFL) :

1.8

Eina_Iterator* eina_inlist_iterator_new

(

const Eina_Inlist *

in_list

)

Returns a new iterator associated to list.

Parameters:

in_list

The list.

Returns:

A new iterator.

This function returns a newly allocated iterator associated to in_list. If in_list is NULL or the count member of in_list is less or equal than 0, this function still returns a valid iterator that will always return false on eina_iterator_next(), thus keeping API sane.

If the memory can not be allocated, NULL is returned. Otherwise, a valid iterator is returned.

Warning:

if the list structure changes then the iterator becomes invalid, and if you add or remove nodes iterator behavior is undefined, and your program may crash!

Since :

2.3

static Eina_Inlist* eina_inlist_last

(

const Eina_Inlist *

list

)

[static]

Gets the last list node in the list.

Parameters:

list	The list to get the last list node from.

Returns:

The last list node in the list.

This function returns the last list node in the list list. If list is NULL, NULL is returned.

This is a O(N) operation (it takes time proportional to the length of the list).

Since (EFL) :

1.8

Eina_Inlist* eina_inlist_prepend	(	Eina_Inlist *	in_list,
		Eina_Inlist *	in_item
	)

Adds a new node to beginning of list.

Note:

This code is meant to be fast: appends are O(1) and do not walk in_list.

new_l is considered to be in no list. If it was in another list before, eina_inlist_remove() it before adding. No check of new_l prev and next pointers is done, so it's safe to have them uninitialized.

Parameters:

in_list	Existing list head or NULL to create a new list.
in_item	New list node, must not be NULL.

Returns:

The new list head. Use it and not in_list anymore.

Since :

2.3

Examples:

eina_inlist_01.c, and eina_inlist_03.c.

Eina_Inlist* eina_inlist_prepend_relative	(	Eina_Inlist *	in_list,
		Eina_Inlist *	in_item,
		Eina_Inlist *	in_relative
	)

Adds a new node before the given relative item in list.

Note:

This code is meant to be fast: appends are O(1) and do not walk in_list.

in_item is considered to be in no list. If it was in another list before, eina_inlist_remove() it before adding. No check of in_item prev and next pointers is done, so it's safe to have them uninitialized.

in_relative is considered to be inside in_list, no checks are done to confirm that and giving nodes from different lists will lead to problems. Giving NULL in_relative is the same as eina_list_prepend().

Parameters:

in_list	Existing list head or NULL to create a new list.
in_item	New list node, must not be NULL.
in_relative	Reference node, in_item will be added before it.

Returns:

The new list head. Use it and not in_list anymore.

Since :

2.3

Eina_Inlist* eina_inlist_promote	(	Eina_Inlist *	list,
		Eina_Inlist *	item
	)

Moves existing node to beginning of list.

Note:

This code is meant to be fast: appends are O(1) and do not walk list.

item is considered to be inside list. No checks are done to confirm this, and giving nodes from different lists will lead to problems.

Parameters:

list	Existing list head or NULL to create a new list.
item	List node to move to beginning (head), must not be NULL.

Returns:

The new list head. Use it and not list anymore.

Since :

2.3

Examples:

eina_inlist_01.c.

Eina_Inlist* eina_inlist_remove	(	Eina_Inlist *	in_list,
		Eina_Inlist *	in_item
	)

Removes node from list.

Note:

This code is meant to be fast: appends are O(1) and do not walk list.

in_item is considered to be inside in_list, no checks are done to confirm that and giving nodes from different lists will lead to problems, especially if in_item is the head since it will be different from list and the wrong new head will be returned.

Parameters:

in_list	Existing list head, must not be NULL.
in_item	Existing list node, must not be NULL.

Returns:

The new list head. Use it and not list anymore.

Since :

2.3

Examples:

eina_inlist_01.c, eina_inlist_02.c, and eina_inlist_03.c.

Eina_Inlist* eina_inlist_sort	(	Eina_Inlist *	head,
		Eina_Compare_Cb	func
	)

Sorts a list according to the ordering func will return.

Parameters:

head	The list handle to sort.
func	A function pointer that can handle comparing the list data nodes.

Returns:

the new head of list.

This function sorts all the elements of head. func is used to compare two elements of head. If head or func are NULL, this function returns NULL.

Note:

in-place: this will change the given list, so you should now point to the new list head that is returned by this function.

Worst case is O(n * log2(n)) comparisons (calls to func()). That means that for 1,000,000 list elements, sort will do 20,000,000 comparisons.

Example:

 typedef struct _Sort_Ex Sort_Ex;
 struct _Sort_Ex
 {
   EINA_INLIST;
   const char *text;
 };

 int
 sort_cb(const Inlist *l1, const Inlist *l2)
 {
    const Sort_Ex *x1;
    const Sort_Ex *x2;

    x1 = EINA_INLIST_CONTAINER_GET(l1, Sort_Ex);
    x2 = EINA_INLIST_CONTAINER_GET(l2, Sort_Ex);

    return(strcmp(x1->text, x2->text));
 }
 extern Eina_Inlist *list;

 list = eina_inlist_sort(list, sort_cb);

Since :

2.3

Examples:

eina_inlist_01.c.

Eina_Inlist* eina_inlist_sorted_insert	(	Eina_Inlist *	list,
		Eina_Inlist *	item,
		Eina_Compare_Cb	func
	)

Inserts a new node into a sorted list.

Parameters:

list	The given linked list, must be sorted.
item	List node to insert, must not be NULL.
func	The function called for the sort.

Returns:

A list pointer.

Since (EFL) :

1.1.0

This function inserts item into a linked list assuming it was sorted and the result will be sorted. If list is NULL, item is returned. On success, a new list pointer that should be used in place of the one given to this function is returned. Otherwise, the old pointer is returned.

Note:

O(log2(n)) comparisons (calls to func) average/worst case performance. As said in eina_list_search_sorted_near_list(), lists do not have O(1) access time, so walking to the correct node can be costly, consider worst case to be almost O(n) pointer dereference (list walk).

Since :

2.3

void eina_inlist_sorted_state_free

(

Eina_Inlist_Sorted_State *

state

)

Frees an Eina_Inlist_Sorted_State.

Parameters:

state

The state to destroy

Since (EFL) :

1.1.0

See eina_inlist_sorted_state_insert() for more information.

Since :

2.3

int eina_inlist_sorted_state_init	(	Eina_Inlist_Sorted_State *	state,
		Eina_Inlist *	list
	)

Forces an Eina_Inlist_Sorted_State to match the content of a list.

Parameters:

state	The state to update
list	The list to match

Returns:

The number of item in the actually in the list

Since (EFL) :

1.1.0

See eina_inlist_sorted_state_insert() for more information. This function is useful if you didn't use eina_inlist_sorted_state_insert() at some point, but still think you have a sorted list. It will only correctly work on a sorted list.

Since :

2.3

Eina_Inlist* eina_inlist_sorted_state_insert	(	Eina_Inlist *	list,
		Eina_Inlist *	item,
		Eina_Compare_Cb	func,
		Eina_Inlist_Sorted_State *	state
	)

Inserts a new node into a sorted list.

Parameters:

list	The given linked list, must be sorted.
item	list node to insert, must not be NULL.
func	The function called for the sort.
state	The current array for initial dichotomic search

Returns:

A list pointer.

Since (EFL) :

1.1.0

This function inserts item into a linked list assuming state match the exact content order of the list. It use state to do a fast first step dichotomic search before starting to walk the inlist itself. This make this code much faster than eina_inlist_sorted_insert() as it doesn't need to walk the list at all. The result is of course a sorted list with an updated state.. If list is NULLL, item is returned. On success, a new list pointer that should be used in place of the one given to this function is returned. Otherwise, the old pointer is returned.

Note:

O(log2(n)) comparisons (calls to func) average/worst case performance. As said in eina_list_search_sorted_near_list(), lists do not have O(1) access time, so walking to the correct node can be costly, but this version try to minimize that by making it a O(log2(n)) for number small number. After n == 256, it start to add a linear cost again. Consider worst case to be almost O(n) pointer dereference (list walk).

Since :

2.3

Eina_Inlist_Sorted_State* eina_inlist_sorted_state_new

(

void

)

Creates state with valid data in it.

Returns:

A valid Eina_Inlist_Sorted_State.

Since (EFL) :

1.1.0

See eina_inlist_sorted_state_insert() for more information.

Since :

2.3