/*
* Copyright © 2010-2012 Intel Corporation
* Copyright © 2010 Francisco Jerez <currojerez@riseup.net>
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*
*/
#ifndef _INTEL_LIST_H_
#define _INTEL_LIST_H_
#include <stdbool.h>
/**
* @file Classic doubly-link circular list implementation.
* For real usage examples of the linked list, see the file test/list.c
*
* Example:
* We need to keep a list of struct foo in the parent struct bar, i.e. what
* we want is something like this.
*
* struct bar {
* ...
* struct foo *list_of_foos; -----> struct foo {}, struct foo {}, struct foo{}
* ...
* }
*
* We need one list head in bar and a list element in all list_of_foos (both are of
* data type 'struct list').
*
* struct bar {
* ...
* struct list list_of_foos;
* ...
* }
*
* struct foo {
* ...
* struct list entry;
* ...
* }
*
* Now we initialize the list head:
*
* struct bar bar;
* ...
* list_init(&bar.list_of_foos);
*
* Then we create the first element and add it to this list:
*
* struct foo *foo = malloc(...);
* ....
* list_add(&foo->entry, &bar.list_of_foos);
*
* Repeat the above for each element you want to add to the list. Deleting
* works with the element itself.
* list_del(&foo->entry);
* free(foo);
*
* Note: calling list_del(&bar.list_of_foos) will set bar.list_of_foos to an empty
* list again.
*
* Looping through the list requires a 'struct foo' as iterator and the
* name of the field the subnodes use.
*
* struct foo *iterator;
* list_for_each_entry(iterator, &bar.list_of_foos, entry) {
* if (iterator->something == ...)
* ...
* }
*
* Note: You must not call list_del() on the iterator if you continue the
* loop. You need to run the safe for-each loop instead:
*
* struct foo *iterator, *next;
* list_for_each_entry_safe(iterator, next, &bar.list_of_foos, entry) {
* if (...)
* list_del(&iterator->entry);
* }
*
*/
/**
* The linkage struct for list nodes. This struct must be part of your
* to-be-linked struct. struct list is required for both the head of the
* list and for each list node.
*
* Position and name of the struct list field is irrelevant.
* There are no requirements that elements of a list are of the same type.
* There are no requirements for a list head, any struct list can be a list
* head.
*/
struct list {
struct list *next, *prev;
};
/**
* Initialize the list as an empty list.
*
* Example:
* list_init(&bar->list_of_foos);
*
* @param The list to initialized.
*/
static void
list_init(struct list *list)
{
list->next = list->prev = list;
}
static inline void
__list_add(struct list *entry,
struct list *prev,
struct list *next)
{
next->prev = entry;
entry->next = next;
entry->prev = prev;
prev->next = entry;
}
/**
* Insert a new element after the given list head. The new element does not
* need to be initialised as empty list.
* The list changes from:
* head → some element → ...
* to
* head → new element → older element → ...
*
* Example:
* struct foo *newfoo = malloc(...);
* list_add(&newfoo->entry, &bar->list_of_foos);
*
* @param entry The new element to prepend to the list.
* @param head The existing list.
*/
static inline void
list_add(struct list *entry, struct list *head)
{
__list_add(entry, head, head->next);
}
static inline void
list_add_tail(struct list *entry, struct list *head)
{
__list_add(entry, head->prev, head);
}
static inline void list_replace(struct list *old,
struct list *new)
{
new->next = old->next;
new->next->prev = new;
new->prev = old->prev;
new->prev->next = new;
}
#define list_last_entry(ptr, type, member) \
list_entry((ptr)->prev, type, member)
#define list_for_each(pos, head) \
for (pos = (head)->next; pos != (head); pos = pos->next)
/**
* Append a new element to the end of the list given with this list head.
*
* The list changes from:
* head → some element → ... → lastelement
* to
* head → some element → ... → lastelement → new element
*
* Example:
* struct foo *newfoo = malloc(...);
* list_append(&newfoo->entry, &bar->list_of_foos);
*
* @param entry The new element to prepend to the list.
* @param head The existing list.
*/
static inline void
list_append(struct list *entry, struct list *head)
{
__list_add(entry, head->prev, head);
}
static inline void
__list_del(struct list *prev, struct list *next)
{
assert(next->prev == prev->next);
next->prev = prev;
prev->next = next;
}
static inline void
_list_del(struct list *entry)
{
assert(entry->prev->next == entry);
assert(entry->next->prev == entry);
__list_del(entry->prev, entry->next);
}
/**
* Remove the element from the list it is in. Using this function will reset
* the pointers to/from this element so it is removed from the list. It does
* NOT free the element itself or manipulate it otherwise.
*
* Using list_del on a pure list head (like in the example at the top of
* this file) will NOT remove the first element from
* the list but rather reset the list as empty list.
*
* Example:
* list_del(&foo->entry);
*
* @param entry The element to remove.
*/
static inline void
list_del(struct list *entry)
{
_list_del(entry);
list_init(entry);
}
static inline void list_move(struct list *list, struct list *head)
{
if (list->prev != head) {
_list_del(list);
list_add(list, head);
}
}
static inline void list_move_tail(struct list *list, struct list *head)
{
_list_del(list);
list_add_tail(list, head);
}
/**
* Check if the list is empty.
*
* Example:
* list_is_empty(&bar->list_of_foos);
*
* @return True if the list contains one or more elements or False otherwise.
*/
static inline bool
list_is_empty(struct list *head)
{
return head->next == head;
}
/**
* Alias of container_of
*/
#define list_entry(ptr, type, member) \
container_of(ptr, type, member)
/**
* Retrieve the first list entry for the given list pointer.
*
* Example:
* struct foo *first;
* first = list_first_entry(&bar->list_of_foos, struct foo, list_of_foos);
*
* @param ptr The list head
* @param type Data type of the list element to retrieve
* @param member Member name of the struct list field in the list element.
* @return A pointer to the first list element.
*/
#define list_first_entry(ptr, type, member) \
list_entry((ptr)->next, type, member)
/**
* Retrieve the last list entry for the given listpointer.
*
* Example:
* struct foo *first;
* first = list_last_entry(&bar->list_of_foos, struct foo, list_of_foos);
*
* @param ptr The list head
* @param type Data type of the list element to retrieve
* @param member Member name of the struct list field in the list element.
* @return A pointer to the last list element.
*/
#define list_last_entry(ptr, type, member) \
list_entry((ptr)->prev, type, member)
#define __container_of(ptr, sample, member) \
(void *)((char *)(ptr) \
- ((char *)&(sample)->member - (char *)(sample)))
/**
* Loop through the list given by head and set pos to struct in the list.
*
* Example:
* struct foo *iterator;
* list_for_each_entry(iterator, &bar->list_of_foos, entry) {
* [modify iterator]
* }
*
* This macro is not safe for node deletion. Use list_for_each_entry_safe
* instead.
*
* @param pos Iterator variable of the type of the list elements.
* @param head List head
* @param member Member name of the struct list in the list elements.
*
*/
#define list_for_each_entry(pos, head, member) \
for (pos = __container_of((head)->next, pos, member); \
&pos->member != (head); \
pos = __container_of(pos->member.next, pos, member))
#define list_for_each_entry_reverse(pos, head, member) \
for (pos = __container_of((head)->prev, pos, member); \
&pos->member != (head); \
pos = __container_of(pos->member.prev, pos, member))
/**
* Loop through the list, keeping a backup pointer to the element. This
* macro allows for the deletion of a list element while looping through the
* list.
*
* See list_for_each_entry for more details.
*/
#define list_for_each_entry_safe(pos, tmp, head, member) \
for (pos = __container_of((head)->next, pos, member), \
tmp = __container_of(pos->member.next, pos, member); \
&pos->member != (head); \
pos = tmp, tmp = __container_of(pos->member.next, tmp, member))
#undef container_of
#define container_of(ptr, type, member) \
((type *)((char *)(ptr) - (char *) &((type *)0)->member))
#endif /* _INTEL_LIST_H_ */