fcafe82575
This is a set of macros to provide a struct list-alike interface for classic linked lists such as the XF86OptionRec or the DeviceIntRec. The typical format for these is to have a "struct foo *next" pointer in each struct foo and walk through those. These macros provide a few basic functions to add to, remove from and iterate through these lists. While struct list is in some ways more flexible, switching legacy code to use struct list is not alway viable. These macros at least reduce the amount of open-coded lists. Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net> Reviewed-by: Alan Coopersmith <alan.coopersmith@oracle.com>
442 lines
12 KiB
C
442 lines
12 KiB
C
/*
|
|
* Copyright © 2010 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 _LIST_H_
|
|
#define _LIST_H_
|
|
|
|
/**
|
|
* @file Classic doubly-link circular list implementation.
|
|
*
|
|
* 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 *foos; -----> struct foo {}, struct foo {}, struct foo{}
|
|
* ...
|
|
* }
|
|
*
|
|
* We need one list head in bar and a list element in all foos (both are of
|
|
* data type 'struct list').
|
|
*
|
|
* struct bar {
|
|
* ...
|
|
* struct list foos;
|
|
* ...
|
|
* }
|
|
*
|
|
* struct foo {
|
|
* ...
|
|
* struct list entry;
|
|
* ...
|
|
* }
|
|
*
|
|
* Now we initialize the list head:
|
|
*
|
|
* struct bar bar;
|
|
* ...
|
|
* list_init(&bar.foos);
|
|
*
|
|
* Then we create the first element and add it to this list:
|
|
*
|
|
* struct foo *foo = malloc(...);
|
|
* ....
|
|
* list_add(&foo->entry, &bar.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.foos) will set bar.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.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.foos, entry) {
|
|
* if (...)
|
|
* list_del(&iterator->entry);
|
|
* }
|
|
*
|
|
*/
|
|
|
|
/**
|
|
* The linkage struct for list nodes. This struct must be part of your
|
|
* to-be-linked struct.
|
|
*
|
|
* Example:
|
|
* struct foo {
|
|
* int a;
|
|
* void *b;
|
|
* struct list *mylist;
|
|
* }
|
|
*
|
|
* 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(&foo->mylist);
|
|
*
|
|
* @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 list changes from:
|
|
* head → some element → ...
|
|
* to
|
|
* head → new element → older element → ...
|
|
*
|
|
* Example:
|
|
* struct foo *newfoo = malloc(...);
|
|
* list_add(&newfoo->mylist, &foo->mylist);
|
|
*
|
|
* @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_del(struct list *prev, struct list *next)
|
|
{
|
|
next->prev = prev;
|
|
prev->next = 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(&newfoo->mylist);
|
|
*
|
|
* @param entry The element to remove.
|
|
*/
|
|
static inline void
|
|
list_del(struct list *entry)
|
|
{
|
|
__list_del(entry->prev, entry->next);
|
|
list_init(entry);
|
|
}
|
|
|
|
/**
|
|
* Check if the list is empty.
|
|
*
|
|
* Example:
|
|
* list_is_empty(&foo->mylist);
|
|
*
|
|
* @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;
|
|
}
|
|
|
|
/**
|
|
* Returns a pointer to the container of this list element.
|
|
*
|
|
* Example:
|
|
* struct foo* f;
|
|
* f = container_of(&foo->mylist, struct foo, mylist);
|
|
* assert(f == foo);
|
|
*
|
|
* @param ptr Pointer to the struct list.
|
|
* @param type Data type of the list element.
|
|
* @param member Member name of the struct list field in the list element.
|
|
* @return A pointer to the data struct containing the list head.
|
|
*/
|
|
#ifndef container_of
|
|
#define container_of(ptr, type, member) \
|
|
(type *)((char *)(ptr) - (char *) &((type *)0)->member)
|
|
#endif
|
|
|
|
/**
|
|
* 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(&foo->mylist, struct foo, mylist);
|
|
*
|
|
* @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)
|
|
|
|
#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, &foo->mylist, mylist) {
|
|
* [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))
|
|
|
|
/**
|
|
* 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))
|
|
|
|
|
|
|
|
/* NULL-Terminated List Interface
|
|
*
|
|
* The interface below does _not_ use the struct list as described above.
|
|
* It is mainly for legacy structures that cannot easily be switched to
|
|
* struct list.
|
|
*
|
|
* This interface is for structs like
|
|
* struct foo {
|
|
* [...]
|
|
* struct foo *next;
|
|
* [...]
|
|
* };
|
|
*
|
|
* The position and field name of "next" are arbitrary.
|
|
*/
|
|
|
|
/**
|
|
* Init the element as null-terminated list.
|
|
*
|
|
* Example:
|
|
* struct foo *list = malloc();
|
|
* nt_list_init(list, next);
|
|
*
|
|
* @param list The list element that will be the start of the list
|
|
* @param member Member name of the field pointing to next struct
|
|
*/
|
|
#define nt_list_init(_list, _member) \
|
|
(_list)->_member = NULL
|
|
|
|
/**
|
|
* Returns the next element in the list or NULL on termination.
|
|
*
|
|
* Example:
|
|
* struct foo *element = list;
|
|
* while ((element = nt_list_next(element, next)) { }
|
|
*
|
|
* This macro is not safe for node deletion. Use list_for_each_entry_safe
|
|
* instead.
|
|
*
|
|
* @param list The list or current element.
|
|
* @param member Member name of the field pointing to next struct.
|
|
*/
|
|
#define nt_list_next(_list, _member) \
|
|
(_list)->_member
|
|
|
|
/**
|
|
* Iterate through each element in the list.
|
|
*
|
|
* Example:
|
|
* struct foo *iterator;
|
|
* nt_list_for_each_entry(iterator, list, next) {
|
|
* [modify iterator]
|
|
* }
|
|
*
|
|
* @param entry Assigned to the current list element
|
|
* @param list The list to iterate through.
|
|
* @param member Member name of the field pointing to next struct.
|
|
*/
|
|
#define nt_list_for_each_entry(_entry, _list, _member) \
|
|
for (_entry = _list; _entry; _entry = (_entry)->_member)
|
|
|
|
/**
|
|
* Iterate through each element in 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 nt_list_for_each_entry for more details.
|
|
*
|
|
* @param entry Assigned to the current list element
|
|
* @param tmp The pointer to the next element
|
|
* @param list The list to iterate through.
|
|
* @param member Member name of the field pointing to next struct.
|
|
*/
|
|
#define nt_list_for_each_entry_safe(_entry, _tmp, _list, _member) \
|
|
for (_entry = _list, _tmp = (_entry) ? (_entry)->_member : NULL;\
|
|
_entry; \
|
|
_entry = _tmp, _tmp = (_tmp) ? (_tmp)->_member: NULL)
|
|
|
|
|
|
/**
|
|
* Append the element to the end of the list. This macro may be used to
|
|
* merge two lists.
|
|
*
|
|
* Example:
|
|
* struct foo *elem = malloc(...);
|
|
* nt_list_init(elem, next)
|
|
* nt_list_append(elem, list, struct foo, next);
|
|
*
|
|
* Resulting list order:
|
|
* list_item_0 -> list_item_1 -> ... -> elem_item_0 -> elem_item_1 ...
|
|
*
|
|
* @param entry An entry (or list) to append to the list
|
|
* @param list The list to append to. This list must be a valid list, not
|
|
* NULL.
|
|
* @param type The list type
|
|
* @param member Member name of the field pointing to next struct
|
|
*/
|
|
#define nt_list_append(_entry, _list, _type, _member) \
|
|
do { \
|
|
_type *__iterator = _list; \
|
|
while (__iterator->_member) { __iterator = __iterator->_member;}\
|
|
__iterator->_member = _entry; \
|
|
} while (0)
|
|
|
|
/**
|
|
* Insert the element at the next position in the list. This macro may be
|
|
* used to insert a list into a list.
|
|
*
|
|
* struct foo *elem = malloc(...);
|
|
* nt_list_init(elem, next)
|
|
* nt_list_insert(elem, list, struct foo, next);
|
|
*
|
|
* Resulting list order:
|
|
* list_item_0 -> elem_item_0 -> elem_item_1 ... -> list_item_1 -> ...
|
|
*
|
|
* @param entry An entry (or list) to append to the list
|
|
* @param list The list to insert to. This list must be a valid list, not
|
|
* NULL.
|
|
* @param type The list type
|
|
* @param member Member name of the field pointing to next struct
|
|
*/
|
|
#define nt_list_insert(_entry, _list, _type, _member) \
|
|
do { \
|
|
nt_list_append((_list)->_member, _entry, _type, _member); \
|
|
(_list)->_member = _entry; \
|
|
} while (0)
|
|
|
|
/**
|
|
* Delete the entry from the list by iterating through the list and
|
|
* removing any reference from the list to the entry.
|
|
*
|
|
* Example:
|
|
* struct foo *elem = <assign to right element>
|
|
* nt_list_del(elem, list, struct foo, next);
|
|
*
|
|
* @param entry The entry to delete from the list. entry is always
|
|
* re-initialized as a null-terminated list.
|
|
* @param list The list containing the entry, set to the new list without
|
|
* the removed entry.
|
|
* @param type The list type
|
|
* @param member Member name of the field pointing to the next entry
|
|
*/
|
|
#define nt_list_del(_entry, _list, _type, _member) \
|
|
do { \
|
|
_type *__e = _entry; \
|
|
if (__e == NULL) break; \
|
|
if ((_list) == __e) { \
|
|
_list = __e->_member; \
|
|
} else { \
|
|
_type *__prev = _list; \
|
|
while (__prev->_member && __prev->_member != __e) \
|
|
__prev = nt_list_next(__prev, _member); \
|
|
if (__prev->_member) \
|
|
__prev->_member = __e->_member; \
|
|
} \
|
|
nt_list_init(__e, _member); \
|
|
} while(0)
|
|
|
|
#endif
|