xenocara/xserver/include/list.h

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/*
* 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 _XORG_LIST_H_
#define _XORG_LIST_H_
#include <stddef.h> /* offsetof() */
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/**
* @file Classic doubly-link circular list implementation.
* For real usage examples of the linked list, see the file test/list.c
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*
* 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{}
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* ...
* }
*
* We need one list head in bar and a list element in all list_of_foos (both are of
* data type 'struct xorg_list').
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*
* struct bar {
* ...
* struct xorg_list list_of_foos;
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* ...
* }
*
* struct foo {
* ...
* struct xorg_list entry;
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* ...
* }
*
* Now we initialize the list head:
*
* struct bar bar;
* ...
* xorg_list_init(&bar.list_of_foos);
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*
* Then we create the first element and add it to this list:
*
* struct foo *foo = malloc(...);
* ....
* xorg_list_add(&foo->entry, &bar.list_of_foos);
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*
* Repeat the above for each element you want to add to the list. Deleting
* works with the element itself.
* xorg_list_del(&foo->entry);
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* free(foo);
*
* Note: calling xorg_list_del(&bar.list_of_foos) will set bar.list_of_foos to an empty
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* list again.
*
* Looping through the list requires a 'struct foo' as iterator and the
* name of the field the subnodes use.
*
* struct foo *iterator;
* xorg_list_for_each_entry(iterator, &bar.list_of_foos, entry) {
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* if (iterator->something == ...)
* ...
* }
*
* Note: You must not call xorg_list_del() on the iterator if you continue the
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* loop. You need to run the safe for-each loop instead:
*
* struct foo *iterator, *next;
* xorg_list_for_each_entry_safe(iterator, next, &bar.list_of_foos, entry) {
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* if (...)
* xorg_list_del(&iterator->entry);
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* }
*
*/
/**
* The linkage struct for list nodes. This struct must be part of your
* to-be-linked struct. struct xorg_list is required for both the head of the
* list and for each list node.
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*
* Position and name of the struct xorg_list field is irrelevant.
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* There are no requirements that elements of a list are of the same type.
* There are no requirements for a list head, any struct xorg_list can be a list
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* head.
*/
struct xorg_list {
struct xorg_list *next, *prev;
};
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/**
* Initialize the list as an empty list.
*
* Example:
* xorg_list_init(&bar->list_of_foos);
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*
* @param The list to initialized.
*/
static inline void
xorg_list_init(struct xorg_list *list)
{
list->next = list->prev = list;
}
static inline void
__xorg_list_add(struct xorg_list *entry,
struct xorg_list *prev, struct xorg_list *next)
{
next->prev = entry;
entry->next = next;
entry->prev = prev;
prev->next = entry;
}
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/**
* Insert a new element after the given list head. The new element does not
* need to be initialised as empty list.
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* The list changes from:
* head some element ...
* to
* head new element older element ...
*
* Example:
* struct foo *newfoo = malloc(...);
* xorg_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
xorg_list_add(struct xorg_list *entry, struct xorg_list *head)
{
__xorg_list_add(entry, head, head->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(...);
* xorg_list_append(&newfoo->entry, &bar->list_of_foos);
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*
* @param entry The new element to prepend to the list.
* @param head The existing list.
*/
static inline void
xorg_list_append(struct xorg_list *entry, struct xorg_list *head)
{
__xorg_list_add(entry, head->prev, head);
}
static inline void
__xorg_list_del(struct xorg_list *prev, struct xorg_list *next)
{
next->prev = prev;
prev->next = next;
}
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/**
* 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 xorg_list_del on a pure list head (like in the example at the top of
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* this file) will NOT remove the first element from
* the list but rather reset the list as empty list.
*
* Example:
* xorg_list_del(&foo->entry);
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*
* @param entry The element to remove.
*/
static inline void
xorg_list_del(struct xorg_list *entry)
{
__xorg_list_del(entry->prev, entry->next);
xorg_list_init(entry);
}
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/**
* Check if the list is empty.
*
* Example:
* xorg_list_is_empty(&bar->list_of_foos);
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*
* @return True if the list contains one or more elements or False otherwise.
*/
static inline int
xorg_list_is_empty(struct xorg_list *head)
{
return head->next == head;
}
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/**
* Returns a pointer to the container of this list element.
*
* Example:
* struct foo* f;
* f = container_of(&foo->entry, struct foo, entry);
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* assert(f == foo);
*
* @param ptr Pointer to the struct xorg_list.
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* @param type Data type of the list element.
* @param member Member name of the struct xorg_list field in the list element.
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* @return A pointer to the data struct containing the list head.
*/
#ifndef container_of
#define container_of(ptr, type, member) \
(type *)((char *)(ptr) - offsetof(type, member))
#endif
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/**
* Alias of container_of
*/
#define xorg_list_entry(ptr, type, member) \
container_of(ptr, type, member)
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/**
* Retrieve the first list entry for the given list pointer.
*
* Example:
* struct foo *first;
* first = xorg_list_first_entry(&bar->list_of_foos, struct foo, list_of_foos);
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*
* @param ptr The list head
* @param type Data type of the list element to retrieve
* @param member Member name of the struct xorg_list field in the list element.
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* @return A pointer to the first list element.
*/
#define xorg_list_first_entry(ptr, type, member) \
xorg_list_entry((ptr)->next, type, member)
/**
* Retrieve the last list entry for the given listpointer.
*
* Example:
* struct foo *first;
* first = xorg_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 xorg_list field in the list element.
* @return A pointer to the last list element.
*/
#define xorg_list_last_entry(ptr, type, member) \
xorg_list_entry((ptr)->prev, type, member)
#ifdef HAVE_TYPEOF
#define __container_of(ptr, sample, member) \
container_of(ptr, typeof(*sample), member)
#else
/* This implementation of __container_of has undefined behavior according
* to the C standard, but it works in many cases. If your compiler doesn't
* support typeof() and fails with this implementation, please try a newer
* compiler.
*/
#define __container_of(ptr, sample, member) \
(void *)((char *)(ptr) \
- ((char *)&(sample)->member - (char *)(sample)))
#endif
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/**
* Loop through the list given by head and set pos to struct in the list.
*
* Example:
* struct foo *iterator;
* xorg_list_for_each_entry(iterator, &bar->list_of_foos, entry) {
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* [modify iterator]
* }
*
* This macro is not safe for node deletion. Use xorg_list_for_each_entry_safe
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* instead.
*
* @param pos Iterator variable of the type of the list elements.
* @param head List head
* @param member Member name of the struct xorg_list in the list elements.
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*
*/
#define xorg_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))
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/**
* 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 xorg_list_for_each_entry for more details.
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*/
#define xorg_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 xorg_list as described above.
* It is mainly for legacy structures that cannot easily be switched to
* struct xorg_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 nt_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 || _list == 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)
/**
* DO NOT USE THIS.
* This is a remainder of the xfree86 DDX attempt of having a set of generic
* list functions. Unfortunately, the xf86OptionRec uses it and we can't
* easily get rid of it. Do not use for new code.
*/
typedef struct generic_list_rec {
void *next;
} GenericListRec, *GenericListPtr, *glp;
#endif