496 lines
15 KiB
C
496 lines
15 KiB
C
/*
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* Copyright © 2010 Intel Corporation
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* Copyright © 2010 Francisco Jerez <currojerez@riseup.net>
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*
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*/
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#ifndef _XORG_LIST_H_
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#define _XORG_LIST_H_
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#include <stddef.h> /* offsetof() */
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/**
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* @file Classic doubly-link circular list implementation.
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* For real usage examples of the linked list, see the file test/list.c
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*
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* Example:
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* We need to keep a list of struct foo in the parent struct bar, i.e. what
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* we want is something like this.
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*
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* struct bar {
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* ...
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* struct foo *list_of_foos; -----> struct foo {}, struct foo {}, struct foo{}
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* ...
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* }
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*
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* We need one list head in bar and a list element in all list_of_foos (both are of
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* data type 'struct xorg_list').
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*
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* struct bar {
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* ...
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* struct xorg_list list_of_foos;
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* ...
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* }
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*
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* struct foo {
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* ...
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* struct xorg_list entry;
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* ...
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* }
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*
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* Now we initialize the list head:
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*
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* struct bar bar;
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* ...
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* xorg_list_init(&bar.list_of_foos);
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*
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* Then we create the first element and add it to this list:
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*
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* struct foo *foo = malloc(...);
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* ....
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* xorg_list_add(&foo->entry, &bar.list_of_foos);
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*
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* Repeat the above for each element you want to add to the list. Deleting
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* works with the element itself.
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* xorg_list_del(&foo->entry);
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* free(foo);
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*
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* Note: calling xorg_list_del(&bar.list_of_foos) will set bar.list_of_foos to an empty
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* list again.
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*
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* Looping through the list requires a 'struct foo' as iterator and the
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* name of the field the subnodes use.
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*
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* struct foo *iterator;
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* xorg_list_for_each_entry(iterator, &bar.list_of_foos, entry) {
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* if (iterator->something == ...)
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* ...
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* }
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*
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* 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:
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*
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* struct foo *iterator, *next;
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* xorg_list_for_each_entry_safe(iterator, next, &bar.list_of_foos, entry) {
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* if (...)
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* xorg_list_del(&iterator->entry);
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* }
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*
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*/
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/**
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* The linkage struct for list nodes. This struct must be part of your
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* to-be-linked struct. struct xorg_list is required for both the head of the
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* list and for each list node.
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*
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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.
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* There are no requirements for a list head, any struct xorg_list can be a list
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* head.
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*/
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struct xorg_list {
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struct xorg_list *next, *prev;
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};
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/**
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* Initialize the list as an empty list.
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*
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* Example:
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* xorg_list_init(&bar->list_of_foos);
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*
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* @param list The list to initialize
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*/
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static inline void
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xorg_list_init(struct xorg_list *list)
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{
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list->next = list->prev = list;
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}
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static inline void
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__xorg_list_add(struct xorg_list *entry,
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struct xorg_list *prev, struct xorg_list *next)
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{
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next->prev = entry;
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entry->next = next;
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entry->prev = prev;
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prev->next = entry;
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}
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/**
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* Insert a new element after the given list head. The new element does not
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* need to be initialised as empty list.
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* The list changes from:
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* head → some element → ...
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* to
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* head → new element → older element → ...
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*
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* Example:
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* struct foo *newfoo = malloc(...);
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* xorg_list_add(&newfoo->entry, &bar->list_of_foos);
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*
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* @param entry The new element to prepend to the list.
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* @param head The existing list.
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*/
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static inline void
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xorg_list_add(struct xorg_list *entry, struct xorg_list *head)
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{
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__xorg_list_add(entry, head, head->next);
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}
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/**
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* Append a new element to the end of the list given with this list head.
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*
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* The list changes from:
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* head → some element → ... → lastelement
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* to
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* head → some element → ... → lastelement → new element
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*
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* Example:
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* struct foo *newfoo = malloc(...);
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* xorg_list_append(&newfoo->entry, &bar->list_of_foos);
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*
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* @param entry The new element to prepend to the list.
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* @param head The existing list.
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*/
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static inline void
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xorg_list_append(struct xorg_list *entry, struct xorg_list *head)
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{
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__xorg_list_add(entry, head->prev, head);
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}
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static inline void
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__xorg_list_del(struct xorg_list *prev, struct xorg_list *next)
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{
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next->prev = prev;
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prev->next = next;
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}
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/**
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* Remove the element from the list it is in. Using this function will reset
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* the pointers to/from this element so it is removed from the list. It does
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* NOT free the element itself or manipulate it otherwise.
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*
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* 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
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* the list but rather reset the list as empty list.
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*
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* Example:
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* xorg_list_del(&foo->entry);
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*
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* @param entry The element to remove.
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*/
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static inline void
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xorg_list_del(struct xorg_list *entry)
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{
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__xorg_list_del(entry->prev, entry->next);
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xorg_list_init(entry);
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}
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/**
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* Check if the list is empty.
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*
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* Example:
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* xorg_list_is_empty(&bar->list_of_foos);
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*
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* @return True if the list is empty or False if the list contains one or more
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* elements.
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*/
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static inline int
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xorg_list_is_empty(struct xorg_list *head)
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{
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return head->next == head;
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}
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/**
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* Returns a pointer to the container of this list element.
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*
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* Example:
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* struct foo* f;
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* f = container_of(&foo->entry, struct foo, entry);
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* assert(f == foo);
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*
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* @param ptr Pointer to the struct xorg_list.
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* @param type Data type of the list element.
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* @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.
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*/
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#ifndef container_of
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#define container_of(ptr, type, member) \
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(type *)((char *)(ptr) - offsetof(type, member))
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#endif
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/**
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* Alias of container_of
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*/
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#define xorg_list_entry(ptr, type, member) \
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container_of(ptr, type, member)
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/**
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* Retrieve the first list entry for the given list pointer.
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*
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* Example:
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* struct foo *first;
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* first = xorg_list_first_entry(&bar->list_of_foos, struct foo, list_of_foos);
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*
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* @param ptr The list head
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* @param type Data type of the list element to retrieve
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* @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.
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*/
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#define xorg_list_first_entry(ptr, type, member) \
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xorg_list_entry((ptr)->next, type, member)
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/**
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* Retrieve the last list entry for the given listpointer.
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*
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* Example:
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* struct foo *first;
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* first = xorg_list_last_entry(&bar->list_of_foos, struct foo, list_of_foos);
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*
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* @param ptr The list head
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* @param type Data type of the list element to retrieve
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* @param member Member name of the struct xorg_list field in the list element.
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* @return A pointer to the last list element.
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*/
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#define xorg_list_last_entry(ptr, type, member) \
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xorg_list_entry((ptr)->prev, type, member)
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#ifdef HAVE_TYPEOF
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#define __container_of(ptr, sample, member) \
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container_of(ptr, typeof(*sample), member)
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#else
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/* This implementation of __container_of has undefined behavior according
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* to the C standard, but it works in many cases. If your compiler doesn't
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* support typeof() and fails with this implementation, please try a newer
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* compiler.
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*/
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#define __container_of(ptr, sample, member) \
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(void *)((char *)(ptr) \
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- ((char *)&(sample)->member - (char *)(sample)))
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#endif
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/**
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* Loop through the list given by head and set pos to struct in the list.
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*
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* Example:
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* struct foo *iterator;
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* xorg_list_for_each_entry(iterator, &bar->list_of_foos, entry) {
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* [modify iterator]
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* }
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*
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* This macro is not safe for node deletion. Use xorg_list_for_each_entry_safe
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* instead.
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*
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* @param pos Iterator variable of the type of the list elements.
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* @param head List head
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* @param member Member name of the struct xorg_list in the list elements.
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*
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*/
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#define xorg_list_for_each_entry(pos, head, member) \
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for (pos = NULL, \
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pos = __container_of((head)->next, pos, member); \
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&pos->member != (head); \
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pos = __container_of(pos->member.next, pos, member))
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/**
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* Loop through the list, keeping a backup pointer to the element. This
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* macro allows for the deletion of a list element while looping through the
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* list.
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*
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* See xorg_list_for_each_entry for more details.
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*/
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#define xorg_list_for_each_entry_safe(pos, tmp, head, member) \
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for (pos = NULL, \
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pos = __container_of((head)->next, pos, member), \
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tmp = __container_of(pos->member.next, pos, member); \
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&pos->member != (head); \
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pos = tmp, tmp = __container_of(pos->member.next, tmp, member))
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/* NULL-Terminated List Interface
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*
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* The interface below does _not_ use the struct xorg_list as described above.
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* It is mainly for legacy structures that cannot easily be switched to
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* struct xorg_list.
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*
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* This interface is for structs like
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* struct foo {
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* [...]
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* struct foo *next;
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* [...]
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* };
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*
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* The position and field name of "next" are arbitrary.
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*/
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/**
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* Init the element as null-terminated list.
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*
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* Example:
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* struct foo *list = malloc();
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* nt_list_init(list, next);
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*
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* @param list The list element that will be the start of the list
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* @param member Member name of the field pointing to next struct
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*/
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#define nt_list_init(_list, _member) \
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(_list)->_member = NULL
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/**
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* Returns the next element in the list or NULL on termination.
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*
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* Example:
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* struct foo *element = list;
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* while ((element = nt_list_next(element, next)) { }
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*
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* This macro is not safe for node deletion. Use nt_list_for_each_entry_safe
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* instead.
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*
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* @param list The list or current element.
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* @param member Member name of the field pointing to next struct.
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*/
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#define nt_list_next(_list, _member) \
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(_list)->_member
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/**
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* Iterate through each element in the list.
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*
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* Example:
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* struct foo *iterator;
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* nt_list_for_each_entry(iterator, list, next) {
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* [modify iterator]
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* }
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*
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* @param entry Assigned to the current list element
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* @param list The list to iterate through.
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* @param member Member name of the field pointing to next struct.
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*/
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#define nt_list_for_each_entry(_entry, _list, _member) \
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for (_entry = _list; _entry; _entry = (_entry)->_member)
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/**
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* Iterate through each element in the list, keeping a backup pointer to the
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* element. This macro allows for the deletion of a list element while
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* looping through the list.
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*
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* See nt_list_for_each_entry for more details.
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*
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* @param entry Assigned to the current list element
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* @param tmp The pointer to the next element
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* @param list The list to iterate through.
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* @param member Member name of the field pointing to next struct.
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*/
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#define nt_list_for_each_entry_safe(_entry, _tmp, _list, _member) \
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for (_entry = _list, _tmp = (_entry) ? (_entry)->_member : NULL;\
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_entry; \
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_entry = _tmp, _tmp = (_tmp) ? (_tmp)->_member: NULL)
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/**
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* Append the element to the end of the list. This macro may be used to
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* merge two lists.
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*
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* Example:
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* struct foo *elem = malloc(...);
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* nt_list_init(elem, next)
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* nt_list_append(elem, list, struct foo, next);
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*
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* Resulting list order:
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* list_item_0 -> list_item_1 -> ... -> elem_item_0 -> elem_item_1 ...
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*
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* @param entry An entry (or list) to append to the list
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* @param list The list to append to. This list must be a valid list, not
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* NULL.
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* @param type The list type
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* @param member Member name of the field pointing to next struct
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*/
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#define nt_list_append(_entry, _list, _type, _member) \
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do { \
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_type *__iterator = _list; \
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while (__iterator->_member) { __iterator = __iterator->_member;}\
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__iterator->_member = _entry; \
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} while (0)
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/**
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* Insert the element at the next position in the list. This macro may be
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* used to insert a list into a list.
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*
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* struct foo *elem = malloc(...);
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* nt_list_init(elem, next)
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* nt_list_insert(elem, list, struct foo, next);
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*
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* Resulting list order:
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* list_item_0 -> elem_item_0 -> elem_item_1 ... -> list_item_1 -> ...
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*
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* @param entry An entry (or list) to append to the list
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* @param list The list to insert to. This list must be a valid list, not
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* NULL.
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* @param type The list type
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* @param member Member name of the field pointing to next struct
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*/
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#define nt_list_insert(_entry, _list, _type, _member) \
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do { \
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nt_list_append((_list)->_member, _entry, _type, _member); \
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(_list)->_member = _entry; \
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} while (0)
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/**
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* Delete the entry from the list by iterating through the list and
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* removing any reference from the list to the entry.
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*
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* Example:
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* struct foo *elem = <assign to right element>
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* nt_list_del(elem, list, struct foo, next);
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*
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* @param entry The entry to delete from the list. entry is always
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* re-initialized as a null-terminated list.
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* @param list The list containing the entry, set to the new list without
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* the removed entry.
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* @param type The list type
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* @param member Member name of the field pointing to the next entry
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*/
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#define nt_list_del(_entry, _list, _type, _member) \
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do { \
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_type *__e = _entry; \
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if (__e == NULL || _list == NULL) break; \
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if ((_list) == __e) { \
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_list = __e->_member; \
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} else { \
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_type *__prev = _list; \
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while (__prev->_member && __prev->_member != __e) \
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__prev = nt_list_next(__prev, _member); \
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if (__prev->_member) \
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__prev->_member = __e->_member; \
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} \
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nt_list_init(__e, _member); \
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} while(0)
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/**
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* DO NOT USE THIS.
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* This is a remainder of the xfree86 DDX attempt of having a set of generic
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* list functions. Unfortunately, the xf86OptionRec uses it and we can't
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* easily get rid of it. Do not use for new code.
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*/
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typedef struct generic_list_rec {
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void *next;
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} GenericListRec, *GenericListPtr, *glp;
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#endif
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