2 Unix SMB/CIFS implementation.
3 some simple double linked list macros
4 Copyright (C) Andrew Tridgell 1998
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>.
20 /* To use these macros you must have a structure containing a next and
27 /* hook into the front of the list */
28 #define DLIST_ADD(list, p) \
32 (p)->next = (p)->prev = NULL; \
41 /* remove an element from a list - element doesn't have to be in list. */
42 #define DLIST_REMOVE(list, p) \
44 if ((p) == (list)) { \
46 if (list) (list)->prev = NULL; \
48 if ((p)->prev) (p)->prev->next = (p)->next; \
49 if ((p)->next) (p)->next->prev = (p)->prev; \
51 if ((p) != (list)) (p)->next = (p)->prev = NULL; \
54 #define DLIST_HEAD(p, result_head) \
56 (result_head) = (p); \
57 while (DLIST_PREV(result_head)) (result_head) = (result_head)->prev; \
60 /* return the last element in the list */
61 #define DLIST_TAIL(list, result_tail) \
63 (result_tail) = (list); \
64 while ((result_tail) && (result_tail)->next) (result_tail) = (result_tail)->next; \
67 /* return the previous element in the list. */
68 #define DLIST_PREV(p) ((p)?(p)->prev:NULL)
70 /* promote an element to the top of the list */
71 #define DLIST_PROMOTE(list, p) \
73 DLIST_REMOVE(list, p); \
77 /* hook into the end of the list - needs the entry type */
78 #define DLIST_ADD_END(list, p, type) \
82 (p)->next = (p)->prev = NULL; \
85 for (tmp = (list); tmp->next; tmp = tmp->next) ; \
92 /* insert 'p' after the given element 'el' in a list. If el is NULL then
93 this is the same as a DLIST_ADD() */
94 #define DLIST_ADD_AFTER(list, p, el) \
96 if (!(list) || !(el)) { \
100 p->next = el->next; \
102 if (p->next) p->next->prev = p; \
106 /* demote an element to the end of the list, needs the entry type */
107 #define DLIST_DEMOTE(list, p, type) \
109 DLIST_REMOVE(list, p); \
110 DLIST_ADD_END(list, p, type); \
113 /* concatenate two lists - putting all elements of the 2nd list at the
114 end of the first list */
115 #define DLIST_CONCATENATE(list1, list2, type) \
121 for (tmp = (list1); tmp->next; tmp = tmp->next) ; \
122 tmp->next = (list2); \
124 (list2)->prev = tmp; \
129 #endif /* _DLINKLIST_H */