1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
6 This file is part of systemd.
8 Copyright 2010 Lennart Poettering
10 systemd is free software; you can redistribute it and/or modify it
11 under the terms of the GNU Lesser General Public License as published by
12 the Free Software Foundation; either version 2.1 of the License, or
13 (at your option) any later version.
15 systemd is distributed in the hope that it will be useful, but
16 WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 Lesser General Public License for more details.
20 You should have received a copy of the GNU Lesser General Public License
21 along with systemd; If not, see <http://www.gnu.org/licenses/>.
24 /* The head of the linked list. Use this in the structure that shall
25 * contain the head of the linked list */
26 #define LIST_HEAD(t,name) \
29 /* The pointers in the linked list's items. Use this in the item structure */
30 #define LIST_FIELDS(t,name) \
31 t *name##_next, *name##_prev
33 /* Initialize the list's head */
34 #define LIST_HEAD_INIT(head) \
39 /* Initialize a list item */
40 #define LIST_INIT(name,item) \
42 typeof(*(item)) *_item = (item); \
44 _item->name##_prev = _item->name##_next = NULL; \
47 /* Prepend an item to the list */
48 #define LIST_PREPEND(name,head,item) \
50 typeof(*(head)) **_head = &(head), *_item = (item); \
52 if ((_item->name##_next = *_head)) \
53 _item->name##_next->name##_prev = _item; \
54 _item->name##_prev = NULL; \
58 /* Remove an item from the list */
59 #define LIST_REMOVE(name,head,item) \
61 typeof(*(head)) **_head = &(head), *_item = (item); \
63 if (_item->name##_next) \
64 _item->name##_next->name##_prev = _item->name##_prev; \
65 if (_item->name##_prev) \
66 _item->name##_prev->name##_next = _item->name##_next; \
68 assert(*_head == _item); \
69 *_head = _item->name##_next; \
71 _item->name##_next = _item->name##_prev = NULL; \
74 /* Find the head of the list */
75 #define LIST_FIND_HEAD(name,item,head) \
77 typeof(*(item)) *_item = (item); \
79 while (_item->name##_prev) \
80 _item = _item->name##_prev; \
84 /* Find the tail of the list */
85 #define LIST_FIND_TAIL(name,item,tail) \
87 typeof(*(item)) *_item = (item); \
89 while (_item->name##_next) \
90 _item = _item->name##_next; \
94 /* Insert an item after another one (a = where, b = what) */
95 #define LIST_INSERT_AFTER(name,head,a,b) \
97 typeof(*(head)) **_head = &(head), *_a = (a), *_b = (b); \
100 if ((_b->name##_next = *_head)) \
101 _b->name##_next->name##_prev = _b; \
102 _b->name##_prev = NULL; \
105 if ((_b->name##_next = _a->name##_next)) \
106 _b->name##_next->name##_prev = _b; \
107 _b->name##_prev = _a; \
108 _a->name##_next = _b; \
112 #define LIST_JUST_US(name,item) \
113 (!(item)->name##_prev && !(item)->name##_next) \
115 #define LIST_FOREACH(name,i,head) \
116 for ((i) = (head); (i); (i) = (i)->name##_next)
118 #define LIST_FOREACH_SAFE(name,i,n,head) \
119 for ((i) = (head); (i) && (((n) = (i)->name##_next), 1); (i) = (n))
121 #define LIST_FOREACH_BEFORE(name,i,p) \
122 for ((i) = (p)->name##_prev; (i); (i) = (i)->name##_prev)
124 #define LIST_FOREACH_AFTER(name,i,p) \
125 for ((i) = (p)->name##_next; (i); (i) = (i)->name##_next)
127 /* Loop starting from p->next until p->prev.
128 p can be adjusted meanwhile. */
129 #define LIST_LOOP_BUT_ONE(name,i,head,p) \
130 for ((i) = (p)->name##_next ? (p)->name##_next : (head); \
132 (i) = (i)->name##_next ? (i)->name##_next : (head))