Merge branch 'es/doc-worktree-guessremote-config'
[git.git] / list.h
blobeb601192f4ca9a6af126c82f4c2a24cb9145009d
1 /*
2 * Copyright (C) 2002 Free Software Foundation, Inc.
3 * (originally part of the GNU C Library and Userspace RCU)
4 * Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
6 * Copyright (C) 2009 Pierre-Marc Fournier
7 * Conversion to RCU list.
8 * Copyright (C) 2010 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
10 * This library is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU Lesser General Public
12 * License as published by the Free Software Foundation; either
13 * version 2.1 of the License, or (at your option) any later version.
15 * This library is distributed in the hope that it will be useful,
16 * but 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
21 * License along with this library; if not, see
22 * <http://www.gnu.org/licenses/>.
25 #ifndef LIST_H
26 #define LIST_H 1
29 * The definitions of this file are adopted from those which can be
30 * found in the Linux kernel headers to enable people familiar with the
31 * latter find their way in these sources as well.
34 /* Basic type for the double-link list. */
35 struct list_head {
36 struct list_head *next, *prev;
39 /* avoid conflicts with BSD-only sys/queue.h */
40 #undef LIST_HEAD
41 /* Define a variable with the head and tail of the list. */
42 #define LIST_HEAD(name) \
43 struct list_head name = { &(name), &(name) }
45 /* Initialize a new list head. */
46 #define INIT_LIST_HEAD(ptr) \
47 (ptr)->next = (ptr)->prev = (ptr)
49 #define LIST_HEAD_INIT(name) { &(name), &(name) }
51 /* Add new element at the head of the list. */
52 static inline void list_add(struct list_head *newp, struct list_head *head)
54 head->next->prev = newp;
55 newp->next = head->next;
56 newp->prev = head;
57 head->next = newp;
60 /* Add new element at the tail of the list. */
61 static inline void list_add_tail(struct list_head *newp, struct list_head *head)
63 head->prev->next = newp;
64 newp->next = head;
65 newp->prev = head->prev;
66 head->prev = newp;
69 /* Remove element from list. */
70 static inline void __list_del(struct list_head *prev, struct list_head *next)
72 next->prev = prev;
73 prev->next = next;
76 /* Remove element from list. */
77 static inline void list_del(struct list_head *elem)
79 __list_del(elem->prev, elem->next);
82 /* Remove element from list, initializing the element's list pointers. */
83 static inline void list_del_init(struct list_head *elem)
85 list_del(elem);
86 INIT_LIST_HEAD(elem);
89 /* Delete from list, add to another list as head. */
90 static inline void list_move(struct list_head *elem, struct list_head *head)
92 __list_del(elem->prev, elem->next);
93 list_add(elem, head);
96 /* Replace an old entry. */
97 static inline void list_replace(struct list_head *old, struct list_head *newp)
99 newp->next = old->next;
100 newp->prev = old->prev;
101 newp->prev->next = newp;
102 newp->next->prev = newp;
105 /* Join two lists. */
106 static inline void list_splice(struct list_head *add, struct list_head *head)
108 /* Do nothing if the list which gets added is empty. */
109 if (add != add->next) {
110 add->next->prev = head;
111 add->prev->next = head->next;
112 head->next->prev = add->prev;
113 head->next = add->next;
117 /* Get typed element from list at a given position. */
118 #define list_entry(ptr, type, member) \
119 ((type *) ((char *) (ptr) - offsetof(type, member)))
121 /* Get first entry from a list. */
122 #define list_first_entry(ptr, type, member) \
123 list_entry((ptr)->next, type, member)
125 /* Iterate forward over the elements of the list. */
126 #define list_for_each(pos, head) \
127 for (pos = (head)->next; pos != (head); pos = pos->next)
130 * Iterate forward over the elements list. The list elements can be
131 * removed from the list while doing this.
133 #define list_for_each_safe(pos, p, head) \
134 for (pos = (head)->next, p = pos->next; \
135 pos != (head); \
136 pos = p, p = pos->next)
138 /* Iterate backward over the elements of the list. */
139 #define list_for_each_prev(pos, head) \
140 for (pos = (head)->prev; pos != (head); pos = pos->prev)
143 * Iterate backwards over the elements list. The list elements can be
144 * removed from the list while doing this.
146 #define list_for_each_prev_safe(pos, p, head) \
147 for (pos = (head)->prev, p = pos->prev; \
148 pos != (head); \
149 pos = p, p = pos->prev)
151 static inline int list_empty(struct list_head *head)
153 return head == head->next;
156 static inline void list_replace_init(struct list_head *old,
157 struct list_head *newp)
159 struct list_head *head = old->next;
161 list_del(old);
162 list_add_tail(newp, head);
163 INIT_LIST_HEAD(old);
167 * This is exactly the same as a normal list_head, except that it can be
168 * declared volatile (e.g., if you have a list that may be accessed from signal
169 * handlers).
171 struct volatile_list_head {
172 volatile struct volatile_list_head *next, *prev;
175 #define VOLATILE_LIST_HEAD(name) \
176 volatile struct volatile_list_head name = { &(name), &(name) }
178 static inline void __volatile_list_del(volatile struct volatile_list_head *prev,
179 volatile struct volatile_list_head *next)
181 next->prev = prev;
182 prev->next = next;
185 static inline void volatile_list_del(volatile struct volatile_list_head *elem)
187 __volatile_list_del(elem->prev, elem->next);
190 static inline int volatile_list_empty(volatile struct volatile_list_head *head)
192 return head == head->next;
195 static inline void volatile_list_add(volatile struct volatile_list_head *newp,
196 volatile struct volatile_list_head *head)
198 head->next->prev = newp;
199 newp->next = head->next;
200 newp->prev = head;
201 head->next = newp;
204 #endif /* LIST_H */