Update list, rculist and hlist
[urcu.git] / urcu / list.h
1 /* Copyright (C) 2002 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, write to the Free
17 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
18 02111-1307 USA. */
19
20 #ifndef _LIST_H
21 #define _LIST_H 1
22
23 /* The definitions of this file are adopted from those which can be
24 found in the Linux kernel headers to enable people familiar with
25 the latter find their way in these sources as well. */
26
27
28 /* Basic type for the double-link list. */
29 typedef struct list_head
30 {
31 struct list_head *next;
32 struct list_head *prev;
33 } list_t;
34
35
36 /* Define a variable with the head and tail of the list. */
37 #define LIST_HEAD(name) \
38 list_t name = { &(name), &(name) }
39
40 /* Initialize a new list head. */
41 #define INIT_LIST_HEAD(ptr) \
42 (ptr)->next = (ptr)->prev = (ptr)
43
44 #define LIST_HEAD_INIT(name) { .prev = &(name), .next = &(name) }
45
46 /* Add new element at the head of the list. */
47 static inline void
48 list_add (list_t *newp, list_t *head)
49 {
50 head->next->prev = newp;
51 newp->next = head->next;
52 newp->prev = head;
53 head->next = newp;
54 }
55
56
57 /* Add new element at the tail of the list. */
58 static inline void
59 list_add_tail (list_t *newp, list_t *head)
60 {
61 head->prev->next = newp;
62 newp->next = head;
63 newp->prev = head->prev;
64 head->prev = newp;
65 }
66
67
68 /* Remove element from list. */
69 static inline void
70 __list_del (list_t *prev, list_t *next)
71 {
72 next->prev = prev;
73 prev->next = next;
74 }
75
76 /* Remove element from list. */
77 static inline void
78 list_del (list_t *elem)
79 {
80 __list_del (elem->prev, elem->next);
81 }
82
83
84 /* Join two lists. */
85 static inline void
86 list_splice (list_t *add, list_t *head)
87 {
88 /* Do nothing if the list which gets added is empty. */
89 if (add != add->next)
90 {
91 add->next->prev = head;
92 add->prev->next = head->next;
93 head->next->prev = add->prev;
94 head->next = add->next;
95 }
96 }
97
98
99 /* Get typed element from list at a given position. */
100 #define list_entry(ptr, type, member) \
101 ((type *) ((char *) (ptr) - (unsigned long) (&((type *) 0)->member)))
102
103
104
105 /* Iterate forward over the elements of the list. */
106 #define list_for_each(pos, head) \
107 for (pos = (head)->next; pos != (head); pos = pos->next)
108
109
110 /* Iterate forward over the elements of the list. */
111 #define list_for_each_prev(pos, head) \
112 for (pos = (head)->prev; pos != (head); pos = pos->prev)
113
114
115 /* Iterate backwards over the elements list. The list elements can be
116 removed from the list while doing this. */
117 #define list_for_each_prev_safe(pos, p, head) \
118 for (pos = (head)->prev, p = pos->prev; \
119 pos != (head); \
120 pos = p, p = pos->prev)
121
122 #define list_for_each_entry(pos, head, member) \
123 for (pos = list_entry((head)->next, typeof(*pos), member); \
124 &pos->member != (head); \
125 pos = list_entry(pos->member.next, typeof(*pos), member))
126
127 #define list_for_each_entry_reverse(pos, head, member) \
128 for (pos = list_entry((head)->prev, typeof(*pos), member); \
129 &pos->member != (head); \
130 pos = list_entry(pos->member.prev, typeof(*pos), member))
131
132 #define list_for_each_entry_safe(pos, p, head, member) \
133 for (pos = list_entry((head)->next, typeof(*pos), member), \
134 p = list_entry(pos->member.next,typeof(*pos), member); \
135 &pos->member != (head); \
136 pos = p, p = list_entry(pos->member.next, typeof(*pos), member))
137
138 static inline int list_empty(list_t *head)
139 {
140 return head == head->next;
141 }
142
143 static inline void list_replace_init(list_t *old,
144 list_t *new)
145 {
146 list_t *head = old->next;
147 list_del(old);
148 list_add_tail(new, head);
149 INIT_LIST_HEAD(old);
150 }
151
152 #endif /* list.h */
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