f3b867839030fb3ceeda4192f2c0f4c20b856971
[urcu.git] / include / urcu / list.h
1 /*
2 * Copyright (C) 2002 Free Software Foundation, Inc.
3 * (originally part of the GNU C Library)
4 * Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
5 *
6 * Copyright (C) 2009 Pierre-Marc Fournier
7 * Conversion to RCU list.
8 * Copyright (C) 2010 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
9 *
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.
14 *
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.
19 *
20 * You should have received a copy of the GNU Lesser General Public
21 * License along with this library; if not, write to the Free Software
22 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 */
24
25 #ifndef _CDS_LIST_H
26 #define _CDS_LIST_H 1
27
28 #include <urcu/compiler.h>
29
30 /*
31 * The definitions of this file are adopted from those which can be
32 * found in the Linux kernel headers to enable people familiar with the
33 * latter find their way in these sources as well.
34 */
35
36 /* Basic type for the double-link list. */
37 struct cds_list_head {
38 struct cds_list_head *next, *prev;
39 };
40
41 /* Define a variable with the head and tail of the list. */
42 #define CDS_LIST_HEAD(name) \
43 struct cds_list_head name = { &(name), &(name) }
44
45 /* Initialize a new list head. */
46 #define CDS_INIT_LIST_HEAD(ptr) \
47 (ptr)->next = (ptr)->prev = (ptr)
48
49 #define CDS_LIST_HEAD_INIT(name) { .prev = &(name), .next = &(name) }
50
51 /* Add new element at the head of the list. */
52 static inline
53 void cds_list_add(struct cds_list_head *newp, struct cds_list_head *head)
54 {
55 head->next->prev = newp;
56 newp->next = head->next;
57 newp->prev = head;
58 head->next = newp;
59 }
60
61 /* Add new element at the tail of the list. */
62 static inline
63 void cds_list_add_tail(struct cds_list_head *newp, struct cds_list_head *head)
64 {
65 head->prev->next = newp;
66 newp->next = head;
67 newp->prev = head->prev;
68 head->prev = newp;
69 }
70
71 /* Remove element from list. */
72 static inline
73 void __cds_list_del(struct cds_list_head *prev, struct cds_list_head *next)
74 {
75 next->prev = prev;
76 prev->next = next;
77 }
78
79 /* Remove element from list. */
80 static inline
81 void cds_list_del(struct cds_list_head *elem)
82 {
83 __cds_list_del(elem->prev, elem->next);
84 }
85
86 /* Remove element from list, initializing the element's list pointers. */
87 static inline
88 void cds_list_del_init(struct cds_list_head *elem)
89 {
90 cds_list_del(elem);
91 CDS_INIT_LIST_HEAD(elem);
92 }
93
94 /* Delete from list, add to another list as head. */
95 static inline
96 void cds_list_move(struct cds_list_head *elem, struct cds_list_head *head)
97 {
98 __cds_list_del(elem->prev, elem->next);
99 cds_list_add(elem, head);
100 }
101
102 /* Replace an old entry. */
103 static inline
104 void cds_list_replace(struct cds_list_head *old, struct cds_list_head *_new)
105 {
106 _new->next = old->next;
107 _new->prev = old->prev;
108 _new->prev->next = _new;
109 _new->next->prev = _new;
110 }
111
112 /* Join two lists. */
113 static inline
114 void cds_list_splice(struct cds_list_head *add, struct cds_list_head *head)
115 {
116 /* Do nothing if the list which gets added is empty. */
117 if (add != add->next) {
118 add->next->prev = head;
119 add->prev->next = head->next;
120 head->next->prev = add->prev;
121 head->next = add->next;
122 }
123 }
124
125 /* Get typed element from list at a given position. */
126 #define cds_list_entry(ptr, type, member) caa_container_of(ptr, type, member)
127
128
129 /* Get first entry from a list. */
130 #define cds_list_first_entry(ptr, type, member) \
131 cds_list_entry((ptr)->next, type, member)
132
133 /* Iterate forward over the elements of the list. */
134 #define cds_list_for_each(pos, head) \
135 for (pos = (head)->next; (pos) != (head); pos = (pos)->next)
136
137 /*
138 * Iterate forward over the elements list. The list elements can be
139 * removed from the list while doing this.
140 */
141 #define cds_list_for_each_safe(pos, p, head) \
142 for (pos = (head)->next, p = (pos)->next; \
143 (pos) != (head); \
144 pos = (p), p = (pos)->next)
145
146 /* Iterate backward over the elements of the list. */
147 #define cds_list_for_each_prev(pos, head) \
148 for (pos = (head)->prev; (pos) != (head); pos = (pos)->prev)
149
150 /*
151 * Iterate backwards over the elements list. The list elements can be
152 * removed from the list while doing this.
153 */
154 #define cds_list_for_each_prev_safe(pos, p, head) \
155 for (pos = (head)->prev, p = (pos)->prev; \
156 (pos) != (head); \
157 pos = (p), p = (pos)->prev)
158
159 #define cds_list_for_each_entry(pos, head, member) \
160 for (pos = cds_list_entry((head)->next, __typeof__(*(pos)), member); \
161 &(pos)->member != (head); \
162 pos = cds_list_entry((pos)->member.next, __typeof__(*(pos)), member))
163
164 #define cds_list_for_each_entry_reverse(pos, head, member) \
165 for (pos = cds_list_entry((head)->prev, __typeof__(*(pos)), member); \
166 &(pos)->member != (head); \
167 pos = cds_list_entry((pos)->member.prev, __typeof__(*(pos)), member))
168
169 #define cds_list_for_each_entry_safe(pos, p, head, member) \
170 for (pos = cds_list_entry((head)->next, __typeof__(*(pos)), member), \
171 p = cds_list_entry((pos)->member.next, __typeof__(*(pos)), member); \
172 &(pos)->member != (head); \
173 pos = (p), p = cds_list_entry((pos)->member.next, __typeof__(*(pos)), member))
174
175 /*
176 * Same as cds_list_for_each_entry_safe, but starts from "pos" which should
177 * point to an entry within the list.
178 */
179 #define cds_list_for_each_entry_safe_from(pos, p, head, member) \
180 for (p = cds_list_entry((pos)->member.next, __typeof__(*(pos)), member); \
181 &(pos)->member != (head); \
182 pos = (p), p = cds_list_entry((pos)->member.next, __typeof__(*(pos)), member))
183
184 static inline
185 int cds_list_empty(struct cds_list_head *head)
186 {
187 return head == head->next;
188 }
189
190 static inline
191 void cds_list_replace_init(struct cds_list_head *old,
192 struct cds_list_head *_new)
193 {
194 struct cds_list_head *head = old->next;
195
196 cds_list_del(old);
197 cds_list_add_tail(_new, head);
198 CDS_INIT_LIST_HEAD(old);
199 }
200
201 #endif /* _CDS_LIST_H */
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