RCU lfqueue: Now works without reference counting (API change)
[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 _CDS_LIST_H
21 #define _CDS_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 struct cds_list_head
30 {
31 struct cds_list_head *next;
32 struct cds_list_head *prev;
33 };
34
35
36 /* Define a variable with the head and tail of the list. */
37 #define CDS_LIST_HEAD(name) \
38 struct cds_list_head name = { &(name), &(name) }
39
40 /* Initialize a new list head. */
41 #define CDS_INIT_LIST_HEAD(ptr) \
42 (ptr)->next = (ptr)->prev = (ptr)
43
44 #define CDS_LIST_HEAD_INIT(name) { .prev = &(name), .next = &(name) }
45
46 /* Add new element at the head of the list. */
47 static inline void
48 cds_list_add (struct cds_list_head *newp, struct cds_list_head *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 cds_list_add_tail (struct cds_list_head *newp, struct cds_list_head *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 __cds_list_del (struct cds_list_head *prev, struct cds_list_head *next)
71 {
72 next->prev = prev;
73 prev->next = next;
74 }
75
76 /* Remove element from list. */
77 static inline void
78 cds_list_del (struct cds_list_head *elem)
79 {
80 __cds_list_del (elem->prev, elem->next);
81 }
82
83 /* Remove element from list, initializing the element's list pointers. */
84 static inline void
85 cds_list_del_init (struct cds_list_head *elem)
86 {
87 cds_list_del(elem);
88 CDS_INIT_LIST_HEAD(elem);
89 }
90
91 /* delete from list, add to another list as head */
92 static inline void
93 cds_list_move (struct cds_list_head *elem, struct cds_list_head *head)
94 {
95 __cds_list_del (elem->prev, elem->next);
96 cds_list_add (elem, head);
97 }
98
99 /* replace an old entry.
100 */
101 static inline void
102 cds_list_replace(struct cds_list_head *old, struct cds_list_head *_new)
103 {
104 _new->next = old->next;
105 _new->prev = old->prev;
106 _new->prev->next = _new;
107 _new->next->prev = _new;
108 }
109
110 /* Join two lists. */
111 static inline void
112 cds_list_splice (struct cds_list_head *add, struct cds_list_head *head)
113 {
114 /* Do nothing if the list which gets added is empty. */
115 if (add != add->next)
116 {
117 add->next->prev = head;
118 add->prev->next = head->next;
119 head->next->prev = add->prev;
120 head->next = add->next;
121 }
122 }
123
124
125 /* Get typed element from list at a given position. */
126 #define cds_list_entry(ptr, type, member) \
127 ((type *) ((char *) (ptr) - (unsigned long) (&((type *) 0)->member)))
128
129
130
131 /* Iterate forward over the elements of the list. */
132 #define cds_list_for_each(pos, head) \
133 for (pos = (head)->next; pos != (head); pos = pos->next)
134
135
136 /* Iterate forward over the elements of the list. */
137 #define cds_list_for_each_prev(pos, head) \
138 for (pos = (head)->prev; pos != (head); pos = pos->prev)
139
140
141 /* Iterate backwards over the elements list. The list elements can be
142 removed from the list while doing this. */
143 #define cds_list_for_each_prev_safe(pos, p, head) \
144 for (pos = (head)->prev, p = pos->prev; \
145 pos != (head); \
146 pos = p, p = pos->prev)
147
148 #define cds_list_for_each_entry(pos, head, member) \
149 for (pos = cds_list_entry((head)->next, typeof(*pos), member); \
150 &pos->member != (head); \
151 pos = cds_list_entry(pos->member.next, typeof(*pos), member))
152
153 #define cds_list_for_each_entry_reverse(pos, head, member) \
154 for (pos = cds_list_entry((head)->prev, typeof(*pos), member); \
155 &pos->member != (head); \
156 pos = cds_list_entry(pos->member.prev, typeof(*pos), member))
157
158 #define cds_list_for_each_entry_safe(pos, p, head, member) \
159 for (pos = cds_list_entry((head)->next, typeof(*pos), member), \
160 p = cds_list_entry(pos->member.next,typeof(*pos), member); \
161 &pos->member != (head); \
162 pos = p, p = cds_list_entry(pos->member.next, typeof(*pos), member))
163
164 static inline int cds_list_empty(struct cds_list_head *head)
165 {
166 return head == head->next;
167 }
168
169 static inline void cds_list_replace_init(struct cds_list_head *old,
170 struct cds_list_head *_new)
171 {
172 struct cds_list_head *head = old->next;
173 cds_list_del(old);
174 cds_list_add_tail(_new, head);
175 CDS_INIT_LIST_HEAD(old);
176 }
177
178 #endif /* _CDS_LIST_H */
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