Phase 1 of deprecating liburcu-signal
[urcu.git] / include / urcu / list.h
1 // SPDX-FileCopyrightText: 2002 Free Software Foundation, Inc.
2 // SPDX-FileCopyrightText: 2009 Pierre-Marc Fournier
3 // SPDX-FileCopyrightText: 2010 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
4 //
5 // SPDX-License-Identifier: LGPL-2.1-or-later
6
7 /*
8 * (originally part of the GNU C Library)
9 * Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
10 */
11
12 #ifndef _CDS_LIST_H
13 #define _CDS_LIST_H 1
14
15 #include <urcu/compiler.h>
16
17 /*
18 * The definitions of this file are adopted from those which can be
19 * found in the Linux kernel headers to enable people familiar with the
20 * latter find their way in these sources as well.
21 */
22
23 /* Basic type for the double-link list. */
24 struct cds_list_head {
25 struct cds_list_head *next, *prev;
26 };
27
28 /* Define a variable with the head and tail of the list. */
29 #define CDS_LIST_HEAD(name) \
30 struct cds_list_head name = { &(name), &(name) }
31
32 /* Initialize a new list head. */
33 #define CDS_INIT_LIST_HEAD(ptr) \
34 (ptr)->next = (ptr)->prev = (ptr)
35
36 #define CDS_LIST_HEAD_INIT(name) { .next = &(name), .prev = &(name) }
37
38 /* Add new element at the head of the list. */
39 static inline
40 void cds_list_add(struct cds_list_head *newp, struct cds_list_head *head)
41 {
42 head->next->prev = newp;
43 newp->next = head->next;
44 newp->prev = head;
45 head->next = newp;
46 }
47
48 /* Add new element at the tail of the list. */
49 static inline
50 void cds_list_add_tail(struct cds_list_head *newp, struct cds_list_head *head)
51 {
52 head->prev->next = newp;
53 newp->next = head;
54 newp->prev = head->prev;
55 head->prev = newp;
56 }
57
58 /* Remove element from list. */
59 static inline
60 void __cds_list_del(struct cds_list_head *prev, struct cds_list_head *next)
61 {
62 next->prev = prev;
63 prev->next = next;
64 }
65
66 /* Remove element from list. */
67 static inline
68 void cds_list_del(struct cds_list_head *elem)
69 {
70 __cds_list_del(elem->prev, elem->next);
71 }
72
73 /* Remove element from list, initializing the element's list pointers. */
74 static inline
75 void cds_list_del_init(struct cds_list_head *elem)
76 {
77 cds_list_del(elem);
78 CDS_INIT_LIST_HEAD(elem);
79 }
80
81 /* Delete from list, add to another list as head. */
82 static inline
83 void cds_list_move(struct cds_list_head *elem, struct cds_list_head *head)
84 {
85 __cds_list_del(elem->prev, elem->next);
86 cds_list_add(elem, head);
87 }
88
89 /* Replace an old entry. */
90 static inline
91 void cds_list_replace(struct cds_list_head *old, struct cds_list_head *_new)
92 {
93 _new->next = old->next;
94 _new->prev = old->prev;
95 _new->prev->next = _new;
96 _new->next->prev = _new;
97 }
98
99 /* Join two lists. */
100 static inline
101 void cds_list_splice(struct cds_list_head *add, struct cds_list_head *head)
102 {
103 /* Do nothing if the list which gets added is empty. */
104 if (add != add->next) {
105 add->next->prev = head;
106 add->prev->next = head->next;
107 head->next->prev = add->prev;
108 head->next = add->next;
109 }
110 }
111
112 /* Get typed element from list at a given position. */
113 #define cds_list_entry(ptr, type, member) caa_container_of(ptr, type, member)
114
115
116 /* Get first entry from a list. */
117 #define cds_list_first_entry(ptr, type, member) \
118 cds_list_entry((ptr)->next, type, member)
119
120 /* Iterate forward over the elements of the list. */
121 #define cds_list_for_each(pos, head) \
122 for (pos = (head)->next; (pos) != (head); pos = (pos)->next)
123
124 /*
125 * Iterate forward over the elements list. The list elements can be
126 * removed from the list while doing this.
127 */
128 #define cds_list_for_each_safe(pos, p, head) \
129 for (pos = (head)->next, p = (pos)->next; \
130 (pos) != (head); \
131 pos = (p), p = (pos)->next)
132
133 /* Iterate backward over the elements of the list. */
134 #define cds_list_for_each_prev(pos, head) \
135 for (pos = (head)->prev; (pos) != (head); pos = (pos)->prev)
136
137 /*
138 * Iterate backwards over the elements list. The list elements can be
139 * removed from the list while doing this.
140 */
141 #define cds_list_for_each_prev_safe(pos, p, head) \
142 for (pos = (head)->prev, p = (pos)->prev; \
143 (pos) != (head); \
144 pos = (p), p = (pos)->prev)
145
146 #define cds_list_for_each_entry(pos, head, member) \
147 for (pos = cds_list_entry((head)->next, __typeof__(*(pos)), member); \
148 &(pos)->member != (head); \
149 pos = cds_list_entry((pos)->member.next, __typeof__(*(pos)), member))
150
151 #define cds_list_for_each_entry_reverse(pos, head, member) \
152 for (pos = cds_list_entry((head)->prev, __typeof__(*(pos)), member); \
153 &(pos)->member != (head); \
154 pos = cds_list_entry((pos)->member.prev, __typeof__(*(pos)), member))
155
156 #define cds_list_for_each_entry_safe(pos, p, head, member) \
157 for (pos = cds_list_entry((head)->next, __typeof__(*(pos)), member), \
158 p = cds_list_entry((pos)->member.next, __typeof__(*(pos)), member); \
159 &(pos)->member != (head); \
160 pos = (p), p = cds_list_entry((pos)->member.next, __typeof__(*(pos)), member))
161
162 /*
163 * Same as cds_list_for_each_entry_safe, but starts from "pos" which should
164 * point to an entry within the list.
165 */
166 #define cds_list_for_each_entry_safe_from(pos, p, head, member) \
167 for (p = cds_list_entry((pos)->member.next, __typeof__(*(pos)), member); \
168 &(pos)->member != (head); \
169 pos = (p), p = cds_list_entry((pos)->member.next, __typeof__(*(pos)), member))
170
171 static inline
172 int cds_list_empty(struct cds_list_head *head)
173 {
174 return head == head->next;
175 }
176
177 static inline
178 void cds_list_replace_init(struct cds_list_head *old,
179 struct cds_list_head *_new)
180 {
181 struct cds_list_head *head = old->next;
182
183 cds_list_del(old);
184 cds_list_add_tail(_new, head);
185 CDS_INIT_LIST_HEAD(old);
186 }
187
188 #endif /* _CDS_LIST_H */
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