1 /**************************************************************************
2 *
3 * Copyright 2006 VMware, Inc., Bismarck, ND. USA.
4 * All Rights Reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the
8 * "Software"), to deal in the Software without restriction, including
9 * without limitation the rights to use, copy, modify, merge, publish,
10 * distribute, sub license, and/or sell copies of the Software, and to
11 * permit persons to whom the Software is furnished to do so, subject to
12 * the following conditions:
13 *
14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
17 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
18 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
19 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
20 * USE OR OTHER DEALINGS IN THE SOFTWARE.
21 *
22 * The above copyright notice and this permission notice (including the
23 * next paragraph) shall be included in all copies or substantial portions
24 * of the Software.
25 *
26 **************************************************************************/
27
28 /**
29 * \file
30 * List macros heavily inspired by the Linux kernel
31 * list handling. No list looping yet.
32 *
33 * Is not threadsafe, so common operations need to
34 * be protected using an external mutex.
35 */
36
37 #ifndef _UTIL_LIST_H_
38 #define _UTIL_LIST_H_
39
40
41 #include <stdbool.h>
42 #include <stddef.h>
43 #include <assert.h>
44
45 struct list_head
46 {
47 struct list_head *prev;
48 struct list_head *next;
49 };
50
list_inithead(struct list_head * item)51 static inline void list_inithead(struct list_head *item)
52 {
53 item->prev = item;
54 item->next = item;
55 }
56
list_add(struct list_head * item,struct list_head * list)57 static inline void list_add(struct list_head *item, struct list_head *list)
58 {
59 item->prev = list;
60 item->next = list->next;
61 list->next->prev = item;
62 list->next = item;
63 }
64
list_addtail(struct list_head * item,struct list_head * list)65 static inline void list_addtail(struct list_head *item, struct list_head *list)
66 {
67 item->next = list;
68 item->prev = list->prev;
69 list->prev->next = item;
70 list->prev = item;
71 }
72
73 static inline bool list_is_empty(const struct list_head *list);
74
list_replace(struct list_head * from,struct list_head * to)75 static inline void list_replace(struct list_head *from, struct list_head *to)
76 {
77 if (list_is_empty(from)) {
78 list_inithead(to);
79 } else {
80 to->prev = from->prev;
81 to->next = from->next;
82 from->next->prev = to;
83 from->prev->next = to;
84 }
85 }
86
list_del(struct list_head * item)87 static inline void list_del(struct list_head *item)
88 {
89 item->prev->next = item->next;
90 item->next->prev = item->prev;
91 item->prev = item->next = NULL;
92 }
93
list_delinit(struct list_head * item)94 static inline void list_delinit(struct list_head *item)
95 {
96 item->prev->next = item->next;
97 item->next->prev = item->prev;
98 item->next = item;
99 item->prev = item;
100 }
101
list_is_empty(const struct list_head * list)102 static inline bool list_is_empty(const struct list_head *list)
103 {
104 return list->next == list;
105 }
106
107 /**
108 * Returns whether the list has exactly one element.
109 */
list_is_singular(const struct list_head * list)110 static inline bool list_is_singular(const struct list_head *list)
111 {
112 return list->next != NULL && list->next != list && list->next->next == list;
113 }
114
list_length(const struct list_head * list)115 static inline unsigned list_length(const struct list_head *list)
116 {
117 struct list_head *node;
118 unsigned length = 0;
119 for (node = list->next; node != list; node = node->next)
120 length++;
121 return length;
122 }
123
list_splice(struct list_head * src,struct list_head * dst)124 static inline void list_splice(struct list_head *src, struct list_head *dst)
125 {
126 if (list_is_empty(src))
127 return;
128
129 src->next->prev = dst;
130 src->prev->next = dst->next;
131 dst->next->prev = src->prev;
132 dst->next = src->next;
133 }
134
list_splicetail(struct list_head * src,struct list_head * dst)135 static inline void list_splicetail(struct list_head *src, struct list_head *dst)
136 {
137 if (list_is_empty(src))
138 return;
139
140 src->prev->next = dst;
141 src->next->prev = dst->prev;
142 dst->prev->next = src->next;
143 dst->prev = src->prev;
144 }
145
list_validate(const struct list_head * list)146 static inline void list_validate(const struct list_head *list)
147 {
148 struct list_head *node;
149 assert(list->next->prev == list && list->prev->next == list);
150 for (node = list->next; node != list; node = node->next)
151 assert(node->next->prev == node && node->prev->next == node);
152 }
153
154 #define LIST_ENTRY(__type, __item, __field) \
155 ((__type *)(((char *)(__item)) - offsetof(__type, __field)))
156
157 /**
158 * Cast from a pointer to a member of a struct back to the containing struct.
159 *
160 * 'sample' MUST be initialized, or else the result is undefined!
161 */
162 #ifndef container_of
163 #define container_of(ptr, sample, member) \
164 (void *)((char *)(ptr) \
165 - ((char *)&(sample)->member - (char *)(sample)))
166 #endif
167
168 #define list_first_entry(ptr, type, member) \
169 LIST_ENTRY(type, (ptr)->next, member)
170
171 #define list_last_entry(ptr, type, member) \
172 LIST_ENTRY(type, (ptr)->prev, member)
173
174
175 #define LIST_FOR_EACH_ENTRY(pos, head, member) \
176 for (pos = NULL, pos = container_of((head)->next, pos, member); \
177 &pos->member != (head); \
178 pos = container_of(pos->member.next, pos, member))
179
180 #define LIST_FOR_EACH_ENTRY_SAFE(pos, storage, head, member) \
181 for (pos = NULL, pos = container_of((head)->next, pos, member), \
182 storage = container_of(pos->member.next, pos, member); \
183 &pos->member != (head); \
184 pos = storage, storage = container_of(storage->member.next, storage, member))
185
186 #define LIST_FOR_EACH_ENTRY_SAFE_REV(pos, storage, head, member) \
187 for (pos = NULL, pos = container_of((head)->prev, pos, member), \
188 storage = container_of(pos->member.prev, pos, member); \
189 &pos->member != (head); \
190 pos = storage, storage = container_of(storage->member.prev, storage, member))
191
192 #define LIST_FOR_EACH_ENTRY_FROM(pos, start, head, member) \
193 for (pos = NULL, pos = container_of((start), pos, member); \
194 &pos->member != (head); \
195 pos = container_of(pos->member.next, pos, member))
196
197 #define LIST_FOR_EACH_ENTRY_FROM_REV(pos, start, head, member) \
198 for (pos = NULL, pos = container_of((start), pos, member); \
199 &pos->member != (head); \
200 pos = container_of(pos->member.prev, pos, member))
201
202 #define list_for_each_entry(type, pos, head, member) \
203 for (type *pos = LIST_ENTRY(type, (head)->next, member), \
204 *__next = LIST_ENTRY(type, pos->member.next, member); \
205 &pos->member != (head); \
206 pos = LIST_ENTRY(type, pos->member.next, member), \
207 __next = LIST_ENTRY(type, __next->member.next, member))
208
209 #define list_for_each_entry_safe(type, pos, head, member) \
210 for (type *pos = LIST_ENTRY(type, (head)->next, member), \
211 *__next = LIST_ENTRY(type, pos->member.next, member); \
212 &pos->member != (head); \
213 pos = __next, \
214 __next = LIST_ENTRY(type, __next->member.next, member))
215
216 #define list_for_each_entry_rev(type, pos, head, member) \
217 for (type *pos = LIST_ENTRY(type, (head)->prev, member), \
218 *__prev = LIST_ENTRY(type, pos->member.prev, member); \
219 &pos->member != (head); \
220 pos = LIST_ENTRY(type, pos->member.prev, member), \
221 __prev = LIST_ENTRY(type, __prev->member.prev, member))
222
223 #define list_for_each_entry_safe_rev(type, pos, head, member) \
224 for (type *pos = LIST_ENTRY(type, (head)->prev, member), \
225 *__prev = LIST_ENTRY(type, pos->member.prev, member); \
226 &pos->member != (head); \
227 pos = __prev, \
228 __prev = LIST_ENTRY(type, __prev->member.prev, member))
229
230 #define list_for_each_entry_from(type, pos, start, head, member) \
231 for (type *pos = LIST_ENTRY(type, (start), member); \
232 &pos->member != (head); \
233 pos = LIST_ENTRY(type, pos->member.next, member))
234
235 #define list_for_each_entry_from_safe(type, pos, start, head, member) \
236 for (type *pos = LIST_ENTRY(type, (start), member), \
237 *__next = LIST_ENTRY(type, pos->member.next, member); \
238 &pos->member != (head); \
239 pos = __next, \
240 __next = LIST_ENTRY(type, __next->member.next, member))
241
242 #define list_for_each_entry_from_rev(type, pos, start, head, member) \
243 for (type *pos = LIST_ENTRY(type, (start), member); \
244 &pos->member != (head); \
245 pos = LIST_ENTRY(type, pos->member.prev, member))
246
247 #define list_pair_for_each_entry(type, pos1, pos2, head1, head2, member) \
248 for (type *pos1 = LIST_ENTRY(type, (head1)->next, member), \
249 *pos2 = LIST_ENTRY(type, (head2)->next, member); \
250 &pos1->member != (head1) && &pos2->member != (head2); \
251 pos1 = LIST_ENTRY(type, pos1->member.next, member), \
252 pos2 = LIST_ENTRY(type, pos2->member.next, member))
253
254 #endif /*_UTIL_LIST_H_*/
255