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 #include "c99_compat.h"
45
46 #ifdef DEBUG
47 # define list_assert(cond, msg) assert(cond && msg)
48 #else
49 # define list_assert(cond, msg) (void)(0 && (cond))
50 #endif
51
52 struct list_head
53 {
54 struct list_head *prev;
55 struct list_head *next;
56 };
57
list_inithead(struct list_head * item)58 static inline void list_inithead(struct list_head *item)
59 {
60 item->prev = item;
61 item->next = item;
62 }
63
list_add(struct list_head * item,struct list_head * list)64 static inline void list_add(struct list_head *item, struct list_head *list)
65 {
66 item->prev = list;
67 item->next = list->next;
68 list->next->prev = item;
69 list->next = item;
70 }
71
list_addtail(struct list_head * item,struct list_head * list)72 static inline void list_addtail(struct list_head *item, struct list_head *list)
73 {
74 item->next = list;
75 item->prev = list->prev;
76 list->prev->next = item;
77 list->prev = item;
78 }
79
80 static inline bool list_is_empty(const struct list_head *list);
81
list_replace(struct list_head * from,struct list_head * to)82 static inline void list_replace(struct list_head *from, struct list_head *to)
83 {
84 if (list_is_empty(from)) {
85 list_inithead(to);
86 } else {
87 to->prev = from->prev;
88 to->next = from->next;
89 from->next->prev = to;
90 from->prev->next = to;
91 }
92 }
93
list_del(struct list_head * item)94 static inline void list_del(struct list_head *item)
95 {
96 item->prev->next = item->next;
97 item->next->prev = item->prev;
98 item->prev = item->next = NULL;
99 }
100
list_delinit(struct list_head * item)101 static inline void list_delinit(struct list_head *item)
102 {
103 item->prev->next = item->next;
104 item->next->prev = item->prev;
105 item->next = item;
106 item->prev = item;
107 }
108
list_is_empty(const struct list_head * list)109 static inline bool list_is_empty(const struct list_head *list)
110 {
111 return list->next == list;
112 }
113
list_is_linked(const struct list_head * list)114 static inline bool list_is_linked(const struct list_head *list)
115 {
116 /* both must be NULL or both must be not NULL */
117 assert((list->prev != NULL) == (list->next != NULL));
118
119 return list->next != NULL;
120 }
121
122 /**
123 * Returns whether the list has exactly one element.
124 */
list_is_singular(const struct list_head * list)125 static inline bool list_is_singular(const struct list_head *list)
126 {
127 return list_is_linked(list) && !list_is_empty(list) && list->next->next == list;
128 }
129
list_length(const struct list_head * list)130 static inline unsigned list_length(const struct list_head *list)
131 {
132 struct list_head *node;
133 unsigned length = 0;
134 for (node = list->next; node != list; node = node->next)
135 length++;
136 return length;
137 }
138
list_splice(struct list_head * src,struct list_head * dst)139 static inline void list_splice(struct list_head *src, struct list_head *dst)
140 {
141 if (list_is_empty(src))
142 return;
143
144 src->next->prev = dst;
145 src->prev->next = dst->next;
146 dst->next->prev = src->prev;
147 dst->next = src->next;
148 }
149
list_splicetail(struct list_head * src,struct list_head * dst)150 static inline void list_splicetail(struct list_head *src, struct list_head *dst)
151 {
152 if (list_is_empty(src))
153 return;
154
155 src->prev->next = dst;
156 src->next->prev = dst->prev;
157 dst->prev->next = src->next;
158 dst->prev = src->prev;
159 }
160
list_validate(const struct list_head * list)161 static inline void list_validate(const struct list_head *list)
162 {
163 struct list_head *node;
164 assert(list_is_linked(list));
165 assert(list->next->prev == list && list->prev->next == list);
166 for (node = list->next; node != list; node = node->next)
167 assert(node->next->prev == node && node->prev->next == node);
168 }
169
170 #define LIST_ENTRY(__type, __item, __field) \
171 ((__type *)(((char *)(__item)) - offsetof(__type, __field)))
172
173 /**
174 * Cast from a pointer to a member of a struct back to the containing struct.
175 *
176 * 'sample' MUST be initialized, or else the result is undefined!
177 */
178 #define list_container_of(ptr, sample, member) \
179 (void *)((char *)(ptr) \
180 - ((char *)&(sample)->member - (char *)(sample)))
181
182 #define list_first_entry(ptr, type, member) \
183 LIST_ENTRY(type, (ptr)->next, member)
184
185 #define list_last_entry(ptr, type, member) \
186 LIST_ENTRY(type, (ptr)->prev, member)
187
188
189 #define LIST_FOR_EACH_ENTRY(pos, head, member) \
190 for (pos = NULL, pos = list_container_of((head)->next, pos, member); \
191 &pos->member != (head); \
192 pos = list_container_of(pos->member.next, pos, member))
193
194 #define LIST_FOR_EACH_ENTRY_SAFE(pos, storage, head, member) \
195 for (pos = NULL, pos = list_container_of((head)->next, pos, member), \
196 storage = list_container_of(pos->member.next, pos, member); \
197 &pos->member != (head); \
198 pos = storage, storage = list_container_of(storage->member.next, storage, member))
199
200 #define LIST_FOR_EACH_ENTRY_SAFE_REV(pos, storage, head, member) \
201 for (pos = NULL, pos = list_container_of((head)->prev, pos, member), \
202 storage = list_container_of(pos->member.prev, pos, member); \
203 &pos->member != (head); \
204 pos = storage, storage = list_container_of(storage->member.prev, storage, member))
205
206 #define LIST_FOR_EACH_ENTRY_FROM(pos, start, head, member) \
207 for (pos = NULL, pos = list_container_of((start), pos, member); \
208 &pos->member != (head); \
209 pos = list_container_of(pos->member.next, pos, member))
210
211 #define LIST_FOR_EACH_ENTRY_FROM_REV(pos, start, head, member) \
212 for (pos = NULL, pos = list_container_of((start), pos, member); \
213 &pos->member != (head); \
214 pos = list_container_of(pos->member.prev, pos, member))
215
216 #define list_for_each_entry(type, pos, head, member) \
217 for (type *pos = LIST_ENTRY(type, (head)->next, member), \
218 *__next = LIST_ENTRY(type, pos->member.next, member); \
219 &pos->member != (head); \
220 pos = LIST_ENTRY(type, pos->member.next, member), \
221 list_assert(pos == __next, "use _safe iterator"), \
222 __next = LIST_ENTRY(type, __next->member.next, member))
223
224 #define list_for_each_entry_safe(type, pos, head, member) \
225 for (type *pos = LIST_ENTRY(type, (head)->next, member), \
226 *__next = LIST_ENTRY(type, pos->member.next, member); \
227 &pos->member != (head); \
228 pos = __next, \
229 __next = LIST_ENTRY(type, __next->member.next, member))
230
231 #define list_for_each_entry_rev(type, pos, head, member) \
232 for (type *pos = LIST_ENTRY(type, (head)->prev, member), \
233 *__prev = LIST_ENTRY(type, pos->member.prev, member); \
234 &pos->member != (head); \
235 pos = LIST_ENTRY(type, pos->member.prev, member), \
236 list_assert(pos == __prev, "use _safe iterator"), \
237 __prev = LIST_ENTRY(type, __prev->member.prev, member))
238
239 #define list_for_each_entry_safe_rev(type, pos, head, member) \
240 for (type *pos = LIST_ENTRY(type, (head)->prev, member), \
241 *__prev = LIST_ENTRY(type, pos->member.prev, member); \
242 &pos->member != (head); \
243 pos = __prev, \
244 __prev = LIST_ENTRY(type, __prev->member.prev, member))
245
246 #define list_for_each_entry_from(type, pos, start, head, member) \
247 for (type *pos = LIST_ENTRY(type, (start), member); \
248 &pos->member != (head); \
249 pos = LIST_ENTRY(type, pos->member.next, member))
250
251 #define list_for_each_entry_from_safe(type, pos, start, head, member) \
252 for (type *pos = LIST_ENTRY(type, (start), member), \
253 *__next = LIST_ENTRY(type, pos->member.next, member); \
254 &pos->member != (head); \
255 pos = __next, \
256 __next = LIST_ENTRY(type, __next->member.next, member))
257
258 #define list_for_each_entry_from_rev(type, pos, start, head, member) \
259 for (type *pos = LIST_ENTRY(type, (start), member); \
260 &pos->member != (head); \
261 pos = LIST_ENTRY(type, pos->member.prev, member))
262
263 #define list_pair_for_each_entry(type, pos1, pos2, head1, head2, member) \
264 for (type *pos1 = LIST_ENTRY(type, (head1)->next, member), \
265 *pos2 = LIST_ENTRY(type, (head2)->next, member); \
266 &pos1->member != (head1) && &pos2->member != (head2); \
267 pos1 = LIST_ENTRY(type, pos1->member.next, member), \
268 pos2 = LIST_ENTRY(type, pos2->member.next, member))
269
270 #endif /*_UTIL_LIST_H_*/
271