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
47struct list_head
48{
49    struct list_head *prev;
50    struct list_head *next;
51};
52
53static inline void list_inithead(struct list_head *item)
54{
55    item->prev = item;
56    item->next = item;
57}
58
59static inline void list_add(struct list_head *item, struct list_head *list)
60{
61    item->prev = list;
62    item->next = list->next;
63    list->next->prev = item;
64    list->next = item;
65}
66
67static inline void list_addtail(struct list_head *item, struct list_head *list)
68{
69    item->next = list;
70    item->prev = list->prev;
71    list->prev->next = item;
72    list->prev = item;
73}
74
75static inline bool list_empty(const struct list_head *list);
76
77static inline void list_replace(struct list_head *from, struct list_head *to)
78{
79    if (list_empty(from)) {
80        list_inithead(to);
81    } else {
82        to->prev = from->prev;
83        to->next = from->next;
84        from->next->prev = to;
85        from->prev->next = to;
86    }
87}
88
89static inline void list_del(struct list_head *item)
90{
91    item->prev->next = item->next;
92    item->next->prev = item->prev;
93    item->prev = item->next = NULL;
94}
95
96static inline void list_delinit(struct list_head *item)
97{
98    item->prev->next = item->next;
99    item->next->prev = item->prev;
100    item->next = item;
101    item->prev = item;
102}
103
104static inline bool list_empty(const struct list_head *list)
105{
106   return list->next == list;
107}
108
109/**
110 * Returns whether the list has exactly one element.
111 */
112static inline bool list_is_singular(const struct list_head *list)
113{
114   return list->next != NULL && list->next != list && list->next->next == list;
115}
116
117static inline unsigned list_length(const struct list_head *list)
118{
119   struct list_head *node;
120   unsigned length = 0;
121   for (node = list->next; node != list; node = node->next)
122      length++;
123   return length;
124}
125
126static inline void list_splice(struct list_head *src, struct list_head *dst)
127{
128   if (list_empty(src))
129      return;
130
131   src->next->prev = dst;
132   src->prev->next = dst->next;
133   dst->next->prev = src->prev;
134   dst->next = src->next;
135}
136
137static inline void list_splicetail(struct list_head *src, struct list_head *dst)
138{
139   if (list_empty(src))
140      return;
141
142   src->prev->next = dst;
143   src->next->prev = dst->prev;
144   dst->prev->next = src->next;
145   dst->prev = src->prev;
146}
147
148static inline void list_validate(const struct list_head *list)
149{
150   struct list_head *node;
151   assert(list->next->prev == list && list->prev->next == list);
152   for (node = list->next; node != list; node = node->next)
153      assert(node->next->prev == node && node->prev->next == node);
154}
155
156#define LIST_INITHEAD(__item) list_inithead(__item)
157#define LIST_ADD(__item, __list) list_add(__item, __list)
158#define LIST_ADDTAIL(__item, __list) list_addtail(__item, __list)
159#define LIST_REPLACE(__from, __to) list_replace(__from, __to)
160#define LIST_DEL(__item) list_del(__item)
161#define LIST_DELINIT(__item) list_delinit(__item)
162
163#define LIST_ENTRY(__type, __item, __field)   \
164    ((__type *)(((char *)(__item)) - offsetof(__type, __field)))
165
166#define LIST_IS_EMPTY(__list)                   \
167    ((__list)->next == (__list))
168
169/**
170 * Cast from a pointer to a member of a struct back to the containing struct.
171 *
172 * 'sample' MUST be initialized, or else the result is undefined!
173 */
174#ifndef container_of
175#define container_of(ptr, sample, member)				\
176    (void *)((char *)(ptr)						\
177	     - ((char *)&(sample)->member - (char *)(sample)))
178#endif
179
180#define list_first_entry(ptr, type, member) \
181        LIST_ENTRY(type, (ptr)->next, member)
182
183#define list_last_entry(ptr, type, member) \
184        LIST_ENTRY(type, (ptr)->prev, member)
185
186
187#define LIST_FOR_EACH_ENTRY(pos, head, member)				\
188   for (pos = NULL, pos = container_of((head)->next, pos, member);	\
189	&pos->member != (head);						\
190	pos = container_of(pos->member.next, pos, member))
191
192#define LIST_FOR_EACH_ENTRY_SAFE(pos, storage, head, member)	\
193   for (pos = NULL, pos = container_of((head)->next, pos, member),	\
194	storage = container_of(pos->member.next, pos, member);	\
195	&pos->member != (head);						\
196	pos = storage, storage = container_of(storage->member.next, storage, member))
197
198#define LIST_FOR_EACH_ENTRY_SAFE_REV(pos, storage, head, member)	\
199   for (pos = NULL, pos = container_of((head)->prev, pos, member),	\
200	storage = container_of(pos->member.prev, pos, member);		\
201	&pos->member != (head);						\
202	pos = storage, storage = container_of(storage->member.prev, storage, member))
203
204#define LIST_FOR_EACH_ENTRY_FROM(pos, start, head, member)		\
205   for (pos = NULL, pos = container_of((start), pos, member);		\
206	&pos->member != (head);						\
207	pos = container_of(pos->member.next, pos, member))
208
209#define LIST_FOR_EACH_ENTRY_FROM_REV(pos, start, head, member)		\
210   for (pos = NULL, pos = container_of((start), pos, member);		\
211	&pos->member != (head);						\
212	pos = container_of(pos->member.prev, pos, member))
213
214#define list_for_each_entry(type, pos, head, member)                    \
215   for (type *pos = LIST_ENTRY(type, (head)->next, member);             \
216	&pos->member != (head);                                         \
217	pos = LIST_ENTRY(type, pos->member.next, member))
218
219#define list_for_each_entry_safe(type, pos, head, member)               \
220   for (type *pos = LIST_ENTRY(type, (head)->next, member),             \
221	     *__next = LIST_ENTRY(type, pos->member.next, member);      \
222	&pos->member != (head);                                         \
223	pos = __next,                                                   \
224        __next = LIST_ENTRY(type, __next->member.next, member))
225
226#define list_for_each_entry_rev(type, pos, head, member)                \
227   for (type *pos = LIST_ENTRY(type, (head)->prev, member);             \
228	&pos->member != (head);                                         \
229	pos = LIST_ENTRY(type, pos->member.prev, member))
230
231#define list_for_each_entry_safe_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 = __prev,                                                   \
236        __prev = LIST_ENTRY(type, __prev->member.prev, member))
237
238#define list_for_each_entry_from(type, pos, start, head, member)        \
239   for (type *pos = LIST_ENTRY(type, (start), member);                  \
240	&pos->member != (head);                                         \
241	pos = LIST_ENTRY(type, pos->member.next, member))
242
243#define list_for_each_entry_from_rev(type, pos, start, head, member)    \
244   for (type *pos = LIST_ENTRY(type, (start), member);                  \
245	&pos->member != (head);                                         \
246	pos = LIST_ENTRY(type, pos->member.prev, member))
247
248#endif /*_UTIL_LIST_H_*/
249