1/*
2 *
3 * Copyright 2006 Tungsten Graphics, 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#ifndef _U_DOUBLE_LIST_H_
37#define _U_DOUBLE_LIST_H_
38
39#include <stddef.h>
40
41struct list_head
42{
43    struct list_head *prev;
44    struct list_head *next;
45};
46
47static void list_inithead(struct list_head *item)
48{
49    item->prev = item;
50    item->next = item;
51}
52
53static void list_add(struct list_head *item, struct list_head *list)
54{
55    item->prev = list;
56    item->next = list->next;
57    list->next->prev = item;
58    list->next = item;
59}
60
61static void list_addtail(struct list_head *item, struct list_head *list)
62{
63    item->next = list;
64    item->prev = list->prev;
65    list->prev->next = item;
66    list->prev = item;
67}
68
69static void list_replace(struct list_head *from, struct list_head *to)
70{
71    to->prev = from->prev;
72    to->next = from->next;
73    from->next->prev = to;
74    from->prev->next = to;
75}
76
77static void list_del(struct list_head *item)
78{
79    item->prev->next = item->next;
80    item->next->prev = item->prev;
81}
82
83static void list_delinit(struct list_head *item)
84{
85    item->prev->next = item->next;
86    item->next->prev = item->prev;
87    item->next = item;
88    item->prev = item;
89}
90
91#define LIST_INITHEAD(__item) list_inithead(__item)
92#define LIST_ADD(__item, __list) list_add(__item, __list)
93#define LIST_ADDTAIL(__item, __list) list_addtail(__item, __list)
94#define LIST_REPLACE(__from, __to) list_replace(__from, __to)
95#define LIST_DEL(__item) list_del(__item)
96#define LIST_DELINIT(__item) list_delinit(__item)
97
98#define LIST_ENTRY(__type, __item, __field)   \
99    ((__type *)(((char *)(__item)) - offsetof(__type, __field)))
100
101#define LIST_IS_EMPTY(__list)                   \
102    ((__list)->next == (__list))
103
104#ifndef container_of
105#define container_of(ptr, sample, member)				\
106    (void *)((char *)(ptr)						\
107	     - ((char *)&(sample)->member - (char *)(sample)))
108#endif
109
110#define LIST_FOR_EACH_ENTRY(pos, head, member)				\
111   for (pos = container_of((head)->next, pos, member);			\
112	&pos->member != (head);						\
113	pos = container_of(pos->member.next, pos, member))
114
115#define LIST_FOR_EACH_ENTRY_SAFE(pos, storage, head, member)	\
116   for (pos = container_of((head)->next, pos, member),			\
117	storage = container_of(pos->member.next, pos, member);	\
118	&pos->member != (head);						\
119	pos = storage, storage = container_of(storage->member.next, storage, member))
120
121#define LIST_FOR_EACH_ENTRY_SAFE_REV(pos, storage, head, member)	\
122   for (pos = container_of((head)->prev, pos, member),			\
123	storage = container_of(pos->member.prev, pos, member);		\
124	&pos->member != (head);						\
125	pos = storage, storage = container_of(storage->member.prev, storage, member))
126
127#define LIST_FOR_EACH_ENTRY_FROM(pos, start, head, member)		\
128   for (pos = container_of((start), pos, member);			\
129	&pos->member != (head);						\
130	pos = container_of(pos->member.next, pos, member))
131
132#define LIST_FOR_EACH_ENTRY_FROM_REV(pos, start, head, member)		\
133   for (pos = container_of((start), pos, member);			\
134	&pos->member != (head);						\
135	pos = container_of(pos->member.prev, pos, member))
136
137#endif /*_U_DOUBLE_LIST_H_*/
138