u_double_list.h revision ccff74971203b533bf16b46b49a9e61753f75e6c 
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
37#ifndef _U_DOUBLE_LIST_H_
38#define _U_DOUBLE_LIST_H_
39
40
41#include <stddef.h>
42#include "pipe/p_compiler.h"
43
44
45struct list_head
46{
47    struct list_head *prev;
48    struct list_head *next;
49};
50
51static INLINE void list_inithead(struct list_head *item)
52{
53    item->prev = item;
54    item->next = item;
55}
56
57static 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
65static 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
73static INLINE void list_replace(struct list_head *from, struct list_head *to)
74{
75    to->prev = from->prev;
76    to->next = from->next;
77    from->next->prev = to;
78    from->prev->next = to;
79}
80
81static INLINE void list_del(struct list_head *item)
82{
83    item->prev->next = item->next;
84    item->next->prev = item->prev;
85}
86
87static INLINE void list_delinit(struct list_head *item)
88{
89    item->prev->next = item->next;
90    item->next->prev = item->prev;
91    item->next = item;
92    item->prev = item;
93}
94
95#define LIST_INITHEAD(__item) list_inithead(__item)
96#define LIST_ADD(__item, __list) list_add(__item, __list)
97#define LIST_ADDTAIL(__item, __list) list_addtail(__item, __list)
98#define LIST_REPLACE(__from, __to) list_replace(__from, __to)
99#define LIST_DEL(__item) list_del(__item)
100#define LIST_DELINIT(__item) list_delinit(__item)
101
102#define LIST_ENTRY(__type, __item, __field)   \
103    ((__type *)(((char *)(__item)) - offsetof(__type, __field)))
104
105#define LIST_IS_EMPTY(__list)                   \
106    ((__list)->next == (__list))
107
108/**
109 * Cast from a pointer to a member of a struct back to the containing struct.
110 *
111 * 'sample' MUST be initialized, or else the result is undefined!
112 */
113#ifndef container_of
114#define container_of(ptr, sample, member)				\
115    (void *)((char *)(ptr)						\
116	     - ((char *)&(sample)->member - (char *)(sample)))
117#endif
118
119#define LIST_FOR_EACH_ENTRY(pos, head, member)				\
120   for (pos = NULL, pos = container_of((head)->next, pos, member);	\
121	&pos->member != (head);						\
122	pos = container_of(pos->member.next, pos, member))
123
124#define LIST_FOR_EACH_ENTRY_SAFE(pos, storage, head, member)	\
125   for (pos = NULL, pos = container_of((head)->next, pos, member),	\
126	storage = container_of(pos->member.next, pos, member);	\
127	&pos->member != (head);						\
128	pos = storage, storage = container_of(storage->member.next, storage, member))
129
130#define LIST_FOR_EACH_ENTRY_SAFE_REV(pos, storage, head, member)	\
131   for (pos = NULL, pos = container_of((head)->prev, pos, member),	\
132	storage = container_of(pos->member.prev, pos, member);		\
133	&pos->member != (head);						\
134	pos = storage, storage = container_of(storage->member.prev, storage, member))
135
136#define LIST_FOR_EACH_ENTRY_FROM(pos, start, head, member)		\
137   for (pos = NULL, pos = container_of((start), pos, member);		\
138	&pos->member != (head);						\
139	pos = container_of(pos->member.next, pos, member))
140
141#define LIST_FOR_EACH_ENTRY_FROM_REV(pos, start, head, member)		\
142   for (pos = NULL, pos = container_of((start), pos, member);		\
143	&pos->member != (head);						\
144	pos = container_of(pos->member.prev, pos, member))
145
146#endif /*_U_DOUBLE_LIST_H_*/
147