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    item->prev = item->next = NULL;
86}
87
88static INLINE void list_delinit(struct list_head *item)
89{
90    item->prev->next = item->next;
91    item->next->prev = item->prev;
92    item->next = item;
93    item->prev = item;
94}
95
96#define LIST_INITHEAD(__item) list_inithead(__item)
97#define LIST_ADD(__item, __list) list_add(__item, __list)
98#define LIST_ADDTAIL(__item, __list) list_addtail(__item, __list)
99#define LIST_REPLACE(__from, __to) list_replace(__from, __to)
100#define LIST_DEL(__item) list_del(__item)
101#define LIST_DELINIT(__item) list_delinit(__item)
102
103#define LIST_ENTRY(__type, __item, __field)   \
104    ((__type *)(((char *)(__item)) - offsetof(__type, __field)))
105
106#define LIST_IS_EMPTY(__list)                   \
107    ((__list)->next == (__list))
108
109/**
110 * Cast from a pointer to a member of a struct back to the containing struct.
111 *
112 * 'sample' MUST be initialized, or else the result is undefined!
113 */
114#ifndef container_of
115#define container_of(ptr, sample, member)				\
116    (void *)((char *)(ptr)						\
117	     - ((char *)&(sample)->member - (char *)(sample)))
118#endif
119
120#define LIST_FOR_EACH_ENTRY(pos, head, member)				\
121   for (pos = NULL, pos = container_of((head)->next, pos, member);	\
122	&pos->member != (head);						\
123	pos = container_of(pos->member.next, pos, member))
124
125#define LIST_FOR_EACH_ENTRY_SAFE(pos, storage, head, member)	\
126   for (pos = NULL, pos = container_of((head)->next, pos, member),	\
127	storage = container_of(pos->member.next, pos, member);	\
128	&pos->member != (head);						\
129	pos = storage, storage = container_of(storage->member.next, storage, member))
130
131#define LIST_FOR_EACH_ENTRY_SAFE_REV(pos, storage, head, member)	\
132   for (pos = NULL, pos = container_of((head)->prev, pos, member),	\
133	storage = container_of(pos->member.prev, pos, member);		\
134	&pos->member != (head);						\
135	pos = storage, storage = container_of(storage->member.prev, storage, member))
136
137#define LIST_FOR_EACH_ENTRY_FROM(pos, start, head, member)		\
138   for (pos = NULL, pos = container_of((start), pos, member);		\
139	&pos->member != (head);						\
140	pos = container_of(pos->member.next, pos, member))
141
142#define LIST_FOR_EACH_ENTRY_FROM_REV(pos, start, head, member)		\
143   for (pos = NULL, pos = container_of((start), pos, member);		\
144	&pos->member != (head);						\
145	pos = container_of(pos->member.prev, pos, member))
146
147#endif /*_U_DOUBLE_LIST_H_*/
148