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1 | /* Copyright (C) 2002 Free Software Foundation, Inc. |
2 | This file is part of the GNU C Library. | |
3 | Contributed by Ulrich Drepper <drepper@redhat.com>, 2002. | |
4 | ||
5 | The GNU C Library is free software; you can redistribute it and/or | |
6 | modify it under the terms of the GNU Lesser General Public | |
7 | License as published by the Free Software Foundation; either | |
8 | version 2.1 of the License, or (at your option) any later version. | |
9 | ||
10 | The GNU C Library is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | Lesser General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU Lesser General Public | |
16 | License along with the GNU C Library; if not, write to the Free | |
17 | Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA | |
18 | 02111-1307 USA. */ | |
19 | ||
20 | #ifndef _LIST_H | |
21 | #define _LIST_H 1 | |
22 | ||
23 | /* The definitions of this file are adopted from those which can be | |
24 | found in the Linux kernel headers to enable people familiar with | |
25 | the latter find their way in these sources as well. */ | |
26 | ||
27 | ||
28 | /* Basic type for the double-link list. */ | |
29 | typedef struct list_head | |
30 | { | |
31 | struct list_head *next; | |
32 | struct list_head *prev; | |
33 | } list_t; | |
34 | ||
35 | ||
36 | /* Define a variable with the head and tail of the list. */ | |
37 | #define LIST_HEAD(name) \ | |
38 | list_t name = { &(name), &(name) } | |
39 | ||
40 | /* Initialize a new list head. */ | |
41 | #define INIT_LIST_HEAD(ptr) \ | |
42 | (ptr)->next = (ptr)->prev = (ptr) | |
43 | ||
44 | #define LIST_HEAD_INIT(name) { .prev = &(name), .next = &(name) } | |
45 | ||
46 | /* Add new element at the head of the list. */ | |
47 | static inline void | |
48 | list_add (list_t *newp, list_t *head) | |
49 | { | |
50 | head->next->prev = newp; | |
51 | newp->next = head->next; | |
52 | newp->prev = head; | |
53 | head->next = newp; | |
54 | } | |
55 | ||
56 | ||
57 | /* Add new element at the tail of the list. */ | |
58 | static inline void | |
59 | list_add_tail (list_t *newp, list_t *head) | |
60 | { | |
61 | head->prev->next = newp; | |
62 | newp->next = head; | |
63 | newp->prev = head->prev; | |
64 | head->prev = newp; | |
65 | } | |
66 | ||
67 | ||
68 | /* Remove element from list. */ | |
69 | static inline void | |
70 | list_del (list_t *elem) | |
71 | { | |
72 | elem->next->prev = elem->prev; | |
73 | elem->prev->next = elem->next; | |
74 | } | |
75 | ||
76 | ||
77 | /* Join two lists. */ | |
78 | static inline void | |
79 | list_splice (list_t *add, list_t *head) | |
80 | { | |
81 | /* Do nothing if the list which gets added is empty. */ | |
82 | if (add != add->next) | |
83 | { | |
84 | add->next->prev = head; | |
85 | add->prev->next = head->next; | |
86 | head->next->prev = add->prev; | |
87 | head->next = add->next; | |
88 | } | |
89 | } | |
90 | ||
91 | ||
92 | /* Get typed element from list at a given position. */ | |
93 | #define list_entry(ptr, type, member) \ | |
94 | ((type *) ((char *) (ptr) - (unsigned long) (&((type *) 0)->member))) | |
95 | ||
96 | ||
97 | ||
98 | /* Iterate forward over the elements of the list. */ | |
99 | #define list_for_each(pos, head) \ | |
100 | for (pos = (head)->next; pos != (head); pos = pos->next) | |
101 | ||
102 | ||
103 | /* Iterate forward over the elements of the list. */ | |
104 | #define list_for_each_prev(pos, head) \ | |
105 | for (pos = (head)->prev; pos != (head); pos = pos->prev) | |
106 | ||
107 | ||
108 | /* Iterate backwards over the elements list. The list elements can be | |
109 | removed from the list while doing this. */ | |
110 | #define list_for_each_prev_safe(pos, p, head) \ | |
111 | for (pos = (head)->prev, p = pos->prev; \ | |
112 | pos != (head); \ | |
113 | pos = p, p = pos->prev) | |
114 | ||
115 | #define list_for_each_entry(pos, head, member) \ | |
116 | for (pos = list_entry((head)->next, typeof(*pos), member); \ | |
117 | &pos->member != (head); \ | |
118 | pos = list_entry(pos->member.next, typeof(*pos), member)) | |
119 | ||
120 | #define list_for_each_entry_reverse(pos, head, member) \ | |
121 | for (pos = list_entry((head)->prev, typeof(*pos), member); \ | |
122 | &pos->member != (head); \ | |
123 | pos = list_entry(pos->member.prev, typeof(*pos), member)) | |
124 | ||
125 | #define list_for_each_entry_safe(pos, p, head, member) \ | |
126 | for (pos = list_entry((head)->next, typeof(*pos), member), \ | |
127 | p = list_entry(pos->member.next,typeof(*pos), member); \ | |
128 | &pos->member != (head); \ | |
129 | pos = p, p = list_entry(pos->member.next, typeof(*pos), member)) | |
130 | ||
131 | static inline int list_empty(list_t *head) | |
132 | { | |
133 | return head == head->next; | |
134 | } | |
135 | ||
136 | static inline void list_replace_init(list_t *old, | |
137 | list_t *new) | |
138 | { | |
139 | list_t *head = old->next; | |
140 | list_del(old); | |
141 | list_add_tail(new, head); | |
142 | INIT_LIST_HEAD(old); | |
143 | } | |
144 | ||
145 | #endif /* list.h */ |