1 | /* Copyright (C) 2002-2017 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, see |
17 | <http://www.gnu.org/licenses/>. */ |
18 | |
19 | #ifndef _LIST_H |
20 | |
21 | #ifndef __need_list_t |
22 | # define _LIST_H 1 |
23 | #endif |
24 | |
25 | /* The definitions of this file are adopted from those which can be |
26 | found in the Linux kernel headers to enable people familiar with |
27 | the latter find their way in these sources as well. */ |
28 | |
29 | |
30 | #if defined __need_list_t || defined _LIST_H |
31 | # ifndef __list_t_defined |
32 | # define __list_t_defined |
33 | /* Basic type for the double-link list. */ |
34 | typedef struct list_head |
35 | { |
36 | struct list_head *next; |
37 | struct list_head *prev; |
38 | } list_t; |
39 | # endif |
40 | # undef __need_list_t |
41 | #endif |
42 | |
43 | #ifdef _LIST_H |
44 | |
45 | # include <atomic.h> |
46 | |
47 | /* Define a variable with the head and tail of the list. */ |
48 | # define LIST_HEAD(name) \ |
49 | list_t name = { &(name), &(name) } |
50 | |
51 | /* Initialize a new list head. */ |
52 | # define INIT_LIST_HEAD(ptr) \ |
53 | (ptr)->next = (ptr)->prev = (ptr) |
54 | |
55 | |
56 | /* Add new element at the head of the list. */ |
57 | static inline void |
58 | list_add (list_t *newp, list_t *head) |
59 | { |
60 | newp->next = head->next; |
61 | newp->prev = head; |
62 | head->next->prev = newp; |
63 | atomic_write_barrier (); |
64 | head->next = 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 | #endif /* _LIST_H */ |
116 | |
117 | #endif /* list.h */ |
118 | |