xref: /onnv-gate/usr/src/lib/libntfs/common/include/ntfs/list.h (revision 9663:ace9a2ac3683)
1 /*
2  * list.h - Linked list implementation. Part of the Linux-NTFS project.
3  *
4  * Copyright (c) 2000-2002 Anton Altaparmakov and others
5  *
6  * This program/include file is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License as published
8  * by the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program/include file is distributed in the hope that it will be
12  * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
13  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program (in the main directory of the Linux-NTFS
18  * distribution in the file COPYING); if not, write to the Free Software
19  * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
20  */
21 
22 #ifndef _NTFS_LIST_H
23 #define _NTFS_LIST_H
24 
25 /**
26  * struct list_head - Simple doubly linked list implementation.
27  *
28  * Copied from Linux kernel 2.4.2-ac18 into Linux-NTFS (with minor
29  * modifications). - AIA
30  *
31  * Some of the internal functions ("__xxx") are useful when
32  * manipulating whole lists rather than single entries, as
33  * sometimes we already know the next/prev entries and we can
34  * generate better code by using them directly rather than
35  * using the generic single-entry routines.
36  */
37 struct list_head {
38 	struct list_head *next, *prev;
39 };
40 
41 #define LIST_HEAD_INIT(name) { &(name), &(name) }
42 
43 #define LIST_HEAD(name) \
44 	struct list_head name = LIST_HEAD_INIT(name)
45 
46 #define INIT_LIST_HEAD(ptr) do { \
47 	(ptr)->next = (ptr); (ptr)->prev = (ptr); \
48 } while (0)
49 
50 /**
51  * __list_add - Insert a new entry between two known consecutive entries.
52  * @new:
53  * @prev:
54  * @next:
55  *
56  * This is only for internal list manipulation where we know the prev/next
57  * entries already!
58  */
__list_add(struct list_head * new,struct list_head * prev,struct list_head * next)59 static __inline__ void __list_add(struct list_head * new,
60 		struct list_head * prev, struct list_head * next)
61 {
62 	next->prev = new;
63 	new->next = next;
64 	new->prev = prev;
65 	prev->next = new;
66 }
67 
68 /**
69  * list_add - add a new entry
70  * @new:	new entry to be added
71  * @head:	list head to add it after
72  *
73  * Insert a new entry after the specified head.
74  * This is good for implementing stacks.
75  */
list_add(struct list_head * new,struct list_head * head)76 static __inline__ void list_add(struct list_head *new, struct list_head *head)
77 {
78 	__list_add(new, head, head->next);
79 }
80 
81 /**
82  * list_add_tail - add a new entry
83  * @new:	new entry to be added
84  * @head:	list head to add it before
85  *
86  * Insert a new entry before the specified head.
87  * This is useful for implementing queues.
88  */
list_add_tail(struct list_head * new,struct list_head * head)89 static __inline__ void list_add_tail(struct list_head *new, struct list_head *head)
90 {
91 	__list_add(new, head->prev, head);
92 }
93 
94 /**
95  * __list_del -
96  * @prev:
97  * @next:
98  *
99  * Delete a list entry by making the prev/next entries point to each other.
100  *
101  * This is only for internal list manipulation where we know the prev/next
102  * entries already!
103  */
__list_del(struct list_head * prev,struct list_head * next)104 static __inline__ void __list_del(struct list_head * prev,
105 		struct list_head * next)
106 {
107 	next->prev = prev;
108 	prev->next = next;
109 }
110 
111 /**
112  * list_del - deletes entry from list.
113  * @entry:	the element to delete from the list.
114  *
115  * Note: list_empty on entry does not return true after this, the entry is in
116  * an undefined state.
117  */
list_del(struct list_head * entry)118 static __inline__ void list_del(struct list_head *entry)
119 {
120 	__list_del(entry->prev, entry->next);
121 }
122 
123 /**
124  * list_del_init - deletes entry from list and reinitialize it.
125  * @entry:	the element to delete from the list.
126  */
list_del_init(struct list_head * entry)127 static __inline__ void list_del_init(struct list_head *entry)
128 {
129 	__list_del(entry->prev, entry->next);
130 	INIT_LIST_HEAD(entry);
131 }
132 
133 /**
134  * list_empty - tests whether a list is empty
135  * @head:	the list to test.
136  */
list_empty(struct list_head * head)137 static __inline__ int list_empty(struct list_head *head)
138 {
139 	return head->next == head;
140 }
141 
142 /**
143  * list_splice - join two lists
144  * @list:	the new list to add.
145  * @head:	the place to add it in the first list.
146  */
list_splice(struct list_head * list,struct list_head * head)147 static __inline__ void list_splice(struct list_head *list,
148 		struct list_head *head)
149 {
150 	struct list_head *first = list->next;
151 
152 	if (first != list) {
153 		struct list_head *last = list->prev;
154 		struct list_head *at = head->next;
155 
156 		first->prev = head;
157 		head->next = first;
158 
159 		last->next = at;
160 		at->prev = last;
161 	}
162 }
163 
164 /**
165  * list_entry - get the struct for this entry
166  * @ptr:	the &struct list_head pointer.
167  * @type:	the type of the struct this is embedded in.
168  * @member:	the name of the list_struct within the struct.
169  */
170 #define list_entry(ptr, type, member) \
171 	((type *)((char *)(ptr)-(unsigned long)(&((type *)0)->member)))
172 
173 /**
174  * list_for_each - iterate over a list
175  * @pos:	the &struct list_head to use as a loop counter.
176  * @head:	the head for your list.
177  */
178 #define list_for_each(pos, head) \
179 	for (pos = (head)->next; pos != (head); pos = pos->next)
180 
181 /**
182  * list_for_each_safe	-	iterate over a list safe against removal of list entry
183  * @pos:	the &struct list_head to use as a loop counter.
184  * @n:		another &struct list_head to use as temporary storage
185  * @head:	the head for your list.
186  */
187 #define list_for_each_safe(pos, n, head) \
188 	for (pos = (head)->next, n = pos->next; pos != (head); \
189 		pos = n, n = pos->next)
190 
191 #endif /* defined _NTFS_LIST_H */
192 
193