list.h revision 158783 
1/*
2 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
3 * Copyright (c) 1997,1999 by Internet Software Consortium.
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
15 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17
18#ifndef LIST_H
19#define LIST_H 1
20#include <isc/assertions.h>
21
22#define LIST(type) struct { type *head, *tail; }
23#define INIT_LIST(list) \
24	do { (list).head = NULL; (list).tail = NULL; } while (0)
25
26#define LINK(type) struct { type *prev, *next; }
27#define INIT_LINK_TYPE(elt, link, type) \
28	do { \
29		(elt)->link.prev = (type *)(-1); \
30		(elt)->link.next = (type *)(-1); \
31	} while (0)
32#define INIT_LINK(elt, link) \
33	INIT_LINK_TYPE(elt, link, void)
34#define LINKED(elt, link) ((void *)((elt)->link.prev) != (void *)(-1))
35
36#define HEAD(list) ((list).head)
37#define TAIL(list) ((list).tail)
38#define EMPTY(list) ((list).head == NULL)
39
40#define PREPEND(list, elt, link) \
41	do { \
42		INSIST(!LINKED(elt, link));\
43		if ((list).head != NULL) \
44			(list).head->link.prev = (elt); \
45		else \
46			(list).tail = (elt); \
47		(elt)->link.prev = NULL; \
48		(elt)->link.next = (list).head; \
49		(list).head = (elt); \
50	} while (0)
51
52#define APPEND(list, elt, link) \
53	do { \
54		INSIST(!LINKED(elt, link));\
55		if ((list).tail != NULL) \
56			(list).tail->link.next = (elt); \
57		else \
58			(list).head = (elt); \
59		(elt)->link.prev = (list).tail; \
60		(elt)->link.next = NULL; \
61		(list).tail = (elt); \
62	} while (0)
63
64#define UNLINK_TYPE(list, elt, link, type) \
65	do { \
66		INSIST(LINKED(elt, link));\
67		if ((elt)->link.next != NULL) \
68			(elt)->link.next->link.prev = (elt)->link.prev; \
69		else \
70			(list).tail = (elt)->link.prev; \
71		if ((elt)->link.prev != NULL) \
72			(elt)->link.prev->link.next = (elt)->link.next; \
73		else \
74			(list).head = (elt)->link.next; \
75		INIT_LINK_TYPE(elt, link, type); \
76	} while (0)
77#define UNLINK(list, elt, link) \
78	UNLINK_TYPE(list, elt, link, void)
79
80#define PREV(elt, link) ((elt)->link.prev)
81#define NEXT(elt, link) ((elt)->link.next)
82
83#define INSERT_BEFORE(list, before, elt, link) \
84	do { \
85		INSIST(!LINKED(elt, link));\
86		if ((before)->link.prev == NULL) \
87			PREPEND(list, elt, link); \
88		else { \
89			(elt)->link.prev = (before)->link.prev; \
90			(before)->link.prev = (elt); \
91			(elt)->link.prev->link.next = (elt); \
92			(elt)->link.next = (before); \
93		} \
94	} while (0)
95
96#define INSERT_AFTER(list, after, elt, link) \
97	do { \
98		INSIST(!LINKED(elt, link));\
99		if ((after)->link.next == NULL) \
100			APPEND(list, elt, link); \
101		else { \
102			(elt)->link.next = (after)->link.next; \
103			(after)->link.next = (elt); \
104			(elt)->link.next->link.prev = (elt); \
105			(elt)->link.prev = (after); \
106		} \
107	} while (0)
108
109#define ENQUEUE(list, elt, link) APPEND(list, elt, link)
110#define DEQUEUE(list, elt, link) UNLINK(list, elt, link)
111
112#endif /* LIST_H */
113