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			   (void *)((elt)->link.next) != (void *)(-1))
36
37#define HEAD(list) ((list).head)
38#define TAIL(list) ((list).tail)
39#define EMPTY(list) ((list).head == NULL)
40
41#define PREPEND(list, elt, link) \
42	do { \
43		INSIST(!LINKED(elt, link));\
44		if ((list).head != NULL) \
45			(list).head->link.prev = (elt); \
46		else \
47			(list).tail = (elt); \
48		(elt)->link.prev = NULL; \
49		(elt)->link.next = (list).head; \
50		(list).head = (elt); \
51	} while (0)
52
53#define APPEND(list, elt, link) \
54	do { \
55		INSIST(!LINKED(elt, link));\
56		if ((list).tail != NULL) \
57			(list).tail->link.next = (elt); \
58		else \
59			(list).head = (elt); \
60		(elt)->link.prev = (list).tail; \
61		(elt)->link.next = NULL; \
62		(list).tail = (elt); \
63	} while (0)
64
65#define UNLINK_TYPE(list, elt, link, type) \
66	do { \
67		INSIST(LINKED(elt, link));\
68		if ((elt)->link.next != NULL) \
69			(elt)->link.next->link.prev = (elt)->link.prev; \
70		else { \
71			INSIST((list).tail == (elt)); \
72			(list).tail = (elt)->link.prev; \
73		} \
74		if ((elt)->link.prev != NULL) \
75			(elt)->link.prev->link.next = (elt)->link.next; \
76		else { \
77			INSIST((list).head == (elt)); \
78			(list).head = (elt)->link.next; \
79		} \
80		INIT_LINK_TYPE(elt, link, type); \
81	} while (0)
82#define UNLINK(list, elt, link) \
83	UNLINK_TYPE(list, elt, link, void)
84
85#define PREV(elt, link) ((elt)->link.prev)
86#define NEXT(elt, link) ((elt)->link.next)
87
88#define INSERT_BEFORE(list, before, elt, link) \
89	do { \
90		INSIST(!LINKED(elt, link));\
91		if ((before)->link.prev == NULL) \
92			PREPEND(list, elt, link); \
93		else { \
94			(elt)->link.prev = (before)->link.prev; \
95			(before)->link.prev = (elt); \
96			(elt)->link.prev->link.next = (elt); \
97			(elt)->link.next = (before); \
98		} \
99	} while (0)
100
101#define INSERT_AFTER(list, after, elt, link) \
102	do { \
103		INSIST(!LINKED(elt, link));\
104		if ((after)->link.next == NULL) \
105			APPEND(list, elt, link); \
106		else { \
107			(elt)->link.next = (after)->link.next; \
108			(after)->link.next = (elt); \
109			(elt)->link.next->link.prev = (elt); \
110			(elt)->link.prev = (after); \
111		} \
112	} while (0)
113
114#define ENQUEUE(list, elt, link) APPEND(list, elt, link)
115#define DEQUEUE(list, elt, link) UNLINK(list, elt, link)
116
117#endif /* LIST_H */
118/*! \file */
119