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/* $FreeBSD$ */
19
20#ifndef LIST_H
21#define LIST_H 1
22#ifdef _LIBC
23#include <assert.h>
24#define INSIST(cond)	assert(cond)
25#else
26#include <isc/assertions.h>
27#endif
28
29#define LIST(type) struct { type *head, *tail; }
30#define INIT_LIST(list) \
31	do { (list).head = NULL; (list).tail = NULL; } while (0)
32
33#define LINK(type) struct { type *prev, *next; }
34#define INIT_LINK_TYPE(elt, link, type) \
35	do { \
36		(elt)->link.prev = (type *)(-1); \
37		(elt)->link.next = (type *)(-1); \
38	} while (0)
39#define INIT_LINK(elt, link) \
40	INIT_LINK_TYPE(elt, link, void)
41#define LINKED(elt, link) ((void *)((elt)->link.prev) != (void *)(-1))
42
43#define HEAD(list) ((list).head)
44#define TAIL(list) ((list).tail)
45#define EMPTY(list) ((list).head == NULL)
46
47#define PREPEND(list, elt, link) \
48	do { \
49		INSIST(!LINKED(elt, link));\
50		if ((list).head != NULL) \
51			(list).head->link.prev = (elt); \
52		else \
53			(list).tail = (elt); \
54		(elt)->link.prev = NULL; \
55		(elt)->link.next = (list).head; \
56		(list).head = (elt); \
57	} while (0)
58
59#define APPEND(list, elt, link) \
60	do { \
61		INSIST(!LINKED(elt, link));\
62		if ((list).tail != NULL) \
63			(list).tail->link.next = (elt); \
64		else \
65			(list).head = (elt); \
66		(elt)->link.prev = (list).tail; \
67		(elt)->link.next = NULL; \
68		(list).tail = (elt); \
69	} while (0)
70
71#define UNLINK_TYPE(list, elt, link, type) \
72	do { \
73		INSIST(LINKED(elt, link));\
74		if ((elt)->link.next != NULL) \
75			(elt)->link.next->link.prev = (elt)->link.prev; \
76		else { \
77			INSIST((list).tail == (elt)); \
78			(list).tail = (elt)->link.prev; \
79		} \
80		if ((elt)->link.prev != NULL) \
81			(elt)->link.prev->link.next = (elt)->link.next; \
82		else { \
83			INSIST((list).head == (elt)); \
84			(list).head = (elt)->link.next; \
85		} \
86		INIT_LINK_TYPE(elt, link, type); \
87	} while (0)
88#define UNLINK(list, elt, link) \
89	UNLINK_TYPE(list, elt, link, void)
90
91#define PREV(elt, link) ((elt)->link.prev)
92#define NEXT(elt, link) ((elt)->link.next)
93
94#define INSERT_BEFORE(list, before, elt, link) \
95	do { \
96		INSIST(!LINKED(elt, link));\
97		if ((before)->link.prev == NULL) \
98			PREPEND(list, elt, link); \
99		else { \
100			(elt)->link.prev = (before)->link.prev; \
101			(before)->link.prev = (elt); \
102			(elt)->link.prev->link.next = (elt); \
103			(elt)->link.next = (before); \
104		} \
105	} while (0)
106
107#define INSERT_AFTER(list, after, elt, link) \
108	do { \
109		INSIST(!LINKED(elt, link));\
110		if ((after)->link.next == NULL) \
111			APPEND(list, elt, link); \
112		else { \
113			(elt)->link.next = (after)->link.next; \
114			(after)->link.next = (elt); \
115			(elt)->link.next->link.prev = (elt); \
116			(elt)->link.prev = (after); \
117		} \
118	} while (0)
119
120#define ENQUEUE(list, elt, link) APPEND(list, elt, link)
121#define DEQUEUE(list, elt, link) UNLINK(list, elt, link)
122
123#endif /* LIST_H */
124/*! \file */
125