list.h revision 270838 
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: stable/10/lib/libc/include/isc/list.h 270838 2014-08-30 10:16:25Z ume $ */
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			   (void *)((elt)->link.next) != (void *)(-1))
43
44#define HEAD(list) ((list).head)
45#define TAIL(list) ((list).tail)
46#define EMPTY(list) ((list).head == NULL)
47
48#define PREPEND(list, elt, link) \
49	do { \
50		INSIST(!LINKED(elt, link));\
51		if ((list).head != NULL) \
52			(list).head->link.prev = (elt); \
53		else \
54			(list).tail = (elt); \
55		(elt)->link.prev = NULL; \
56		(elt)->link.next = (list).head; \
57		(list).head = (elt); \
58	} while (0)
59
60#define APPEND(list, elt, link) \
61	do { \
62		INSIST(!LINKED(elt, link));\
63		if ((list).tail != NULL) \
64			(list).tail->link.next = (elt); \
65		else \
66			(list).head = (elt); \
67		(elt)->link.prev = (list).tail; \
68		(elt)->link.next = NULL; \
69		(list).tail = (elt); \
70	} while (0)
71
72#define UNLINK_TYPE(list, elt, link, type) \
73	do { \
74		INSIST(LINKED(elt, link));\
75		if ((elt)->link.next != NULL) \
76			(elt)->link.next->link.prev = (elt)->link.prev; \
77		else { \
78			INSIST((list).tail == (elt)); \
79			(list).tail = (elt)->link.prev; \
80		} \
81		if ((elt)->link.prev != NULL) \
82			(elt)->link.prev->link.next = (elt)->link.next; \
83		else { \
84			INSIST((list).head == (elt)); \
85			(list).head = (elt)->link.next; \
86		} \
87		INIT_LINK_TYPE(elt, link, type); \
88	} while (0)
89#define UNLINK(list, elt, link) \
90	UNLINK_TYPE(list, elt, link, void)
91
92#define PREV(elt, link) ((elt)->link.prev)
93#define NEXT(elt, link) ((elt)->link.next)
94
95#define INSERT_BEFORE(list, before, elt, link) \
96	do { \
97		INSIST(!LINKED(elt, link));\
98		if ((before)->link.prev == NULL) \
99			PREPEND(list, elt, link); \
100		else { \
101			(elt)->link.prev = (before)->link.prev; \
102			(before)->link.prev = (elt); \
103			(elt)->link.prev->link.next = (elt); \
104			(elt)->link.next = (before); \
105		} \
106	} while (0)
107
108#define INSERT_AFTER(list, after, elt, link) \
109	do { \
110		INSIST(!LINKED(elt, link));\
111		if ((after)->link.next == NULL) \
112			APPEND(list, elt, link); \
113		else { \
114			(elt)->link.next = (after)->link.next; \
115			(after)->link.next = (elt); \
116			(elt)->link.next->link.prev = (elt); \
117			(elt)->link.prev = (after); \
118		} \
119	} while (0)
120
121#define ENQUEUE(list, elt, link) APPEND(list, elt, link)
122#define DEQUEUE(list, elt, link) UNLINK(list, elt, link)
123
124#endif /* LIST_H */
125/*! \file */
126