1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License, Version 1.0 only
6 * (the "License").  You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22/*
23 * Copyright (c) 1999 by Sun Microsystems, Inc.
24 * All rights reserved.
25 */
26
27#pragma ident	"%Z%%M%	%I%	%E% SMI"
28
29#include <mdb/mdb_list.h>
30#include <mdb/mdb_debug.h>
31#include <unistd.h>
32
33/*
34 * Simple doubly-linked list implementation.  This implementation assumes that
35 * each list element contains an embedded mdb_list_t (previous and next
36 * pointers), which is typically the first member of the element struct.
37 * An additional mdb_list_t is used to store the head (ml_next) and tail
38 * (ml_prev) pointers.  The current head and tail list elements have their
39 * previous and next pointers set to NULL, respectively.
40 */
41
42void
43mdb_list_append(mdb_list_t *mlp, void *new)
44{
45	mdb_list_t *p = mlp->ml_prev;	/* p = tail list element */
46	mdb_list_t *q = new;		/* q = new list element */
47
48	mlp->ml_prev = q;
49	q->ml_prev = p;
50	q->ml_next = NULL;
51
52	if (p != NULL) {
53		ASSERT(p->ml_next == NULL);
54		p->ml_next = q;
55	} else {
56		ASSERT(mlp->ml_next == NULL);
57		mlp->ml_next = q;
58	}
59}
60
61void
62mdb_list_prepend(mdb_list_t *mlp, void *new)
63{
64	mdb_list_t *p = new;		/* p = new list element */
65	mdb_list_t *q = mlp->ml_next;	/* q = head list element */
66
67	mlp->ml_next = p;
68	p->ml_prev = NULL;
69	p->ml_next = q;
70
71	if (q != NULL) {
72		ASSERT(q->ml_prev == NULL);
73		q->ml_prev = p;
74	} else {
75		ASSERT(mlp->ml_prev == NULL);
76		mlp->ml_prev = p;
77	}
78}
79
80void
81mdb_list_insert(mdb_list_t *mlp, void *after_me, void *new)
82{
83	mdb_list_t *p = after_me;
84	mdb_list_t *q = new;
85
86	if (p == NULL || p->ml_next == NULL) {
87		mdb_list_append(mlp, new);
88		return;
89	}
90
91	q->ml_next = p->ml_next;
92	q->ml_prev = p;
93	p->ml_next = q;
94	q->ml_next->ml_prev = q;
95}
96
97void
98mdb_list_delete(mdb_list_t *mlp, void *existing)
99{
100	mdb_list_t *p = existing;
101
102	if (p->ml_prev != NULL)
103		p->ml_prev->ml_next = p->ml_next;
104	else
105		mlp->ml_next = p->ml_next;
106
107	if (p->ml_next != NULL)
108		p->ml_next->ml_prev = p->ml_prev;
109	else
110		mlp->ml_prev = p->ml_prev;
111}
112
113void
114mdb_list_move(mdb_list_t *src, mdb_list_t *dst)
115{
116	dst->ml_prev = src->ml_prev;
117	dst->ml_next = src->ml_next;
118	src->ml_prev = NULL;
119	src->ml_next = NULL;
120}
121