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
42 void
mdb_list_append(mdb_list_t * mlp,void * new)43 mdb_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
61 void
mdb_list_prepend(mdb_list_t * mlp,void * new)62 mdb_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
80 void
mdb_list_insert(mdb_list_t * mlp,void * after_me,void * new)81 mdb_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
97 void
mdb_list_delete(mdb_list_t * mlp,void * existing)98 mdb_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
113 void
mdb_list_move(mdb_list_t * src,mdb_list_t * dst)114 mdb_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