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 #include <mdb/mdb_list.h>
28 #include <mdb/mdb_debug.h>
29 #include <unistd.h>
30
31 /*
32 * Simple doubly-linked list implementation. This implementation assumes that
33 * each list element contains an embedded mdb_list_t (previous and next
34 * pointers), which is typically the first member of the element struct.
35 * An additional mdb_list_t is used to store the head (ml_next) and tail
36 * (ml_prev) pointers. The current head and tail list elements have their
37 * previous and next pointers set to NULL, respectively.
38 */
39
40 void
mdb_list_append(mdb_list_t * mlp,void * new)41 mdb_list_append(mdb_list_t *mlp, void *new)
42 {
43 mdb_list_t *p = mlp->ml_prev; /* p = tail list element */
44 mdb_list_t *q = new; /* q = new list element */
45
46 mlp->ml_prev = q;
47 q->ml_prev = p;
48 q->ml_next = NULL;
49
50 if (p != NULL) {
51 ASSERT(p->ml_next == NULL);
52 p->ml_next = q;
53 } else {
54 ASSERT(mlp->ml_next == NULL);
55 mlp->ml_next = q;
56 }
57 }
58
59 void
mdb_list_prepend(mdb_list_t * mlp,void * new)60 mdb_list_prepend(mdb_list_t *mlp, void *new)
61 {
62 mdb_list_t *p = new; /* p = new list element */
63 mdb_list_t *q = mlp->ml_next; /* q = head list element */
64
65 mlp->ml_next = p;
66 p->ml_prev = NULL;
67 p->ml_next = q;
68
69 if (q != NULL) {
70 ASSERT(q->ml_prev == NULL);
71 q->ml_prev = p;
72 } else {
73 ASSERT(mlp->ml_prev == NULL);
74 mlp->ml_prev = p;
75 }
76 }
77
78 void
mdb_list_insert(mdb_list_t * mlp,void * after_me,void * new)79 mdb_list_insert(mdb_list_t *mlp, void *after_me, void *new)
80 {
81 mdb_list_t *p = after_me;
82 mdb_list_t *q = new;
83
84 if (p == NULL || p->ml_next == NULL) {
85 mdb_list_append(mlp, new);
86 return;
87 }
88
89 q->ml_next = p->ml_next;
90 q->ml_prev = p;
91 p->ml_next = q;
92 q->ml_next->ml_prev = q;
93 }
94
95 void
mdb_list_delete(mdb_list_t * mlp,void * existing)96 mdb_list_delete(mdb_list_t *mlp, void *existing)
97 {
98 mdb_list_t *p = existing;
99
100 if (p->ml_prev != NULL)
101 p->ml_prev->ml_next = p->ml_next;
102 else
103 mlp->ml_next = p->ml_next;
104
105 if (p->ml_next != NULL)
106 p->ml_next->ml_prev = p->ml_prev;
107 else
108 mlp->ml_prev = p->ml_prev;
109 }
110
111 void
mdb_list_move(mdb_list_t * src,mdb_list_t * dst)112 mdb_list_move(mdb_list_t *src, mdb_list_t *dst)
113 {
114 dst->ml_prev = src->ml_prev;
115 dst->ml_next = src->ml_next;
116 src->ml_prev = NULL;
117 src->ml_next = NULL;
118 }
119