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 (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21 /*
22 * Copyright 2008 Sun Microsystems, Inc. All rights reserved.
23 * Use is subject to license terms.
24 */
25
26 #pragma ident "%Z%%M% %I% %E% SMI"
27
28 /*
29 * Embedded Linked Lists
30 *
31 * Simple doubly-linked list implementation. This implementation assumes that
32 * each list element contains an embedded ipmi_list_t (previous and next
33 * pointers), which is typically the first member of the element struct.
34 * An additional ipmi_list_t is used to store the head (l_next) and tail
35 * (l_prev) pointers. The current head and tail list elements have their
36 * previous and next pointers set to NULL, respectively.
37 */
38
39 #include <assert.h>
40 #include <ipmi_impl.h>
41
42 void
ipmi_list_append(ipmi_list_t * lp,void * new)43 ipmi_list_append(ipmi_list_t *lp, void *new)
44 {
45 ipmi_list_t *p = lp->l_prev; /* p = tail list element */
46 ipmi_list_t *q = new; /* q = new list element */
47
48 lp->l_prev = q;
49 q->l_prev = p;
50 q->l_next = NULL;
51
52 if (p != NULL) {
53 assert(p->l_next == NULL);
54 p->l_next = q;
55 } else {
56 assert(lp->l_next == NULL);
57 lp->l_next = q;
58 }
59 }
60
61 void
ipmi_list_prepend(ipmi_list_t * lp,void * new)62 ipmi_list_prepend(ipmi_list_t *lp, void *new)
63 {
64 ipmi_list_t *p = new; /* p = new list element */
65 ipmi_list_t *q = lp->l_next; /* q = head list element */
66
67 lp->l_next = p;
68 p->l_prev = NULL;
69 p->l_next = q;
70
71 if (q != NULL) {
72 assert(q->l_prev == NULL);
73 q->l_prev = p;
74 } else {
75 assert(lp->l_prev == NULL);
76 lp->l_prev = p;
77 }
78 }
79
80 void
ipmi_list_insert_before(ipmi_list_t * lp,void * before_me,void * new)81 ipmi_list_insert_before(ipmi_list_t *lp, void *before_me, void *new)
82 {
83 ipmi_list_t *p = before_me;
84 ipmi_list_t *q = new;
85
86 if (p == NULL || p->l_prev == NULL) {
87 ipmi_list_prepend(lp, new);
88 return;
89 }
90
91 q->l_prev = p->l_prev;
92 q->l_next = p;
93 p->l_prev = q;
94 q->l_prev->l_next = q;
95 }
96
97 void
ipmi_list_insert_after(ipmi_list_t * lp,void * after_me,void * new)98 ipmi_list_insert_after(ipmi_list_t *lp, void *after_me, void *new)
99 {
100 ipmi_list_t *p = after_me;
101 ipmi_list_t *q = new;
102
103 if (p == NULL || p->l_next == NULL) {
104 ipmi_list_append(lp, new);
105 return;
106 }
107
108 q->l_next = p->l_next;
109 q->l_prev = p;
110 p->l_next = q;
111 q->l_next->l_prev = q;
112 }
113
114 void
ipmi_list_delete(ipmi_list_t * lp,void * existing)115 ipmi_list_delete(ipmi_list_t *lp, void *existing)
116 {
117 ipmi_list_t *p = existing;
118
119 if (p->l_prev != NULL)
120 p->l_prev->l_next = p->l_next;
121 else
122 lp->l_next = p->l_next;
123
124 if (p->l_next != NULL)
125 p->l_next->l_prev = p->l_prev;
126 else
127 lp->l_prev = p->l_prev;
128 }
129