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
42void
43ipmi_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
61void
62ipmi_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
80void
81ipmi_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
97void
98ipmi_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
114void
115ipmi_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