xref: /illumos-gate/usr/src/lib/libipmi/common/ipmi_list.c (revision 1da57d551424de5a9d469760be7c4b4d4f10a755)
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 /*
27  * Embedded Linked Lists
28  *
29  * Simple doubly-linked list implementation.  This implementation assumes that
30  * each list element contains an embedded ipmi_list_t (previous and next
31  * pointers), which is typically the first member of the element struct.
32  * An additional ipmi_list_t is used to store the head (l_next) and tail
33  * (l_prev) pointers.  The current head and tail list elements have their
34  * previous and next pointers set to NULL, respectively.
35  */
36 
37 #include <assert.h>
38 #include <ipmi_impl.h>
39 
40 void
ipmi_list_append(ipmi_list_t * lp,void * new)41 ipmi_list_append(ipmi_list_t *lp, void *new)
42 {
43 	ipmi_list_t *p = lp->l_prev;	/* p = tail list element */
44 	ipmi_list_t *q = new;		/* q = new list element */
45 
46 	lp->l_prev = q;
47 	q->l_prev = p;
48 	q->l_next = NULL;
49 
50 	if (p != NULL) {
51 		assert(p->l_next == NULL);
52 		p->l_next = q;
53 	} else {
54 		assert(lp->l_next == NULL);
55 		lp->l_next = q;
56 	}
57 }
58 
59 void
ipmi_list_prepend(ipmi_list_t * lp,void * new)60 ipmi_list_prepend(ipmi_list_t *lp, void *new)
61 {
62 	ipmi_list_t *p = new;		/* p = new list element */
63 	ipmi_list_t *q = lp->l_next;	/* q = head list element */
64 
65 	lp->l_next = p;
66 	p->l_prev = NULL;
67 	p->l_next = q;
68 
69 	if (q != NULL) {
70 		assert(q->l_prev == NULL);
71 		q->l_prev = p;
72 	} else {
73 		assert(lp->l_prev == NULL);
74 		lp->l_prev = p;
75 	}
76 }
77 
78 void
ipmi_list_insert_before(ipmi_list_t * lp,void * before_me,void * new)79 ipmi_list_insert_before(ipmi_list_t *lp, void *before_me, void *new)
80 {
81 	ipmi_list_t *p = before_me;
82 	ipmi_list_t *q = new;
83 
84 	if (p == NULL || p->l_prev == NULL) {
85 		ipmi_list_prepend(lp, new);
86 		return;
87 	}
88 
89 	q->l_prev = p->l_prev;
90 	q->l_next = p;
91 	p->l_prev = q;
92 	q->l_prev->l_next = q;
93 }
94 
95 void
ipmi_list_insert_after(ipmi_list_t * lp,void * after_me,void * new)96 ipmi_list_insert_after(ipmi_list_t *lp, void *after_me, void *new)
97 {
98 	ipmi_list_t *p = after_me;
99 	ipmi_list_t *q = new;
100 
101 	if (p == NULL || p->l_next == NULL) {
102 		ipmi_list_append(lp, new);
103 		return;
104 	}
105 
106 	q->l_next = p->l_next;
107 	q->l_prev = p;
108 	p->l_next = q;
109 	q->l_next->l_prev = q;
110 }
111 
112 void
ipmi_list_delete(ipmi_list_t * lp,void * existing)113 ipmi_list_delete(ipmi_list_t *lp, void *existing)
114 {
115 	ipmi_list_t *p = existing;
116 
117 	if (p->l_prev != NULL)
118 		p->l_prev->l_next = p->l_next;
119 	else
120 		lp->l_next = p->l_next;
121 
122 	if (p->l_next != NULL)
123 		p->l_next->l_prev = p->l_prev;
124 	else
125 		lp->l_prev = p->l_prev;
126 }
127