1 /* $NetBSD: lstInsert.c,v 1.14 2009/01/23 21:26:30 dsl Exp $ */
2
3 /*
4 * Copyright (c) 1988, 1989, 1990, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Adam de Boor.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35 #ifndef MAKE_NATIVE
36 static char rcsid[] = "$NetBSD: lstInsert.c,v 1.14 2009/01/23 21:26:30 dsl Exp $";
37 #else
38 #include <sys/cdefs.h>
39 #ifndef lint
40 #if 0
41 static char sccsid[] = "@(#)lstInsert.c 8.1 (Berkeley) 6/6/93";
42 #else
43 __RCSID("$NetBSD: lstInsert.c,v 1.14 2009/01/23 21:26:30 dsl Exp $");
44 #endif
45 #endif /* not lint */
46 #endif
47
48 /*-
49 * LstInsert.c --
50 * Insert a new datum before an old one
51 */
52
53 #include "lstInt.h"
54
55 /*-
56 *-----------------------------------------------------------------------
57 * Lst_InsertBefore --
58 * Insert a new node with the given piece of data before the given
59 * node in the given list.
60 *
61 * Input:
62 * l list to manipulate
63 * ln node before which to insert d
64 * d datum to be inserted
65 *
66 * Results:
67 * SUCCESS or FAILURE.
68 *
69 * Side Effects:
70 * the firstPtr field will be changed if ln is the first node in the
71 * list.
72 *
73 *-----------------------------------------------------------------------
74 */
75 ReturnStatus
Lst_InsertBefore(Lst l,LstNode ln,void * d)76 Lst_InsertBefore(Lst l, LstNode ln, void *d)
77 {
78 ListNode nLNode; /* new lnode for d */
79 ListNode lNode = ln;
80 List list = l;
81
82
83 /*
84 * check validity of arguments
85 */
86 if (LstValid (l) && (LstIsEmpty (l) && ln == NULL))
87 goto ok;
88
89 if (!LstValid (l) || LstIsEmpty (l) || !LstNodeValid (ln, l)) {
90 return (FAILURE);
91 }
92
93 ok:
94 PAlloc (nLNode, ListNode);
95
96 nLNode->datum = d;
97 nLNode->useCount = nLNode->flags = 0;
98
99 if (ln == NULL) {
100 if (list->isCirc) {
101 nLNode->prevPtr = nLNode->nextPtr = nLNode;
102 } else {
103 nLNode->prevPtr = nLNode->nextPtr = NULL;
104 }
105 list->firstPtr = list->lastPtr = nLNode;
106 } else {
107 nLNode->prevPtr = lNode->prevPtr;
108 nLNode->nextPtr = lNode;
109
110 if (nLNode->prevPtr != NULL) {
111 nLNode->prevPtr->nextPtr = nLNode;
112 }
113 lNode->prevPtr = nLNode;
114
115 if (lNode == list->firstPtr) {
116 list->firstPtr = nLNode;
117 }
118 }
119
120 return (SUCCESS);
121 }
122
123