1 /* $NetBSD: lstInsert.c,v 1.14 2009/01/23 21:26:30 dsl Exp $ */
4 * Copyright (c) 1988, 1989, 1990, 1993
5 * The Regents of the University of California. All rights reserved.
7 * This code is derived from software contributed to Berkeley by
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11 * modification, are permitted provided that the following conditions
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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
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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.
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
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31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 static char rcsid[] = "$NetBSD: lstInsert.c,v 1.14 2009/01/23 21:26:30 dsl Exp $";
38 #include <sys/cdefs.h>
41 static char sccsid[] = "@(#)lstInsert.c 8.1 (Berkeley) 6/6/93";
43 __RCSID("$NetBSD: lstInsert.c,v 1.14 2009/01/23 21:26:30 dsl Exp $");
50 * Insert a new datum before an old one
56 *-----------------------------------------------------------------------
58 * Insert a new node with the given piece of data before the given
59 * node in the given list.
62 * l list to manipulate
63 * ln node before which to insert d
64 * d datum to be inserted
70 * the firstPtr field will be changed if ln is the first node in the
73 *-----------------------------------------------------------------------
76 Lst_InsertBefore(Lst l, LstNode ln, void *d)
78 ListNode nLNode; /* new lnode for d */
84 * check validity of arguments
86 if (LstValid (l) && (LstIsEmpty (l) && ln == NULL))
89 if (!LstValid (l) || LstIsEmpty (l) || !LstNodeValid (ln, l)) {
94 PAlloc (nLNode, ListNode);
97 nLNode->useCount = nLNode->flags = 0;
101 nLNode->prevPtr = nLNode->nextPtr = nLNode;
103 nLNode->prevPtr = nLNode->nextPtr = NULL;
105 list->firstPtr = list->lastPtr = nLNode;
107 nLNode->prevPtr = lNode->prevPtr;
108 nLNode->nextPtr = lNode;
110 if (nLNode->prevPtr != NULL) {
111 nLNode->prevPtr->nextPtr = nLNode;
113 lNode->prevPtr = nLNode;
115 if (lNode == list->firstPtr) {
116 list->firstPtr = nLNode;