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
36static char rcsid[] = "$NetBSD: lstInsert.c,v 1.14 2009/01/23 21:26:30 dsl Exp $";
37#else
38#include <sys/cdefs.h>
39#ifndef lint
40#if 0
41static char sccsid[] = "@(#)lstInsert.c	8.1 (Berkeley) 6/6/93";
42#else
43__RCSID("$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 */
75ReturnStatus
76Lst_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