1/*	$OpenBSD: lstRemove.c,v 1.19 2010/07/19 19:46:44 espie Exp $	*/
2/*	$NetBSD: lstRemove.c,v 1.5 1996/11/06 17:59:50 christos Exp $	*/
3
4/*
5 * Copyright (c) 1988, 1989, 1990, 1993
6 *	The Regents of the University of California.  All rights reserved.
7 *
8 * This code is derived from software contributed to Berkeley by
9 * Adam de Boor.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 *    notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 *    notice, this list of conditions and the following disclaimer in the
18 *    documentation and/or other materials provided with the distribution.
19 * 3. Neither the name of the University nor the names of its contributors
20 *    may be used to endorse or promote products derived from this software
21 *    without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36/*-
37 * LstRemove.c --
38 *	Remove an element from a list
39 */
40
41#include	"lstInt.h"
42#include	<stdlib.h>
43
44
45/*-
46 *-----------------------------------------------------------------------
47 * Lst_Remove --
48 *	Remove the given node from the given list.
49 *
50 * Side Effects:
51 *	The list's firstPtr will be set to NULL if ln is the last
52 *	node on the list. firsPtr and lastPtr will be altered if ln is
53 *	either the first or last node, respectively, on the list.
54 *
55 *-----------------------------------------------------------------------
56 */
57void
58Lst_Remove(Lst l, LstNode ln)
59{
60	if (ln == NULL)
61		return;
62
63	/* unlink it from the list */
64	if (ln->nextPtr != NULL)
65		ln->nextPtr->prevPtr = ln->prevPtr;
66	if (ln->prevPtr != NULL)
67		ln->prevPtr->nextPtr = ln->nextPtr;
68
69	/* if either the firstPtr or lastPtr of the list point to this node,
70	 * adjust them accordingly */
71	if (l->firstPtr == ln)
72		l->firstPtr = ln->nextPtr;
73	if (l->lastPtr == ln)
74		l->lastPtr = ln->prevPtr;
75
76	/* note that the datum is unmolested. The caller must free it as
77	 * necessary and as expected.  */
78	free(ln);
79}
80
81