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/* $OpenBSD: lstRemove.c,v 1.9 2000/06/17 14:43:40 espie Exp $ */
/* $NetBSD: lstRemove.c,v 1.5 1996/11/06 17:59:50 christos Exp $ */
/*
* Copyright (c) 1988, 1989, 1990, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Adam de Boor.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef lint
#if 0
static char sccsid[] = "@(#)lstRemove.c 8.1 (Berkeley) 6/6/93";
#else
static char rcsid[] = "$OpenBSD: lstRemove.c,v 1.9 2000/06/17 14:43:40 espie Exp $";
#endif
#endif /* not lint */
/*-
* LstRemove.c --
* Remove an element from a list
*/
#include "lstInt.h"
/*-
*-----------------------------------------------------------------------
* Lst_Remove --
* Remove the given node from the given list.
*
* Results:
* SUCCESS or FAILURE.
*
* Side Effects:
* The list's firstPtr will be set to NULL if ln is the last
* node on the list. firsPtr and lastPtr will be altered if ln is
* either the first or last node, respectively, on the list.
*
*-----------------------------------------------------------------------
*/
void
Lst_Remove(l, ln)
Lst l;
LstNode ln;
{
if (!LstNodeValid(ln, l))
return;
/* unlink it from the list */
if (ln->nextPtr != NULL)
ln->nextPtr->prevPtr = ln->prevPtr;
if (ln->prevPtr != NULL)
ln->prevPtr->nextPtr = ln->nextPtr;
/*
* if either the firstPtr or lastPtr of the list point to this node,
* adjust them accordingly
*/
if (l->firstPtr == ln)
l->firstPtr = ln->nextPtr;
if (l->lastPtr == ln)
l->lastPtr = ln->prevPtr;
/*
* Sequential access stuff. If the node we're removing is the current
* node in the list, reset the current node to the previous one. If the
* previous one was non-existent (prevPtr == NULL), we set the
* end to be Unknown, since it is.
*/
if (l->isOpen && l->curPtr == ln) {
l->curPtr = l->prevPtr;
if (l->curPtr == NULL)
l->atEnd = Unknown;
}
/*
* the only way firstPtr can still point to ln is if ln is the last
* node on the list (the list is circular, so ln->nextptr == ln in
* this case). The list is, therefore, empty and is marked as such
*/
if (l->firstPtr == ln)
l->firstPtr = NULL;
/*
* note that the datum is unmolested. The caller must free it as
* necessary and as expected.
*/
if (ln->useCount == 0)
free(ln);
else
ln->flags |= LN_DELETED;
}
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