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/*
* 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.
*
* $FreeBSD$
*/
#ifndef lint
static char sccsid[] = "@(#)lstRemove.c 8.1 (Berkeley) 6/6/93";
#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 NilListNode 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.
*
*-----------------------------------------------------------------------
*/
ReturnStatus
Lst_Remove (l, ln)
Lst l;
LstNode ln;
{
register List list = (List) l;
register ListNode lNode = (ListNode) ln;
if (!LstValid (l) ||
!LstNodeValid (ln, l)) {
return (FAILURE);
}
/*
* unlink it from the list
*/
if (lNode->nextPtr != NilListNode) {
lNode->nextPtr->prevPtr = lNode->prevPtr;
}
if (lNode->prevPtr != NilListNode) {
lNode->prevPtr->nextPtr = lNode->nextPtr;
}
/*
* if either the firstPtr or lastPtr of the list point to this node,
* adjust them accordingly
*/
if (list->firstPtr == lNode) {
list->firstPtr = lNode->nextPtr;
}
if (list->lastPtr == lNode) {
list->lastPtr = lNode->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 == NilListNode), we set the
* end to be Unknown, since it is.
*/
if (list->isOpen && (list->curPtr == lNode)) {
list->curPtr = list->prevPtr;
if (list->curPtr == NilListNode) {
list->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 lNode->nextptr == lNode in
* this case). The list is, therefore, empty and is marked as such
*/
if (list->firstPtr == lNode) {
list->firstPtr = NilListNode;
}
/*
* note that the datum is unmolested. The caller must free it as
* necessary and as expected.
*/
if (lNode->useCount == 0) {
free ((Address)ln);
} else {
lNode->flags |= LN_DELETED;
}
return (SUCCESS);
}
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