134 lines
4.2 KiB
C
134 lines
4.2 KiB
C
/*
|
|
* 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.
|
|
*
|
|
* $Id$
|
|
*/
|
|
|
|
#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);
|
|
}
|
|
|