1 /* $NetBSD: lstRemove.c,v 1.16 2014/09/07 20:55:34 joerg Exp $ */
4 * Copyright (c) 1988, 1989, 1990, 1993
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36 static char rcsid[] = "$NetBSD: lstRemove.c,v 1.16 2014/09/07 20:55:34 joerg Exp $";
38 #include <sys/cdefs.h>
41 static char sccsid[] = "@(#)lstRemove.c 8.1 (Berkeley) 6/6/93";
43 __RCSID("$NetBSD: lstRemove.c,v 1.16 2014/09/07 20:55:34 joerg Exp $");
50 * Remove an element from a list
56 *-----------------------------------------------------------------------
58 * Remove the given node from the given list.
64 * The list's firstPtr will be set to NULL if ln is the last
65 * node on the list. firsPtr and lastPtr will be altered if ln is
66 * either the first or last node, respectively, on the list.
68 *-----------------------------------------------------------------------
71 Lst_Remove(Lst l, LstNode ln)
77 !LstNodeValid (ln, l)) {
82 * unlink it from the list
84 if (lNode->nextPtr != NULL) {
85 lNode->nextPtr->prevPtr = lNode->prevPtr;
87 if (lNode->prevPtr != NULL) {
88 lNode->prevPtr->nextPtr = lNode->nextPtr;
92 * if either the firstPtr or lastPtr of the list point to this node,
93 * adjust them accordingly
95 if (list->firstPtr == lNode) {
96 list->firstPtr = lNode->nextPtr;
98 if (list->lastPtr == lNode) {
99 list->lastPtr = lNode->prevPtr;
103 * Sequential access stuff. If the node we're removing is the current
104 * node in the list, reset the current node to the previous one. If the
105 * previous one was non-existent (prevPtr == NULL), we set the
106 * end to be Unknown, since it is.
108 if (list->isOpen && (list->curPtr == lNode)) {
109 list->curPtr = list->prevPtr;
110 if (list->curPtr == NULL) {
111 list->atEnd = Unknown;
116 * the only way firstPtr can still point to ln is if ln is the last
117 * node on the list (the list is circular, so lNode->nextptr == lNode in
118 * this case). The list is, therefore, empty and is marked as such
120 if (list->firstPtr == lNode) {
121 list->firstPtr = NULL;
125 * note that the datum is unmolested. The caller must free it as
126 * necessary and as expected.
128 if (lNode->useCount == 0) {
131 lNode->flags |= LN_DELETED;