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36 * $FreeBSD: src/usr.bin/make/lst.lib/lstRemove.c,v 1.6 1999/08/28 01:03:56 peter Exp $
37 * $DragonFly: src/usr.bin/make/lst.lib/Attic/lstRemove.c,v 1.2 2003/06/17 04:29:29 dillon Exp $
39 * @(#)lstRemove.c 8.1 (Berkeley) 6/6/93
44 * Remove an element from a list
50 *-----------------------------------------------------------------------
52 * Remove the given node from the given list.
58 * The list's firstPtr will be set to NilListNode if ln is the last
59 * node on the list. firsPtr and lastPtr will be altered if ln is
60 * either the first or last node, respectively, on the list.
62 *-----------------------------------------------------------------------
69 register List list = (List) l;
70 register ListNode lNode = (ListNode) ln;
73 !LstNodeValid (ln, l)) {
78 * unlink it from the list
80 if (lNode->nextPtr != NilListNode) {
81 lNode->nextPtr->prevPtr = lNode->prevPtr;
83 if (lNode->prevPtr != NilListNode) {
84 lNode->prevPtr->nextPtr = lNode->nextPtr;
88 * if either the firstPtr or lastPtr of the list point to this node,
89 * adjust them accordingly
91 if (list->firstPtr == lNode) {
92 list->firstPtr = lNode->nextPtr;
94 if (list->lastPtr == lNode) {
95 list->lastPtr = lNode->prevPtr;
99 * Sequential access stuff. If the node we're removing is the current
100 * node in the list, reset the current node to the previous one. If the
101 * previous one was non-existent (prevPtr == NilListNode), we set the
102 * end to be Unknown, since it is.
104 if (list->isOpen && (list->curPtr == lNode)) {
105 list->curPtr = list->prevPtr;
106 if (list->curPtr == NilListNode) {
107 list->atEnd = Unknown;
112 * the only way firstPtr can still point to ln is if ln is the last
113 * node on the list (the list is circular, so lNode->nextptr == lNode in
114 * this case). The list is, therefore, empty and is marked as such
116 if (list->firstPtr == lNode) {
117 list->firstPtr = NilListNode;
121 * note that the datum is unmolested. The caller must free it as
122 * necessary and as expected.
124 if (lNode->useCount == 0) {
127 lNode->flags |= LN_DELETED;