| 1 | /*
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| 2 | * Copyright (c) 1988, 1989, 1990, 1993
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| 3 | * The Regents of the University of California. All rights reserved.
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| 4 | *
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| 5 | * This code is derived from software contributed to Berkeley by
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| 6 | * Adam de Boor.
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| 7 | *
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| 8 | * Redistribution and use in source and binary forms, with or without
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| 9 | * modification, are permitted provided that the following conditions
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| 10 | * are met:
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| 11 | * 1. Redistributions of source code must retain the above copyright
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| 12 | * notice, this list of conditions and the following disclaimer.
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| 13 | * 2. Redistributions in binary form must reproduce the above copyright
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| 14 | * notice, this list of conditions and the following disclaimer in the
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| 15 | * documentation and/or other materials provided with the distribution.
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| 16 | * 3. All advertising materials mentioning features or use of this software
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| 17 | * must display the following acknowledgement:
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| 18 | * This product includes software developed by the University of
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| 19 | * California, Berkeley and its contributors.
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| 20 | * 4. Neither the name of the University nor the names of its contributors
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| 21 | * may be used to endorse or promote products derived from this software
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| 22 | * without specific prior written permission.
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| 23 | *
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| 24 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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| 25 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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| 26 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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| 27 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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| 28 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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| 29 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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| 30 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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| 31 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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| 32 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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| 33 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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| 34 | * SUCH DAMAGE.
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| 35 | *
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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 $
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| 37 | */
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| 38 |
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| 39 | #ifndef lint
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| 40 | static char sccsid[] = "@(#)lstRemove.c 8.1 (Berkeley) 6/6/93";
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| 41 | #endif /* not lint */
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| 42 |
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| 43 | /*-
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| 44 | * LstRemove.c --
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| 45 | * Remove an element from a list
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| 46 | */
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| 47 |
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| 48 | #include "lstInt.h"
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| 49 |
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| 50 | /*-
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| 51 | *-----------------------------------------------------------------------
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| 52 | * Lst_Remove --
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| 53 | * Remove the given node from the given list.
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| 54 | *
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| 55 | * Results:
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| 56 | * SUCCESS or FAILURE.
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| 57 | *
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| 58 | * Side Effects:
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| 59 | * The list's firstPtr will be set to NilListNode if ln is the last
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| 60 | * node on the list. firsPtr and lastPtr will be altered if ln is
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| 61 | * either the first or last node, respectively, on the list.
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| 62 | *
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| 63 | *-----------------------------------------------------------------------
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| 64 | */
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| 65 | ReturnStatus
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| 66 | Lst_Remove (l, ln)
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| 67 | Lst l;
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| 68 | LstNode ln;
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| 69 | {
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| 70 | register List list = (List) l;
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| 71 | register ListNode lNode = (ListNode) ln;
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| 72 |
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| 73 | if (!LstValid (l) ||
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| 74 | !LstNodeValid (ln, l)) {
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| 75 | return (FAILURE);
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| 76 | }
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| 77 |
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| 78 | /*
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| 79 | * unlink it from the list
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| 80 | */
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| 81 | if (lNode->nextPtr != NilListNode) {
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| 82 | lNode->nextPtr->prevPtr = lNode->prevPtr;
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| 83 | }
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| 84 | if (lNode->prevPtr != NilListNode) {
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| 85 | lNode->prevPtr->nextPtr = lNode->nextPtr;
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| 86 | }
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| 87 |
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| 88 | /*
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| 89 | * if either the firstPtr or lastPtr of the list point to this node,
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| 90 | * adjust them accordingly
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| 91 | */
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| 92 | if (list->firstPtr == lNode) {
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| 93 | list->firstPtr = lNode->nextPtr;
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| 94 | }
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| 95 | if (list->lastPtr == lNode) {
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| 96 | list->lastPtr = lNode->prevPtr;
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| 97 | }
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| 98 |
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| 99 | /*
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| 100 | * Sequential access stuff. If the node we're removing is the current
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| 101 | * node in the list, reset the current node to the previous one. If the
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| 102 | * previous one was non-existent (prevPtr == NilListNode), we set the
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| 103 | * end to be Unknown, since it is.
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| 104 | */
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| 105 | if (list->isOpen && (list->curPtr == lNode)) {
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| 106 | list->curPtr = list->prevPtr;
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| 107 | if (list->curPtr == NilListNode) {
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| 108 | list->atEnd = Unknown;
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| 109 | }
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| 110 | }
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| 111 |
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| 112 | /*
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| 113 | * the only way firstPtr can still point to ln is if ln is the last
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| 114 | * node on the list (the list is circular, so lNode->nextptr == lNode in
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| 115 | * this case). The list is, therefore, empty and is marked as such
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| 116 | */
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| 117 | if (list->firstPtr == lNode) {
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| 118 | list->firstPtr = NilListNode;
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| 119 | }
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| 120 |
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| 121 | /*
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| 122 | * note that the datum is unmolested. The caller must free it as
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| 123 | * necessary and as expected.
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| 124 | */
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| 125 | if (lNode->useCount == 0) {
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| 126 | free ((Address)ln);
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| 127 | } else {
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| 128 | lNode->flags |= LN_DELETED;
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| 129 | }
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| 130 |
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| 131 | return (SUCCESS);
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| 132 | }
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| 133 |
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