1/* $NetBSD: lstRemove.c,v 1.14 2008/12/13 15:19:29 dsl Exp $ */ 2 3/* 4 * Copyright (c) 1988, 1989, 1990, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Adam de Boor. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35#ifndef MAKE_NATIVE 36static char rcsid[] = "$NetBSD: lstRemove.c,v 1.14 2008/12/13 15:19:29 dsl Exp $"; 37#else 38#include <sys/cdefs.h> 39#ifndef lint 40#if 0 41static char sccsid[] = "@(#)lstRemove.c 8.1 (Berkeley) 6/6/93"; 42#else 43__RCSID("$NetBSD: lstRemove.c,v 1.14 2008/12/13 15:19:29 dsl Exp $"); 44#endif 45#endif /* not lint */ 46#endif 47 48/*- 49 * LstRemove.c -- 50 * Remove an element from a list 51 */ 52 53#include "lstInt.h" 54 55/*- 56 *----------------------------------------------------------------------- 57 * Lst_Remove -- 58 * Remove the given node from the given list. 59 * 60 * Results: 61 * SUCCESS or FAILURE. 62 * 63 * Side Effects: 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. 67 * 68 *----------------------------------------------------------------------- 69 */ 70ReturnStatus 71Lst_Remove(Lst l, LstNode ln) 72{ 73 List list = l; 74 ListNode lNode = ln; 75 76 if (!LstValid (l) || 77 !LstNodeValid (ln, l)) { 78 return (FAILURE); 79 } 80 81 /* 82 * unlink it from the list 83 */ 84 if (lNode->nextPtr != NULL) { 85 lNode->nextPtr->prevPtr = lNode->prevPtr; 86 } 87 if (lNode->prevPtr != NULL) { 88 lNode->prevPtr->nextPtr = lNode->nextPtr; 89 } 90 91 /* 92 * if either the firstPtr or lastPtr of the list point to this node, 93 * adjust them accordingly 94 */ 95 if (list->firstPtr == lNode) { 96 list->firstPtr = lNode->nextPtr; 97 } 98 if (list->lastPtr == lNode) { 99 list->lastPtr = lNode->prevPtr; 100 } 101 102 /* 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. 107 */ 108 if (list->isOpen && (list->curPtr == lNode)) { 109 list->curPtr = list->prevPtr; 110 if (list->curPtr == NULL) { 111 list->atEnd = Unknown; 112 } 113 } 114 115 /* 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 119 */ 120 if (list->firstPtr == lNode) { 121 list->firstPtr = NULL; 122 } 123 124 /* 125 * note that the datum is unmolested. The caller must free it as 126 * necessary and as expected. 127 */ 128 if (lNode->useCount == 0) { 129 free(ln); 130 } else { 131 lNode->flags |= LN_DELETED; 132 } 133 134 return (SUCCESS); 135} 136 137