1 /* $OpenPackages$ */ 2 /* $OpenBSD: lstInsert.c,v 1.16 2004/04/07 13:11:36 espie Exp $ */ 3 /* $NetBSD: lstInsert.c,v 1.5 1996/11/06 17:59:44 christos Exp $ */ 4 5 /* 6 * Copyright (c) 1988, 1989, 1990, 1993 7 * The Regents of the University of California. All rights reserved. 8 * 9 * This code is derived from software contributed to Berkeley by 10 * Adam de Boor. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 /*- 38 * LstInsert.c -- 39 * Insert a new datum before an old one 40 */ 41 42 #include "lstInt.h" 43 #include <sys/types.h> 44 #include <stdlib.h> 45 #include "memory.h" 46 47 /*- 48 *----------------------------------------------------------------------- 49 * Lst_Insert -- 50 * Insert a new node with the given piece of data before the given 51 * node in the given list. 52 * 53 * Side Effects: 54 * the firstPtr field will be changed if ln is the first node in the 55 * list. 56 * 57 *----------------------------------------------------------------------- 58 */ 59 void 60 Lst_Insert(Lst l, LstNode before, void *d) 61 { 62 LstNode nLNode; /* new lnode for d */ 63 64 65 if (before == NULL && !Lst_IsEmpty(l)) 66 return; 67 68 if (before != NULL && Lst_IsEmpty(l)) 69 return; 70 71 PAlloc(nLNode, LstNode); 72 73 nLNode->datum = d; 74 75 if (before == NULL) { 76 nLNode->prevPtr = nLNode->nextPtr = NULL; 77 l->firstPtr = l->lastPtr = nLNode; 78 } else { 79 nLNode->prevPtr = before->prevPtr; 80 nLNode->nextPtr = before; 81 82 if (nLNode->prevPtr != NULL) 83 nLNode->prevPtr->nextPtr = nLNode; 84 before->prevPtr = nLNode; 85 86 if (before == l->firstPtr) 87 l->firstPtr = nLNode; 88 } 89 } 90 91 void 92 Lst_AtFront(Lst l, void *d) 93 { 94 LstNode ln; 95 96 PAlloc(ln, LstNode); 97 ln->datum = d; 98 99 ln->nextPtr = l->firstPtr; 100 ln->prevPtr = NULL; 101 if (l->firstPtr == NULL) 102 l->lastPtr = ln; 103 else 104 l->firstPtr->prevPtr = ln; 105 l->firstPtr = ln; 106 } 107