1 /* $OpenBSD: lstInsert.c,v 1.20 2010/07/19 19:46:44 espie Exp $ */ 2 /* $NetBSD: lstInsert.c,v 1.5 1996/11/06 17:59:44 christos Exp $ */ 3 4 /* 5 * Copyright (c) 1988, 1989, 1990, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * This code is derived from software contributed to Berkeley by 9 * Adam de Boor. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 /*- 37 * LstInsert.c -- 38 * Insert a new datum before an old one 39 */ 40 41 #include "lstInt.h" 42 #include <sys/types.h> 43 #include <stdlib.h> 44 #include "memory.h" 45 46 /*- 47 *----------------------------------------------------------------------- 48 * Lst_Insert -- 49 * Insert a new node with the given piece of data before the given 50 * node in the given list. 51 * 52 * Side Effects: 53 * the firstPtr field will be changed if ln is the first node in the 54 * list. 55 * 56 *----------------------------------------------------------------------- 57 */ 58 void 59 Lst_Insert(Lst l, LstNode before, void *d) 60 { 61 LstNode nLNode; 62 63 64 if (before == NULL && !Lst_IsEmpty(l)) 65 return; 66 67 if (before != NULL && Lst_IsEmpty(l)) 68 return; 69 70 PAlloc(nLNode, LstNode); 71 72 nLNode->datum = d; 73 74 if (before == NULL) { 75 nLNode->prevPtr = nLNode->nextPtr = NULL; 76 l->firstPtr = l->lastPtr = nLNode; 77 } else { 78 nLNode->prevPtr = before->prevPtr; 79 nLNode->nextPtr = before; 80 81 if (nLNode->prevPtr != NULL) 82 nLNode->prevPtr->nextPtr = nLNode; 83 before->prevPtr = nLNode; 84 85 if (before == l->firstPtr) 86 l->firstPtr = nLNode; 87 } 88 } 89 90 void 91 Lst_AtFront(Lst l, void *d) 92 { 93 LstNode ln; 94 95 PAlloc(ln, LstNode); 96 ln->datum = d; 97 98 ln->nextPtr = l->firstPtr; 99 ln->prevPtr = NULL; 100 if (l->firstPtr == NULL) 101 l->lastPtr = ln; 102 else 103 l->firstPtr->prevPtr = ln; 104 l->firstPtr = ln; 105 } 106