1 /* $OpenPackages$ */ 2 /* $OpenBSD: lstInsert.c,v 1.14 2001/05/29 12:53:46 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. All advertising materials mentioning features or use of this software 21 * must display the following acknowledgement: 22 * This product includes software developed by the University of 23 * California, Berkeley and its contributors. 24 * 4. Neither the name of the University nor the names of its contributors 25 * may be used to endorse or promote products derived from this software 26 * without specific prior written permission. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 31 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 38 * SUCH DAMAGE. 39 */ 40 41 /*- 42 * LstInsert.c -- 43 * Insert a new datum before an old one 44 */ 45 46 #include "lstInt.h" 47 #include <sys/types.h> 48 #include <stdlib.h> 49 #include "memory.h" 50 51 /*- 52 *----------------------------------------------------------------------- 53 * Lst_Insert -- 54 * Insert a new node with the given piece of data before the given 55 * node in the given list. 56 * 57 * Side Effects: 58 * the firstPtr field will be changed if ln is the first node in the 59 * list. 60 * 61 *----------------------------------------------------------------------- 62 */ 63 void 64 Lst_Insert(l, ln, d) 65 Lst l; /* list to manipulate */ 66 LstNode ln; /* node before which to insert d */ 67 void *d; /* datum to be inserted */ 68 { 69 LstNode nLNode; /* new lnode for d */ 70 71 72 if (ln == NULL && !Lst_IsEmpty(l)) 73 return; 74 75 if (ln != NULL && Lst_IsEmpty(l)) 76 return; 77 78 PAlloc(nLNode, LstNode); 79 80 nLNode->datum = d; 81 82 if (ln == NULL) { 83 nLNode->prevPtr = nLNode->nextPtr = NULL; 84 l->firstPtr = l->lastPtr = nLNode; 85 } else { 86 nLNode->prevPtr = ln->prevPtr; 87 nLNode->nextPtr = ln; 88 89 if (nLNode->prevPtr != NULL) 90 nLNode->prevPtr->nextPtr = nLNode; 91 ln->prevPtr = nLNode; 92 93 if (ln == l->firstPtr) 94 l->firstPtr = nLNode; 95 } 96 } 97 98 void 99 Lst_AtFront(l, d) 100 Lst l; 101 void *d; 102 { 103 LstNode ln; 104 105 PAlloc(ln, LstNode); 106 ln->datum = d; 107 108 ln->nextPtr = l->firstPtr; 109 ln->prevPtr = NULL; 110 if (l->firstPtr == NULL) 111 l->lastPtr = ln; 112 else 113 l->firstPtr->prevPtr = ln; 114 l->firstPtr = ln; 115 } 116