1 /* $OpenPackages$ */ 2 /* $OpenBSD: lstInsert.c,v 1.15 2003/06/03 02:56:12 millert 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(l, ln, d) 61 Lst l; /* list to manipulate */ 62 LstNode ln; /* node before which to insert d */ 63 void *d; /* datum to be inserted */ 64 { 65 LstNode nLNode; /* new lnode for d */ 66 67 68 if (ln == NULL && !Lst_IsEmpty(l)) 69 return; 70 71 if (ln != NULL && Lst_IsEmpty(l)) 72 return; 73 74 PAlloc(nLNode, LstNode); 75 76 nLNode->datum = d; 77 78 if (ln == NULL) { 79 nLNode->prevPtr = nLNode->nextPtr = NULL; 80 l->firstPtr = l->lastPtr = nLNode; 81 } else { 82 nLNode->prevPtr = ln->prevPtr; 83 nLNode->nextPtr = ln; 84 85 if (nLNode->prevPtr != NULL) 86 nLNode->prevPtr->nextPtr = nLNode; 87 ln->prevPtr = nLNode; 88 89 if (ln == l->firstPtr) 90 l->firstPtr = nLNode; 91 } 92 } 93 94 void 95 Lst_AtFront(l, d) 96 Lst l; 97 void *d; 98 { 99 LstNode ln; 100 101 PAlloc(ln, LstNode); 102 ln->datum = d; 103 104 ln->nextPtr = l->firstPtr; 105 ln->prevPtr = NULL; 106 if (l->firstPtr == NULL) 107 l->lastPtr = ln; 108 else 109 l->firstPtr->prevPtr = ln; 110 l->firstPtr = ln; 111 } 112