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
Lst_Insert(Lst l,LstNode before,void * d)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
Lst_AtFront(Lst l,void * d)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