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 */
58void
59Lst_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
90void
91Lst_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