xref: /openbsd-src/usr.bin/make/lst.lib/lstConcatDestroy.c (revision b2ea75c1b17e1a9a339660e7ed45cd24946b230e)
1 /*	$OpenPackages$ */
2 /*	$OpenBSD: lstConcatDestroy.c,v 1.5 2001/05/29 12:53:45 espie Exp $	*/
3 /*	$NetBSD: lstConcat.c,v 1.6 1996/11/06 17:59:34 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  * listConcat.c --
43  *	Function to concatentate two lists.
44  */
45 
46 #include    "lstInt.h"
47 #include    <stddef.h>
48 
49 /*-
50  *-----------------------------------------------------------------------
51  * Lst_ConcatDestroy --
52  *	Concatenate two lists.	The elements of the second list are
53  *	destructively added to the first list.	If the elements should
54  *	be duplicated to avoid confusion with another list, the
55  *	Lst_Duplicate function should be called first.
56  *
57  * Side Effects:
58  *	The second list is destroyed.
59  *-----------------------------------------------------------------------
60  */
61 void
62 Lst_ConcatDestroy(l1, l2)
63     Lst 		l1;	/* The list to which l2 is to be appended */
64     Lst 		l2;	/* The list to append to l1 */
65 {
66     if (l2->firstPtr != NULL) {
67 	/*
68 	 * So long as the second list isn't empty, we just link the
69 	 * first element of the second list to the last element of the
70 	 * first list. If the first list isn't empty, we then link the
71 	 * last element of the list to the first element of the second list
72 	 * The last element of the second list, if it exists, then becomes
73 	 * the last element of the first list.
74 	 */
75 	l2->firstPtr->prevPtr = l1->lastPtr;
76 	if (l1->lastPtr != NULL)
77 	    l1->lastPtr->nextPtr = l2->firstPtr;
78 	else
79 	    l1->firstPtr = l2->firstPtr;
80 	l1->lastPtr = l2->lastPtr;
81     }
82 }
83 
84