xref: /openbsd-src/usr.bin/make/lst.lib/lstConcatDestroy.c (revision 2b0358df1d88d06ef4139321dd05bd5e05d91eaf)
1 /*	$OpenPackages$ */
2 /*	$OpenBSD: lstConcatDestroy.c,v 1.10 2007/09/16 09:46:14 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. 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  * listConcat.c --
39  *	Function to concatentate two lists.
40  */
41 
42 #include    "lstInt.h"
43 #include    <stddef.h>
44 
45 /*-
46  *-----------------------------------------------------------------------
47  * Lst_ConcatDestroy --
48  *	Concatenate two lists.	The elements of the second list are
49  *	destructively added to the first list.	If the elements should
50  *	be duplicated to avoid confusion with another list, the
51  *	Lst_Duplicate function should be called first.
52  *
53  * Side Effects:
54  *	The second list is destroyed.
55  *-----------------------------------------------------------------------
56  */
57 void
58 Lst_ConcatDestroy(Lst l1, Lst l2)
59 {
60 	if (l2->firstPtr != NULL) {
61 		/*
62 		 * So long as the second list isn't empty, we just link the
63 		 * first element of the second list to the last element of the
64 		 * first list. If the first list isn't empty, we then link the
65 		 * last element of the list to the first element of the second
66 		 * list The last element of the second list, if it exists, then
67 		 * becomes the last element of the first list.
68 		 */
69 		l2->firstPtr->prevPtr = l1->lastPtr;
70 		if (l1->lastPtr != NULL)
71 			l1->lastPtr->nextPtr = l2->firstPtr;
72 		else
73 			l1->firstPtr = l2->firstPtr;
74 		l1->lastPtr = l2->lastPtr;
75 	}
76 }
77 
78