1 /* $OpenPackages$ */
2 /* $OpenBSD: lstConcat.c,v 1.16 2004/04/07 13:11:36 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 copy a list and append it to another.
40 */
41
42 #include "lstInt.h"
43 #include <sys/types.h>
44 #include <stddef.h>
45 #include "memory.h"
46
47 /*-
48 *-----------------------------------------------------------------------
49 * Lst_Concat --
50 * Concatenate two lists. New elements are created to hold the data
51 * elements but the elements themselves are not copied.
52 * If the elements themselves should be duplicated to avoid
53 * confusion with another list, the Lst_Duplicate function
54 * should be called first.
55 *
56 * Side Effects:
57 * New elements are created and appended to the first list.
58 *-----------------------------------------------------------------------
59 */
60 void
Lst_Concat(Lst l1,Lst l2)61 Lst_Concat(Lst l1, Lst l2)
62 {
63 LstNode ln; /* original LstNode */
64 LstNode nln; /* new LstNode */
65 LstNode last; /* the last element in the list. Keeps
66 * bookkeeping until the end */
67 if (l2->firstPtr != NULL) {
68 /* The loop simply goes through the entire second list creating new
69 * LstNodes and filling in the nextPtr, and prevPtr to fit into l1
70 * and its datum field from the datum field of the corresponding
71 * element in l2. The 'last' node follows the last of the new nodes
72 * along until the entire l2 has been appended. Only then does the
73 * bookkeeping catch up with the changes. During the first iteration
74 * of the loop, if 'last' is NULL, the first list must have been empty
75 * so the newly-created node is made the first node of the list. */
76 for (last = l1->lastPtr, ln = l2->firstPtr;
77 ln != NULL;
78 ln = ln->nextPtr) {
79 PAlloc(nln, LstNode);
80 nln->datum = ln->datum;
81 if (last != NULL)
82 last->nextPtr = nln;
83 else
84 l1->firstPtr = nln;
85 nln->prevPtr = last;
86 last = nln;
87 }
88
89 /* Finish bookkeeping. The last new element becomes the last element
90 * of l1. */
91 l1->lastPtr = last;
92 last->nextPtr = NULL;
93 }
94 }
95
96