1 /* $OpenBSD: lstConcat.c,v 1.20 2010/07/19 19:46:44 espie Exp $ */
2 /* $NetBSD: lstConcat.c,v 1.6 1996/11/06 17:59:34 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 * listConcat.c --
38 * Function to copy a list and append it to another.
39 */
40
41 #include "lstInt.h"
42 #include <sys/types.h>
43 #include <stddef.h>
44 #include "memory.h"
45
46 /*-
47 *-----------------------------------------------------------------------
48 * Lst_Concat --
49 * Concatenate two lists. New elements are created to hold the data
50 * elements but the elements themselves are not copied.
51 * If the elements themselves should be duplicated to avoid
52 * confusion with another list, the Lst_Duplicate function
53 * should be called first.
54 *
55 * Side Effects:
56 * New elements are created and appended to the first list.
57 *-----------------------------------------------------------------------
58 */
59 void
Lst_Concat(Lst l1,Lst l2)60 Lst_Concat(Lst l1, Lst l2)
61 {
62 LstNode ln; /* original LstNode */
63 LstNode nln; /* new LstNode */
64 LstNode last; /* the last element in the list. Keeps
65 * bookkeeping until the end */
66 if (l2->firstPtr != NULL) {
67 /* The loop simply goes through the entire second list creating
68 * new LstNodes and filling in the nextPtr, and prevPtr to fit
69 * into l1 and its datum field from the datum field of the
70 * corresponding element in l2. The 'last' node follows the
71 * last of the new nodes along until the entire l2 has been
72 * appended. Only then does the bookkeeping catch up with the
73 * changes. During the first iteration of the loop, if 'last'
74 * is NULL, the first list must have been empty so the
75 * newly-created node is made the first node of the list. */
76 for (last = l1->lastPtr, ln = l2->firstPtr; ln != NULL;
77 ln = ln->nextPtr) {
78 PAlloc(nln, LstNode);
79 nln->datum = ln->datum;
80 if (last != NULL)
81 last->nextPtr = nln;
82 else
83 l1->firstPtr = nln;
84 nln->prevPtr = last;
85 last = nln;
86 }
87
88 /* Finish bookkeeping. The last new element becomes the last
89 * element of l1. */
90 l1->lastPtr = last;
91 last->nextPtr = NULL;
92 }
93 }
94
95