1*bb4544dfSespie /* $OpenBSD: lstConcat.c,v 1.20 2010/07/19 19:46:44 espie Exp $ */
2789486c7Smillert /* $NetBSD: lstConcat.c,v 1.6 1996/11/06 17:59:34 christos Exp $ */
3df930be7Sderaadt
4df930be7Sderaadt /*
5789486c7Smillert * Copyright (c) 1988, 1989, 1990, 1993
6789486c7Smillert * The Regents of the University of California. All rights reserved.
7df930be7Sderaadt *
8df930be7Sderaadt * This code is derived from software contributed to Berkeley by
9df930be7Sderaadt * Adam de Boor.
10df930be7Sderaadt *
11df930be7Sderaadt * Redistribution and use in source and binary forms, with or without
12df930be7Sderaadt * modification, are permitted provided that the following conditions
13df930be7Sderaadt * are met:
14df930be7Sderaadt * 1. Redistributions of source code must retain the above copyright
15df930be7Sderaadt * notice, this list of conditions and the following disclaimer.
16df930be7Sderaadt * 2. Redistributions in binary form must reproduce the above copyright
17df930be7Sderaadt * notice, this list of conditions and the following disclaimer in the
18df930be7Sderaadt * documentation and/or other materials provided with the distribution.
19f75387cbSmillert * 3. Neither the name of the University nor the names of its contributors
20df930be7Sderaadt * may be used to endorse or promote products derived from this software
21df930be7Sderaadt * without specific prior written permission.
22df930be7Sderaadt *
23df930be7Sderaadt * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24df930be7Sderaadt * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25df930be7Sderaadt * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26df930be7Sderaadt * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27df930be7Sderaadt * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28df930be7Sderaadt * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29df930be7Sderaadt * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30df930be7Sderaadt * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31df930be7Sderaadt * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32df930be7Sderaadt * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33df930be7Sderaadt * SUCH DAMAGE.
34df930be7Sderaadt */
35df930be7Sderaadt
36df930be7Sderaadt /*-
37df930be7Sderaadt * listConcat.c --
3804ed836eSespie * Function to copy a list and append it to another.
39df930be7Sderaadt */
40df930be7Sderaadt
41df930be7Sderaadt #include "lstInt.h"
429d9c3e66Sespie #include <sys/types.h>
439d9c3e66Sespie #include <stddef.h>
44f7923656Sespie #include "memory.h"
4504ed836eSespie
46df930be7Sderaadt /*-
47df930be7Sderaadt *-----------------------------------------------------------------------
48df930be7Sderaadt * Lst_Concat --
49df930be7Sderaadt * Concatenate two lists. New elements are created to hold the data
5004ed836eSespie * elements but the elements themselves are not copied.
5104ed836eSespie * If the elements themselves should be duplicated to avoid
5204ed836eSespie * confusion with another list, the Lst_Duplicate function
5304ed836eSespie * should be called first.
54df930be7Sderaadt *
55df930be7Sderaadt * Side Effects:
56ad2b054bSespie * New elements are created and appended to the first list.
57df930be7Sderaadt *-----------------------------------------------------------------------
58df930be7Sderaadt */
596cbd4985Sespie void
Lst_Concat(Lst l1,Lst l2)60ad2b054bSespie Lst_Concat(Lst l1, Lst l2)
61df930be7Sderaadt {
6218e775c1Sespie LstNode ln; /* original LstNode */
6318e775c1Sespie LstNode nln; /* new LstNode */
6418e775c1Sespie LstNode last; /* the last element in the list. Keeps
65df930be7Sderaadt * bookkeeping until the end */
6618e775c1Sespie if (l2->firstPtr != NULL) {
67d9792fdcSespie /* The loop simply goes through the entire second list creating
68d9792fdcSespie * new LstNodes and filling in the nextPtr, and prevPtr to fit
69d9792fdcSespie * into l1 and its datum field from the datum field of the
70d9792fdcSespie * corresponding element in l2. The 'last' node follows the
71d9792fdcSespie * last of the new nodes along until the entire l2 has been
72d9792fdcSespie * appended. Only then does the bookkeeping catch up with the
73d9792fdcSespie * changes. During the first iteration of the loop, if 'last'
74d9792fdcSespie * is NULL, the first list must have been empty so the
75d9792fdcSespie * newly-created node is made the first node of the list. */
76d9792fdcSespie for (last = l1->lastPtr, ln = l2->firstPtr; ln != NULL;
7718e775c1Sespie ln = ln->nextPtr) {
7818e775c1Sespie PAlloc(nln, LstNode);
79df930be7Sderaadt nln->datum = ln->datum;
8018e775c1Sespie if (last != NULL)
81df930be7Sderaadt last->nextPtr = nln;
8218e775c1Sespie else
8318e775c1Sespie l1->firstPtr = nln;
84df930be7Sderaadt nln->prevPtr = last;
85df930be7Sderaadt last = nln;
86df930be7Sderaadt }
87df930be7Sderaadt
88d9792fdcSespie /* Finish bookkeeping. The last new element becomes the last
89d9792fdcSespie * element of l1. */
9018e775c1Sespie l1->lastPtr = last;
91324380a3Sespie last->nextPtr = NULL;
92df930be7Sderaadt }
93df930be7Sderaadt }
94df930be7Sderaadt
95