1 /* $OpenPackages$ */ 2 /* $OpenBSD: lstConcat.c,v 1.19 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 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 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 69 * new LstNodes and filling in the nextPtr, and prevPtr to fit 70 * into l1 and its datum field from the datum field of the 71 * corresponding element in l2. The 'last' node follows the 72 * last of the new nodes along until the entire l2 has been 73 * appended. Only then does the bookkeeping catch up with the 74 * changes. During the first iteration of the loop, if 'last' 75 * is NULL, the first list must have been empty so the 76 * newly-created node is made the first node of the list. */ 77 for (last = l1->lastPtr, ln = l2->firstPtr; 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 90 * element of l1. */ 91 l1->lastPtr = last; 92 last->nextPtr = NULL; 93 } 94 } 95 96