1 /* 2 * Copyright (c) 1988, 1989, 1990 The Regents of the University of California. 3 * All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Adam de Boor. 7 * 8 * Redistribution and use in source and binary forms are permitted 9 * provided that the above copyright notice and this paragraph are 10 * duplicated in all such forms and that any documentation, 11 * advertising materials, and other materials related to such 12 * distribution and use acknowledge that the software was developed 13 * by the University of California, Berkeley. The name of the 14 * University may not be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 18 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 19 */ 20 21 #ifndef lint 22 static char sccsid[] = "@(#)lstIsAtEnd.c 5.2 (Berkeley) 03/11/90"; 23 #endif /* not lint */ 24 25 /*- 26 * LstIsAtEnd.c -- 27 * Tell if the current node is at the end of the list. 28 * The sequential functions access the list in a slightly different way. 29 * CurPtr points to their idea of the current node in the list and they 30 * access the list based on it. Because the list is circular, Lst_Next 31 * and Lst_Prev will go around the list forever. Lst_IsAtEnd must be 32 * used to determine when to stop. 33 */ 34 35 #include "lstInt.h" 36 37 /*- 38 *----------------------------------------------------------------------- 39 * Lst_IsAtEnd -- 40 * Return true if have reached the end of the given list. 41 * 42 * Results: 43 * TRUE if at the end of the list (this includes the list not being 44 * open or being invalid) or FALSE if not. We return TRUE if the list 45 * is invalid or unopend so as to cause the caller to exit its loop 46 * asap, the assumption being that the loop is of the form 47 * while (!Lst_IsAtEnd (l)) { 48 * ... 49 * } 50 * 51 * Side Effects: 52 * None. 53 * 54 *----------------------------------------------------------------------- 55 */ 56 Boolean 57 Lst_IsAtEnd (l) 58 Lst l; 59 { 60 register List list = (List) l; 61 62 return (!LstValid (l) || !list->isOpen || 63 (list->atEnd == Head) || (list->atEnd == Tail)); 64 } 65 66