1 /* $NetBSD: lstPrev.c,v 1.3 2008/12/13 15:19:29 dsl Exp $ */ 2 3 /* 4 * Copyright (c) 1988, 1989, 1990, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Adam de Boor. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #ifndef MAKE_NATIVE 36 static char rcsid[] = "$NetBSD: lstPrev.c,v 1.3 2008/12/13 15:19:29 dsl Exp $"; 37 #else 38 #include <sys/cdefs.h> 39 #ifndef lint 40 #if 0 41 static char sccsid[] = "@(#)lstSucc.c 8.1 (Berkeley) 6/6/93"; 42 #else 43 __RCSID("$NetBSD: lstPrev.c,v 1.3 2008/12/13 15:19:29 dsl Exp $"); 44 #endif 45 #endif /* not lint */ 46 #endif 47 48 /*- 49 * LstPrev.c -- 50 * return the predecessor to a given node 51 */ 52 53 #include "lstInt.h" 54 55 /*- 56 *----------------------------------------------------------------------- 57 * Lst_Prev -- 58 * Return the predecessor to the given node on its list. 59 * 60 * Results: 61 * The predecessor of the node, if it exists (note that on a circular 62 * list, if the node is the only one in the list, it is its own 63 * predecessor). 64 * 65 * Side Effects: 66 * None. 67 * 68 *----------------------------------------------------------------------- 69 */ 70 LstNode 71 Lst_Prev(LstNode ln) 72 { 73 if (ln == NULL) { 74 return NULL; 75 } else { 76 return (ln->prevPtr); 77 } 78 } 79 80