diff options
Diffstat (limited to '20130123/lst.lib/lstPrev.c')
| -rw-r--r-- | 20130123/lst.lib/lstPrev.c | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/20130123/lst.lib/lstPrev.c b/20130123/lst.lib/lstPrev.c new file mode 100644 index 0000000..0ec865d --- /dev/null +++ b/20130123/lst.lib/lstPrev.c @@ -0,0 +1,79 @@ +/* $NetBSD: lstPrev.c,v 1.3 2008/12/13 15:19:29 dsl Exp $ */ + +/* + * Copyright (c) 1988, 1989, 1990, 1993 + * The Regents of the University of California. All rights reserved. + * + * This code is derived from software contributed to Berkeley by + * Adam de Boor. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#ifndef MAKE_NATIVE +static char rcsid[] = "$NetBSD: lstPrev.c,v 1.3 2008/12/13 15:19:29 dsl Exp $"; +#else +#include <sys/cdefs.h> +#ifndef lint +#if 0 +static char sccsid[] = "@(#)lstSucc.c 8.1 (Berkeley) 6/6/93"; +#else +__RCSID("$NetBSD: lstPrev.c,v 1.3 2008/12/13 15:19:29 dsl Exp $"); +#endif +#endif /* not lint */ +#endif + +/*- + * LstPrev.c -- + * return the predecessor to a given node + */ + +#include "lstInt.h" + +/*- + *----------------------------------------------------------------------- + * Lst_Prev -- + * Return the predecessor to the given node on its list. + * + * Results: + * The predecessor of the node, if it exists (note that on a circular + * list, if the node is the only one in the list, it is its own + * predecessor). + * + * Side Effects: + * None. + * + *----------------------------------------------------------------------- + */ +LstNode +Lst_Prev(LstNode ln) +{ + if (ln == NULL) { + return NULL; + } else { + return (ln->prevPtr); + } +} + |
