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Diffstat (limited to 'lst.lib/lstDeQueue.c')
| -rw-r--r-- | lst.lib/lstDeQueue.c | 87 |
1 files changed, 87 insertions, 0 deletions
diff --git a/lst.lib/lstDeQueue.c b/lst.lib/lstDeQueue.c new file mode 100644 index 0000000..bdb05cc --- /dev/null +++ b/lst.lib/lstDeQueue.c @@ -0,0 +1,87 @@ +/* $NetBSD: lstDeQueue.c,v 1.14 2009/01/23 21:26:30 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: lstDeQueue.c,v 1.14 2009/01/23 21:26:30 dsl Exp $"; +#else +#include <sys/cdefs.h> +#ifndef lint +#if 0 +static char sccsid[] = "@(#)lstDeQueue.c 8.1 (Berkeley) 6/6/93"; +#else +__RCSID("$NetBSD: lstDeQueue.c,v 1.14 2009/01/23 21:26:30 dsl Exp $"); +#endif +#endif /* not lint */ +#endif + +/*- + * LstDeQueue.c -- + * Remove the node and return its datum from the head of the list + */ + +#include "lstInt.h" + +/*- + *----------------------------------------------------------------------- + * Lst_DeQueue -- + * Remove and return the datum at the head of the given list. + * + * Results: + * The datum in the node at the head or NULL if the list + * is empty. + * + * Side Effects: + * The head node is removed from the list. + * + *----------------------------------------------------------------------- + */ +void * +Lst_DeQueue(Lst l) +{ + void *rd; + ListNode tln; + + tln = Lst_First(l); + if (tln == NULL) { + return NULL; + } + + rd = tln->datum; + if (Lst_Remove(l, tln) == FAILURE) { + return NULL; + } else { + return (rd); + } +} + |