uuid_is_nil.c revision 331722 
1/*-
2 * Copyright (c) 2002,2005 Marcel Moolenaar
3 * Copyright (c) 2002 Hiten Mahesh Pandya
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 *
27 * $FreeBSD: stable/11/lib/libc/uuid/uuid_is_nil.c 331722 2018-03-29 02:50:57Z eadler $
28 */
29
30#include <uuid.h>
31
32/*
33 * uuid_is_nil() - return whether the UUID is a nil UUID.
34 * See also:
35 *	http://www.opengroup.org/onlinepubs/009629399/uuid_is_nil.htm
36 */
37int32_t
38uuid_is_nil(const uuid_t *u, uint32_t *status)
39{
40	const uint32_t *p;
41
42	if (status)
43		*status = uuid_s_ok;
44
45	if (!u)
46		return (1);
47
48	/*
49	 * Pick the largest type that has equivalent alignment constraints
50	 * as an UUID and use it to test if the UUID consists of all zeroes.
51	 */
52	p = (const uint32_t*)u;
53	return ((p[0] == 0 && p[1] == 0 && p[2] == 0 && p[3] == 0) ? 1 : 0);
54}
55