1/*	$OpenBSD: uuid_compare.c,v 1.3 2015/09/10 18:13:46 guenther Exp $	*/
2/*	$NetBSD: uuid_compare.c,v 1.2 2008/04/23 07:52:32 plunky Exp $	*/
3
4/*-
5 * Copyright (c) 2002,2005 Marcel Moolenaar
6 * Copyright (c) 2002 Hiten Mahesh Pandya
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 *
30 * $FreeBSD: src/lib/libc/uuid/uuid_compare.c,v 1.6 2007/04/05 02:07:33 delphij Exp $
31 */
32
33#include <string.h>
34#include <uuid.h>
35
36/* A macro used to improve the readability of uuid_compare(). */
37#define DIFF_RETURN(a, b, field)	do {			\
38	if ((a)->field != (b)->field)				\
39		return (((a)->field < (b)->field) ? -1 : 1);	\
40} while (0)
41
42/*
43 * uuid_compare() - compare two UUIDs.
44 * See also:
45 *	http://www.opengroup.org/onlinepubs/009629399/uuid_compare.htm
46 *
47 * NOTE: Either UUID can be NULL, meaning a nil UUID. nil UUIDs are smaller
48 *	 than any non-nil UUID.
49 */
50int32_t
51uuid_compare(const uuid_t *a, const uuid_t *b, uint32_t *status)
52{
53	int res;
54
55	if (status != NULL)
56		*status = uuid_s_ok;
57
58	/* Deal with NULL or equal pointers. */
59	if (a == b)
60		return (0);
61	if (a == NULL)
62		return ((uuid_is_nil(b, NULL)) ? 0 : -1);
63	if (b == NULL)
64		return ((uuid_is_nil(a, NULL)) ? 0 : 1);
65
66	/* We have to compare the hard way. */
67	DIFF_RETURN(a, b, time_low);
68	DIFF_RETURN(a, b, time_mid);
69	DIFF_RETURN(a, b, time_hi_and_version);
70	DIFF_RETURN(a, b, clock_seq_hi_and_reserved);
71	DIFF_RETURN(a, b, clock_seq_low);
72
73	res = memcmp(a->node, b->node, sizeof(a->node));
74	if (res)
75		return ((res < 0) ? -1 : 1);
76	return (0);
77}
78
79#undef DIFF_RETURN
80