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 * $FreeBSD$
28 */
29
30#include <string.h>
31#include <uuid.h>
32
33/* A macro used to improve the readability of uuid_compare(). */
34#define DIFF_RETURN(a, b, field)	do {			\
35	if ((a)->field != (b)->field)				\
36		return (((a)->field < (b)->field) ? -1 : 1);	\
37} while (0)
38
39/*
40 * uuid_compare() - compare two UUIDs.
41 * See also:
42 *	http://www.opengroup.org/onlinepubs/009629399/uuid_compare.htm
43 *
44 * NOTE: Either UUID can be NULL, meaning a nil UUID. nil UUIDs are smaller
45 *	 than any non-nil UUID.
46 */
47int32_t
48uuid_compare(const uuid_t *a, const uuid_t *b, uint32_t *status)
49{
50	int	res;
51
52	if (status != NULL)
53		*status = uuid_s_ok;
54
55	/* Deal with NULL or equal pointers. */
56	if (a == b)
57		return (0);
58	if (a == NULL)
59		return ((uuid_is_nil(b, NULL)) ? 0 : -1);
60	if (b == NULL)
61		return ((uuid_is_nil(a, NULL)) ? 0 : 1);
62
63	/* We have to compare the hard way. */
64	DIFF_RETURN(a, b, time_low);
65	DIFF_RETURN(a, b, time_mid);
66	DIFF_RETURN(a, b, time_hi_and_version);
67	DIFF_RETURN(a, b, clock_seq_hi_and_reserved);
68	DIFF_RETURN(a, b, clock_seq_low);
69
70	res = memcmp(a->node, b->node, sizeof(a->node));
71	if (res)
72		return ((res < 0) ? -1 : 1);
73	return (0);
74}
75
76#undef DIFF_RETURN
77