uuid_compare.c revision 160938 
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: head/lib/libc/uuid/uuid_compare.c 160938 2006-08-03 03:34:36Z delphij $
28 */
29
30#include <string.h>
31#include <uuid.h>
32
33/*
34 * uuid_compare() - compare two UUIDs.
35 * See also:
36 *	http://www.opengroup.org/onlinepubs/009629399/uuid_compare.htm
37 *
38 * NOTE: Either UUID can be NULL, meaning a nil UUID. nil UUIDs are smaller
39 *	 than any non-nil UUID.
40 */
41int32_t
42uuid_compare(const uuid_t *a, const uuid_t *b, uint32_t *status)
43{
44	int	res;
45	int64_t res64;
46
47	if (status != NULL)
48		*status = uuid_s_ok;
49
50	/* Deal with NULL or equal pointers. */
51	if (a == b)
52		return (0);
53	if (a == NULL)
54		return ((uuid_is_nil(b, NULL)) ? 0 : -1);
55	if (b == NULL)
56		return ((uuid_is_nil(a, NULL)) ? 0 : 1);
57
58	/*
59	 * We have to compare the hard way.
60	 *
61	 * Note that time_low is defined as unsigned 32-bit
62	 * integer, therefore, with a significantly large
63	 * a->time_low and a small b->time_low, we will end
64	 * up with a value which is larger than 0x7fffffff
65	 * which is negative if casted to signed 32-bit
66	 * integer.
67	 */
68	res64 = (int64_t)a->time_low - (int64_t)b->time_low;
69	if (res64)
70		return ((res64 < 0) ? -1 : 1);
71	res = (int)a->time_mid - (int)b->time_mid;
72	if (res)
73		return ((res < 0) ? -1 : 1);
74	res = (int)a->time_hi_and_version - (int)b->time_hi_and_version;
75	if (res)
76		return ((res < 0) ? -1 : 1);
77	res = (int)a->clock_seq_hi_and_reserved -
78	    (int)b->clock_seq_hi_and_reserved;
79	if (res)
80		return ((res < 0) ? -1 : 1);
81	res = (int)a->clock_seq_low - (int)b->clock_seq_low;
82	if (res)
83		return ((res < 0) ? -1 : 1);
84	res = memcmp(a->node, b->node, sizeof(a->node));
85	if (res)
86		return ((res < 0) ? -1 : 1);
87	return (0);
88}
89