uuid_compare.c revision 330897 
1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2002,2005 Marcel Moolenaar
5 * Copyright (c) 2002 Hiten Mahesh Pandya
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * $FreeBSD: stable/11/lib/libc/uuid/uuid_compare.c 330897 2018-03-14 03:19:51Z eadler $
30 */
31
32#include <string.h>
33#include <uuid.h>
34
35/* A macro used to improve the readability of uuid_compare(). */
36#define DIFF_RETURN(a, b, field)	do {			\
37	if ((a)->field != (b)->field)				\
38		return (((a)->field < (b)->field) ? -1 : 1);	\
39} while (0)
40
41/*
42 * uuid_compare() - compare two UUIDs.
43 * See also:
44 *	http://www.opengroup.org/onlinepubs/009629399/uuid_compare.htm
45 *
46 * NOTE: Either UUID can be NULL, meaning a nil UUID. nil UUIDs are smaller
47 *	 than any non-nil UUID.
48 */
49int32_t
50uuid_compare(const uuid_t *a, const uuid_t *b, uint32_t *status)
51{
52	int	res;
53
54	if (status != NULL)
55		*status = uuid_s_ok;
56
57	/* Deal with NULL or equal pointers. */
58	if (a == b)
59		return (0);
60	if (a == NULL)
61		return ((uuid_is_nil(b, NULL)) ? 0 : -1);
62	if (b == NULL)
63		return ((uuid_is_nil(a, NULL)) ? 0 : 1);
64
65	/* We have to compare the hard way. */
66	DIFF_RETURN(a, b, time_low);
67	DIFF_RETURN(a, b, time_mid);
68	DIFF_RETURN(a, b, time_hi_and_version);
69	DIFF_RETURN(a, b, clock_seq_hi_and_reserved);
70	DIFF_RETURN(a, b, clock_seq_low);
71
72	res = memcmp(a->node, b->node, sizeof(a->node));
73	if (res)
74		return ((res < 0) ? -1 : 1);
75	return (0);
76}
77
78#undef DIFF_RETURN
79