xref: /dragonfly/lib/libc/uuid/uuid_compare.c (revision b7367ef6)
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: src/lib/libc/uuid/uuid_compare.c,v 1.6 2007/04/05 02:07:33 delphij Exp $
28  * $DragonFly: src/lib/libc/uuid/uuid_compare.c,v 1.1 2007/06/16 19:57:14 dillon Exp $
29  */
30 
31 #include <string.h>
32 #include <uuid.h>
33 
34 /* A macro used to improve the readability of uuid_compare(). */
35 #define DIFF_RETURN(a, b, field)	do {			\
36 	if ((a)->field != (b)->field)				\
37 		return (((a)->field < (b)->field) ? -1 : 1);	\
38 } while (0)
39 
40 /*
41  * uuid_compare() - compare two UUIDs.
42  * See also:
43  *	http://www.opengroup.org/onlinepubs/009629399/uuid_compare.htm
44  *
45  * NOTE: Either UUID can be NULL, meaning a nil UUID. nil UUIDs are smaller
46  *	 than any non-nil UUID.
47  */
48 int32_t
49 uuid_compare(const uuid_t *a, const uuid_t *b, uint32_t *status)
50 {
51 	int	res;
52 
53 	if (status != NULL)
54 		*status = uuid_s_ok;
55 
56 	/* Deal with NULL or equal pointers. */
57 	if (a == b)
58 		return (0);
59 	if (a == NULL)
60 		return ((uuid_is_nil(b, NULL)) ? 0 : -1);
61 	if (b == NULL)
62 		return ((uuid_is_nil(a, NULL)) ? 0 : 1);
63 
64 	/* We have to compare the hard way. */
65 	DIFF_RETURN(a, b, time_low);
66 	DIFF_RETURN(a, b, time_mid);
67 	DIFF_RETURN(a, b, time_hi_and_version);
68 	DIFF_RETURN(a, b, clock_seq_hi_and_reserved);
69 	DIFF_RETURN(a, b, clock_seq_low);
70 
71 	res = memcmp(a->node, b->node, sizeof(a->node));
72 	if (res)
73 		return ((res < 0) ? -1 : 1);
74 	return (0);
75 }
76 
77 #undef DIFF_RETURN
78