uuid_to_string.c revision 293468 
1/*-
2 * Copyright (c) 2015 M. Warner Losh
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD: head/lib/libstand/uuid_to_string.c 293468 2016-01-09 08:04:29Z ae $
27 */
28
29
30/*
31 * Note: some comments taken from lib/libc/uuid/uuid_to_string.c
32 * Copyright (c) 2002,2005 Marcel Moolenaar
33 * Copyright (c) 2002 Hiten Mahesh Pandya
34 */
35
36#include <stand.h>
37#include <uuid.h>
38
39/*
40 * Dump len characters into *buf from val as hex and update *buf
41 */
42static void
43tohex(char **buf, int len, uint32_t val)
44{
45	static const char *hexstr = "0123456789abcdef";
46	char *walker = *buf;
47	int i;
48
49	for (i = len - 1; i >= 0; i--) {
50		walker[i] = hexstr[val & 0xf];
51		val >>= 4;
52	}
53	*buf = walker + len;
54}
55
56/*
57 * uuid_to_string() - Convert a binary UUID into a string representation.
58 * See also:
59 *	http://www.opengroup.org/onlinepubs/009629399/uuid_to_string.htm
60 *
61 * NOTE: The references given above do not have a status code for when
62 *	 the string could not be allocated. The status code has been
63 *	 taken from the Hewlett-Packard implementation.
64 *
65 * NOTE: we don't support u == NULL for a nil UUID, sorry.
66 *
67 * NOTE: The sequence field is in big-endian, while the time fields are in
68 *	 native byte order.
69 *
70 *	 hhhhhhhh-hhhh-hhhh-bbbb-bbbbbbbbbbbb
71 *	 01234567-89ab-cdef-0123-456789abcdef
72 */
73void
74uuid_to_string(const uuid_t *u, char **s, uint32_t *status)
75{
76	uuid_t nil;
77	char *w;
78
79	if (status != NULL)
80		*status = uuid_s_ok;
81	if (s == NULL)	/* Regular version does this odd-ball behavior too */
82		return;
83	w = *s = malloc(37);
84	if (*s == NULL) {
85		if (status != NULL)
86			*status = uuid_s_no_memory;
87		return;
88	}
89	if (u == NULL) {
90		u = &nil;
91		uuid_create_nil(&nil, NULL);
92	}
93	/* native */
94	tohex(&w, 8, u->time_low);
95	*w++ = '-';
96	tohex(&w, 4, u->time_mid);
97	*w++ = '-';
98	tohex(&w, 4, u->time_hi_and_version);
99	*w++ = '-';
100	/* Big endian, so do a byte at a time */
101	tohex(&w, 2, u->clock_seq_hi_and_reserved);
102	tohex(&w, 2, u->clock_seq_low);
103	*w++ = '-';
104	tohex(&w, 2, u->node[0]);
105	tohex(&w, 2, u->node[1]);
106	tohex(&w, 2, u->node[2]);
107	tohex(&w, 2, u->node[3]);
108	tohex(&w, 2, u->node[4]);
109	tohex(&w, 2, u->node[5]);
110	*w++ = '\0';
111}
112