freebsd-dev/lib/libstand/uuid_to_string.c

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/*-
* Copyright (c) 2015 M. Warner Losh
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
/*
* Note: some comments taken from lib/libc/uuid/uuid_to_string.c
* Copyright (c) 2002,2005 Marcel Moolenaar
* Copyright (c) 2002 Hiten Mahesh Pandya
*/
#include <stand.h>
#include <uuid.h>
/*
* Dump len characters into *buf from val as hex and update *buf
*/
static void
tohex(char **buf, int len, uint32_t val)
{
static const char *hexstr = "0123456789abcdef";
char *walker = *buf;
int i;
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for (i = len - 1; i >= 0; i--) {
walker[i] = hexstr[val & 0xf];
val >>= 4;
}
*buf = walker + len;
}
/*
* uuid_to_string() - Convert a binary UUID into a string representation.
* See also:
* http://www.opengroup.org/onlinepubs/009629399/uuid_to_string.htm
*
* NOTE: The references given above do not have a status code for when
* the string could not be allocated. The status code has been
* taken from the Hewlett-Packard implementation.
*
* NOTE: we don't support u == NULL for a nil UUID, sorry.
*
* NOTE: The sequence field is in big-endian, while the time fields are in
* native byte order.
*
* hhhhhhhh-hhhh-hhhh-bbbb-bbbbbbbbbbbb
* 01234567-89ab-cdef-0123-456789abcdef
*/
void
uuid_to_string(const uuid_t *u, char **s, uint32_t *status)
{
uuid_t nil;
char *w;
if (status != NULL)
*status = uuid_s_ok;
if (s == NULL) /* Regular version does this odd-ball behavior too */
return;
w = *s = malloc(37);
if (*s == NULL) {
if (status != NULL)
*status = uuid_s_no_memory;
return;
}
if (u == NULL) {
u = &nil;
uuid_create_nil(&nil, NULL);
}
/* native */
tohex(&w, 8, u->time_low);
*w++ = '-';
tohex(&w, 4, u->time_mid);
*w++ = '-';
tohex(&w, 4, u->time_hi_and_version);
*w++ = '-';
/* Big endian, so do a byte at a time */
tohex(&w, 2, u->clock_seq_hi_and_reserved);
tohex(&w, 2, u->clock_seq_low);
*w++ = '-';
tohex(&w, 2, u->node[0]);
tohex(&w, 2, u->node[1]);
tohex(&w, 2, u->node[2]);
tohex(&w, 2, u->node[3]);
tohex(&w, 2, u->node[4]);
tohex(&w, 2, u->node[5]);
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*w++ = '\0';
}