uuid_misc.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2000,2002 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/*
* The copyright in this file is taken from the original Leach
* & Salz UUID specification, from which this implementation
* is derived.
*/
/*
* Copyright (c) 1990- 1993, 1996 Open Software Foundation, Inc.
* Copyright (c) 1989 by Hewlett-Packard Company, Palo Alto, Ca. &
* Digital Equipment Corporation, Maynard, Mass. Copyright (c) 1998
* Microsoft. To anyone who acknowledges that this file is provided
* "AS IS" without any express or implied warranty: permission to use,
* copy, modify, and distribute this file for any purpose is hereby
* granted without fee, provided that the above copyright notices and
* this notice appears in all source code copies, and that none of the
* names of Open Software Foundation, Inc., Hewlett-Packard Company,
* or Digital Equipment Corporation be used in advertising or
* publicity pertaining to distribution of the software without
* specific, written prior permission. Neither Open Software
* Foundation, Inc., Hewlett-Packard Company, Microsoft, nor Digital
* Equipment Corporation makes any representations about the
* suitability of this software for any purpose.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
#include <uuid/uuid.h>
#include <stdlib.h>
#include <strings.h>
#include "uuid_misc.h"
#define UUCMP(u1, u2) if (u1 != u2) return ((u1 < u2) ? -1 : 1)
#define UUIDS_PER_TOD_CALL 10 /* tv_usec is multiplied by 10 */
void struct_to_string(uuid_t, struct uuid *);
void string_to_struct(struct uuid *, uuid_t);
void get_system_time(uuid_time_t *);
/*
* Name: _get_current_time
*
* Description: get-current_time -- get time as 60 bit 100ns ticks
* since the beginning of unix time.
* Compensate for the fact that real clock resolution is
* less than 100ns.
*
* Returns: None.
*
*/
void
_get_current_time(uuid_time_t *timestamp)
{
uuid_time_t time_now;
static uuid_time_t time_last = 0;
static uint16_t uuids_this_tick = 0;
int done;
done = 0;
while (!done) {
get_system_time(&time_now);
/*
* if clock reading changed since last UUID generated...
*/
if (time_last != time_now) {
/*
* reset count of uuids generated with
* this clock reading
*/
uuids_this_tick = 0;
done = 1;
} else {
uuids_this_tick++;
if (uuids_this_tick < UUIDS_PER_TOD_CALL)
done = 1;
}
/*
* too many UUIDs for this gettimeofday call; spin
*/
}
time_last = time_now;
/*
* add the count of uuids to low order bits of the clock reading
*/
*timestamp = time_now + uuids_this_tick;
}
/*
* Name: _get_random
*
* Description: Gets a random number.
*
* Returns: nbytes of random information.
*
*/
uint16_t
_get_random(void)
{
static int initted = 0;
uuid_time_t time_now;
long seed;
if (!initted) {
get_system_time(&time_now);
time_now = time_now/UUIDS_PER_TOD_CALL;
seed = (unsigned)(((time_now >> 32) ^ time_now)&0xffffffff);
srand48(seed);
initted = 1;
}
return (mrand48());
}
/*
* Name: uuid_compare
*
* Description: Compares 2 uuid strings
*
* Returns: -1 if u1 < u2, 1 if u1 > u2 and 0 if both are equal
*/
int
uuid_compare(uuid_t uu1, uuid_t uu2)
{
struct uuid uuid1, uuid2;
string_to_struct(&uuid1, uu1);
string_to_struct(&uuid2, uu2);
UUCMP(uuid1.time_low, uuid2.time_low);
UUCMP(uuid1.time_mid, uuid2.time_mid);
UUCMP(uuid1.time_hi_and_version, uuid2.time_hi_and_version);
UUCMP(uuid1.clock_seq_hi_and_reserved, uuid2.clock_seq_hi_and_reserved);
UUCMP(uuid1.clock_seq_low, uuid2.clock_seq_low);
return (memcmp(uuid1.node_addr, uuid2.node_addr, 6));
}
/*
* Name: get_system_time
*
* Description: system dependent call to get the current system time.
* Returned as 100ns ticks since Oct 15, 1582, but
* resolution may be less than 100ns.
*
* Returns: None
*/
void
get_system_time(uuid_time_t *uuid_time)
{
struct timeval tp;
(void) gettimeofday(&tp, (struct timezone *)0);
/*
* Offset between UUID formatted times and Unix formatted times.
* UUID UTC base time is October 15, 1582.
* Unix base time is January 1, 1970.
*/
*uuid_time = (uint64_t)tp.tv_sec * 10000000;
*uuid_time += tp.tv_usec * 10;
*uuid_time += 0x01B21DD213814000;
}