/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (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 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 * Copyright (c) 2015, Joyent, Inc.
 */

/*
 * 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.
 */

#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)
{
        return (arc4random_uniform(UINT16_MAX));
}

/*
 * 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 += 0x01B21DD213814000ULL;
}