318 lines
9.9 KiB
C++
318 lines
9.9 KiB
C++
/*------------------------------------------------------------------------------
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Copyright (c) 2004 Media Development Loan Fund
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This file is part of the LiveSupport project.
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http://livesupport.campware.org/
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To report bugs, send an e-mail to bugs@campware.org
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LiveSupport is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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LiveSupport is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with LiveSupport; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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Author : $Author: maroy $
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Version : $Revision: 1.1 $
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Location : $Source: /home/paul/cvs2svn-livesupport/newcvsrepo/livesupport/modules/core/src/Uuid.cxx,v $
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------------------------------------------------------------------------------*/
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/* ============================================================ include files */
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#ifdef HAVE_CONFIG_H
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#include "configure.h"
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#endif
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#ifdef HAVE_SYS_TIME_H
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#include <sys/time.h>
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#else
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#error need sys/time.h
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#endif
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#ifdef HAVE_UNISTD_H
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#include <unistd.h>
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#else
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#error need unistd.h
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#endif
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#include <cstdlib>
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#include <iomanip>
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#include <sstream>
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#include "LiveSupport/Core/Uuid.h"
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using namespace LiveSupport::Core;
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/* =================================================== local data structures */
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/* ================================================ local constants & macros */
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/*------------------------------------------------------------------------------
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* Set the following to the number of 100ns ticks of the actual
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* resolution of your system's clock
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*----------------------------------------------------------------------------*/
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#define UUIDS_PER_TICK 1024
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/* =============================================== local function prototypes */
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/* ============================================================= module code */
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/*------------------------------------------------------------------------------
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* Generate a globally unique id.
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*----------------------------------------------------------------------------*/
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Ptr<Uuid>::Ref
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Uuid :: generateId(void) throw ()
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{
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Ptr<Uuid>::Ref id(new Uuid());
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UuidTime timestamp;
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UuidTime lastTime;
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uint16_t clockseq;
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UuidNode node;
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UuidNode lastNode;
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int f;
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/* acquire system wide lock so we're alone */
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//LOCK;
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/* get current time */
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getCurrentTime(×tamp);
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/* get node ID */
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getIeeeNodeIdentifier(&node);
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/* get saved state from NV storage */
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f = id->readState(&clockseq, &lastTime, &lastNode);
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/* if no NV state, or if clock went backwards, or node ID changed
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(e.g., net card swap) change clockseq */
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if (!f || memcmp(&node, &lastNode, sizeof(UuidNode))) {
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clockseq = trueRandom();
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} else if (timestamp < lastTime) {
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clockseq++;
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}
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/* stuff fields into the UUID */
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id->format(clockseq, timestamp, node);
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id->representAsString();
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/* save the state for next time */
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id->writeState(clockseq, timestamp, node);
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//UNLOCK;
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return id;
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}
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/*------------------------------------------------------------------------------
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* Format the UUID
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*----------------------------------------------------------------------------*/
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void
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Uuid :: format(uint16_t clockSeq,
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UuidTime timestamp,
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UuidNode node) throw ()
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{
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/* Construct a version 1 uuid with the information we've gathered
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* plus a few constants. */
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timeLow = (unsigned long)(timestamp & 0xFFFFFFFF);
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timeMid = (unsigned short)((timestamp >> 32) & 0xFFFF);
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timeHiAndVersion = (unsigned short)((timestamp >> 48) & 0x0FFF);
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timeHiAndVersion |= (1 << 12);
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clockSeqLow = clockSeq & 0xFF;
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clockSeqHiAndReserved = (clockSeq & 0x3F00) >> 8;
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clockSeqHiAndReserved |= 0x80;
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for (int i = 0; i < 6; ++i) {
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this->node[i] = node.nodeId[i];
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}
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}
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/*------------------------------------------------------------------------------
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* Create a string representation of the UUID
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*----------------------------------------------------------------------------*/
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void
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Uuid :: representAsString(void) throw ()
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{
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std::stringstream sstr;
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sstr << std::hex << std::setw(8) << std::setfill('0') << timeLow << '-'
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<< std::hex << std::setw(4) << std::setfill('0') << timeMid << '-'
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<< std::hex << std::setw(4) << std::setfill('0')
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<< timeHiAndVersion << '-'
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<< std::hex << std::setw(2) << std::setfill('0')
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<< (unsigned short) clockSeqHiAndReserved << '-'
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<< std::hex << std::setw(2) << std::setfill('0')
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<< (unsigned short) clockSeqLow << '-';
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for (int i = 0; i < 6; ++i) {
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sstr << std::hex << std::setw(2) << std::setfill('0')
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<< (unsigned short) this->node[i];
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}
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idAsString = sstr.str();
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}
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/*------------------------------------------------------------------------------
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* Read the current state from non-volatile storage
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*----------------------------------------------------------------------------*/
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int
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Uuid :: readState(uint16_t * clockSeq,
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UuidTime * timestamp,
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UuidNode * node) throw ()
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{
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// TODO: read the state from non-volatile storage
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return 0;
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}
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/*------------------------------------------------------------------------------
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* Write the current state to non-volatile storage
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*----------------------------------------------------------------------------*/
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void
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Uuid :: writeState(uint16_t clockSeq,
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UuidTime timestamp,
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UuidNode node) throw ()
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{
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// TODO: write the current state to non-volatile storage
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}
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/*------------------------------------------------------------------------------
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* Get the current time into a timestamp
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*----------------------------------------------------------------------------*/
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void
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Uuid :: getCurrentTime(UuidTime *timestamp) throw ()
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{
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UuidTime timeNow;
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static UuidTime timeLast;
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static uint16_t uuidsThisTick;
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static bool inited = false;
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if (!inited) {
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getSystemTime(&timeNow);
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uuidsThisTick = UUIDS_PER_TICK;
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inited = true;
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};
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while (true) {
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getSystemTime(&timeNow);
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/* if clock reading changed since last UUID generated... */
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if (timeLast != timeNow) {
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/* reset count of uuids gen'd with this clock reading */
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uuidsThisTick = 0;
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break;
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};
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if (uuidsThisTick < UUIDS_PER_TICK) {
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uuidsThisTick++;
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break;
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};
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/* going too fast for our clock; spin */
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};
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/* add the count of uuids to low order bits of the clock reading */
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*timestamp = timeNow + uuidsThisTick;
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}
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/*------------------------------------------------------------------------------
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* Get the system time in the UUID UTC base time, which is October 15, 1582
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*----------------------------------------------------------------------------*/
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void
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Uuid :: getSystemTime(UuidTime * uuidTime) throw ()
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{
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struct timeval tp;
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gettimeofday(&tp, (struct timezone *)0);
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/* Offset between UUID formatted times and Unix formatted times.
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UUID UTC base time is October 15, 1582.
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Unix base time is January 1, 1970.
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*/
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*uuidTime = (tp.tv_sec * 10000000)
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+ (tp.tv_usec * 10)
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+ 0x01B21DD213814000LL;
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}
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/*------------------------------------------------------------------------------
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* Get the IEEE node identifier
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*----------------------------------------------------------------------------*/
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void
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Uuid :: getIeeeNodeIdentifier(UuidNode * node) throw ()
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{
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long hostId = gethostid();
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node->nodeId[5] = (char) (hostId & 0x0000000000ffL);
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node->nodeId[4] = (char) ((hostId & 0x00000000ff00L) >> 8);
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node->nodeId[3] = (char) ((hostId & 0x000000ff0000L) >> 16);
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node->nodeId[2] = (char) ((hostId & 0x0000ff000000L) >> 24);
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// these will be 0, as the returned node is only 32 bits
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node->nodeId[1] = 0;
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node->nodeId[0] = 0;
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}
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/*------------------------------------------------------------------------------
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* Generate a random number
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*----------------------------------------------------------------------------*/
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uint16_t
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Uuid :: trueRandom(void) throw ()
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{
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static bool inited = false;
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UuidTime timeNow;
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if (!inited) {
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getSystemTime(&timeNow);
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timeNow = timeNow/UUIDS_PER_TICK;
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srand((unsigned int)(((timeNow >> 32) ^ timeNow)&0xffffffff));
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inited = true;
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};
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return rand();
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}
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/*------------------------------------------------------------------------------
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* Compare two ids.
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*----------------------------------------------------------------------------*/
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bool
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Uuid :: compare(const Uuid & id1,
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const Uuid & id2) throw ()
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{
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if (!(id1.timeLow == id2.timeLow
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&& id1.timeMid == id2.timeMid
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&& id1.timeHiAndVersion == id2.timeHiAndVersion
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&& id1.clockSeqHiAndReserved == id2.clockSeqHiAndReserved
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&& id1.clockSeqLow == id2.clockSeqLow)) {
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return false;
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}
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for (int i = 0; i < 6; ++i) {
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if (id1.node[i] != id2.node[i]) {
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return false;
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}
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}
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return true;
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}
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