sintonia/livesupport/modules/core/src/Uuid.cxx
2005-04-28 14:36:00 +00:00

318 lines
9.9 KiB
C++

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