source: trunk/src/ajax/javascripts/external/UUID.js

/*
uuid.js - Version 0.3
JavaScript Class to create a UUID like identifier
 
Copyright (C) 2006-2008, Erik Giberti (AF-Design), All rights reserved.
 
This program 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.
 
This program 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 
this program; if not, write to the Free Software Foundation, Inc., 59 Temple 
Place, Suite 330, Boston, MA 02111-1307 USA
 
The latest version of this file can be downloaded from
http://www.af-design.com/resources/javascript_uuid.php
 
HISTORY:
6/5/06  - Initial Release
5/22/08 - Updated code to run faster, removed randrange(min,max) in favor of
          a simpler rand(max) function. Reduced overhead by using getTime() 
          method of date class (suggestion by James Hall).
9/5/08  - Fixed a bug with rand(max) and additional efficiencies pointed out 
          by Robert Kieffer http://broofa.com/
 
KNOWN ISSUES:
- Still no way to get MAC address in JavaScript
- Research into other versions of UUID show promising possibilities 
  (more research needed)
- Documentation needs improvement
 
*/
 
// On creation of a UUID object, set it's initial value
function UUID(){
        this.id = this.createUUID();
}
 
// When asked what this Object is, lie and return it's value
UUID.prototype.valueOf = function(){ return this.id; }
UUID.prototype.toString = function(){ return this.id; }
 
//
// INSTANCE SPECIFIC METHODS
//
 
UUID.prototype.createUUID = function(){
        //
        // Loose interpretation of the specification DCE 1.1: Remote Procedure Call
        // described at http://www.opengroup.org/onlinepubs/009629399/apdxa.htm#tagtcjh_37
        // since JavaScript doesn't allow access to internal systems, the last 48 bits 
        // of the node section is made up using a series of random numbers (6 octets long).
        //  
        var dg = new Date(1582, 10, 15, 0, 0, 0, 0);
        var dc = new Date();
        var t = dc.getTime() - dg.getTime();
        var h = '-';
        var tl = UUID.getIntegerBits(t,0,31);
        var tm = UUID.getIntegerBits(t,32,47);
        var thv = UUID.getIntegerBits(t,48,59) + '1'; // version 1, security version is 2
        var csar = UUID.getIntegerBits(UUID.rand(4095),0,7);
        var csl = UUID.getIntegerBits(UUID.rand(4095),0,7);
 
        // since detection of anything about the machine/browser is far to buggy, 
        // include some more random numbers here
        // if NIC or an IP can be obtained reliably, that should be put in
        // here instead.
        var n = UUID.getIntegerBits(UUID.rand(8191),0,7) + 
                        UUID.getIntegerBits(UUID.rand(8191),8,15) + 
                        UUID.getIntegerBits(UUID.rand(8191),0,7) + 
                        UUID.getIntegerBits(UUID.rand(8191),8,15) + 
                        UUID.getIntegerBits(UUID.rand(8191),0,15); // this last number is two octets long
        return tl + h + tm + h + thv + h + csar + csl + h + n; 
}
 
 
//
// GENERAL METHODS (Not instance specific)
//
 
 
// Pull out only certain bits from a very large integer, used to get the time
// code information for the first part of a UUID. Will return zero's if there 
// aren't enough bits to shift where it needs to.
UUID.getIntegerBits = function(val,start,end){
        var base16 = UUID.returnBase(val,16);
        var quadArray = new Array();
        var quadString = '';
        var i = 0;
        for(i=0;i<base16.length;i++){
                quadArray.push(base16.substring(i,i+1));        
        }
        for(i=Math.floor(start/4);i<=Math.floor(end/4);i++){
                if(!quadArray[i] || quadArray[i] == '') quadString += '0';
                else quadString += quadArray[i];
        }
        return quadString;
}
 
// Replaced from the original function to leverage the built in methods in
// JavaScript. Thanks to Robert Kieffer for pointing this one out
UUID.returnBase = function(number, base){
        return (number).toString(base).toUpperCase();
}
 
// pick a random number within a range of numbers
// int b rand(int a); where 0 <= b <= a
UUID.rand = function(max){
        return Math.floor(Math.random() * (max + 1));
}
 
// end of UUID class file