/*

 uuid_wev8.js - Version 0.2
 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).

 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;
}

// Numeric Base Conversion algorithm from irt.org
// In base 16: 0=0, 5=5, 10=A, 15=F
UUID.returnBase = function (number, base) {
    //
    // Copyright 1996-2006 irt.org, All Rights Reserved.
    //
    // Downloaded from: http://www.irt.org/script/146.htm
    // modified to work in this class by Erik Giberti
    var convert = ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'];
    if (number < base) var output = convert[number];
    else {
        var MSD = '' + Math.floor(number / base);
        var LSD = number - MSD * base;
        if (MSD >= base) var output = this.returnBase(MSD, base) + convert[LSD];
        else var output = convert[MSD] + convert[LSD];
    }
    return output;
}

// 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);
}

// end of UUID class file