dojo.provide("dojox.uuid.generateRandomUuid");

dojox.uuid.generateRandomUuid = function(){
	// summary:
	//		This function generates random UUIDs, meaning "version 4" UUIDs.
	// description:
	//		A typical generated value would be something like this:
	//		"3b12f1df-5232-4804-897e-917bf397618a"
	//		
	//		For more information about random UUIDs, see sections 4.4 and 
	//		4.5 of RFC 4122: http://tools.ietf.org/html/rfc4122#section-4.4
	//		
	//		This generator function is designed to be small and fast,
	//		but not necessarily good.
	//		
	//		Small: This generator has a small footprint. Once comments are
	//		stripped, it's only about 25 lines of code, and it doesn't 
	//		dojo.require() any other modules.
	//		
	//		Fast: This generator can generate lots of new UUIDs fairly quickly 
	//		(at least, more quickly than the other dojo UUID generators).
	//		
	//		Not necessarily good: We use Math.random() as our source
	//		of randomness, which may or may not provide much randomness. 
	// examples: 
	//		var string = dojox.uuid.generateRandomUuid();
	var HEX_RADIX = 16;

	function _generateRandomEightCharacterHexString(){
		// Make random32bitNumber be a randomly generated floating point number
		// between 0 and (4,294,967,296 - 1), inclusive.
		var random32bitNumber = Math.floor( (Math.random() % 1) * Math.pow(2, 32) );
		var eightCharacterHexString = random32bitNumber.toString(HEX_RADIX);
		while(eightCharacterHexString.length < 8){
			eightCharacterHexString = "0" + eightCharacterHexString;
		}
		return eightCharacterHexString; // for example: "3B12F1DF"
	}

	var hyphen = "-";
	var versionCodeForRandomlyGeneratedUuids = "4"; // 8 == binary2hex("0100")
	var variantCodeForDCEUuids = "8"; // 8 == binary2hex("1000")
	var a = _generateRandomEightCharacterHexString();
	var b = _generateRandomEightCharacterHexString();
	b = b.substring(0, 4) + hyphen + versionCodeForRandomlyGeneratedUuids + b.substring(5, 8);
	var c = _generateRandomEightCharacterHexString();
	c = variantCodeForDCEUuids + c.substring(1, 4) + hyphen + c.substring(4, 8);
	var d = _generateRandomEightCharacterHexString();
	var returnValue = a + hyphen + b + hyphen + c + d;
	returnValue = returnValue.toLowerCase();
	return returnValue; // String
};
