/*
Copyright (c) 2004-2006, The Dojo Foundation
All Rights Reserved.
Licensed under the Academic Free License version 2.1 or above OR the
modified BSD license. For more information on Dojo licensing, see:
http://dojotoolkit.org/community/licensing.shtml
*/
dojo.provide("dojo.uuid.TimeBasedGenerator");
dojo.require("dojo.lang.*");
dojo.uuid.TimeBasedGenerator = new function() {
// --------------------------------------------------
// Public constants
// --------------------------------------------------
// Number of hours between October 15, 1582 and January 1, 1970:
this.GREGORIAN_CHANGE_OFFSET_IN_HOURS = 3394248;
// Number of seconds between October 15, 1582 and January 1, 1970:
// this.GREGORIAN_CHANGE_OFFSET_IN_SECONDS = 12219292800;
// --------------------------------------------------
// Private variables
// --------------------------------------------------
var _uuidPseudoNodeString = null;
var _uuidClockSeqString = null;
var _dateValueOfPreviousUuid = null;
var _nextIntraMillisecondIncrement = 0;
var _cachedMillisecondsBetween1582and1970 = null;
var _cachedHundredNanosecondIntervalsPerMillisecond = null;
var _uniformNode = null;
var HEX_RADIX = 16;
// --------------------------------------------------
// Private functions
// --------------------------------------------------
/**
* Given an array which holds a 64-bit number broken into 4 16-bit elements,
* this method carries any excess bits (greater than 16-bits) from each array
* element into the next.
*
* @param arrayA An array with 4 elements, each of which is a 16-bit number.
*/
function _carry(arrayA) {
arrayA[2] += arrayA[3] >>> 16;
arrayA[3] &= 0xFFFF;
arrayA[1] += arrayA[2] >>> 16;
arrayA[2] &= 0xFFFF;
arrayA[0] += arrayA[1] >>> 16;
arrayA[1] &= 0xFFFF;
dojo.lang.assert((arrayA[0] >>> 16) === 0);
}
/**
* Given a floating point number, this method returns an array which holds a
* 64-bit number broken into 4 16-bit elements.
*
* @param x A floating point number.
* @return An array with 4 elements, each of which is a 16-bit number.
*/
function _get64bitArrayFromFloat(x) {
var result = new Array(0, 0, 0, 0);
result[3] = x % 0x10000;
x -= result[3];
x /= 0x10000;
result[2] = x % 0x10000;
x -= result[2];
x /= 0x10000;
result[1] = x % 0x10000;
x -= result[1];
x /= 0x10000;
result[0] = x;
return result;
}
/**
* Takes two arrays, each of which holds a 64-bit number broken into 4
* 16-bit elements, and returns a new array that holds a 64-bit number
* that is the sum of the two original numbers.
*
* @param arrayA An array with 4 elements, each of which is a 16-bit number.
* @param arrayB An array with 4 elements, each of which is a 16-bit number.
* @return An array with 4 elements, each of which is a 16-bit number.
*/
function _addTwo64bitArrays(arrayA, arrayB) {
dojo.lang.assertType(arrayA, Array);
dojo.lang.assertType(arrayB, Array);
dojo.lang.assert(arrayA.length == 4);
dojo.lang.assert(arrayB.length == 4);
var result = new Array(0, 0, 0, 0);
result[3] = arrayA[3] + arrayB[3];
result[2] = arrayA[2] + arrayB[2];
result[1] = arrayA[1] + arrayB[1];
result[0] = arrayA[0] + arrayB[0];
_carry(result);
return result;
}
/**
* Takes two arrays, each of which holds a 64-bit number broken into 4
* 16-bit elements, and returns a new array that holds a 64-bit number
* that is the product of the two original numbers.
*
* @param arrayA An array with 4 elements, each of which is a 16-bit number.
* @param arrayB An array with 4 elements, each of which is a 16-bit number.
* @return An array with 4 elements, each of which is a 16-bit number.
*/
function _multiplyTwo64bitArrays(arrayA, arrayB) {
dojo.lang.assertType(arrayA, Array);
dojo.lang.assertType(arrayB, Array);
dojo.lang.assert(arrayA.length == 4);
dojo.lang.assert(arrayB.length == 4);
var overflow = false;
if (arrayA[0] * arrayB[0] !== 0) { overflow = true; }
if (arrayA[0] * arrayB[1] !== 0) { overflow = true; }
if (arrayA[0] * arrayB[2] !== 0) { overflow = true; }
if (arrayA[1] * arrayB[0] !== 0) { overflow = true; }
if (arrayA[1] * arrayB[1] !== 0) { overflow = true; }
if (arrayA[2] * arrayB[0] !== 0) { overflow = true; }
dojo.lang.assert(!overflow);
var result = new Array(0, 0, 0, 0);
result[0] += arrayA[0] * arrayB[3];
_carry(result);
result[0] += arrayA[1] * arrayB[2];
_carry(result);
result[0] += arrayA[2] * arrayB[1];
_carry(result);
result[0] += arrayA[3] * arrayB[0];
_carry(result);
result[1] += arrayA[1] * arrayB[3];
_carry(result);
result[1] += arrayA[2] * arrayB[2];
_carry(result);
result[1] += arrayA[3] * arrayB[1];
_carry(result);
result[2] += arrayA[2] * arrayB[3];
_carry(result);
result[2] += arrayA[3] * arrayB[2];
_carry(result);
result[3] += arrayA[3] * arrayB[3];
_carry(result);
return result;
}
/**
* Pads a string with leading zeros and returns the result.
* For example:
*
* result = _padWithLeadingZeros("abc", 6);
* dojo.lang.assert(result == "000abc");
*
*
* @param string A string to add padding to.
* @param desiredLength The number of characters the return string should have.
* @return A string.
*/
function _padWithLeadingZeros(string, desiredLength) {
while (string.length < desiredLength) {
string = "0" + string;
}
return string;
}
/**
* Returns a randomly generated 8-character string of hex digits.
*
* @return An 8-character hex string.
*/
function _generateRandomEightCharacterHexString() {
// FIXME: This probably isn't a very high quality random number.
// 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 eightCharacterString = random32bitNumber.toString(HEX_RADIX);
while (eightCharacterString.length < 8) {
eightCharacterString = "0" + eightCharacterString;
}
return eightCharacterString;
}
/**
* Generates a time-based UUID, meaning a version 1 UUID. JavaScript
* code running in a browser doesn't have access to the IEEE 802.3 address
* of the computer, so if a node value isn't supplied, we generate a random
* pseudonode value instead.
*
* @param node Optional. A 12-character string to use as the node in the new UUID.
* @return Returns a 36 character string, which will look something like "b4308fb0-86cd-11da-a72b-0800200c9a66".
*/
function _generateUuidString(node) {
dojo.lang.assertType(node, [String, "optional"]);
if (node) {
dojo.lang.assert(node.length == 12);
} else {
if (_uniformNode) {
node = _uniformNode;
} else {
if (!_uuidPseudoNodeString) {
var pseudoNodeIndicatorBit = 0x8000;
var random15bitNumber = Math.floor( (Math.random() % 1) * Math.pow(2, 15) );
var leftmost4HexCharacters = (pseudoNodeIndicatorBit | random15bitNumber).toString(HEX_RADIX);
_uuidPseudoNodeString = leftmost4HexCharacters + _generateRandomEightCharacterHexString();
}
node = _uuidPseudoNodeString;
}
}
if (!_uuidClockSeqString) {
var variantCodeForDCEUuids = 0x8000; // 10--------------, i.e. uses only first two of 16 bits.
var random14bitNumber = Math.floor( (Math.random() % 1) * Math.pow(2, 14) );
_uuidClockSeqString = (variantCodeForDCEUuids | random14bitNumber).toString(HEX_RADIX);
}
// Maybe we should think about trying to make the code more readable to
// newcomers by creating a class called "WholeNumber" that encapsulates
// the methods and data structures for working with these arrays that
// hold 4 16-bit numbers? And then these variables below have names
// like "wholeSecondsPerHour" rather than "arraySecondsPerHour"?
var now = new Date();
var millisecondsSince1970 = now.valueOf(); // milliseconds since midnight 01 January, 1970 UTC.
var nowArray = _get64bitArrayFromFloat(millisecondsSince1970);
if (!_cachedMillisecondsBetween1582and1970) {
var arraySecondsPerHour = _get64bitArrayFromFloat(60 * 60);
var arrayHoursBetween1582and1970 = _get64bitArrayFromFloat(dojo.uuid.TimeBasedGenerator.GREGORIAN_CHANGE_OFFSET_IN_HOURS);
var arraySecondsBetween1582and1970 = _multiplyTwo64bitArrays(arrayHoursBetween1582and1970, arraySecondsPerHour);
var arrayMillisecondsPerSecond = _get64bitArrayFromFloat(1000);
_cachedMillisecondsBetween1582and1970 = _multiplyTwo64bitArrays(arraySecondsBetween1582and1970, arrayMillisecondsPerSecond);
_cachedHundredNanosecondIntervalsPerMillisecond = _get64bitArrayFromFloat(10000);
}
var arrayMillisecondsSince1970 = nowArray;
var arrayMillisecondsSince1582 = _addTwo64bitArrays(_cachedMillisecondsBetween1582and1970, arrayMillisecondsSince1970);
var arrayHundredNanosecondIntervalsSince1582 = _multiplyTwo64bitArrays(arrayMillisecondsSince1582, _cachedHundredNanosecondIntervalsPerMillisecond);
if (now.valueOf() == _dateValueOfPreviousUuid) {
arrayHundredNanosecondIntervalsSince1582[3] += _nextIntraMillisecondIncrement;
_carry(arrayHundredNanosecondIntervalsSince1582);
_nextIntraMillisecondIncrement += 1;
if (_nextIntraMillisecondIncrement == 10000) {
// If we've gotten to here, it means we've already generated 10,000
// UUIDs in this single millisecond, which is the most that the UUID
// timestamp field allows for. So now we'll just sit here and wait
// for a fraction of a millisecond, so as to ensure that the next
// time this method is called there will be a different millisecond
// value in the timestamp field.
while (now.valueOf() == _dateValueOfPreviousUuid) {
now = new Date();
}
}
} else {
_dateValueOfPreviousUuid = now.valueOf();
_nextIntraMillisecondIncrement = 1;
}
var hexTimeLowLeftHalf = arrayHundredNanosecondIntervalsSince1582[2].toString(HEX_RADIX);
var hexTimeLowRightHalf = arrayHundredNanosecondIntervalsSince1582[3].toString(HEX_RADIX);
var hexTimeLow = _padWithLeadingZeros(hexTimeLowLeftHalf, 4) + _padWithLeadingZeros(hexTimeLowRightHalf, 4);
var hexTimeMid = arrayHundredNanosecondIntervalsSince1582[1].toString(HEX_RADIX);
hexTimeMid = _padWithLeadingZeros(hexTimeMid, 4);
var hexTimeHigh = arrayHundredNanosecondIntervalsSince1582[0].toString(HEX_RADIX);
hexTimeHigh = _padWithLeadingZeros(hexTimeHigh, 3);
var hyphen = "-";
var versionCodeForTimeBasedUuids = "1"; // binary2hex("0001")
var resultUuid = hexTimeLow + hyphen + hexTimeMid + hyphen +
versionCodeForTimeBasedUuids + hexTimeHigh + hyphen +
_uuidClockSeqString + hyphen + node;
resultUuid = resultUuid.toLowerCase();
return resultUuid;
}
// --------------------------------------------------
// Public functions
// --------------------------------------------------
/**
* Sets the 'node' value that will be included in generated UUIDs.
*
* @param node A 12-character hex string representing a pseudoNode or hardwareNode.
*/
this.setNode = function(node) {
dojo.lang.assert((node === null) || (node.length == 12));
_uniformNode = node;
};
/**
* Returns the 'node' value that will be included in generated UUIDs.
*
* @return A 12-character hex string representing a pseudoNode or hardwareNode.
*/
this.getNode = function() {
return _uniformNode;
};
/**
* This function generates time-based UUIDs, meaning "version 1" UUIDs.
*
* For more info, see
* http://www.webdav.org/specs/draft-leach-uuids-guids-01.txt
* http://www.infonuovo.com/dma/csdocs/sketch/instidid.htm
* http://kruithof.xs4all.nl/uuid/uuidgen
* http://www.opengroup.org/onlinepubs/009629399/apdxa.htm#tagcjh_20
* http://jakarta.apache.org/commons/sandbox/id/apidocs/org/apache/commons/id/uuid/clock/Clock.html
*
* Examples:
*
* var generate = dojo.uuid.TimeBasedGenerator.generate;
* var uuid; // an instance of dojo.uuid.Uuid
* var string; // a simple string literal
* string = generate();
* string = generate(String);
* uuid = generate(dojo.uuid.Uuid);
* string = generate("017bf397618a");
* string = generate({node: "017bf397618a"}); // hardwareNode
* string = generate({node: "f17bf397618a"}); // pseudoNode
* string = generate({hardwareNode: "017bf397618a"});
* string = generate({pseudoNode: "f17bf397618a"});
* string = generate({node: "017bf397618a", returnType: String});
* uuid = generate({node: "017bf397618a", returnType: dojo.uuid.Uuid});
* dojo.uuid.TimeBasedGenerator.setNode("017bf397618a");
* string = generate(); // the generated UUID has node == "017bf397618a"
* uuid = generate(dojo.uuid.Uuid); // the generated UUID has node == "017bf397618a"
*
*
* @param class The type of instance to return.
* @param node A 12-character hex string representing a pseudoNode or hardwareNode.
* @namedParam node A 12-character hex string representing a pseudoNode or hardwareNode.
* @namedParam hardwareNode A 12-character hex string containing an IEEE 802.3 network node identificator.
* @namedParam pseudoNode A 12-character hex string representing a pseudoNode.
* @namedParam returnType The type of instance to return.
* @return A newly generated version 1 UUID.
*/
this.generate = function(input) {
var nodeString = null;
var returnType = null;
if (input) {
if (dojo.lang.isObject(input) && !dojo.lang.isBuiltIn(input)) {
var namedParameters = input;
dojo.lang.assertValidKeywords(namedParameters, ["node", "hardwareNode", "pseudoNode", "returnType"]);
var node = namedParameters["node"];
var hardwareNode = namedParameters["hardwareNode"];
var pseudoNode = namedParameters["pseudoNode"];
nodeString = (node || pseudoNode || hardwareNode);
if (nodeString) {
var firstCharacter = nodeString.charAt(0);
var firstDigit = parseInt(firstCharacter, HEX_RADIX);
if (hardwareNode) {
dojo.lang.assert((firstDigit >= 0x0) && (firstDigit <= 0x7));
}
if (pseudoNode) {
dojo.lang.assert((firstDigit >= 0x8) && (firstDigit <= 0xF));
}
}
returnType = namedParameters["returnType"];
dojo.lang.assertType(returnType, [Function, "optional"]);
} else {
if (dojo.lang.isString(input)) {
nodeString = input;
returnType = null;
} else {
if (dojo.lang.isFunction(input)) {
nodeString = null;
returnType = input;
}
}
}
if (nodeString) {
dojo.lang.assert(nodeString.length == 12);
var integer = parseInt(nodeString, HEX_RADIX);
dojo.lang.assert(isFinite(integer));
}
dojo.lang.assertType(returnType, [Function, "optional"]);
}
var uuidString = _generateUuidString(nodeString);
var returnValue;
if (returnType && (returnType != String)) {
returnValue = new returnType(uuidString);
} else {
returnValue = uuidString;
}
return returnValue;
};
}();