dojo.provide("dojox.uuid.generateTimeBasedUuid"); dojox.uuid.generateTimeBasedUuid = function(/*String?*/ node){ // summary: // This function generates time-based UUIDs, meaning "version 1" UUIDs. // description: // 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 // node: // A 12-character hex string representing either a pseudo-node or // hardware-node (an IEEE 802.3 network node). A hardware-node // will be something like "017bf397618a", always with the first bit // being 0. A pseudo-node will be something like "f17bf397618a", // always with the first bit being 1. // examples: // string = dojox.uuid.generateTimeBasedUuid(); // string = dojox.uuid.generateTimeBasedUuid("017bf397618a"); // dojox.uuid.generateTimeBasedUuid.setNode("017bf397618a"); // string = dojox.uuid.generateTimeBasedUuid(); // the generated UUID has node == "017bf397618a" var uuidString = dojox.uuid.generateTimeBasedUuid._generator.generateUuidString(node); return uuidString; // String }; dojox.uuid.generateTimeBasedUuid.isValidNode = function(/*String?*/ node){ var HEX_RADIX = 16; var integer = parseInt(node, HEX_RADIX); var valid = dojo.isString(node) && node.length == 12 && isFinite(integer); return valid; // Boolean }; dojox.uuid.generateTimeBasedUuid.setNode = function(/*String?*/ node){ // summary: // Sets the 'node' value that will be included in generated UUIDs. // node: A 12-character hex string representing a pseudoNode or hardwareNode. dojox.uuid.assert((node === null) || this.isValidNode(node)); this._uniformNode = node; }; dojox.uuid.generateTimeBasedUuid.getNode = function(){ // summary: // Returns the 'node' value that will be included in generated UUIDs. return this._uniformNode; // String (a 12-character hex string representing a pseudoNode or hardwareNode) }; dojox.uuid.generateTimeBasedUuid._generator = new function(){ // 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: // dojox.uuid.generateTimeBasedUuid.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; // -------------------------------------------------- // Private constants: var HEX_RADIX = 16; function _carry(/* array */ arrayA){ // summary: // 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. // arrayA: An array with 4 elements, each of which is a 16-bit number. arrayA[2] += arrayA[3] >>> 16; arrayA[3] &= 0xFFFF; arrayA[1] += arrayA[2] >>> 16; arrayA[2] &= 0xFFFF; arrayA[0] += arrayA[1] >>> 16; arrayA[1] &= 0xFFFF; dojox.uuid.assert((arrayA[0] >>> 16) === 0); } function _get64bitArrayFromFloat(/* float */ x){ // summary: // Given a floating point number, this method returns an array which // holds a 64-bit number broken into 4 16-bit elements. 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; // Array with 4 elements, each of which is a 16-bit number. } function _addTwo64bitArrays(/* array */ arrayA, /* array */ arrayB){ // summary: // 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. // arrayA: An array with 4 elements, each of which is a 16-bit number. // arrayB: An array with 4 elements, each of which is a 16-bit number. dojox.uuid.assert(dojo.isArray(arrayA)); dojox.uuid.assert(dojo.isArray(arrayB)); dojox.uuid.assert(arrayA.length == 4); dojox.uuid.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; // Array with 4 elements, each of which is a 16-bit number. } function _multiplyTwo64bitArrays(/* array */ arrayA, /* array */ arrayB){ // summary: // 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. // arrayA: An array with 4 elements, each of which is a 16-bit number. // arrayB: An array with 4 elements, each of which is a 16-bit number. dojox.uuid.assert(dojo.isArray(arrayA)); dojox.uuid.assert(dojo.isArray(arrayB)); dojox.uuid.assert(arrayA.length == 4); dojox.uuid.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; } dojox.uuid.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; // Array with 4 elements, each of which is a 16-bit number. } function _padWithLeadingZeros(/* string */ string, /* int */ desiredLength){ // summary: // Pads a string with leading zeros and returns the result. // string: A string to add padding to. // desiredLength: The number of characters the return string should have. // examples: // result = _padWithLeadingZeros("abc", 6); // dojox.uuid.assert(result == "000abc"); while(string.length < desiredLength){ string = "0" + string; } return string; // string } function _generateRandomEightCharacterHexString() { // summary: // Returns a randomly generated 8-character string of hex digits. // 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; // String (an 8-character hex string) } this.generateUuidString = function(/*String?*/ node){ // summary: // Generates a time-based UUID, meaning a version 1 UUID. // description: // 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. // node: An optional 12-character string to use as the node in the new UUID. if(node){ dojox.uuid.assert(dojox.uuid.generateTimeBasedUuid.isValidNode(node)); }else{ if(dojox.uuid.generateTimeBasedUuid._uniformNode){ node = dojox.uuid.generateTimeBasedUuid._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(dojox.uuid.generateTimeBasedUuid._generator.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; // String (a 36 character string, which will look something like "b4308fb0-86cd-11da-a72b-0800200c9a66") } }();