392 lines
14 KiB
JavaScript
392 lines
14 KiB
JavaScript
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/*
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Copyright (c) 2004-2006, The Dojo Foundation
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All Rights Reserved.
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Licensed under the Academic Free License version 2.1 or above OR the
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modified BSD license. For more information on Dojo licensing, see:
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http://dojotoolkit.org/community/licensing.shtml
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*/
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dojo.provide("dojo.uuid.TimeBasedGenerator");
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dojo.require("dojo.lang.*");
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dojo.uuid.TimeBasedGenerator = new function() {
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// --------------------------------------------------
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// Public constants
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// --------------------------------------------------
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// Number of hours between October 15, 1582 and January 1, 1970:
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this.GREGORIAN_CHANGE_OFFSET_IN_HOURS = 3394248;
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// Number of seconds between October 15, 1582 and January 1, 1970:
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// this.GREGORIAN_CHANGE_OFFSET_IN_SECONDS = 12219292800;
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// --------------------------------------------------
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// Private variables
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// --------------------------------------------------
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var _uuidPseudoNodeString = null;
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var _uuidClockSeqString = null;
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var _dateValueOfPreviousUuid = null;
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var _nextIntraMillisecondIncrement = 0;
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var _cachedMillisecondsBetween1582and1970 = null;
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var _cachedHundredNanosecondIntervalsPerMillisecond = null;
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var _uniformNode = null;
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var HEX_RADIX = 16;
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// --------------------------------------------------
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// Private functions
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// --------------------------------------------------
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/**
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* Given an array which holds a 64-bit number broken into 4 16-bit elements,
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* this method carries any excess bits (greater than 16-bits) from each array
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* element into the next.
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*
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* @param arrayA An array with 4 elements, each of which is a 16-bit number.
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*/
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function _carry(arrayA) {
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arrayA[2] += arrayA[3] >>> 16;
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arrayA[3] &= 0xFFFF;
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arrayA[1] += arrayA[2] >>> 16;
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arrayA[2] &= 0xFFFF;
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arrayA[0] += arrayA[1] >>> 16;
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arrayA[1] &= 0xFFFF;
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dojo.lang.assert((arrayA[0] >>> 16) === 0);
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}
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/**
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* Given a floating point number, this method returns an array which holds a
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* 64-bit number broken into 4 16-bit elements.
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*
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* @param x A floating point number.
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* @return An array with 4 elements, each of which is a 16-bit number.
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*/
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function _get64bitArrayFromFloat(x) {
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var result = new Array(0, 0, 0, 0);
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result[3] = x % 0x10000;
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x -= result[3];
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x /= 0x10000;
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result[2] = x % 0x10000;
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x -= result[2];
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x /= 0x10000;
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result[1] = x % 0x10000;
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x -= result[1];
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x /= 0x10000;
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result[0] = x;
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return result;
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}
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/**
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* Takes two arrays, each of which holds a 64-bit number broken into 4
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* 16-bit elements, and returns a new array that holds a 64-bit number
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* that is the sum of the two original numbers.
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*
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* @param arrayA An array with 4 elements, each of which is a 16-bit number.
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* @param arrayB An array with 4 elements, each of which is a 16-bit number.
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* @return An array with 4 elements, each of which is a 16-bit number.
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*/
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function _addTwo64bitArrays(arrayA, arrayB) {
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dojo.lang.assertType(arrayA, Array);
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dojo.lang.assertType(arrayB, Array);
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dojo.lang.assert(arrayA.length == 4);
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dojo.lang.assert(arrayB.length == 4);
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var result = new Array(0, 0, 0, 0);
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result[3] = arrayA[3] + arrayB[3];
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result[2] = arrayA[2] + arrayB[2];
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result[1] = arrayA[1] + arrayB[1];
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result[0] = arrayA[0] + arrayB[0];
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_carry(result);
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return result;
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}
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/**
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* Takes two arrays, each of which holds a 64-bit number broken into 4
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* 16-bit elements, and returns a new array that holds a 64-bit number
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* that is the product of the two original numbers.
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*
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* @param arrayA An array with 4 elements, each of which is a 16-bit number.
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* @param arrayB An array with 4 elements, each of which is a 16-bit number.
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* @return An array with 4 elements, each of which is a 16-bit number.
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*/
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function _multiplyTwo64bitArrays(arrayA, arrayB) {
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dojo.lang.assertType(arrayA, Array);
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dojo.lang.assertType(arrayB, Array);
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dojo.lang.assert(arrayA.length == 4);
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dojo.lang.assert(arrayB.length == 4);
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var overflow = false;
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if (arrayA[0] * arrayB[0] !== 0) { overflow = true; }
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if (arrayA[0] * arrayB[1] !== 0) { overflow = true; }
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if (arrayA[0] * arrayB[2] !== 0) { overflow = true; }
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if (arrayA[1] * arrayB[0] !== 0) { overflow = true; }
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if (arrayA[1] * arrayB[1] !== 0) { overflow = true; }
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if (arrayA[2] * arrayB[0] !== 0) { overflow = true; }
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dojo.lang.assert(!overflow);
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var result = new Array(0, 0, 0, 0);
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result[0] += arrayA[0] * arrayB[3];
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_carry(result);
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result[0] += arrayA[1] * arrayB[2];
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_carry(result);
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result[0] += arrayA[2] * arrayB[1];
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_carry(result);
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result[0] += arrayA[3] * arrayB[0];
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_carry(result);
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result[1] += arrayA[1] * arrayB[3];
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_carry(result);
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result[1] += arrayA[2] * arrayB[2];
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_carry(result);
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result[1] += arrayA[3] * arrayB[1];
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_carry(result);
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result[2] += arrayA[2] * arrayB[3];
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_carry(result);
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result[2] += arrayA[3] * arrayB[2];
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_carry(result);
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result[3] += arrayA[3] * arrayB[3];
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_carry(result);
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return result;
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}
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/**
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* Pads a string with leading zeros and returns the result.
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* For example:
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* <pre>
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* result = _padWithLeadingZeros("abc", 6);
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* dojo.lang.assert(result == "000abc");
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* </pre>
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*
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* @param string A string to add padding to.
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* @param desiredLength The number of characters the return string should have.
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* @return A string.
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*/
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function _padWithLeadingZeros(string, desiredLength) {
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while (string.length < desiredLength) {
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string = "0" + string;
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}
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return string;
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}
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/**
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* Returns a randomly generated 8-character string of hex digits.
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*
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* @return An 8-character hex string.
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*/
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function _generateRandomEightCharacterHexString() {
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// FIXME: This probably isn't a very high quality random number.
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// Make random32bitNumber be a randomly generated floating point number
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// between 0 and (4,294,967,296 - 1), inclusive.
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var random32bitNumber = Math.floor( (Math.random() % 1) * Math.pow(2, 32) );
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var eightCharacterString = random32bitNumber.toString(HEX_RADIX);
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while (eightCharacterString.length < 8) {
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eightCharacterString = "0" + eightCharacterString;
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}
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return eightCharacterString;
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}
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/**
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* Generates a time-based UUID, meaning a version 1 UUID. JavaScript
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* code running in a browser doesn't have access to the IEEE 802.3 address
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* of the computer, so if a node value isn't supplied, we generate a random
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* pseudonode value instead.
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*
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* @param node Optional. A 12-character string to use as the node in the new UUID.
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* @return Returns a 36 character string, which will look something like "b4308fb0-86cd-11da-a72b-0800200c9a66".
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*/
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function _generateUuidString(node) {
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dojo.lang.assertType(node, [String, "optional"]);
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if (node) {
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dojo.lang.assert(node.length == 12);
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} else {
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if (_uniformNode) {
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node = _uniformNode;
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} else {
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if (!_uuidPseudoNodeString) {
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var pseudoNodeIndicatorBit = 0x8000;
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var random15bitNumber = Math.floor( (Math.random() % 1) * Math.pow(2, 15) );
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var leftmost4HexCharacters = (pseudoNodeIndicatorBit | random15bitNumber).toString(HEX_RADIX);
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_uuidPseudoNodeString = leftmost4HexCharacters + _generateRandomEightCharacterHexString();
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}
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node = _uuidPseudoNodeString;
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}
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}
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if (!_uuidClockSeqString) {
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var variantCodeForDCEUuids = 0x8000; // 10--------------, i.e. uses only first two of 16 bits.
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var random14bitNumber = Math.floor( (Math.random() % 1) * Math.pow(2, 14) );
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_uuidClockSeqString = (variantCodeForDCEUuids | random14bitNumber).toString(HEX_RADIX);
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}
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// Maybe we should think about trying to make the code more readable to
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// newcomers by creating a class called "WholeNumber" that encapsulates
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// the methods and data structures for working with these arrays that
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// hold 4 16-bit numbers? And then these variables below have names
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// like "wholeSecondsPerHour" rather than "arraySecondsPerHour"?
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var now = new Date();
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var millisecondsSince1970 = now.valueOf(); // milliseconds since midnight 01 January, 1970 UTC.
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var nowArray = _get64bitArrayFromFloat(millisecondsSince1970);
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if (!_cachedMillisecondsBetween1582and1970) {
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var arraySecondsPerHour = _get64bitArrayFromFloat(60 * 60);
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var arrayHoursBetween1582and1970 = _get64bitArrayFromFloat(dojo.uuid.TimeBasedGenerator.GREGORIAN_CHANGE_OFFSET_IN_HOURS);
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var arraySecondsBetween1582and1970 = _multiplyTwo64bitArrays(arrayHoursBetween1582and1970, arraySecondsPerHour);
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var arrayMillisecondsPerSecond = _get64bitArrayFromFloat(1000);
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_cachedMillisecondsBetween1582and1970 = _multiplyTwo64bitArrays(arraySecondsBetween1582and1970, arrayMillisecondsPerSecond);
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_cachedHundredNanosecondIntervalsPerMillisecond = _get64bitArrayFromFloat(10000);
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}
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var arrayMillisecondsSince1970 = nowArray;
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var arrayMillisecondsSince1582 = _addTwo64bitArrays(_cachedMillisecondsBetween1582and1970, arrayMillisecondsSince1970);
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var arrayHundredNanosecondIntervalsSince1582 = _multiplyTwo64bitArrays(arrayMillisecondsSince1582, _cachedHundredNanosecondIntervalsPerMillisecond);
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if (now.valueOf() == _dateValueOfPreviousUuid) {
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arrayHundredNanosecondIntervalsSince1582[3] += _nextIntraMillisecondIncrement;
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_carry(arrayHundredNanosecondIntervalsSince1582);
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_nextIntraMillisecondIncrement += 1;
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if (_nextIntraMillisecondIncrement == 10000) {
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// If we've gotten to here, it means we've already generated 10,000
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// UUIDs in this single millisecond, which is the most that the UUID
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// timestamp field allows for. So now we'll just sit here and wait
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// for a fraction of a millisecond, so as to ensure that the next
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// time this method is called there will be a different millisecond
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// value in the timestamp field.
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while (now.valueOf() == _dateValueOfPreviousUuid) {
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now = new Date();
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}
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}
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} else {
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_dateValueOfPreviousUuid = now.valueOf();
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_nextIntraMillisecondIncrement = 1;
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}
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var hexTimeLowLeftHalf = arrayHundredNanosecondIntervalsSince1582[2].toString(HEX_RADIX);
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var hexTimeLowRightHalf = arrayHundredNanosecondIntervalsSince1582[3].toString(HEX_RADIX);
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var hexTimeLow = _padWithLeadingZeros(hexTimeLowLeftHalf, 4) + _padWithLeadingZeros(hexTimeLowRightHalf, 4);
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var hexTimeMid = arrayHundredNanosecondIntervalsSince1582[1].toString(HEX_RADIX);
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hexTimeMid = _padWithLeadingZeros(hexTimeMid, 4);
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var hexTimeHigh = arrayHundredNanosecondIntervalsSince1582[0].toString(HEX_RADIX);
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hexTimeHigh = _padWithLeadingZeros(hexTimeHigh, 3);
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var hyphen = "-";
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var versionCodeForTimeBasedUuids = "1"; // binary2hex("0001")
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var resultUuid = hexTimeLow + hyphen + hexTimeMid + hyphen +
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versionCodeForTimeBasedUuids + hexTimeHigh + hyphen +
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_uuidClockSeqString + hyphen + node;
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resultUuid = resultUuid.toLowerCase();
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return resultUuid;
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}
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// --------------------------------------------------
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// Public functions
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// --------------------------------------------------
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/**
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* Sets the 'node' value that will be included in generated UUIDs.
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*
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* @param node A 12-character hex string representing a pseudoNode or hardwareNode.
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*/
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this.setNode = function(node) {
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dojo.lang.assert((node === null) || (node.length == 12));
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_uniformNode = node;
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};
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/**
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* Returns the 'node' value that will be included in generated UUIDs.
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*
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* @return A 12-character hex string representing a pseudoNode or hardwareNode.
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*/
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this.getNode = function() {
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return _uniformNode;
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};
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/**
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* This function generates time-based UUIDs, meaning "version 1" UUIDs.
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*
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* For more info, see
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* http://www.webdav.org/specs/draft-leach-uuids-guids-01.txt
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* http://www.infonuovo.com/dma/csdocs/sketch/instidid.htm
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* http://kruithof.xs4all.nl/uuid/uuidgen
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* http://www.opengroup.org/onlinepubs/009629399/apdxa.htm#tagcjh_20
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* http://jakarta.apache.org/commons/sandbox/id/apidocs/org/apache/commons/id/uuid/clock/Clock.html
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*
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* Examples:
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* <pre>
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* var generate = dojo.uuid.TimeBasedGenerator.generate;
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* var uuid; // an instance of dojo.uuid.Uuid
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* var string; // a simple string literal
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* string = generate();
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* string = generate(String);
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* uuid = generate(dojo.uuid.Uuid);
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* string = generate("017bf397618a");
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* string = generate({node: "017bf397618a"}); // hardwareNode
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* string = generate({node: "f17bf397618a"}); // pseudoNode
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* string = generate({hardwareNode: "017bf397618a"});
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* string = generate({pseudoNode: "f17bf397618a"});
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* string = generate({node: "017bf397618a", returnType: String});
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* uuid = generate({node: "017bf397618a", returnType: dojo.uuid.Uuid});
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* dojo.uuid.TimeBasedGenerator.setNode("017bf397618a");
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* string = generate(); // the generated UUID has node == "017bf397618a"
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* uuid = generate(dojo.uuid.Uuid); // the generated UUID has node == "017bf397618a"
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* </pre>
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*
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* @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;
|
||
|
|
};
|
||
|
|
}();
|