82 lines
3 KiB
JavaScript
82 lines
3 KiB
JavaScript
/*
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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.LightweightGenerator");
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/**
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* The LightweightGenerator is intended to be small and fast,
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* but not necessarily good.
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*
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* Small: The LightweightGenerator has a small footprint.
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* Once comments are stripped, it's only about 25 lines of
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* code, and it doesn't dojo.require() any other packages.
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*
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* Fast: The LightweightGenerator can generate lots of new
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* UUIDs fairly quickly (at least, more quickly than the other
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* dojo UUID generators).
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*
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* Not necessarily good: We use Math.random() as our source
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* of randomness, which may or may not provide much randomness.
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*/
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dojo.uuid.LightweightGenerator = new function() {
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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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function _generateRandomEightCharacterHexString() {
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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 eightCharacterHexString = random32bitNumber.toString(HEX_RADIX);
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while (eightCharacterHexString.length < 8) {
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eightCharacterHexString = "0" + eightCharacterHexString;
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}
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return eightCharacterHexString; // for example: "3B12F1DF"
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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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* This function generates random UUIDs, meaning "version 4" UUIDs.
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* For example, a typical generated value would be something like
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* "3b12f1df-5232-4804-897e-917bf397618a".
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*
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* Examples:
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* <pre>
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* var string = dojo.uuid.LightweightGenerator.generate();
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* var string = dojo.uuid.LightweightGenerator.generate(String);
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* var uuid = dojo.uuid.LightweightGenerator.generate(dojo.uuid.Uuid);
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* </pre>
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*
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* @param returnType Optional. The type of instance to return.
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* @return A newly generated version 4 UUID.
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*/
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this.generate = function(returnType) {
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var hyphen = "-";
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var versionCodeForRandomlyGeneratedUuids = "4"; // 8 == binary2hex("0100")
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var variantCodeForDCEUuids = "8"; // 8 == binary2hex("1000")
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var a = _generateRandomEightCharacterHexString();
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var b = _generateRandomEightCharacterHexString();
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b = b.substring(0, 4) + hyphen + versionCodeForRandomlyGeneratedUuids + b.substring(5, 8);
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var c = _generateRandomEightCharacterHexString();
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c = variantCodeForDCEUuids + c.substring(1, 4) + hyphen + c.substring(4, 8);
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var d = _generateRandomEightCharacterHexString();
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var returnValue = a + hyphen + b + hyphen + c + d;
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returnValue = returnValue.toLowerCase();
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if (returnType && (returnType != String)) {
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returnValue = new returnType(returnValue);
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}
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return returnValue;
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};
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}();
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