I'm a bit surprised that ByteArray.writeByte is faster but maybe Array.join isn't that fast. I would also like to see a test of a single static bytearray and resetting it and/or overwriting the old bytes.
Maybe if you put a SWF with various algorithms in your people.a.o folder folks can hit it and make sure we all get the same results and then we'll know which algorithm to check in. Thanks for this idea as well. -Alex On 10/18/13 3:05 PM, "Maurice Amsellem" <maurice.amsel...@systar.com> wrote: >Any answer ? > >-----Message d'origine----- >De : Maurice Amsellem [mailto:maurice.amsel...@systar.com] >Envoyé : vendredi 18 octobre 2013 14:39 >À : dev@flex.apache.org >Objet : RE: UID performance > >Hi, > >I shouldn't have mixed the two options, because it's confusing. > >Actually, V3 option generates uppercase, exactly as the current UUID, and >it's 2x faster. >So let's forget about V4... > >Here is the code: > > private static const HEX_CHARS:String = "0123456789ABCDEF"; > private static const DASH:int = 45; // "-" > >public static function createUID():String > { > var ba:ByteArray = new ByteArray(); > var i:int; > var j:int; > > for (i = 0; i < 8; i++) { > ba.writeByte(HEX_CHARS.charCodeAt(Math.random() * 16)); > } > > for (i = 0; i < 3; i++) > { > ba.writeByte(DASH); > for (j = 0; j < 4; j++) > { > ba.writeByte(HEX_CHARS.charCodeAt(Math.random() * 16)); > } > } > > ba.writeByte(DASH); > > var time:Number = new Date().getTime(); > > var timeString:String = ("0000000" + >time.toString(16).toUpperCase()).substr(-8); > ba.writeUTFBytes(timeString); > > for (i = 0; i < 4; i++) > { > ba.writeByte(HEX_CHARS.charCodeAt(Math.random() * 16)); > } > > return ba.toString(); > } > >-----Message d'origine----- >De : Justin Mclean [mailto:jus...@classsoftware.com] Envoyé : vendredi 18 >octobre 2013 14:34 À : dev@flex.apache.org Objet : Re: UID performance > >Hi, > >> V3: generates the random hex bytes one by one, and writes them to the >> BA >> V4: generates 4 or 8 random bytes in one shot, and writes them to the >> BA (hexa in lowercase, to avoid call toUppercase() ) >Probably best not too fiddle too much with the UID construction. While I >can't think of any major issues it would cause there could be subtle >issues due to seeding of random numbers and the like. > >> I don't know if this is acceptable (are we breaking some code if we use >>lowercase instead of uppercase). > >Again can't think of any issues but probably safer if we kept it upper >case. > >Go ahead and post the code it could be interesting/useful to someone. > >Thanks, >Justin
