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Hello flexcoders; Has anyone else experienced terrible performance building
nested XML trees? I wrote a test ActionScript app that builds a nested XML
document with the structure: <or>
<t/>
<or>
<t/>
<or>
<t/>
<t/>
</or> </or> I wrote two functions to generate the XML. One using
recursion (ToDeepXML), and one using only iteration (ToDeepXMLNoRecurse). (I
also wrote ToWideXML which builds a balanced tree). The timing results for 200
terms are as follows: ToWideXml
343 ms ToDeepXml
434213 ms ToDeepXmlNoRecurs
31 ms There is a performance penalty to paid for using recursion,
but I don’t think this could account for an exponential difference in
performance, like what we’re seeing here. If XML object are represented
internally as strings, then the performance difference could be explained by
the fact that the recursive algorithm does insertions, while the non-recursive
algorithm only ever appends. The insertions would involve a lot memory copying,
which never helps performance. Here’s the code I used for testing: <?xml version="1.0"
encoding="utf-8"?> <mx:Application
xmlns:mx="http://www.adobe.com/2006/mxml" xmlns="*"
layout="absolute" creationComplete="OnCreationComplete()"> <mx:Script> <![CDATA[ import
mx.utils.ObjectUtil; private
function OnCreationComplete() : void { var
a : Array = []; for(
var i : uint = 0; i < 200; i++ ) { a.push(
uint( Math.random() * 10000 ) ); } var
b : Array = ObjectUtil.copy( a ) as Array; var
c : Array = ObjectUtil.copy( a ) as Array Time(
function() : void{ ToWideXml( a ) }, "ToWideXml" ); Time(
function() : void{ ToDeepXml( b ) }, "ToDeepXml" ); Time(
function() : void{ ToDeepXmlNoRecurs( c ) }, "ToDeepXmlNoRecurs" ); } private
function ToDeepXml( a : Array ) : XML { if(
a.length == 1 ) { return
<t>{a[0]}</t>; } var
n : Number = Number( a.pop() ); return
<or><t>{n}</t>{ToDeepXml( a )}</or>; } private
function ToDeepXmlNoRecurs( a : Array ) : XML { var
result : XML = <or/>; var
curNode: XML = result; for(
var i : uint = 0; i < a.length - 2; i++ ) { curNode.appendChild(
<t>{a[ i ]}</t> ); curNode.appendChild(
<or/> ); curNode
= curNode.children()[ 1 ]; } curNode.appendChild(
<t>{ a[ a.length - 1 ] }</t> ); curNode.appendChild(
<t>{ a[ a.length ] }</t> ); return
result; } private
function ToWideXml( a : Array ) : XML { if(
a.length == 1 ) { return
<t>{a[0]}</t>; } var
a1 : Array = a.splice( 0, a.length / 2 ); return
<or><t>{ToWideXml( a1 )}</t><t>{ToWideXml( a
)}</t></or>; } private
function Time( f : Function, msg : String = "") : void { var
t : uint = new Date().time; f(); var
t1 : uint = new Date().time; trace(
msg, t1 - t, "ms" ); } ]]> </mx:Script> </mx:Application> Kodak Graphic Communications Canada Company Tobias Patton | Software Developer | Tel: +1.604.451.2700
ext: 5148 | mailto:[EMAIL PROTECTED] | http://www.creo.com -- Flexcoders Mailing List FAQ: http://groups.yahoo.com/group/flexcoders/files/flexcodersFAQ.txt Search Archives: http://www.mail-archive.com/flexcoders%40yahoogroups.com
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