Adobe AIR Mobile on iOS - processing text very slow - ios

Question

I am writing an iOS app in Flash Builder 4.6 that will need to process a large text file. So far, I am just trying to get the version information from the file, a simple task that runs very fast in the simulator but takes a very long time (on the order of 10 seconds) on my iPad 2.
As the file is large (about 11MB), I am trying to only read far enough into the file to get the version data. Is it possible that the filestream loads the whole file into memory anyway? If so, how do I avoid that?
Note that the code works correctly, and displays the correct version info.
Any advice on how to speed it up would be greatly appreciated.
The file being processed can be found here: http://oanda.sca.org:80/oanda.db
The code is as follows:
Calling code:
protected function view1_viewActivateHandler(event:ViewNavigatorEvent):void
{
var DT:DatabaseTools = new DatabaseTools();
var version:String;
//Get version information from local file:
version = DT.GetLocalVer("oanda.db");
lblLclVer.text=version;
}
Actual function:
public function GetLocalVer(fileName:String):String
{
var out:ByteArray = new ByteArray();
var line_Out:String;
var char:int;
var line:ByteArray = new ByteArray();
var stream:FileStream = new FileStream();
var file:File = File.documentsDirectory.resolvePath(fileName);
var lineString:String;
var result:String = "Error";
stream.open(file,FileMode.READ);
var found:Boolean=false;
while((stream.bytesAvailable > 0) && !found)
{
char=stream.readByte();
if(String.fromCharCode(char) == "\n")
{
//reset the line
out=line;
line = new ByteArray();
//process the line to see if its the version info.
lineString=out.toString(); //since the version line never has UTF characters, convert it to a regular string
if(lineString.length > 25) //Any line shorter than this can't be the version line
{
var startOfLine:String = lineString.substr(0,17);
if(startOfLine == " ||C|Last update:")
{
result = lineString.substr(19,6);
found = true;
}
}
}
else
{
line.writeByte(char);
}
}
stream.close();
return result;
}
Thanks.