Detect AIR SWF version

Test2.as

package
{
    
    public class Test
    {

        public function Test()
        {
            trace( "SWF version = " + _parseSWFVersion() );
        }

        private function _getAIRSWF():String
        {
            var na:NativeApplication = NativeApplication.nativeApplication;
            var swf_file:String      = "";
            
            if( na )
            {
                var descriptor:XML = na.applicationDescriptor;
                var ns:Namespace   = descriptor.namespace();
                
                swf_file = descriptor.ns::initialWindow.ns::content;
            }
            
            return swf_file;
        }
        
        private function _parseSWFVersion():uint
        {
            var air_swf:String = _getAIRSWF();
            var air_file:File = File.applicationDirectory;
                air_file = air_file.resolvePath( air_swf );
            
            if( air_file.exists )
            {
                var fs:FileStream = new FileStream();
                    fs.endian = Endian.LITTLE_ENDIAN;
                    fs.open( air_file, FileMode.READ );
                    trace( "endian = " + fs.endian );
                    trace( "bytesAvailable = " + fs.bytesAvailable );
                    trace( "position = " + fs.position );
                    
                // SWF magic number
                var magic:Array = [ fs.readUnsignedByte(), fs.readUnsignedByte(), fs.readUnsignedByte() ];
                    magic.reverse();
                    magic.forEach( function(el:*, i:int, a:Array):void { a[i] = String.fromCharCode(el); } );
                
                var signature:String = magic.join("");
                if( (signature == "SWC") || (signature == "SWF") )
                {
                    // valid signature found
                    
                    var version:uint = fs.readUnsignedByte();
                    fs.close();
                    return version;
                }
                else
                {
                    trace( "This is not a valid SWF file (signature=" + signature + ")" );
                    fs.close();
                    return 0;
                }
            }
            
            return 0;
        }

    }

}