anyone understand this code?

[ydoisuck]

Hey, I'm trying to get this code to work...its a barcode decoder works ok if u enter a 12 digit code but if u enter an 8 or 13 digit EAN or UPC-A it doesn't so i've tried to change it so it reverts to 12 digits each time, only thing is i can't get it to work fluidly and I don't really understand it. Any help would be much appreciated!

 

THANKS GUYS!

 

<?php
extract($_GET);
if(isset($upc))
{
?>
<form method="get" action="<?php print $_SERVER[php_SELF]; ?>">
<p><input type="text" name="upc" value=""/></p>
<p><input type="submit" value="Search"/></p>
</form>
<?php

require_once 'XML/RPC.php';

$rpc_key = 'c737eb5b608f31e5fa022718860f1578cf2cc2a6';	// Set your rpc_key here

// Setup the URL of the XML-RPC service
$client = new XML_RPC_Client('/xmlrpc', 'http://www.upcdatabase.com');

// Construct the entire parameter list (an array) for the call.
// The array contains a single XML_RPC_Value object, a struct.
// The struct is constructed from a PHP associative array, and each
// value needs to be an XML_RPC_Value object.

	//convert the string length to 12
$upc = str_pad(ltrim($upc,'0'), 12, '0', STR_PAD_LEFT);

$params = array( new XML_RPC_Value( array(
	'rpc_key' => new XML_RPC_Value($rpc_key, 'string'),
	'upc' => new XML_RPC_Value($_REQUEST['upc'], 'string'),
	), 'struct'));

// Construct the XML-RPC request.  Substitute your chosen method name
$msg = new XML_RPC_Message('lookup', $params);

//Actually have the client send the message to the server.  Save response.
$resp = $client->send($msg);

//If there was a problem sending the message, the resp will be false
if (!$resp)
{
	//print the error code from the client and exit
	echo 'Communication error: ' . $client->errstr;
	exit;
}

//If the response doesn't have a fault code, show the response as the array it is
if(!$resp->faultCode())
{

	//Store the value of the response in a variable
	$val = $resp->value();
	//Decode the value, into an array.
	$data = XML_RPC_decode($val);
	//Optionally print the array to the screen to inspect the values
	echo "<pre>" . print_r($data, true) . "</pre>";
	echo '<p>'.$data['status'].'</p>';
	echo '<p>'.$data['upc'].'</p>';
	echo '<p>'.$data['description'].'</p>';

}else{
	//If something went wrong, show the error
	echo 'Fault Code: ' . $resp->faultCode() . "\n";
	echo 'Fault Reason: ' . $resp->faultString() . "\n";

}	
}

?>

<p>Enter a 12 digit UPC Barcode</p>
<form method="get" action="<?php print $_SERVER[php_SELF]; ?>">
<p><input type="text" name="upc" value=""/></p>
<p><input type="submit" value="Search"/></p>
</form>