Verification function of Postcode needed - Auspost

if(empty($order->shipping_address->address_post_code)){
						$zoneClass=hikashop_get('class.zone');
							$zones = $zoneClass->getOrderZones($order);
							$db =& JFactory::getDBO();
						$db->setQuery('SELECT zone_namekey FROM '.hikashop_table('zone').' WHERE zone_code_3='.$db->Quote('AUS'));
						$australia_zone = $db->loadResult();
						if(in_array($australia_zone,$zones)){
							$messages['post_code_missing'] = 'The Australia Post shipping plugin requires the user to enter a postal code when goods are shipped within Australia. Please go to "Display->Custom fields" and set the post code field to required.';
							continue;
						}
					}

$check = false;
					if(empty($order->shipping_address->address_post_code)){
						$check = true;
						$message = 'The Australia Post shipping plugin requires the user to enter a postal code when goods are shipped within Australia. Please go to "Display->Custom fields" and set the post code field to required.';
					}elseif(!preg_match('#[0-9]{4}#',$order->shipping_address->address_post_code)){
						$check = true;
						$message = 'The post code entered is not valid';
					}
					if($check){
						$zoneClass=hikashop_get('class.zone');
							$zones = $zoneClass->getOrderZones($order);
							$db =& JFactory::getDBO();
						$db->setQuery('SELECT zone_namekey FROM '.hikashop_table('zone').' WHERE zone_code_3='.$db->Quote('AUS'));
						$australia_zone = $db->loadResult();
						if(in_array($australia_zone,$zones)){
							$messages['post_code_missing'] = $message;
							continue;
						}
					}

if(empty($order->shipping_address->address_post_code)){
						$zoneClass=hikashop_get('class.zone');
							$zones = $zoneClass->getOrderZones($order);
							$db =& JFactory::getDBO();
						$db->setQuery('SELECT zone_namekey FROM '.hikashop_table('zone').' WHERE zone_code_3='.$db->Quote('USA'));
						$usa_zone = $db->loadResult();
						if(in_array($us_zone,$zones)){
							$messages['post_code_missing'] = 'The USPS shipping plugin requires the user to enter a postal code when goods are shipped within the United States. Please go to "Display->Custom fields" and set the post code field to required.';
							continue;
						}
					}

$check = false;
					if(empty($order->shipping_address->address_post_code)){
						$check = true;
						$message = 'The USPS shipping plugin requires the user to enter a postal code when goods are shipped within the United States. Please go to "Display->Custom fields" and set the post code field to required.';
					}elseif(!preg_match('#^[0-9]{5}(-?[0-9]{4})?$#',$order->shipping_address->address_post_code)){
						$check = true;
						$message = 'The post code entered is not valid';
					}
					if($check){
						$zoneClass=hikashop_get('class.zone');
							$zones = $zoneClass->getOrderZones($order);
							$db =& JFactory::getDBO();
						$db->setQuery('SELECT zone_namekey FROM '.hikashop_table('zone').' WHERE zone_code_3='.$db->Quote('USA'));
						$usa_zone = $db->loadResult();
						if(in_array($usa_zone,$zones)){
							$messages['post_code_missing'] = $message;
							continue;
						}
					}