$file_data['target_file_name'] = '';
while (strlen($file_data['target_file_name']) < $settings['random_name_len'])
$file_data['target_file_name'] .= $settings['random_name_alphabet'][mt_rand(0, strlen($settings['random_name_alphabet']) - 1)];
$file_data['target_file_name'] = '';
while (strlen($file_data['target_file_name']) < $settings['random_name_len'])
$file_data['target_file_name'] .= $settings['random_name_alphabet'][mt_rand(0, strlen($settings['random_name_alphabet']) - 1)];