f::safe_name PHP Method

    static function safe_name($string)
    {
        return str::urlify($string);
    }

 function file($field, $destination, $params = array())
 {
     $allowed = a::get($params, 'allowed', c::get('upload.allowed', array('image/jpeg', 'image/png', 'image/gif')));
     $maxsize = a::get($params, 'maxsize', c::get('upload.maxsize', self::max_size()));
     $overwrite = a::get($params, 'overwrite', c::get('upload.overwrite', true));
     $sanitize = a::get($params, 'sanitize', true);
     $file = a::get($_FILES, $field);
     if (empty($file)) {
         return array('status' => 'error', 'msg' => l::get('upload.errors.missing-file', 'The file has not been found'));
     }
     $name = a::get($file, 'name');
     $type = a::get($file, 'type');
     $tmp_name = a::get($file, 'tmp_name');
     $error = a::get($file, 'error');
     $size = a::get($file, 'size');
     $msg = false;
     $extension = self::mime_to_extension($type, 'jpg');
     // convert the filename to a save name
     $fname = $sanitize ? f::safe_name(f::name($name)) : f::name($name);
     // setup the destination
     $destination = str_replace('{name}', $fname, $destination);
     $destination = str_replace('{extension}', $extension, $destination);
     if (file_exists($destination) && $overwrite == false) {
         return array('status' => 'error', 'msg' => l::get('upload.errors.file-exists', 'The file exists and cannot be overwritten'));
     }
     if (empty($tmp_name)) {
         return array('status' => 'error', 'msg' => l::get('upload.errors.missing-file', 'The file has not been found'));
     }
     if ($error != 0) {
         return array('status' => 'error', 'msg' => l::get('upload.errors.invalid-upload', 'The upload failed'));
     }
     if ($size > $maxsize) {
         return array('status' => 'error', 'msg' => l::get('upload.errors.too-big', 'The file is too big'));
     }
     if (!in_array($type, $allowed)) {
         return array('status' => 'error', 'msg' => l::get('upload.errors.invalid-file', 'The file type is not allowed') . ': ' . $type);
     }
     // try to change the permissions for the destination
     @chmod(dirname($destination), 0777);
     if (!@copy($tmp_name, $destination)) {
         return array('status' => 'error', 'msg' => l::get('upload.errors.move-error', 'The file could not be moved to the server'));
     }
     // try to change the permissions for the final file
     @chmod($destination, 0777);
     return array('status' => 'success', 'msg' => l::get('upload.success', 'The file has been uploaded'), 'type' => $type, 'extension' => $extension, 'file' => $destination, 'size' => $size, 'name' => f::filename($destination));
 }