CI validation rules

class Some_controller extends CI_Controller {

    public validate(){
        $rules = $this->some_model->get_custom_rules(array('rule1','rule2'));
        $this->form_validation->set_rules($rules);
    }

}

class Some_model extends CI_Model{
    public $validation_rules = array(
            array('field' => 'rule1', 'label' => 'label1', 'rules' => 'required|max_length[255]'),
            array('field' => 'rule2', 'label' => 'label2', 'rules' => 'required|max_length[255]'),
        );

    public function get_custom_rules(array $componets) {
            $rules = array();
            foreach ($this->validation_rules as $value) {
                    if (in_array($value['field'], $componets)) {
                        $rules[] = $value;
                    }
            }
            return $rules;
        }
}