/**
 * Verifies that the field beeing validated matches the value of the
 * field in the second parameter. If omitted and the field beeing
 * validated's name is NAME_verification, the value will be compared
 * to that of the NAME field.
 *
 * Examples:
 * <code>
 * var $validate(
 *      'password_check' => array(
 *              'rule' => array('verifies', 'password'),
 *              'message' => 'The passwords don\'t match'
 *      ),    
 *      'email_verification' => array(
 *              'rule' => array('verifies'),
 *              'message' => 'The email addresses don\'t match'
 *      ),    
 * )
 * </code>
 * 
 * The second case will verify automagically against the "email" field.
 *
 * By Vicente Aguilar
 * http://www.bisente.com/blog/2008/10/14/validar-campos-de-verificacion-en-cakephp/
 */
function verifies($data, $field=null) {
        $keys = array_keys($data);
        $key = $keys[0];
        if(!is_string($field)) {
                if( ($pos = strpos($key, "_verification")) === FALSE ) {
                        return FALSE;
                }
                $field = substr($key, 0, $pos);
        }
        return ($data[$key] == $this->data[$this->name][$field]);
}