ARC2::getCleanedIndex PHP Method

    static function getCleanedIndex()
    {
        /* removes triples from a given index */
        $indexes = func_get_args();
        $r = $indexes[0];
        for ($i = 1, $i_max = count($indexes); $i < $i_max; $i++) {
            $index = $indexes[$i];
            foreach ($index as $s => $ps) {
                if (!isset($r[$s])) {
                    continue;
                }
                foreach ($ps as $p => $os) {
                    if (!isset($r[$s][$p])) {
                        continue;
                    }
                    $r_os = $r[$s][$p];
                    $new_os = array();
                    foreach ($r_os as $r_o) {
                        $r_o_val = is_array($r_o) ? $r_o['value'] : $r_o;
                        $keep = 1;
                        foreach ($os as $o) {
                            $del_o_val = is_array($o) ? $o['value'] : $o;
                            if ($del_o_val == $r_o_val) {
                                $keep = 0;
                                break;
                            }
                        }
                        if ($keep) {
                            $new_os[] = $r_o;
                        }
                    }
                    if ($new_os) {
                        $r[$s][$p] = $new_os;
                    } else {
                        unset($r[$s][$p]);
                    }
                }
            }
        }
        /* check r */
        $has_data = 0;
        foreach ($r as $s => $ps) {
            if ($ps) {
                $has_data = 1;
                break;
            }
        }
        return $has_data ? $r : array();
    }

 function delete($doc, $g = 'http://localhost/')
 {
     $index = $this->v($g, array(), $this->data);
     $this->data[$g] = ARC2::getCleanedIndex($index, $this->toIndex($doc));
 }