private static function make_crc_table() { for ($n = 0; $n < 256; $n++) { $c = $n; for ($k = 0; $k < 8; $k++) { if (($c & 1) == 1) { $c = 0xedb88320 ^ self::SHR($c, 1); } else { $c = self::SHR($c, 1); } } self::$crc_table[$n] = $c; } self::$crc_table_computed = true; }