if ( !preg_match( '/^[0-9]{10}$/', $code ) )

return false;

for( $i = 0; $i < 10; $i++ )

if ( preg_match( '/^' . $i . '{10}$/', $code ) )

return false;

for( $i = 0, $sum = 0; $i < 9; $i++ )

$sum += ( ( 10 - $i ) * intval( substr( $code, $i, 1 ) ) );

$ret = $sum % 11;

$parity = intval( substr( $code, 9, 1 ) );

if( ( $ret < 2 && $ret == $parity ) || ( $ret >= 2 && $ret == 11 - $parity ) )

return true;

return false;