private long computeUndefNum ( final Tristate [ ] bits ) { long sum = 0 ; for ( int i = bits . length - 1 ; i >= 0 ; i -- ) if ( bits [ i ] == Tristate . UNDEF ) sum += Math . pow ( 2 , bits . length - 1 - i ) ; return sum ; }
Computes a number representing the number and position of the UNDEF states in the bit array .