question: public long [ ] selectZero ( long rank , long [ ] dest , final int offset , final int length ) { if ( length == 0 ) return dest ; long s = selectZero ( rank ) ; dest [ offset ] = s ; int curr = ( int ) ( s / Long . SIZE ) ; long window = ~ bits [ curr ] & - 1L << s ; window &= window - 1 ; for ( int i = 1 ; i < length ; i ++ ) { while ( window == 0 ) window = ~ bits [ ++ curr ] ; dest [ offset + i ] = curr * Long . SIZE + Long . numberOfTrailingZeros ( window ) ; window &= window - 1 ; } return dest ; }
target:  Performs a bulk select of consecutive ranks into a given array fragment.