Is it possible to shift a Java BitSet using the logical operators?-CodePudding

For example I have a BitSet BitSet x = new BitSet(32); and I set bit 3 x.set(2, true);
Is there anyways to do a logical shift like x << someAmount; that pads with 0's?

CodePudding user response：

Here is how you would shift them right and left 8 bits.

BitSet bits = new BitSet();
bits.set(10);
bits.set(30);
System.out.println("unshifted:"   bits);
System.out.println("right shift: "   shift(bits, 8));
System.out.println("left shift: "   shift(bits,-8));

Prints

unshifted: {10, 30}
right shift: {18, 38}
left shift: {2, 22}

Here is the method

it streams the current positions
and adjusts them based on the shift amount.
Positions due to negative shifts are dropped as they would be out of range.
the new BitSet is returned.

    
public static BitSet shift(BitSet bitset, int shiftAmount) {
    BitSet b = new BitSet();
    bitset.stream().map(bitPos -> bitPos   shiftAmount)
            .dropWhile(bitPos -> bitPos < 0)
            .forEach(bitPos -> b.set(bitPos));
    return b;
}

Note the a BitSet is oriented starting with 1,2,4,8 which is opposite of a normal binary number. Also note that in the above left shifted bits will lose trailing zeros. Right shifted will gain padded ones on the left.