Method Sub

libs/bits/bit_array.go:187–208

Sub subtracts the two bit-arrays bitwise, without carrying the bits. Note that carryless subtraction of a - b is (a and not b). The output is the same as bA, regardless of o's size. If bA is longer than o, o is right padded with zeroes

(o *BitArray)

// The output is the same as bA, regardless of o's size.
// If bA is longer than o, o is right padded with zeroes
func (bA *BitArray) Sub(o *BitArray) *BitArray {
	if bA == nil || o == nil {
		// TODO: Decide if we should do 1's complement here?
		return nil
	}
	bA.mtx.Lock()
	o.mtx.Lock()
	// output is the same size as bA
	c := bA.copyBits(bA.Bits)
	// Only iterate to the minimum size between the two.
	// If o is longer, those bits are ignored.
	// If bA is longer, then skipping those iterations is equivalent
	// to right padding with 0's
	smaller := tmmath.MinInt(len(bA.Elems), len(o.Elems))
	for i := 0; i < smaller; i++ {
		// &^ is and not in golang
		c.Elems[i] &^= o.Elems[i]
	}
	bA.mtx.Unlock()
	o.mtx.Unlock()
	return c
}

// IsEmpty returns true iff all bits in the bit array are 0
func (bA *BitArray) IsEmpty() bool {