Bit interleaving and de-interleaving in Ruby (also known as Morton Numbers.)

bit_interleaving.rb

class Integer

  def interleave(y)
    x_bit_size = self > 0 ? Math.log2(self) : 1
    y_bit_size = y > 0 ? Math.log2(y) : 1
    z = 0
    
    ((((x_bit_size <=> y_bit_size) == -1) ? y_bit_size : x_bit_size).floor + 1).times do | i | 
      z |= (self & 1 << i) << i | (y & 1 << i) << (i + 1)
    end
    
    return z
  end

  def deinterleave
    return 0, 0 if self == 0
    x, y = 0, 0
    ((Math.log2(self)).floor + 1).times do | i |
      if (0 != self & (1 << i))
        (i & 1 == 0) ? x |= 1 << (i / 2) : y |= 1 << (i / 2) 
      end
    end
    return x, y
  end

end