another array rotaion

rotate.cr

class Array
  def new_rotate!(n = 1)
    return self if empty?
    sz = @size
    n %= sz
    return self if n == 0
    st = to_unsafe
    ed = st + sz
 
    while (sz > 1 && n != 0)
      if n <= (sz // 2)
        p = st
        q = p + n
            
        while q != ed
          q.value, p.value = p.value, q.value
          p += 1
          q += 1
        end
        st = p
        sz, n = n, -sz % n
      else
        p = st + n - 1 
        q = ed - 1 
 
        while st <= p
          q.value, p.value = p.value, q.value
          p -= 1
          q -= 1
        end
        ed = q + 1
        n = sz - n
        sz, n = n, sz % n
      end
    end
    self
    end
end
  
pp (0...144).to_a.new_rotate!(55)