def findIndex(pos)
      index = pos / @blen
      index -= 1 while                    @bpos[index] > pos
      index += 1 while @bpos[index + 1] && (@bpos[index + 1] < pos)
      index
    end
def findIndex(pos)
      index = pos / @blen
      index -= 1 while                    @bpos[index] > pos
      index += 1 while @bpos[index + 1] && (@bpos[index + 1] < pos)
      index
    end
Initialization