iovars.rb

# before

def reset!
  @start = @used = 0
  @eof = false
  @write_synced = true
end

def discard(skip)
  while @start < @used
    break unless @storage[@start] == skip
    @start += 1
  end
end


# after some "fp" is added

class IOVars
  def initialize(start = 0, used = 0, eof = false, write_synced = true, *args)
    @start = start
    @used = used
    @eof = eof
    @write_synced = write_synced
    # other ivars initialized here...
  end
  
  def reset!
    new
  end
  
  def advance_start(count)
    new(@start + count, @used, @write_synced)
  end
end

def discard(skip)
  while @ivars.remaining_bytes?
    break unless @storage[@ivars.start] == skip
    @ivars = @iovars.advance_start(1)
  end
end