<human>:  get line count
<bot>: Here is some code to get line count of file `filename`

def bufcount(filename):
  f = open(filename)
  lines = 0
  buf_size = (1024 * 1024)
  read_f = f.read
  buf = read_f(buf_size)
  while buf:
    lines += buf.count('\n')
    buf = read_f(buf_size)
  return lines

#Warning: this code generation is experimental. Please inspect the code for any bugs before executing.