Python格式化css文件的方法

import string, sys
import re, StringIO
TAB=4
def format(ss):
  f = open (ss, "r")
  data = f.read()
  f.close()
  dlen = len(data)
  i = 0
  buf = StringIO.StringIO()
  start = 0
  while i < dlen:
    if data[i] == '{':
      buf.write(data[start:i] + ' { ')
      i = i + 1
      start = i
    elif data[i] == '}':
      last = string.strip(data[start:i])
      if last:
        buf.write(' '*TAB + last + ';')
      buf.write(' } ')
      i = i + 1
      start = i
    elif data[i] == ';':
      line = string.strip(data[start:i])
      buf.write(' '*TAB + line + '; ')
      i = i + 1
      start = i
    else:
      i = i + 1
  buf.write(data[start:i+1])
  return buf.getvalue()
if __name__ == '__main__':
  if len(sys.argv) == 1:
    print 'usage: cssformat.py filename'
    sys.exit()
  ret = format(sys.argv[1])
  print ret