def __init__(self, row = 2, mask = None):
  if row < 2:
   raise ValueError(u'Not acceptable row number or mask value')
  self.Row = row
  if mask != None and not isinstance(mask, (types.StringType, types.UnicodeType)):
   raise ValueError(u'Not acceptable mask value')
  self.Mask = mask
  self.Length = 0
  self.Column = 0

def encrypt(self, src, nowhitespace = False):
  if not isinstance(src, (types.StringType, types.UnicodeType)):
   raise TypeError(u'Encryption src text is not string')
  if nowhitespace:
   self.NoWhiteSpace = ''
   for i in src:
    if i in string.whitespace: continue
    self.NoWhiteSpace += i
  else:
   self.NoWhiteSpace = src
  
  self.Length = len(self.NoWhiteSpace)
  self.Column = int(math.ceil(self.Length / self.Row))
  try:
   self.__check()
  except Exception, msg:
   print msg
  #get mask order
  self.__getOrder()
  
  grid = [[] for i in range(self.Row)]
  for c in range(self.Column):
   endIndex = (c + 1) * self.Row
   if endIndex > self.Length:
    endIndex = self.Length
   r = self.NoWhiteSpace[c * self.Row : endIndex]
   for i,j in enumerate(r):
    if self.Mask != None and len(self.Order) > 0:
     grid[self.Order[i]].append(j)
    else:
     grid[i].append(j)
  return ''.join([''.join(l) for l in grid])

def decrypt(self, dst):
  if not isinstance(dst, (types.StringType, types.UnicodeType)):
   raise TypeError(u'Decryption dst text is not string')
  self.Length = len(dst)
  self.Column = int(math.ceil(self.Length / self.Row))
  try:
   self.__check()
  except Exception, msg:
   print msg
  #get mask order
  self.__getOrder()
  
  grid = [[] for i in range(self.Row)]
  space = self.Row * self.Column - self.Length
  ns = self.Row - space
  prevE = 0
  for i in range(self.Row):
   if self.Mask != None:
    s = prevE
    O = 0
    for x,y in enumerate(self.Order):
     if i == y:
      O = x
      break
    if O < ns: e = s + self.Column
    else: e = s + (self.Column - 1)
    r = dst[s : e]
    prevE = e
    grid[O] = list(r)
   else:
    startIndex = 0
    endIndex = 0
    if i < self.Row - space:
     startIndex = i * self.Column
     endIndex = startIndex + self.Column
    else:    
     startIndex = ns * self.Column + (i - ns) * (self.Column - 1)
     endIndex = startIndex + (self.Column - 1)
    r = dst[startIndex:endIndex]
    grid[i] = list(r)
  res = ''
  for c in range(self.Column):
   for i in range(self.Row):
    line = grid[i]
    if len(line) == c:
     res += ' '
    else:
     res += line[c]
  return res

rf = RailFence(4, 'bcaf')
e = rf.encrypt('the anwser is wctf{C01umnar},if u is a big new,u can help us think more question,tks.')
print "Encrypt: ",e
print "Decrypt: ", rf.decrypt(e)