872 def _buildencodefun():

   873     e = '_'

   874     win_reserved = [ord(x) for x in '|\?*<":>+[]']

   875     cmap = dict([ (chr(x), chr(x)) for x in xrange(127) ])

   876     for x in (range(32) + range(126, 256) + win_reserved):

   877         cmap[chr(x)] = "~%02x" % x

   878     for x in range(ord("A"), ord("Z")+1) + [ord(e)]:

   879         cmap[chr(x)] = e + chr(x).lower()

   880     dmap = {}

   881     for k, v in cmap.iteritems():

   882         dmap[v] = k

   883     def decode(s):

   884         i = 0

   885         while i < len(s):

   886             for l in xrange(1, 4):

   887                 try:

   888                     yield dmap[s[i:i+l]]

   889                     i += l

   890                     break

   891                 except KeyError:

   892                     pass

   893             else:

   894                 raise KeyError

   895     return (lambda s: "".join([cmap[c] for c in s]),

   896             lambda s: "".join(list(decode(s))))

   897 

   898 encodefilename, decodefilename = _buildencodefun()

   899