908 def _buildencodefun():

   909     e = '_'

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

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

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

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

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

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

   916     dmap = {}

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

   918         dmap[v] = k

   919     def decode(s):

   920         i = 0

   921         while i < len(s):

   922             for l in xrange(1, 4):

   923                 try:

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

   925                     i += l

   926                     break

   927                 except KeyError:

   928                     pass

   929             else:

   930                 raise KeyError

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

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

   933 

   934 encodefilename, decodefilename = _buildencodefun()

   935 

   936 def encodedopener(openerfn, fn):

   937     def o(path, *args, **kw):

   938         return openerfn(fn(path), *args, **kw)

   939     return o