coping directories

[Gigs_]

hi people

I have problem with this example, not actually the problem, but
[code]
class FileVisitor(object):
     def __init__(self, data=None):
         self.context = data
     def run(self, startdir=os.curdir):
         os.path.walk(startdir, self.visitor, None)
     def visitor(self, data, dirname, filesindir):
         self.visitdir(dirname)
         for fname in filesindir:
             fpath = os.path.join(dirname, fname)
             if not os.path.isdir(fpath):
                 self.visitfile(fpath)
     def visitdir(self, dirpath):            # override or extend this 
method
         print dirpath, '...'
     def visitfile(self, filepath):          # override or extend this 
method
         print self.fcount, '=>', filepath
#
class CVisitor(FileVisitor):
     def __init__(self, fromdir, todir):
         self.fromdirLen = len(fromdir) + 1        # here is my problem
         self.todir = todir
         FileVisitor.__init__(self, fromdir)
     def visitdir(self, dirpath):
         topath = os.path.join(self.todir, dirpath[self.fromdirLen:])
         os.mkdir(topath)
     def visitfile(self, filepath):
         topath = os.path.join(self.todir, filepath[self.fromdirLen:])
         cpfile(filepath, topath)    #copy contents from filepath to 
topath[/code]


When I copy contents from C:\IronPython to C:\temp
its all goes fine when self.fromdirLen = len(fromdir) + 1 is like this 
self.fromdirLen = len(fromdir) + 1
but when I change self.fromdirLen = len(fromdir) + 1 to self.fromdirLen 
= len(fromdir) i get contents copied to C:\ (actually to parent dir)

Can anyone explain me that?

Thanks!!!
  :o