--- a/mercurial/windows.py	Wed Jul 08 09:48:48 2009 -0400
+++ b/mercurial/windows.py	Thu Jul 09 21:39:19 2009 +0900
@@ -209,11 +209,9 @@
     dircache = {} # dirname -> filename -> status | None if file does not exist
     for nf in files:
         nf  = ncase(nf)
-        pos = nf.rfind(sep)
-        if pos == -1:
-            dir, base = '.', nf
-        else:
-            dir, base = nf[:pos+1], nf[pos+1:]
+        dir, base = os.path.split(nf)
+        if not dir:
+            dir = '.'
         cache = dircache.get(dir, None)
         if cache is None:
             try: