diff --git a/ChangeLog b/ChangeLog
index 21e6ad2bfe..9d7508b9c0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Thu Oct 22 17:49:05 2009  Akinori MUSHA  <knu@iDaemons.org>
+
+	* lib/fileutils.rb (FileUtils#fu_get_uid, fu_get_gid): Do not
+	  convert an integer back and forth.
+
 Thu Oct 22 17:29:51 2009  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* parse.y (arg_prepend): removed.  a patch from Mikhail T. in
diff --git a/lib/fileutils.rb b/lib/fileutils.rb
index 58e3f1d684..8c522ced55 100644
--- a/lib/fileutils.rb
+++ b/lib/fileutils.rb
@@ -977,20 +977,26 @@ module FileUtils
 
     def fu_get_uid(user)   #:nodoc:
       return nil unless user
-      user = user.to_s
-      if /\A\d+\z/ =~ user
-      then user.to_i
-      else Etc.getpwnam(user).uid
+      case user
+      when Integer
+        user
+      when /\A\d+\z/
+        user.to_i
+      else
+        Etc.getpwnam(user).uid
       end
     end
     private_module_function :fu_get_uid
 
     def fu_get_gid(group)   #:nodoc:
       return nil unless group
-      group = group.to_s
-      if /\A\d+\z/ =~ group
-      then group.to_i
-      else Etc.getgrnam(group).gid
+      case group
+      when Integer
+        group
+      when /\A\d+\z/
+        group.to_i
+      else
+        Etc.getgrnam(group).gid
       end
     end
     private_module_function :fu_get_gid