diff --git a/ChangeLog b/ChangeLog
index 7c455ff44a..4e32dfbb2b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Sun Nov  4 11:47:39 2012  Masaki Matsushita  <glass.saga@gmail.com>
+
+	* lib/fileutils.rb (module FileUtils): repatch [ruby-core:39622]
+	  [Feature #5337]. improve performance of FileUtils.compare_stream.
+	  [ruby-core:47545] [Feature #7028]
+
 Sun Nov  4 11:27:54 2012  Masaki Matsushita  <glass.saga@gmail.com>
 
 	* array.c (recursive_equal): fix to return true when self and other
diff --git a/lib/fileutils.rb b/lib/fileutils.rb
index 67cc79f02f..3d74eac385 100644
--- a/lib/fileutils.rb
+++ b/lib/fileutils.rb
@@ -894,16 +894,13 @@ public
   #
   def compare_stream(a, b)
     bsize = fu_stream_blksize(a, b)
-    sa = sb = nil
-    while sa == sb
-      sa = a.read(bsize)
-      sb = b.read(bsize)
-      unless sa and sb
-        if sa.nil? and sb.nil?
-          return true
-        end
-      end
-    end
+    sa = ""
+    sb = ""
+    begin
+      a.read(bsize, sa)
+      b.read(bsize, sb)
+      return true if sa.empty? && sb.empty?
+    end while sa == sb
     false
   end