Index: trunk/Mars/mcore/checksum.h
===================================================================
--- trunk/Mars/mcore/checksum.h	(revision 20101)
+++ trunk/Mars/mcore/checksum.h	(revision 20102)
@@ -46,4 +46,9 @@
     }
 
+    Checksum &operator=(const Checksum &sum)
+    {
+        buffer = sum.buffer;
+        return *this;
+    }
 
     bool add(const char *buf, size_t len, bool big_endian = true)