Fixed incorrect result when file size >= 512M.

tests/test.js

@@ -175,5 +175,12 @@
         }
       });
     });
+
+    context('when large size', function () {
+      var hash = sha1.create();
+      hash.bytes = 4294967295;
+      hash.update('any');
+      expect(hash.hBytes).to.be(1);
+    });
   });
 })(sha1);