diff --git a/lib/rqrcode/core_ext/array.rb b/lib/rqrcode/core_ext/array.rb
index 84ac7964..c0ea8a90 100644
--- a/lib/rqrcode/core_ext/array.rb
+++ b/lib/rqrcode/core_ext/array.rb
@@ -1,5 +1,5 @@
 require 'rqrcode/core_ext/array/behavior'
 
 class Array #:nodoc:
-  include CoreExtensions::Array::Behavior
+  include RQRCode::CoreExtensions::Array::Behavior
 end
diff --git a/lib/rqrcode/core_ext/array/behavior.rb b/lib/rqrcode/core_ext/array/behavior.rb
index d8f008a9..981e39c4 100644
--- a/lib/rqrcode/core_ext/array/behavior.rb
+++ b/lib/rqrcode/core_ext/array/behavior.rb
@@ -1,9 +1,12 @@
-module CoreExtensions #:nodoc:
-  module Array #:nodoc:
-    module Behavior
-      def extract_options!
-        last.is_a?(::Hash) ? pop : {}
+module RQRCode
+  module CoreExtensions #:nodoc:
+    module Array #:nodoc:
+      module Behavior
+        def extract_options!
+          last.is_a?(::Hash) ? pop : {}
+        end unless [].respond_to?(:extract_options!)
       end
     end
   end
 end
+
diff --git a/lib/rqrcode/core_ext/integer.rb b/lib/rqrcode/core_ext/integer.rb
index 1b12f1c0..acd37490 100644
--- a/lib/rqrcode/core_ext/integer.rb
+++ b/lib/rqrcode/core_ext/integer.rb
@@ -1,5 +1,5 @@
 require 'rqrcode/core_ext/integer/bitwise'
 
 class Integer #:nodoc:
-  include CoreExtensions::Integer::Bitwise
+  include RQRCode::CoreExtensions::Integer::Bitwise
 end
diff --git a/lib/rqrcode/core_ext/integer/bitwise.rb b/lib/rqrcode/core_ext/integer/bitwise.rb
index 249e11b7..bb5fadcd 100644
--- a/lib/rqrcode/core_ext/integer/bitwise.rb
+++ b/lib/rqrcode/core_ext/integer/bitwise.rb
@@ -1,9 +1,11 @@
-module CoreExtensions #:nodoc:
-  module Integer #:nodoc:
-    module Bitwise
-      def rszf(count)
-        # zero fill right shift
-        (self >> count) & ((2 ** ((self.size * 8) - count))-1)
+module RQRCode
+  module CoreExtensions #:nodoc:
+    module Integer #:nodoc:
+      module Bitwise
+        def rszf(count)
+          # zero fill right shift
+          (self >> count) & ((2 ** ((self.size * 8) - count))-1)
+        end
       end
     end
   end