diff --git a/source/utf8/checked.h b/source/utf8/checked.h
index 1331155..0e662e2 100644
--- a/source/utf8/checked.h
+++ b/source/utf8/checked.h
@@ -30,6 +30,7 @@ DEALINGS IN THE SOFTWARE.
 
 #include "core.h"
 #include <stdexcept>
+#include <cassert>
 
 namespace utf8
 {
@@ -263,8 +264,52 @@ namespace utf8
         return result;
     }
 
+	// Error policies for the iterator class
+    template <typename I>
+    class ErrorPolicyThrow {
+      public:
+      static void check_in_range(const I& it, const I& range_start, const I& range_end)
+	  {
+          if (it < range_start || it > range_end)
+              throw std::out_of_range("Invalid utf-8 iterator position");
+      }
+      static void check_same_range(const I& range_start_a, const I& range_start_b, const I& range_end_a, const I& range_end_b)
+	  {
+          if (range_start_a != range_start_b || range_end_a != range_end_b)
+              throw std::logic_error("Comparing utf-8 iterators defined with different ranges");
+      }
+    };
+    template <typename I>
+    class ErrorPolicyAssert {
+      public:
+      static void check_in_range(const I& it, const I& range_start, const I& range_end)
+	  {
+#if defined(NDEBUG)
+          (void)it;
+          (void)range_start;
+          (void)range_end;
+#else
+		  assert(it >= range_start && it <= range_end);
+#endif
+      }
+      static void check_same_range(const I& range_start_a, const I& range_start_b, const I& range_end_a, const I& range_end_b)
+	  {
+#if defined(NDEBUG)
+          (void)range_start_a;
+          (void)range_start_b;
+          (void)range_end_a;
+          (void)range_end_b;
+#else
+          assert(range_start_a == range_start_b && range_end_a == range_end_b);
+#endif
+      }
+    };
+
     // The iterator class
-    template <typename octet_iterator>
+    template <
+		typename octet_iterator,
+		typename error_policy=ErrorPolicyThrow<octet_iterator>
+	>
     class iterator : public std::iterator <std::bidirectional_iterator_tag, uint32_t> {
       octet_iterator it;
       octet_iterator range_start;
@@ -276,8 +321,7 @@ namespace utf8
                          const octet_iterator& range_end) :
                it(octet_it), range_start(range_start), range_end(range_end)
       {
-          if (it < range_start || it > range_end)
-              throw std::out_of_range("Invalid utf-8 iterator position");
+          error_policy::check_in_range(it, range_start, range_end);
       }
       // the default "big three" are OK
       octet_iterator base () const { return it; }
@@ -288,8 +332,7 @@ namespace utf8
       }
       bool operator == (const iterator& rhs) const
       {
-          if (range_start != rhs.range_start || range_end != rhs.range_end)
-              throw std::logic_error("Comparing utf-8 iterators defined with different ranges");
+          error_policy::check_same_range(range_start, rhs.range_start, range_end, rhs.range_end);
           return (it == rhs.it);
       }
       bool operator != (const iterator& rhs) const
@@ -323,5 +366,3 @@ namespace utf8
 } // namespace utf8
 
 #endif //header guard
-
-