diff --git a/src/hb-cff-interp-common.hh b/src/hb-cff-interp-common.hh
index 8a79c7afb..fa03d672a 100644
--- a/src/hb-cff-interp-common.hh
+++ b/src/hb-cff-interp-common.hh
@@ -327,13 +327,14 @@ struct byte_str_ref_t
     }
   }
 
+  unsigned get_offset () const { return offset; }
+
   void set_error ()      { error = true; }
   bool in_error () const { return error; }
 
+  protected:
   hb_ubytes_t       str;
   unsigned int  offset; /* beginning of the sub-string within str */
-
-  protected:
   bool	  error;
 };
 
@@ -521,16 +522,16 @@ struct parsed_values_t
   {
     VAL *val = values.push ();
     val->op = op;
-    val->str = str_ref.sub_array (opStart, str_ref.offset - opStart);
-    opStart = str_ref.offset;
+    val->str = str_ref.sub_array (opStart, str_ref.get_offset () - opStart);
+    opStart = str_ref.get_offset ();
   }
 
   void add_op (op_code_t op, const byte_str_ref_t& str_ref, const VAL &v)
   {
     VAL *val = values.push (v);
     val->op = op;
-    val->str = str_ref.sub_array ( opStart, str_ref.offset - opStart);
-    opStart = str_ref.offset;
+    val->str = str_ref.sub_array (opStart, str_ref.get_offset () - opStart);
+    opStart = str_ref.get_offset ();
   }
 
   bool has_op (op_code_t op) const
diff --git a/src/hb-ot-cff1-table.hh b/src/hb-ot-cff1-table.hh
index 17b029661..007225c84 100644
--- a/src/hb-ot-cff1-table.hh
+++ b/src/hb-ot-cff1-table.hh
@@ -813,7 +813,7 @@ struct cff1_top_dict_opset_t : top_dict_opset_t<cff1_top_dict_val_t>
 	break;
 
       default:
-	env.last_offset = env.str_ref.offset;
+	env.last_offset = env.str_ref.get_offset ();
 	top_dict_opset_t<cff1_top_dict_val_t>::process_op (op, env, dictval);
 	/* Record this operand below if stack is empty, otherwise done */
 	if (!env.argStack.is_empty ()) return;