1 files changed, 13 insertions, 3 deletions
diff --git a/boost/geometry/algorithms/detail/overlay/turn_info.hpp b/boost/geometry/algorithms/detail/overlay/turn_info.hpp
index aa6b428f19..89a60b21ab 100644
--- a/boost/geometry/algorithms/detail/overlay/turn_info.hpp
+++ b/boost/geometry/algorithms/detail/overlay/turn_info.hpp
@@ -28,7 +28,8 @@ enum operation_type
     operation_union,
     operation_intersection,
     operation_blocked,
-    operation_continue
+    operation_continue,
+    operation_opposite
 };
 
 
@@ -102,6 +103,12 @@ struct turn_info
     {
         return has12(type, type);
     }
+    
+    inline bool has(operation_type type) const
+    {
+        return this->operations[0].operation == type
+            || this->operations[1].operation == type;
+    }
 
     inline bool combination(operation_type type1, operation_type type2) const
     {
@@ -114,10 +121,13 @@ struct turn_info
     {
         return both(operation_blocked);
     }
+    inline bool opposite() const
+    {
+        return both(operation_opposite);
+    }
     inline bool any_blocked() const
     {
-        return this->operations[0].operation == operation_blocked
-            || this->operations[1].operation == operation_blocked;
+        return has(operation_blocked);
     }