Fixed sizeof

construct · Aug 29, 2016 · 3234c56 · 3234c56
1 parent 553baae
commit 3234c56
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/construct/core.py b/construct/core.py
@@ -563,6 +563,8 @@ def _build(self, obj, stream, context):
                     (self.mincount, self.maxcount, len(obj)), sys.exc_info()[1])
 
     def _sizeof(self, context):
+        if context is None:
+            raise SizeofError("cannot calculate size")
         if not len(context) <= self.mincount <= self.maxcout <= len(context):
             raise SizeofError("expected between %d and %d, but found %d" % 
             (self.mincount, self.maxcout, len(context)))