Don't assume TDRC is an instance of TextIdentificationFrame (#831)

If TDRC is encrypted, FrameFactory::createFrame() returns UnknownFrame
which causes problems in rebuildAggregateFrames() when it is assumed
that TDRC is a TextIdentificationFrame

diff --git a/taglib/mpeg/id3v2/id3v2framefactory.cpp b/taglib/mpeg/id3v2/id3v2framefactory.cpp
index 759a9b7be6737da28f933fa19c17f706f21e22f2..9347ab86972a32ea31229dfd719f8a4f0cd84947 100644 (file)
--- a/taglib/mpeg/id3v2/id3v2framefactory.cpp
+++ b/taglib/mpeg/id3v2/id3v2framefactory.cpp
@@ -334,10 +334,11 @@ void FrameFactory::rebuildAggregateFrames(ID3v2::Tag *tag) const
      tag->frameList("TDAT").size() == 1)
   {
     TextIdentificationFrame *tdrc =
-      static_cast<TextIdentificationFrame *>(tag->frameList("TDRC").front());
+      dynamic_cast<TextIdentificationFrame *>(tag->frameList("TDRC").front());
     UnknownFrame *tdat = static_cast<UnknownFrame *>(tag->frameList("TDAT").front());
 
-    if(tdrc->fieldList().size() == 1 &&
+    if(tdrc &&
+       tdrc->fieldList().size() == 1 &&
        tdrc->fieldList().front().size() == 4 &&
        tdat->data().size() >= 5)
     {