diff --git a/libdjvu/DjVuPort.cpp b/libdjvu/DjVuPort.cpp

index 2b3e0d2..ede7f6b 100644

--- a/libdjvu/DjVuPort.cpp

+++ b/libdjvu/DjVuPort.cpp

@@ -507,10 +507,19 @@ GP<DjVuFile>

 DjVuPortcaster::id_to_file(const DjVuPort * source, const GUTF8String &id)

 {

    GPList<DjVuPort> list;

+

+   if (!!opening_id && opening_id == id)

+      G_THROW("DjVuPortcaster: recursive opening of the same file (corrupted file?)");

+   else

+      opening_id = id;

+

    compute_closure(source, list, true);

    GP<DjVuFile> file;

    for(GPosition pos=list;pos;++pos)

       if ((file=list[pos]->id_to_file(source, id))) break;

+

+   opening_id = GUTF8String();

+

    return file;

 }

diff --git a/libdjvu/DjVuPort.h b/libdjvu/DjVuPort.h

index e2b3125..313dc2b 100644

--- a/libdjvu/DjVuPort.h

+++ b/libdjvu/DjVuPort.h

@@ -484,6 +484,7 @@ private:

                        const DjVuPort *dst, int distance);

    void compute_closure(const DjVuPort *src, GPList<DjVuPort> &list,

                         bool sorted=false);

+   GUTF8String opening_id;

 };