X-Git-Url: http://git.nguyen.vg/gitweb/?a=blobdiff_plain;f=XMLTree.cpp;h=bb861a9765e31a34e4114013c26abbeb093b987f;hb=0f2d33d4ee4291d61750769c2918263c7e485ffa;hp=f155d3e8e18ec4c55f3171fdc0b19894e2e7fdc4;hpb=eb43419905c2956230f4c773a0b5b6fa3ff694d8;p=SXSI%2FXMLTree.git

diff --git a/XMLTree.cpp b/XMLTree.cpp
index f155d3e..bb861a9 100644
--- a/XMLTree.cpp
+++ b/XMLTree.cpp
@@ -539,6 +539,9 @@ treeNode XMLTree::TaggedFoll(treeNode x, TagType tag)
     }
 
     int r, s;
+    if (x == Root() || (next_sibling(Par,x) == -1 ))
+      return NULLT;
+    
     r = (int) Tags->rank(tag, node2tagpos(next_sibling(Par, x))-1);
     s = (int) Tags->select(tag, r+1);  // select returns -1 in case that there is no r+1-th tag.
     if (s==-1) return NULLT;