Fix SequenceHandle checks for GetOneLetterCode

git-svn-id: https://dng.biozentrum.unibas.ch/svn/openstructure/trunk@2199 5a81b35b-ba03-0410-adc8-b2c5c5119f08

modules/seq/base/src/impl/sequence_impl.cc

@@ -170,6 +170,8 @@ int SequenceImpl::GetLength() const {
 
 char SequenceImpl::GetOneLetterCode(int position) const
 {
+  if (position<0 || position>=static_cast<int>(seq_string_.length()))
+    throw Error("Position is not covered in sequence");
   return seq_string_[position];
 }