Fixed regression of issue #644

lstm/lstmtrainer.h

@@ -301,6 +301,7 @@ class LSTMTrainer : public LSTMRecognizer {
   // language model. trainer is the model that is restored.
   bool ReadTrainingDump(const GenericVector<char>& data,
                         LSTMTrainer* trainer) const {
+    if (data.empty()) return false;
     return ReadSizedTrainingDump(&data[0], data.size(), trainer);
   }
   bool ReadSizedTrainingDump(const char* data, int size,