diff --git a/core/fpdfapi/parser/cpdf_document.cpp b/core/fpdfapi/parser/cpdf_document.cpp
index 1505834..05b5f47 100644
--- a/core/fpdfapi/parser/cpdf_document.cpp
+++ b/core/fpdfapi/parser/cpdf_document.cpp
@@ -59,7 +59,9 @@
     if (objnum == pNode->GetObjNum())
       return *index;
 
-    (*skip_count)--;
+    if (*skip_count != 0)
+      (*skip_count)--;
+
     (*index)++;
     return -1;
   }