Make nsd compare methods handle NULLs

(raptor_nsd_compare, raptor_xml_writer_nsd_compare): Sort NULLs
separate and avoid strcmp() where those are undefined.

2 files changed, 12 insertions, 0 deletions

diff --git a/src/raptor_xml.c b/src/raptor_xml.c
index 2b60a3ff..77644ca9 100644
--- a/src/raptor_xml.c
+++ b/src/raptor_xml.c
@@ -319,6 +319,12 @@ raptor_nsd_compare(const void *a, const void *b)
 {
   struct nsd* nsd_a = (struct nsd*)a;
   struct nsd* nsd_b = (struct nsd*)b;
+
+  /* Sort NULLs earlier */
+  if(!nsd_a->declaration)
+    return -1;
+  else if(!nsd_b->declaration)
+    return 1;
   return strcmp((const char*)nsd_a->declaration, (const char*)nsd_b->declaration);
 }
 
diff --git a/src/raptor_xml_writer.c b/src/raptor_xml_writer.c
index 0d3a36a5..2f442ba8 100644
--- a/src/raptor_xml_writer.c
+++ b/src/raptor_xml_writer.c
@@ -164,6 +164,12 @@ raptor_xml_writer_nsd_compare(const void *a, const void *b)
 {
   struct nsd* nsd_a = (struct nsd*)a;
   struct nsd* nsd_b = (struct nsd*)b;
+
+  /* Sort NULLs earlier */
+  if(!nsd_a->declaration)
+    return -1;
+  else if(!nsd_b->declaration)
+    return 1;
   return strcmp((const char*)nsd_a->declaration, (const char*)nsd_b->declaration);
 }