X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=src%2Flibpspp%2Fintern.c;fp=src%2Flibpspp%2Fintern.c;h=b8eb5198b4d9ac902ef2ce67c2fd1c994b5f0de2;hb=4ae5f1b099bc4de1f59898bc609e34dcb722b39c;hp=fc31acf0b439fec19c339296abe3e5fe8f5ce314;hpb=44c7a157afd05dace564c39e73a257c2758263b0;p=pspp

diff --git a/src/libpspp/intern.c b/src/libpspp/intern.c
index fc31acf0b4..b8eb5198b4 100644
--- a/src/libpspp/intern.c
+++ b/src/libpspp/intern.c
@@ -77,6 +77,13 @@ intern_new (const char *s)
   return is->string;
 }
 
+const char *
+intern_new_if_nonnull (const char *s)
+{
+  return s ? intern_new (s) : NULL;
+}
+
+
 static struct interned_string *
 interned_string_from_string (const char *s_)
 {
@@ -96,17 +103,26 @@ intern_ref (const char *s)
   return s;
 }
 
+const char *
+intern_ref_if_nonnull (const char *s)
+{
+  return s ? intern_ref (s) : NULL;
+}
+
 /* Decreases the reference count on S, which must be an interned string
    returned by intern_new().  If the reference count reaches 0, frees the
    interned string. */
 void
 intern_unref (const char *s)
 {
-  struct interned_string *is = interned_string_from_string (s);
-  if (--is->ref_cnt == 0)
+  if (s)
     {
-      hmap_delete (&interns, &is->node);
-      free (is);
+      struct interned_string *is = interned_string_from_string (s);
+      if (--is->ref_cnt == 0)
+        {
+          hmap_delete (&interns, &is->node);
+          free (is);
+        }
     }
 }