Add vtref_*(), and nvti_ref*() functions.

This add vref_type(), vtref_id(), nvt_ref() and
nvt_ref_len() to the API.
These functions allow to work with the actual reference
object rather than with the serialized strings.
The names are choosen to be consistent with the prefs
handling.

base/nvti.c

@@ -103,6 +103,34 @@ vtref_free (vtref_t *ref)
   g_free (ref);
 }
 
+/**
+ * @brief Get the type of a reference.
+ *
+ * @param r The VT Reference structure of which the type should
+ *          be returned.
+ *
+ * @return The type string. Don't free this.
+ */
+gchar *
+vtref_type (const vtref_t *r)
+{
+  return (r ? r->type : NULL);
+}
+
+/**
+ * @brief Get the id of a reference.
+ *
+ * @param r The VT Reference structure of which the id should
+ *          be returned.
+ *
+ * @return The id string. Don't free this.
+ */
+gchar *
+vtref_id (const vtref_t *r)
+{
+  return (r ? r->ref_id : NULL);
+}
+
 /**
  * @brief Add a reference to the VT Info.
  *
@@ -298,6 +326,34 @@ nvti_name (const nvti_t *n)
   return (n ? n->name : NULL);
 }
 
+/**
+ * @brief Get the number of references of the NVT.
+ *
+ * @param n The NVT Info structure.
+ *
+ * @return The number of references.
+ */
+guint
+nvti_ref_len (const nvti_t *n)
+{
+  return (n ? g_slist_length (n->refs) : 0);
+}
+
+/**
+ * @brief Get the n'th reference of the NVT.
+ *
+ * @param n The NVT Info structure.
+ *
+ * @param p The position of the reference to return.
+ *
+ * @return The reference. NULL on error.
+ */
+vtref_t *
+nvti_ref (const nvti_t *n, guint p)
+{
+  return (n ? g_slist_nth_data (n->refs, p) : NULL);
+}
+
 /**
  * @brief Get references as string.
  *
@@ -521,7 +577,7 @@ nvti_pref_len (const nvti_t *n)
  *
  * @param p The position of the preference to return.
  *
- * @return The number of preferences. NULL if
+ * @return The preference. NULL on error.
  */
 const nvtpref_t *
 nvti_pref (const nvti_t *n, guint p)

base/nvti.h

@@ -110,8 +110,17 @@ vtref_t *
 vtref_new (const gchar *, const gchar *, const gchar *);
 void
 vtref_free (vtref_t *);
+gchar *
+vtref_type (const vtref_t *);
+gchar *
+vtref_id (const vtref_t *);
+
 int
 nvti_add_ref (nvti_t *, vtref_t *);
+guint
+nvti_ref_len (const nvti_t *);
+vtref_t *
+nvti_ref (const nvti_t *, guint);
 
 nvti_t *
 nvti_new (void);