+/* This function is the same as ovsdb_datum_sort(), except that the caller
+ * knows that 'datum' is unique. The operation therefore "cannot fail", so
+ * this function assert-fails if it actually does. */
+void
+ovsdb_datum_sort_assert(struct ovsdb_datum *datum,
+ enum ovsdb_atomic_type key_type)
+{
+ struct ovsdb_error *error = ovsdb_datum_sort(datum, key_type);
+ if (error) {
+ OVS_NOT_REACHED();
+ }
+}
+
+/* This is similar to ovsdb_datum_sort(), except that it drops duplicate keys
+ * instead of reporting an error. In a map type, the smallest value among a
+ * group of duplicate pairs is retained and the others are dropped.
+ *
+ * Returns the number of keys (or pairs) that were dropped. */
+size_t
+ovsdb_datum_sort_unique(struct ovsdb_datum *datum,
+ enum ovsdb_atomic_type key_type,
+ enum ovsdb_atomic_type value_type)
+{
+ size_t src, dst;
+
+ if (datum->n < 2) {
+ return 0;
+ }
+
+ ovsdb_datum_sort__(datum, key_type, value_type);
+
+ dst = 1;
+ for (src = 1; src < datum->n; src++) {
+ if (ovsdb_atom_equals(&datum->keys[src], &datum->keys[dst - 1],
+ key_type)) {
+ ovsdb_atom_destroy(&datum->keys[src], key_type);
+ if (value_type != OVSDB_TYPE_VOID) {
+ ovsdb_atom_destroy(&datum->values[src], value_type);
+ }
+ } else {
+ if (src != dst) {
+ datum->keys[dst] = datum->keys[src];
+ if (value_type != OVSDB_TYPE_VOID) {
+ datum->values[dst] = datum->values[src];
+ }
+ }
+ dst++;
+ }