+struct casereader *casefile_get_destructive_reader (struct casefile *);
+
+const struct casefile *casereader_get_casefile (const struct casereader *);
+int casereader_read (struct casereader *, struct ccase *);
+int casereader_read_xfer (struct casereader *, struct ccase *);
+void casereader_read_xfer_assert (struct casereader *, struct ccase *);