+/* PSPP - a program for statistical analysis.
+ Copyright (C) 2007 Free Software Foundation, Inc.
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+/* Lazy casereader.
+
+ A "lazy casereader" is a casereader that saves an underlying
+ casereader from the need to be instantiated in the case where
+ it is never used. If any casereader operation is ever
+ performed on a lazy casereader, it invokes a callback function
+ (provided by the lazy casereader's creator) to instantiate the
+ underlying reader. */
+
+#ifndef DATA_LAZY_CASEREADER_H
+#define DATA_LAZY_CASEREADER_H 1
+
+#include <stdbool.h>
+#include <data/case.h>
+
+struct casereader *lazy_casereader_create (size_t value_cnt,
+ casenumber case_cnt,
+ struct casereader *(*) (void *aux),
+ void *aux,
+ unsigned long int *serial);
+bool lazy_casereader_destroy (struct casereader *, unsigned long int serial);
+
+#endif /* data/lazy-casereader.h */