/* PSPP - a program for statistical analysis.
- Copyright (C) 2007 Free Software Foundation, Inc.
+ Copyright (C) 2007, 2009 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
#include <stdbool.h>
#include <libpspp/abt.h>
+#include <libpspp/cast.h>
/* Returns the data structure corresponding to the given NODE,
assuming that NODE is embedded as the given MEMBER name in
data type STRUCT. */
-#define tower_data(NODE, STRUCT, MEMBER) \
- ((STRUCT *) ((char *) (NODE) - offsetof (STRUCT, MEMBER)))
+#define tower_data(NODE, STRUCT, MEMBER) \
+ (CHECK_POINTER_HAS_TYPE (NODE, struct tower_node *), \
+ UP_CAST (NODE, STRUCT, MEMBER))
/* A node within a tower. */
struct tower_node