X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=src%2Flibpspp%2Ftower.h;h=2ec5a0d820b354a91f19cfa1dd961f5407f52dc0;hb=81579d9e9f994fb2908f50af41c3eb033d216e58;hp=246984a2c1bfd6cd1c46100fbe95f84140843a92;hpb=7fbfc32fc3c636959b0a25b3e76609f86519e84a;p=pspp-builds.git

diff --git a/src/libpspp/tower.h b/src/libpspp/tower.h
index 246984a2..2ec5a0d8 100644
--- a/src/libpspp/tower.h
+++ b/src/libpspp/tower.h
@@ -1,5 +1,5 @@
 /* PSPP - a program for statistical analysis.
-   Copyright (C) 2007 Free Software Foundation, Inc.
+   Copyright (C) 2007, 2009, 2011 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
@@ -50,13 +50,15 @@
 #define LIBPSPP_TOWER_H
 
 #include <stdbool.h>
-#include <libpspp/abt.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