-/* PSPP - computes sample statistics.
- Copyright (C) 2007 Free Software Foundation, Inc.
+/* PSPP - a program for statistical analysis.
+ Copyright (C) 2007, 2009, 2010 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 2 of the
- License, or (at your option) any later version.
+ 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.
+ 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, write to the Free Software
- Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
- 02110-1301, USA. */
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
#ifndef LIBPSPP_BT_H
#define LIBPSPP_BT_H 1
balancing applied to the balanced tree, as its operation is
fully encapsulated. */
+#include <stdbool.h>
#include <stddef.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 bt_data(NODE, STRUCT, MEMBER) \
- ((STRUCT *) ((char *) (NODE) - offsetof (STRUCT, MEMBER)))
+#define bt_data(NODE, STRUCT, MEMBER) \
+ (CHECK_POINTER_HAS_TYPE (NODE, struct bt_node *), \
+ UP_CAST (NODE, STRUCT, MEMBER))
/* Node in a balanced binary tree. */
-struct bt_node
+struct bt_node
{
struct bt_node *up; /* Parent (NULL for root). */
struct bt_node *down[2]; /* Left child, right child. */
const void *aux);
/* A balanced binary tree. */
-struct bt
+struct bt
{
struct bt_node *root; /* Tree's root, NULL if empty. */
bt_compare_func *compare; /* To compare nodes. */
void bt_moved (struct bt *, struct bt_node *);
/* Returns the number of nodes currently in BT. */
-static inline size_t bt_count (const struct bt *bt)
+static inline size_t bt_count (const struct bt *bt)
{
return bt->size;
}
+/* Return true if BT contains no nodes,
+ false if BT contains at least one node. */
+static inline bool bt_is_empty (const struct bt *bt)
+{
+ return bt->size == 0;
+}
+
#endif /* libpspp/bt.h */