-/* PSPP - computes sample statistics.
- Copyright (C) 2007 Free Software Foundation, Inc.
+/* PSPP - a program for statistical analysis.
+ 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 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/>. */
/* Embedded priority queue, implemented as a heap.
heap and delete it:
struct heap *h = ...;
- if (!heap_is_empty (h))
+ if (!heap_is_empty (h))
{
struct foo *foo = heap_data (heap_minimum (h), struct foo, node);
printf ("Minimum is %d.\n", foo->x);
#ifndef LIBPSPP_HEAP_H
#define LIBPSPP_HEAP_H 1
+#include "libpspp/cast.h"
#include <stdbool.h>
#include <stddef.h>
/* Returns the data structure corresponding to the given heap
NODE, assuming that NODE is embedded as the given MEMBER name
in data type STRUCT. */
-#define heap_data(NODE, STRUCT, MEMBER) \
- ((STRUCT *) ((char *) (NODE) - offsetof (STRUCT, MEMBER)))
+#define heap_data(NODE, STRUCT, MEMBER) \
+ (CHECK_POINTER_HAS_TYPE (NODE, struct heap_node *), \
+ UP_CAST (NODE, STRUCT, MEMBER))
/* A node in a heap. Opaque.
One of these structures must be embedded in your heap node. */