1 files changed, 160 insertions, 0 deletions
diff --git a/lib/heap.h b/lib/heap.h
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+/* Generic heap data structure -- header.
+ * Copyright (C) 2009 Chris Hall (GMCH), Highwayman
+ *.
+ * This file is part of GNU Zebra.
+ *
+ * GNU Zebra 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 GNU Zebra; see the file COPYING.  If not, write to the Free
+ * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.
+ */
+
+#ifndef _ZEBRA_HEAP_H
+#define _ZEBRA_HEAP_H
+
+#include "vector.h"
+
+/* Macro in case there are particular compiler issues.    */
+#ifndef Inline
+  #define Inline static inline
+#endif
+
+/*==============================================================================
+ * Data structures etc.
+ */
+
+typedef int heap_cmp(p_vector_item* a, p_vector_item*) ;
+
+enum heap_state {
+  Heap_Has_Backlink  = 0x01,    /* Set if backlink set  */
+} ;
+
+typedef vector_index heap_backlink_t ;
+
+typedef struct heap* heap ;
+
+struct heap
+{
+  heap_cmp* cmp ;
+
+  enum heap_state state ;
+  unsigned int backlink_offset ;
+
+  struct vector v ;
+} ;
+
+/*==============================================================================
+ * Prototypes.
+ */
+
+extern heap heap_init_new(heap h, unsigned int size, heap_cmp* cmp,
+                            int with_backlink, unsigned int backlink_offset) ;
+#define heap_init_new_simple(h, size, cmp) \
+  heap_init_new(h, size, cmp, 0, 0)
+#define heap_init_new_backlinked(h, size, cmp, offset) \
+  heap_init_new(h, size, cmp, 1, offset)
+
+extern heap heap_re_init(heap h, unsigned int size, heap_cmp* cmp,
+			    int with_backlink, unsigned int backlink_offset) ;
+#define heap_re_init_simple(h, size, cmp) \
+  heap_re_init(h, size, cmp, 0, 0)
+#define heap_re_init_backlinked(h, size, cmp, offset) \
+  heap_re_init(h, size, cmp, 1, offset)
+
+extern heap heap_reset(heap h, int free_structure) ;
+extern p_vector_item heap_ream(heap h, int free_structure) ;
+
+/* Reset heap and free the heap structure.	*/
+#define heap_reset_free(h) heap_reset(h, 1)
+/* Reset heap but keep the heap structure.	*/
+#define heap_reset_keep(h) heap_reset(h, 0)
+/* Ream out heap and free the heap structure.	*/
+#define heap_ream_free(h) heap_ream(h, 1)
+/* Ream out heap but keep the heap structure.	*/
+#define heap_ream_keep(h) heap_ream(h, 0)
+
+Inline void heap_push_item(heap h, p_vector_item p_v) ;
+extern p_vector_item heap_pop_item(heap h) ;
+extern p_vector_item heap_pop_push_item(heap h, p_vector_item p_v) ;
+Inline p_vector_item heap_top_item(heap h) ;
+Inline void heap_update_top_item(heap h) ;
+
+extern void heap_delete_item(heap h, p_vector_item p_v) ;
+Inline void heap_update_item(heap h, p_vector_item p_v) ;
+
+extern void heap_push_vector(heap h, vector v, int move_vector) ;
+#define heap_push_vector_copy(h, v) \
+  heap_push_vector(h, v, 0)
+#define heap_push_vector_move(h, v) \
+  heap_push_vector(h, v, 1)
+extern vector heap_pop_vector(vector v, heap h, int move_heap) ;
+#define heap_pop_vector_copy(v, h)  \
+  heap_pop_vector(v, h, 0)
+#define heap_pop_vector_move(v, h)  \
+  heap_pop_vector(v, h, 1)
+
+/*==============================================================================
+ * This are extern only for use in Inline and other friends
+ */
+
+#ifndef private
+  #define private extern
+#endif
+
+private void
+heap_bubble(heap h, vector_index i, p_vector_item p_v) ;
+
+private void
+heap_bubble_up(heap h, vector_index i, p_vector_item p_v) ;
+
+private void
+heap_bubble_down(heap h, vector_index i, p_vector_item p_v) ;
+
+private vector_index
+heap_find_item(heap h, p_vector_item p_v) ;
+
+/*==============================================================================
+ * Inline Functions
+ */
+
+/* Push given item onto the heap
+ */
+Inline void
+heap_push_item(heap h, p_vector_item p_v)
+{
+  dassert(p_v != NULL) ;        /* no NULLs, thank you.  */
+  heap_bubble_up(h, vector_extend_by_1(&h->v), p_v) ;
+} ;
+
+/* Get copy of top heap item (does not pop).
+ *
+ * Returns NULL if heap is empty.
+ */
+Inline p_vector_item
+heap_top_item(heap h)
+{
+  return vector_get_first_item(&h->v) ;  /* if any */
+} ;
+
+/* Update heap to reflect new value of top item.
+ */
+Inline void
+heap_update_top_item(heap h)
+{
+  heap_bubble_down(h, 0, heap_top_item(h)) ;
+} ;
+
+/* Update heap to reflect new value of given item.
+ */
+Inline void
+heap_update_item(heap h, p_vector_item p_v)
+{
+  heap_bubble(h, heap_find_item(h, p_v), p_v) ;
+} ;
+
+#endif /* _ZEBRA_HEAP_H */