/*
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * 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 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.
 *
 * ***** END GPL LICENSE BLOCK *****
 */
 
#ifndef __BLI_HEAP_H__
#define __BLI_HEAP_H__

/** \file BLI_heap.h
 *  \ingroup bli
 *  \brief A heap / priority queue ADT
 */

struct Heap;
struct HeapNode;
typedef struct Heap Heap;
typedef struct HeapNode HeapNode;

typedef void (*HeapFreeFP)(void *ptr);

/* Creates a new heap. BLI_memarena is used for allocating nodes. Removed nodes
 * are recycled, so memory usage will not shrink. */
Heap           *BLI_heap_new_ex(unsigned int tot_reserve) ATTR_WARN_UNUSED_RESULT;
Heap           *BLI_heap_new(void) ATTR_WARN_UNUSED_RESULT;
void            BLI_heap_clear(Heap *heap, HeapFreeFP ptrfreefp) ATTR_NONNULL(1);
void            BLI_heap_free(Heap *heap, HeapFreeFP ptrfreefp) ATTR_NONNULL(1);

/* Insert heap node with a value (often a 'cost') and pointer into the heap,
 * duplicate values are allowed. */
HeapNode       *BLI_heap_insert(Heap *heap, float value, void *ptr) ATTR_NONNULL(1);

/* Remove a heap node. */
void            BLI_heap_remove(Heap *heap, HeapNode *node) ATTR_NONNULL(1, 2);

/* Return 0 if the heap is empty, 1 otherwise. */
bool            BLI_heap_is_empty(Heap *heap) ATTR_NONNULL(1);

/* Return the size of the heap. */
unsigned int    BLI_heap_size(Heap *heap) ATTR_WARN_UNUSED_RESULT ATTR_NONNULL(1);

/* Return the top node of the heap. This is the node with the lowest value. */
HeapNode       *BLI_heap_top(Heap *heap) ATTR_WARN_UNUSED_RESULT ATTR_NONNULL(1);

/* Pop the top node off the heap and return it's pointer. */
void           *BLI_heap_popmin(Heap *heap) ATTR_NONNULL(1);

/* Return the value or pointer of a heap node. */
float           BLI_heap_node_value(HeapNode *heap) ATTR_WARN_UNUSED_RESULT ATTR_NONNULL(1);
void           *BLI_heap_node_ptr(HeapNode *heap) ATTR_WARN_UNUSED_RESULT ATTR_NONNULL(1);

#endif  /* __BLI_HEAP_H__ */