codekingpro/portable-devtools

1/*2 * binaryheap.h3 *4 * A simple binary heap implementation5 *6 * Portions Copyright (c) 2012-2023, PostgreSQL Global Development Group7 *8 * src/include/lib/binaryheap.h9 */10 11#ifndef BINARYHEAP_H12#define BINARYHEAP_H13 14/*15 * For a max-heap, the comparator must return <0 iff a < b, 0 iff a == b,16 * and >0 iff a > b.  For a min-heap, the conditions are reversed.17 */18typedef int (*binaryheap_comparator) (Datum a, Datum b, void *arg);19 20/*21 * binaryheap22 *23 *		bh_size			how many nodes are currently in "nodes"24 *		bh_space		how many nodes can be stored in "nodes"25 *		bh_has_heap_property	no unordered operations since last heap build26 *		bh_compare		comparison function to define the heap property27 *		bh_arg			user data for comparison function28 *		bh_nodes		variable-length array of "space" nodes29 */30typedef struct binaryheap31{32	int			bh_size;33	int			bh_space;34	bool		bh_has_heap_property;	/* debugging cross-check */35	binaryheap_comparator bh_compare;36	void	   *bh_arg;37	Datum		bh_nodes[FLEXIBLE_ARRAY_MEMBER];38} binaryheap;39 40extern binaryheap *binaryheap_allocate(int capacity,41									   binaryheap_comparator compare,42									   void *arg);43extern void binaryheap_reset(binaryheap *heap);44extern void binaryheap_free(binaryheap *heap);45extern void binaryheap_add_unordered(binaryheap *heap, Datum d);46extern void binaryheap_build(binaryheap *heap);47extern void binaryheap_add(binaryheap *heap, Datum d);48extern Datum binaryheap_first(binaryheap *heap);49extern Datum binaryheap_remove_first(binaryheap *heap);50extern void binaryheap_replace_first(binaryheap *heap, Datum d);51 52#define binaryheap_empty(h)			((h)->bh_size == 0)53 54#endif							/* BINARYHEAP_H */55