/* Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License, version 2.0,
   as published by the Free Software Foundation.

   This program is also distributed with certain software (including
   but not limited to OpenSSL) that is licensed under separate terms,
   as designated in a particular file or component or in included license
   documentation.  The authors of MySQL hereby grant you an additional
   permission to link the program and your derivative works with the
   separately licensed software that they have included with MySQL.

   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, version 2.0, 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 St, Fifth Floor, Boston, MA 02110-1301  USA */

/*
  Code for generell handling of priority Queues.
  Implemention of queues from "Algoritms in C" by Robert Sedgewick.
  Copyright Monty Program KB.
  By monty.
*/

#ifndef _queues_h
#define _queues_h

#include "my_global.h"                          /* uchar */

#ifdef	__cplusplus
extern "C" {
#endif

typedef struct st_queue {
  uchar **root;
  void *first_cmp_arg;
  uint elements;
  uint max_elements;
  uint offset_to_key;	/* compare is done on element+offset */
  int max_at_top;	/* Normally 1, set to -1 if queue_top gives max */
  int  (*compare)(void *, uchar *,uchar *);
  uint auto_extent;
} QUEUE;

#define queue_top(queue) ((queue)->root[1])
#define queue_element(queue,index) ((queue)->root[index+1])
#define queue_end(queue) ((queue)->root[(queue)->elements])
#define queue_replaced(queue) _downheap(queue,1)
#define queue_set_compare(queue, cmp) (queue)->compare= cmp
#define queue_set_cmp_arg(queue, set_arg) (queue)->first_cmp_arg= set_arg
#define queue_set_max_at_top(queue, set_arg) \
  (queue)->max_at_top= set_arg ? -1 : 1
typedef int (*queue_compare)(void *,uchar *, uchar *);

int init_queue(QUEUE *queue,uint max_elements,uint offset_to_key,
	       pbool max_at_top, queue_compare compare,
	       void *first_cmp_arg);
int init_queue_ex(QUEUE *queue,uint max_elements,uint offset_to_key,
	       pbool max_at_top, queue_compare compare,
	       void *first_cmp_arg, uint auto_extent);
int reinit_queue(QUEUE *queue,uint max_elements,uint offset_to_key,
                 pbool max_at_top, queue_compare compare,
                 void *first_cmp_arg);
int resize_queue(QUEUE *queue, uint max_elements);
void delete_queue(QUEUE *queue);
void queue_insert(QUEUE *queue,uchar *element);
int queue_insert_safe(QUEUE *queue, uchar *element);
uchar *queue_remove(QUEUE *queue,uint idx);
#define queue_remove_all(queue) { (queue)->elements= 0; }
#define queue_is_full(queue) (queue->elements == queue->max_elements)
void _downheap(QUEUE *queue,uint idx);
void queue_fix(QUEUE *queue);
#define is_queue_inited(queue) ((queue)->root != 0)

#ifdef	__cplusplus
}
#endif
#endif
