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/* Copyright (C) 2000 MySQL AB
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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 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
#ifdef __cplusplus
extern "C" {
#endif
typedef struct st_queue {
byte **root;
void *first_cmp_arg;
uint elements;
uint max_elements;
uint offset_to_key; /* compare is done on element+offset */
int max_at_top; /* Set if queue_top gives max */
int (*compare)(void *, byte *,byte *);
} 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)
typedef int (*queue_compare)(void *,byte *, byte *);
int init_queue(QUEUE *queue,uint max_elements,uint offset_to_key,
pbool max_at_top, queue_compare compare,
void *first_cmp_arg);
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,byte *element);
byte *queue_remove(QUEUE *queue,uint idx);
void _downheap(QUEUE *queue,uint idx);
void queue_fix(QUEUE *queue);
#define is_queue_inited(queue) ((queue)->root != 0)
#ifdef __cplusplus
}
#endif
#endif
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