mariadb/include/queues.h
bk@work.mysql.com f4c589ff6c Import changeset
2000-07-31 21:29:14 +02:00

57 lines
1.9 KiB
C

/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.
This library 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with this library; 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)
int init_queue(QUEUE *queue,uint max_elements,uint offset_to_key,
pbool max_at_top, int (*compare)(void *,byte *, byte *),
void *first_cmp_arg);
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);
#ifdef __cplusplus
}
#endif
#endif