~drizzle-trunk/drizzle/development

/* 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; version 2 of the License.

   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 {

  unsigned char **root;

  void *first_cmp_arg;

  uint32_t elements;

  uint32_t max_elements;

  uint32_t 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 *, unsigned char *,unsigned char *);

  uint32_t 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_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 *,unsigned char *, unsigned char *);

int init_queue(QUEUE *queue,uint32_t max_elements,uint32_t offset_to_key,

               bool max_at_top, queue_compare compare,

               void *first_cmp_arg);

int init_queue_ex(QUEUE *queue,uint32_t max_elements,uint32_t offset_to_key,

                  bool max_at_top, queue_compare compare,

                  void *first_cmp_arg, uint32_t auto_extent);

int reinit_queue(QUEUE *queue,uint32_t max_elements,uint32_t offset_to_key,

                 bool max_at_top, queue_compare compare,

                 void *first_cmp_arg);

int resize_queue(QUEUE *queue, uint32_t max_elements);

void delete_queue(QUEUE *queue);

void queue_insert(QUEUE *queue,unsigned char *element);

int queue_insert_safe(QUEUE *queue, unsigned char *element);

unsigned char *queue_remove(QUEUE *queue,uint32_t idx);

#define queue_remove_all(queue) { (queue)->elements= 0; }

#define queue_is_full(queue) (queue->elements == queue->max_elements)

void _downheap(QUEUE *queue,uint32_t idx);

void queue_fix(QUEUE *queue);

#define is_queue_inited(queue) ((queue)->root != 0)

#ifdef	__cplusplus

}

#endif

#endif