73 lines
2.6 KiB
C
73 lines
2.6 KiB
C
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/* Copyright (C) 2000 MySQL AB
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
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/*
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Code for generell handling of priority Queues.
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Implemention of queues from "Algoritms in C" by Robert Sedgewick.
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Copyright Monty Program KB.
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By monty.
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*/
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#ifndef _queues_h
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#define _queues_h
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#ifdef __cplusplus
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extern "C" {
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#endif
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typedef struct st_queue {
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uchar **root;
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void *first_cmp_arg;
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uint elements;
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uint max_elements;
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uint offset_to_key; /* compare is done on element+offset */
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int max_at_top; /* Normally 1, set to -1 if queue_top gives max */
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int (*compare)(void *, uchar *,uchar *);
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uint auto_extent;
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} QUEUE;
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#define queue_top(queue) ((queue)->root[1])
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#define queue_element(queue,index) ((queue)->root[index+1])
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#define queue_end(queue) ((queue)->root[(queue)->elements])
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#define queue_replaced(queue) _downheap(queue,1)
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#define queue_set_cmp_arg(queue, set_arg) (queue)->first_cmp_arg= set_arg
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#define queue_set_max_at_top(queue, set_arg) \
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(queue)->max_at_top= set_arg ? -1 : 1
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typedef int (*queue_compare)(void *,uchar *, uchar *);
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int init_queue(QUEUE *queue,uint max_elements,uint offset_to_key,
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pbool max_at_top, queue_compare compare,
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void *first_cmp_arg);
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int init_queue_ex(QUEUE *queue,uint max_elements,uint offset_to_key,
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pbool max_at_top, queue_compare compare,
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void *first_cmp_arg, uint auto_extent);
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int reinit_queue(QUEUE *queue,uint max_elements,uint offset_to_key,
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pbool max_at_top, queue_compare compare,
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void *first_cmp_arg);
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int resize_queue(QUEUE *queue, uint max_elements);
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void delete_queue(QUEUE *queue);
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void queue_insert(QUEUE *queue,uchar *element);
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int queue_insert_safe(QUEUE *queue, uchar *element);
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uchar *queue_remove(QUEUE *queue,uint idx);
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#define queue_remove_all(queue) { (queue)->elements= 0; }
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#define queue_is_full(queue) (queue->elements == queue->max_elements)
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void _downheap(QUEUE *queue,uint idx);
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void queue_fix(QUEUE *queue);
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#define is_queue_inited(queue) ((queue)->root != 0)
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#ifdef __cplusplus
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}
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#endif
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#endif
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