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90 lines
3.0 KiB
90 lines
3.0 KiB
/* Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.
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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, version 2.0,
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as published by the Free Software Foundation.
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This program is also distributed with certain software (including
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but not limited to OpenSSL) that is licensed under separate terms,
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as designated in a particular file or component or in included license
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documentation. The authors of MySQL hereby grant you an additional
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permission to link the program and your derivative works with the
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separately licensed software that they have included with MySQL.
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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, version 2.0, 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
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#ifndef QUEUES_INCLUDED
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#define QUEUES_INCLUDED
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/**
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@file storage/myisam/queues.h
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Code for handling of priority queues.
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Implementation of queues from "Algoritms in C" by Robert Sedgewick.
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*/
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#include <stddef.h>
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#include <sys/types.h>
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#include "my_inttypes.h"
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#include "mysql/psi/psi_memory.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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struct 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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};
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void _downheap(QUEUE *queue, uint idx);
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void queue_fix(QUEUE *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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static inline void queue_replaced(QUEUE *queue) { _downheap(queue, 1); }
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static inline void queue_set_max_at_top(QUEUE *queue, int set_arg) {
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queue->max_at_top = set_arg ? -1 : 1;
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}
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typedef int (*queue_compare)(void *, uchar *, uchar *);
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int init_queue(QUEUE *queue, PSI_memory_key psi_key, uint max_elements,
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uint offset_to_key, bool max_at_top, queue_compare compare,
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void *first_cmp_arg);
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int reinit_queue(QUEUE *queue, PSI_memory_key psi_key, uint max_elements,
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uint offset_to_key, bool max_at_top, queue_compare compare,
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void *first_cmp_arg);
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void delete_queue(QUEUE *queue);
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void queue_insert(QUEUE *queue, uchar *element);
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uchar *queue_remove(QUEUE *queue, uint idx);
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static inline void queue_remove_all(QUEUE *queue) { queue->elements = 0; }
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static inline bool queue_is_full(QUEUE *queue) {
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return queue->elements == queue->max_elements;
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}
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static inline bool is_queue_inited(QUEUE *queue) { return queue->root != NULL; }
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#ifdef __cplusplus
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}
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#endif
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#endif // QUEUES_INCLUDED
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