From 354bb40e75d94466e91fe6960523612c9d17ccfb Mon Sep 17 00:00:00 2001
From: Karen Arutyunov <karen@codesynthesis.com>
Date: Thu, 2 Nov 2017 23:11:29 +0300
Subject: Add implementation

---
 mysql/queues.h | 93 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 93 insertions(+)
 create mode 100644 mysql/queues.h

(limited to 'mysql/queues.h')

diff --git a/mysql/queues.h b/mysql/queues.h
new file mode 100644
index 0000000..4ce6598
--- /dev/null
+++ b/mysql/queues.h
@@ -0,0 +1,93 @@
+/* Copyright (c) 2000, 2014, Oracle and/or its affiliates. All rights reserved.
+
+   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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */
+
+#ifndef QUEUES_INCLUDED
+#define QUEUES_INCLUDED
+
+/*
+  Code for handling of priority Queues.
+  Implemention of queues from "Algoritms in C" by Robert Sedgewick.
+  By monty.
+*/
+
+#include "my_global.h"                          /* uchar */
+
+#ifdef	__cplusplus
+extern "C" {
+#endif
+
+typedef struct st_queue {
+  uchar **root;
+  void *first_cmp_arg;
+  uint elements;
+  uint max_elements;
+  uint 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 *, uchar *,uchar *);
+  uint auto_extent;
+} QUEUE;
+
+void _downheap(QUEUE *queue,uint idx);
+void queue_fix(QUEUE *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])
+
+static inline void queue_replaced(QUEUE *queue)
+{
+  _downheap(queue, 1);
+}
+
+static inline void queue_set_max_at_top(QUEUE *queue, int set_arg)
+{
+  queue->max_at_top= set_arg ? -1 : 1;
+}
+
+typedef int (*queue_compare)(void *,uchar *, uchar *);
+
+int init_queue(QUEUE *queue,uint max_elements,uint offset_to_key,
+	       pbool max_at_top, queue_compare compare,
+	       void *first_cmp_arg);
+int init_queue_ex(QUEUE *queue,uint max_elements,uint offset_to_key,
+	       pbool max_at_top, queue_compare compare,
+	       void *first_cmp_arg, uint auto_extent);
+int reinit_queue(QUEUE *queue,uint max_elements,uint offset_to_key,
+                 pbool max_at_top, queue_compare compare,
+                 void *first_cmp_arg);
+void delete_queue(QUEUE *queue);
+void queue_insert(QUEUE *queue,uchar *element);
+uchar *queue_remove(QUEUE *queue,uint idx);
+
+static inline void queue_remove_all(QUEUE *queue)
+{
+  queue->elements= 0;
+}
+
+static inline my_bool queue_is_full(QUEUE *queue)
+{
+  return queue->elements == queue->max_elements;
+}
+
+static inline my_bool is_queue_inited(QUEUE *queue)
+{
+  return queue->root != NULL;
+}
+
+#ifdef	__cplusplus
+}
+#endif
+
+#endif  // QUEUES_INCLUDED
-- 
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