1 files changed, 87 insertions, 0 deletions
diff --git a/include/queues.h b/include/queues.h
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+/* Copyright (C) 2010 Monty Program Ab
+   All Rights reserved
+
+   Redistribution and use in source and binary forms, with or without
+   modification, are permitted provided that the following conditions are met:
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the following disclaimer
+      in the documentation and/or other materials provided with the
+      distribution.
+
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+  FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+  <COPYRIGHT HOLDER> BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+  USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+  OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+  SUCH DAMAGE.
+*/
+
+/*
+  Code for general handling of priority Queues.
+  Implementation of queues from "Algorithms in C" by Robert Sedgewick.
+*/
+
+#ifndef _queues_h
+#define _queues_h
+
+#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 */
+  uint offset_to_queue_pos;    /* If we want to store position in element */
+  uint auto_extent;
+  int max_at_top;	/* Normally 1, set to -1 if queue_top gives max */
+  int  (*compare)(void *, uchar *,uchar *);
+} QUEUE;
+
+#define queue_first_element(queue) 1
+#define queue_last_element(queue) (queue)->elements
+#define queue_empty(queue) ((queue)->elements == 0)
+#define queue_top(queue) ((queue)->root[1])
+#define queue_element(queue,index) ((queue)->root[index])
+#define queue_end(queue) ((queue)->root[(queue)->elements])
+#define queue_replace_top(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
+#define queue_remove_top(queue_arg) queue_remove((queue_arg), queue_first_element(queue_arg))
+typedef int (*queue_compare)(void *,uchar *, uchar *);
+
+int init_queue(QUEUE *queue,uint max_elements,uint offset_to_key,
+	       my_bool max_at_top, queue_compare compare,
+	       void *first_cmp_arg, uint offset_to_queue_pos,
+               uint auto_extent);
+int reinit_queue(QUEUE *queue,uint max_elements,uint offset_to_key,
+                 my_bool max_at_top, queue_compare compare,
+                 void *first_cmp_arg, uint offset_to_queue_pos,
+                 uint auto_extent);
+int resize_queue(QUEUE *queue, uint max_elements);
+void delete_queue(QUEUE *queue);
+void queue_insert(QUEUE *queue, uchar *element);
+int queue_insert_safe(QUEUE *queue, uchar *element);
+uchar *queue_remove(QUEUE *queue,uint idx);
+void queue_replace(QUEUE *queue,uint idx);
+
+#define queue_remove_all(queue) { (queue)->elements= 0; }
+#define queue_is_full(queue) (queue->elements == queue->max_elements)
+void _downheap(QUEUE *queue, uint idx);
+void queue_fix(QUEUE *queue);
+#define is_queue_inited(queue) ((queue)->root != 0)
+
+#ifdef	__cplusplus
+}
+#endif
+#endif