moving files to /server to make merge possible

server/include/buffer.h

@@ -0,0 +1,98 @@
+#ifndef _BUFFER_H
+#define _BUFFER_H
+/*
+ * This file is distributed as part of the SkySQL Gateway.  It 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.
+ *
+ * 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 Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Copyright SkySQL Ab 2013
+ */
+
+/**
+ * @file buffer.h  Definitions relating the gateway buffer manipulation facilities.
+ *
+ * These are used to store all data coming in form or going out to the client and the
+ * backend structures.
+ *
+ * The buffers are designed to be used in linked lists and such that they may be passed
+ * from one side of the gateway to another without the need to copy data. It may be the case
+ * that not all of the data in the buffer is valid, to this end a start and end pointer are
+ * included that point to the first valid byte in the buffer and the first byte after the
+ * last valid byte. This allows data to be consumed from either end of the buffer whilst
+ * still allowing for the copy free semantics of the buffering system.
+ *
+ * @verbatim
+ * Revision History
+ *
+ * Date		Who			Description
+ * 10/06/2013	Mark Riddoch		Initial implementation
+ * 11/07/2013	Mark Riddoch		Addition of reference count in the gwbuf
+ * 16/07/2013	Massimiliano Pinto	Added command type for the queue
+ *
+ * @endverbatim
+ */
+
+/**
+ * A structure to encapsualte the data in a form that the data itself can be
+ * shared between multiple GWBUF's without the need to make multiple copies
+ * but still maintain separate data pointers.
+ */
+typedef struct  {
+	unsigned char	*data;			/**< Physical memory that was allocated */
+	int		refcount;		/**< Reference count on the buffer */
+} SHARED_BUF;
+
+/**
+ * The buffer structure used by the descriptor control blocks.
+ *
+ * Linked lists of buffers are created as data is read from a descriptor
+ * or written to a descriptor. The use of linked lists of buffers with
+ * flexible data pointers is designed to minimise the need for data to
+ * be copied within the gateway.
+ */
+typedef struct gwbuf {
+	struct gwbuf	*next;			/**< Next buffer in a linked chain of buffers */
+	void		*start;			/**< Start of the valid data */
+	void		*end;			/**< First byte after the valid data */
+	SHARED_BUF	*sbuf;			/**< The shared buffer with the real data */
+	int		command;		/**< The command type for the queue */
+} GWBUF;
+
+/*
+ * Macros to access the data in the buffers
+ */
+#define GWBUF_DATA(b)		((b)->start)			/**< First valid, uncomsumed
+								 *   byte in the buffer
+								 */
+#define GWBUF_LENGTH(b)		((b)->end - (b)->start)		/**< Number of bytes in the
+								 *   individual buffer
+								 */
+#define GWBUF_EMPTY(b)		((b)->start == (b)->end)	/**< True if all bytes in the
+								 *   buffer have been consumed
+								 */
+#define GWBUF_CONSUME(b, bytes)	(b)->start += bytes		/**< Consume a number of bytes
+								 *   in the buffer
+								 */
+
+/*
+ * Function prototypes for the API to maniplate the buffers
+ */
+extern GWBUF		*gwbuf_alloc(unsigned int size);
+extern void		gwbuf_free(GWBUF *buf);
+extern GWBUF		*gwbuf_clone(GWBUF *buf);
+extern GWBUF		*gwbuf_append(GWBUF *head, GWBUF *tail);
+extern GWBUF		*gwbuf_consume(GWBUF *head, unsigned int length);
+extern unsigned int	gwbuf_length(GWBUF *head);
+
+
+#endif