/*
 *	PROGRAM:	JRD Access Method
 *	MODULE:		blb.h
 *	DESCRIPTION:	Blob handling definitions
 *
 * The contents of this file are subject to the Interbase Public
 * License Version 1.0 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy
 * of the License at http://www.Inprise.com/IPL.html
 *
 * Software distributed under the License is distributed on an
 * "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either express
 * or implied. See the License for the specific language governing
 * rights and limitations under the License.
 *
 * The Original Code was created by Inprise Corporation
 * and its predecessors. Portions created by Inprise Corporation are
 * Copyright (C) Inprise Corporation.
 *
 * All Rights Reserved.
 * Contributor(s): ______________________________________.
 *
 * 2002.10.28 Sean Leyne - Code cleanup, removed obsolete "DecOSF" port
 *
 */

#ifndef JRD_BLB_H
#define JRD_BLB_H

/* Blob id.  A blob has two states -- temporary and permanent.  In each
   case, the blob id is 8 bytes (2 longwords) long.  In the case of a
   temporary blob, the first word is NULL and the second word points to
   an internal blob block.  In the case of a permanent blob, the first
   word contains the relation id of the blob and the second the record
   number of the first segment-clump.  The two types of blobs can be
   reliably distinguished by a zero or non-zero relation id. */

typedef struct bid {
	ULONG bid_relation_id;		/* Relation id (or null) */
	union {
		class blb *bid_blob;	/* Pointer to blob block */
		ULONG bid_number;		/* Record number */
	} bid_stuff;
} *BID;

/* Your basic blob block. */

class blb : public pool_alloc_rpt<UCHAR, type_blb>
{
    public:
	att *blb_attachment;	/* database attachment */
	jrd_rel *blb_relation;	/* Relation, if known */
	struct jrd_tra *blb_transaction;	/* Parent transaction block */
	blb *blb_next;		/* Next blob in transaction */
	UCHAR *blb_segment;			/* Next segment to be addressed */
	struct ctl *blb_filter;		/* Blob filter control block, if any */
	struct bid blb_blob_id;		/* Id of materialized blob */
	struct jrd_req *blb_request;	/* request that assigned temporary blob */
	vcl *blb_pages;		/* Vector of pages */
	USHORT blb_pointers;		/* Max pointer on a page */
	USHORT blb_level;			/* Storage type */
	USHORT blb_max_segment;		/* Longest segment */
	USHORT blb_flags;			/* Interesting stuff (see below) */
	USHORT blb_clump_size;		/* Size of data clump */
	USHORT blb_space_remaining;	/* Data space left */
	USHORT blb_max_pages;		/* Max pages in vector */
	USHORT blb_fragment_size;	/* Residual fragment size */
	USHORT blb_source_interp;	/* source interp (for writing) */
	USHORT blb_target_interp;	/* destination interp (for reading) */
	SSHORT blb_sub_type;		/* Blob's declared sub-type */
	ULONG blb_sequence;			/* Blob page sequence */
	ULONG blb_max_sequence;		/* Number of data pages */
	ULONG blb_count;			/* Number of segments */
	ULONG blb_length;			/* Total length of data sans segments */
	ULONG blb_lead_page;		/* First page number */
	ULONG blb_seek;				/* Seek location */
	/* blb_data must be longword aligned */
	UCHAR blb_data[1];			/* A page's worth of blob */
};
typedef blb *BLB;

#define BLB_temporary	1		/* Newly created blob */
#define BLB_eof		2			/* This blob is exhausted */
#define BLB_stream	4			/* Stream style blob */
#define BLB_closed	8			/* Temporary blob has been closed */
#define BLB_damaged	16			/* Blob is busted */
#define BLB_seek	32			/* Seek is pending */
#define BLB_user_def	64		/* Blob is user created */
#define BLB_large_scan	128		/* Blob is larger than page buffer cache */

/* Blob levels are:

	0	small blob -- blob "record" is actual data
	1	medium blob -- blob "record" is pointer to pages
	2	large blob -- blob "record" is pointer to pages of pointers
*/

/* mapping blob ids for REPLAY */
class map : public pool_alloc<type_map>
{
    public:
	map *map_next;
	blb *map_old_blob;
	blb *map_new_blob;
};
typedef map *MAP;

#endif /* _JRD_BLB_H_ */