firebird-mirror/src/jrd/btr.h

/*
 *	PROGRAM:	JRD Access Method
 *	MODULE:		btr.h
 *	DESCRIPTION:	Index walking data structures
 *
 * 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): ______________________________________.
 */
/*
$Id: btr.h,v 1.2 2001-12-24 02:50:50 tamlin Exp $
*/

#ifndef _JRD_BTR_H_
#define _JRD_BTR_H_

#include "../jrd/jrd_blks.h"
#include "../include/fb_blk.h"

#include <vector>

#include "../jrd/err_proto.h"    /* Index error types */

#define MAX_IDX		 64			/* that should be plenty of indexes */
#define MAX_KEY		256


/* Index descriptor block -- used to hold info from index root page */

typedef struct idx {
	SLONG idx_root;				/* Index root */
	float idx_selectivity;		/* selectivity of index */
	UCHAR idx_id;
	UCHAR idx_flags;
	UCHAR idx_runtime_flags;	/* flags used at runtime, not stored on disk */
	UCHAR idx_primary_index;	/* id for primary key partner index */
	USHORT idx_primary_relation;	/* id for primary key partner relation */
	USHORT idx_count;			/* number of keys */
	struct vec *idx_foreign_primaries;	/* ids for primary/unique indexes with partners */
	struct vec *idx_foreign_relations;	/* ids for foreign key partner relations */
	struct vec *idx_foreign_indexes;	/* ids for foreign key partner indexes */
	struct nod *idx_expression;	/* node tree for indexed expresssion */
	struct dsc idx_expression_desc;	/* descriptor for expression result */
	struct req *idx_expression_request;	/* stored request for expression evaluation */
	struct idx_repeat {
		USHORT idx_field;		/* field id */
		USHORT idx_itype;		/* data of field in index */
	} idx_rpt[16];
} IDX;

/* index types and flags */

/* See jrd/intl.h for notes on idx_itype and dsc_sub_type considerations */
/* idx_numeric .. idx_byte_array values are compatible with VMS values */

#define idx_numeric		0
#define idx_string		1
#define idx_timestamp1		2
#define idx_byte_array		3
#define idx_metadata		4
#define idx_sql_date		5
#define idx_sql_time		6
#define idx_timestamp2		7
#define idx_numeric2		8	/* Introduced for 64-bit Integer support */

/* Historical alias for pre v6 applications */
#define idx_date		idx_timestamp1

				   /* idx_itype space for future expansion */
#define	idx_first_intl_string	64	/* .. MAX (short) Range of computed key strings */

#define idx_offset_intl_range	(0x7FFF + idx_first_intl_string)

/* these flags must match the irt_flags */

#define idx_unique	1
#define idx_descending	2
#define idx_in_progress	4
#define idx_foreign	8
#define idx_primary	16
#define idx_expressn	32

/* these flags are for idx_runtime_flags */

#define idx_plan_dont_use	1	/* index is not mentioned in user-specified access plan */
#define idx_plan_navigate	2	/* plan specifies index to be used for ordering */
#define idx_used 		4		/* index was in fact selected for retrieval */
#define idx_navigate		8	/* index was in fact selected for navigation */
#define	idx_plan_missing	16	/* index mentioned in missing clause */
#define	idx_plan_starts		32	/* index mentioned in starts clause */

/* Macro to locate the next IDX block */

#ifndef DECOSF
#define NEXT_IDX(buffer,count)	(IDX*) (buffer + count)
#else
#define NEXT_IDX(buffer,count)	(IDX*) FB_ALIGN((U_IPTR) (buffer + count), ALIGNMENT)
#endif


/* Index insertion block -- parameter block for index insertions */

typedef struct iib {
	SLONG iib_number;			/* record number (or lower level page) */
	SLONG iib_sibling;			/* right sibling page */
	struct idx *iib_descriptor;	/* index descriptor */
	struct rel *iib_relation;	/* relation block */
	struct key *iib_key;		/* varying string for insertion */
	struct sbm *iib_duplicates;	/* spare bit map of duplicates */
	struct tra *iib_transaction;	/* insertion transaction */
} IIB;


/* Temporary key block */

typedef struct key {
#ifdef IGNORE_NULL_IDX_KEY
	USHORT key_flags;			/* could be UCHAR, but left as USHORT 
								   because of SHORT boundary requirement 
								   for key_data (explained below) */
#endif							/* IGNORE_NULL_IDX_KEY */
	USHORT key_length;
	UCHAR key_data[MAX_KEY * 2];	/* This needs to be on a SHORT boundary. 
									   This is because key_data is complemented as 
									   (SSHORT *) if value is negative.
									   See compress() (JRD/btr.c) for more details */
} KEY;

#ifdef IGNORE_NULL_IDX_KEY
#define KEY_first_segment_is_null	1	/* first segment in index key is for NULL value */
#endif /* IGNORE_NULL_IDX_KEY */

/* Index Sort Record -- fix part of sort record for index fast load */

typedef struct isr {
	USHORT isr_key_length;
	USHORT isr_flags;
	ULONG isr_record_number;
} *ISR;

#define ISR_secondary	1		/* Record is secondary verion */



/* Index retrieval block -- hold stuff for index retrieval */

class irb : public pool_alloc_rpt<nod*, type_irb>
{
    public:
	IDX irb_desc;				/* Index descriptor */
	USHORT irb_index;			/* Index id */
	USHORT irb_generic;			/* Flags for generic search */
	struct rel *irb_relation;	/* Relation for retrieval */
	USHORT irb_lower_count;		/* Number of segments for retrieval */
	USHORT irb_upper_count;		/* Number of segments for retrieval */
	KEY *irb_key;				/* key for equality retrival */
	nod* irb_value[1];
};
typedef irb *IRB;

#define irb_partial	1			/* Partial match: not all segments or starting of key only */
#define irb_starting	2		/* Only compute "starting with" key for index segment */
#define irb_equality	4		/* Probing index for equality match */
#define irb_ignore_null_value_key  8	/* if lower bound is specified and upper bound unspecified,
										   * ignore looking at null value keys */
#define irb_descending	16		/* ?Base index uses descending order */


#define DATA_SIZE	1

/* format of expanded index node, used for backwards navigation */

typedef struct btx {
	UCHAR btx_previous_length;	/* length of data for previous node  */
	UCHAR btx_btr_previous_length;	/* length of data for previous node on btree page */
	UCHAR btx_data[DATA_SIZE];	/* expanded data element */
} *BTX;

#define BTX_SIZE	2

/* format of expanded index buffer */

typedef struct exp {
	USHORT exp_length;
	ULONG exp_incarnation;
	struct btx exp_nodes[1];
} *EXP;

#define EXP_SIZE	OFFSETA (EXP, exp_nodes)


/* macros used to manipulate btree nodes */

#define BTN_PREFIX(node)	node->btn_prefix
#define BTN_LENGTH(node)	node->btn_length
#define BTN_NUMBER(node)	node->btn_number
#define BTN_DATA(node)		node->btn_data

#define QUAD_MOVE(a,b)	quad_move(a, b)

#define QE(a,b,n)	(((UCHAR*) b)[n] == ((UCHAR*) a)[n])
#define QUAD_EQUAL(a,b)	(QE(a,b,0) && QE(a,b,1) && QE(a,b,2) && QE(a,b,3))

#define NEXT_NODE(xxx)	(BTN) (BTN_DATA (xxx) + BTN_LENGTH (xxx))
#define LAST_NODE(page)	(BTN) ((UCHAR*) page + page->btr_length)

#define NEXT_EXPANDED(xxx,yyy)	(BTX) ((UCHAR*) xxx->btx_data + BTN_PREFIX (yyy) + BTN_LENGTH (yyy))

#endif /* _JRD_BTR_H_ */