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DarkSide SQL Mini Version 1, The embedded database

, 23 Mar 2006 BSD
An embedded database library in C++.
/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 1996-2002
 *	Sleepycat Software.  All rights reserved.
 */
/*
 * Copyright (c) 1990, 1993, 1994
 *	Margo Seltzer.  All rights reserved.
 */
/*
 * Copyright (c) 1990, 1993, 1994
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Margo Seltzer.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 THE REGENTS OR CONTRIBUTORS 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.
 *
 * $Id: hash.h,v 11.26 2002/03/27 04:34:54 bostic Exp $
 */

#ifndef	_DB_HASH_H_
#define	_DB_HASH_H_

/* Hash internal structure. */
typedef struct hash_t {
	db_pgno_t meta_pgno;	/* Page number of the meta data page. */
	u_int32_t h_ffactor;	/* Fill factor. */
	u_int32_t h_nelem;	/* Number of elements. */
				/* Hash function. */
	u_int32_t (*h_hash) __P((DB *, const void *, u_int32_t));
} HASH;

/* Cursor structure definitions. */
typedef struct cursor_t {
	/* struct __dbc_internal */
	__DBC_INTERNAL

	/* Hash private part */

	/* Per-thread information */
	DB_LOCK hlock;			/* Metadata page lock. */
	HMETA *hdr;			/* Pointer to meta-data page. */
	PAGE *split_buf;		/* Temporary buffer for splits. */

	/* Hash cursor information */
	db_pgno_t	bucket;		/* Bucket we are traversing. */
	db_pgno_t	lbucket;	/* Bucket for which we are locked. */
	db_indx_t	dup_off;	/* Offset within a duplicate set. */
	db_indx_t	dup_len;	/* Length of current duplicate. */
	db_indx_t	dup_tlen;	/* Total length of duplicate entry. */
	u_int32_t	seek_size;	/* Number of bytes we need for add. */
	db_pgno_t	seek_found_page;/* Page on which we can insert. */
	u_int32_t	order;		/* Relative order among deleted curs. */

#define	H_CONTINUE	0x0001		/* Join--search strictly fwd for data */
#define	H_DELETED	0x0002		/* Cursor item is deleted. */
#define	H_DIRTY		0x0004		/* Meta-data page needs to be written */
#define	H_DUPONLY	0x0008		/* Dups only; do not change key. */
#define	H_EXPAND	0x0010		/* Table expanded. */
#define	H_ISDUP		0x0020		/* Cursor is within duplicate set. */
#define	H_NEXT_NODUP	0x0040		/* Get next non-dup entry. */
#define	H_NOMORE	0x0080		/* No more entries in bucket. */
#define	H_OK		0x0100		/* Request succeeded. */
	u_int32_t	flags;
} HASH_CURSOR;

/* Test string. */
#define	CHARKEY			"%$sniglet^&"

/* Overflow management */
/*
 * The spares table indicates the page number at which each doubling begins.
 * From this page number we subtract the number of buckets already allocated
 * so that we can do a simple addition to calculate the page number here.
 */
#define	BS_TO_PAGE(bucket, spares)		\
	((bucket) + (spares)[__db_log2((bucket) + 1)])
#define	BUCKET_TO_PAGE(I, B)	(BS_TO_PAGE((B), (I)->hdr->spares))

/* Constraints about much data goes on a page. */

#define	MINFILL		4
#define	ISBIG(I, N)	(((N) > ((I)->hdr->dbmeta.pagesize / MINFILL)) ? 1 : 0)

/* Shorthands for accessing structure */
#define	NDX_INVALID	0xFFFF
#define	BUCKET_INVALID	0xFFFFFFFF

/* On page duplicates are stored as a string of size-data-size triples. */
#define	DUP_SIZE(len)	((len) + 2 * sizeof(db_indx_t))

/* Log messages types (these are subtypes within a record type) */
#define	PAIR_KEYMASK		0x1
#define	PAIR_DATAMASK		0x2
#define	PAIR_DUPMASK		0x4
#define	PAIR_MASK		0xf
#define	PAIR_ISKEYBIG(N)	(N & PAIR_KEYMASK)
#define	PAIR_ISDATABIG(N)	(N & PAIR_DATAMASK)
#define	PAIR_ISDATADUP(N)	(N & PAIR_DUPMASK)
#define	OPCODE_OF(N)	(N & ~PAIR_MASK)

#define	PUTPAIR		0x20
#define	DELPAIR		0x30
#define	PUTOVFL		0x40
#define	DELOVFL		0x50
#define	HASH_UNUSED1	0x60
#define	HASH_UNUSED2	0x70
#define	SPLITOLD	0x80
#define	SPLITNEW	0x90

typedef enum {
	DB_HAM_CHGPG = 1,
	DB_HAM_DELFIRSTPG = 2,
	DB_HAM_DELMIDPG = 3,
	DB_HAM_DELLASTPG = 4,
	DB_HAM_DUP   = 5,
	DB_HAM_SPLIT = 6
} db_ham_mode;

#include "dbinc_auto/hash_auto.h"
#include "dbinc_auto/hash_ext.h"
#include "dbinc/db_am.h"
#endif /* !_DB_HASH_H_ */

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This article, along with any associated source code and files, is licensed under The BSD License

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