hash_conv.c

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/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 1996, 1997, 1998, 1999, 2000
 *      Sleepycat Software.  All rights reserved.
 */
#include "config.h"

#ifndef lint
static const char revid[] = "$Id: hash__conv_8c-source.html,v 1.1 2008/06/08 10:19:24 sebdiaz Exp $";
#endif /* not lint */

#ifndef NO_SYSTEM_INCLUDES
#include <sys/types.h>
#endif

#include "db_int.h"
#include "db_page.h"
#include "db_swap.h"
#include "hash.h"

/*
 * CDB___ham_pgin --
 *      Convert host-specific page layout from the host-independent format
 *      stored on disk.
 *
 * PUBLIC: int CDB___ham_pgin __P((DB_ENV *, db_pgno_t, void *, DBT *));
 */
int
CDB___ham_pgin(dbenv, pg, pp, cookie)
        DB_ENV *dbenv;
        db_pgno_t pg;
        void *pp;
        DBT *cookie;
{
        DB_PGINFO *pginfo;
        PAGE *h;

        h = pp;
        pginfo = (DB_PGINFO *)cookie->data;

        /*
         * The hash access method does blind reads of pages, causing them
         * to be created.  If the type field isn't set it's one of them,
         * initialize the rest of the page and return.
         */
        if (TYPE(h) != P_HASHMETA && h->pgno == PGNO_INVALID) {
                P_INIT(pp, pginfo->db_pagesize,
                    pg, PGNO_INVALID, PGNO_INVALID, 0, P_HASH, 0);
                return (0);
        }

        if (!pginfo->needswap)
                return (0);

        return (TYPE(h) == P_HASHMETA ?  CDB___ham_mswap(pp) :
            CDB___db_byteswap(dbenv, pg, pp, pginfo->db_pagesize, 1));
}

/*
 * CDB___ham_pgout --
 *      Convert host-specific page layout to the host-independent format
 *      stored on disk.
 *
 * PUBLIC: int CDB___ham_pgout __P((DB_ENV *, db_pgno_t, void *, DBT *));
 */
int
CDB___ham_pgout(dbenv, pg, pp, cookie)
        DB_ENV *dbenv;
        db_pgno_t pg;
        void *pp;
        DBT *cookie;
{
        DB_PGINFO *pginfo;
        PAGE *h;

        pginfo = (DB_PGINFO *)cookie->data;
        if (!pginfo->needswap)
                return (0);

        h = pp;
        return (TYPE(h) == P_HASHMETA ?  CDB___ham_mswap(pp) :
             CDB___db_byteswap(dbenv, pg, pp, pginfo->db_pagesize, 0));
}

/*
 * CDB___ham_mswap --
 *      Swap the bytes on the hash metadata page.
 *
 * PUBLIC: int CDB___ham_mswap __P((void *));
 */
int
CDB___ham_mswap(pg)
        void *pg;
{
        u_int8_t *p;
        int i;

        CDB___db_metaswap(pg);

        p = (u_int8_t *)pg + sizeof(DBMETA);

        SWAP32(p);              /* max_bucket */
        SWAP32(p);              /* high_mask */
        SWAP32(p);              /* low_mask */
        SWAP32(p);              /* ffactor */
        SWAP32(p);              /* nelem */
        SWAP32(p);              /* h_charkey */
        for (i = 0; i < NCACHED; ++i)
                SWAP32(p);      /* spares */
        return (0);
}

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