hash_conv.c

/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 1996-2005
 *      Sleepycat Software.  All rights reserved.
 *
 * $Id: hash_conv.c,v 12.1 2005/06/16 20:22:50 bostic Exp $
 */

#include "db_config.h"

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

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

/*
 * __ham_pgin --
 *      Convert host-specific page layout from the host-independent format
 *      stored on disk.
 *
 * PUBLIC: int __ham_pgin __P((DB_ENV *, DB *, db_pgno_t, void *, DBT *));
 */
int
__ham_pgin(dbenv, dummydbp, pg, pp, cookie)
        DB_ENV *dbenv;
        DB *dummydbp;
        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 (h->type != P_HASHMETA && h->pgno == PGNO_INVALID) {
                P_INIT(pp, (db_indx_t)pginfo->db_pagesize,
                    pg, PGNO_INVALID, PGNO_INVALID, 0, P_HASH);
                return (0);
        }

        if (!F_ISSET(pginfo, DB_AM_SWAP))
                return (0);

        return (h->type == P_HASHMETA ?  __ham_mswap(pp) :
            __db_byteswap(dbenv, dummydbp, pg, pp, pginfo->db_pagesize, 1));
}

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

        pginfo = (DB_PGINFO *)cookie->data;
        if (!F_ISSET(pginfo, DB_AM_SWAP))
                return (0);

        h = pp;
        return (h->type == P_HASHMETA ?  __ham_mswap(pp) :
            __db_byteswap(dbenv, dummydbp, pg, pp, pginfo->db_pagesize, 0));
}

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

        __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 */
        p += 59 * sizeof(u_int32_t); /* unused */
        SWAP32(p);              /* crypto_magic */
        return (0);
}

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