bt_conv.c

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/*-
 * 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
 * Mike Olson.
 *
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *  This product includes software developed by the University of
 *  California, Berkeley and its contributors.
 * 4. 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.
 */
 
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)bt_conv.c   8.5 (Berkeley) 8/17/94";
#endif /* LIBC_SCCS and not lint */
 
#include <sys/param.h>
 
#include <stdio.h>
 
#include "../include/db.h"
#include "btree.h"
 
static void mswap __P((PAGE *));
 
/*
 * __BT_BPGIN, __BT_BPGOUT --
 *  Convert host-specific number layout to/from the host-independent
 *  format stored on disk.
 *
 * Parameters:
 *  t:  tree
 *  pg: page number
 *  h:  page to convert
 */
void
__bt_pgin(t, pg, pp)
    void *t;
    pgno_t pg;
    void *pp;
{
    PAGE *h;
    indx_t i, top;
    u_char flags;
    char *p;
 
    if (!F_ISSET(((BTREE *)t), B_NEEDSWAP))
        return;
    if (pg == P_META) {
        mswap(pp);
        return;
    }
 
    h = pp;
    M_32_SWAP(h->pgno);
    M_32_SWAP(h->prevpg);
    M_32_SWAP(h->nextpg);
    M_32_SWAP(h->flags);
    M_16_SWAP(h->lower);
    M_16_SWAP(h->upper);
 
    top = NEXTINDEX(h);
    if ((h->flags & P_TYPE) == P_BINTERNAL)
        for (i = 0; i < top; i++) {
            M_16_SWAP(h->linp[i]);
            p = (char *)GETBINTERNAL(h, i);
            P_32_SWAP(p);
            p += sizeof(u_int32_t);
            P_32_SWAP(p);
            p += sizeof(pgno_t);
            if (*(u_char *)p & P_BIGKEY) {
                p += sizeof(u_char);
                P_32_SWAP(p);
                p += sizeof(pgno_t);
                P_32_SWAP(p);
            }
        }
    else if ((h->flags & P_TYPE) == P_BLEAF)
        for (i = 0; i < top; i++) {
            M_16_SWAP(h->linp[i]);
            p = (char *)GETBLEAF(h, i);
            P_32_SWAP(p);
            p += sizeof(u_int32_t);
            P_32_SWAP(p);
            p += sizeof(u_int32_t);
            flags = *(u_char *)p;
            if (flags & (P_BIGKEY | P_BIGDATA)) {
                p += sizeof(u_char);
                if (flags & P_BIGKEY) {
                    P_32_SWAP(p);
                    p += sizeof(pgno_t);
                    P_32_SWAP(p);
                }
                if (flags & P_BIGDATA) {
                    p += sizeof(u_int32_t);
                    P_32_SWAP(p);
                    p += sizeof(pgno_t);
                    P_32_SWAP(p);
                }
            }
        }
}
 
void
__bt_pgout(t, pg, pp)
    void *t;
    pgno_t pg;
    void *pp;
{
    PAGE *h;
    indx_t i, top;
    u_char flags;
    char *p;
 
    if (!F_ISSET(((BTREE *)t), B_NEEDSWAP))
        return;
    if (pg == P_META) {
        mswap(pp);
        return;
    }
 
    h = pp;
    top = NEXTINDEX(h);
    if ((h->flags & P_TYPE) == P_BINTERNAL)
        for (i = 0; i < top; i++) {
            p = (char *)GETBINTERNAL(h, i);
            P_32_SWAP(p);
            p += sizeof(u_int32_t);
            P_32_SWAP(p);
            p += sizeof(pgno_t);
            if (*(u_char *)p & P_BIGKEY) {
                p += sizeof(u_char);
                P_32_SWAP(p);
                p += sizeof(pgno_t);
                P_32_SWAP(p);
            }
            M_16_SWAP(h->linp[i]);
        }
    else if ((h->flags & P_TYPE) == P_BLEAF)
        for (i = 0; i < top; i++) {
            p = (char *)GETBLEAF(h, i);
            P_32_SWAP(p);
            p += sizeof(u_int32_t);
            P_32_SWAP(p);
            p += sizeof(u_int32_t);
            flags = *(u_char *)p;
            if (flags & (P_BIGKEY | P_BIGDATA)) {
                p += sizeof(u_char);
                if (flags & P_BIGKEY) {
                    P_32_SWAP(p);
                    p += sizeof(pgno_t);
                    P_32_SWAP(p);
                }
                if (flags & P_BIGDATA) {
                    p += sizeof(u_int32_t);
                    P_32_SWAP(p);
                    p += sizeof(pgno_t);
                    P_32_SWAP(p);
                }
            }
            M_16_SWAP(h->linp[i]);
        }
 
    M_32_SWAP(h->pgno);
    M_32_SWAP(h->prevpg);
    M_32_SWAP(h->nextpg);
    M_32_SWAP(h->flags);
    M_16_SWAP(h->lower);
    M_16_SWAP(h->upper);
}
 
/*
 * MSWAP -- Actually swap the bytes on the meta page.
 *
 * Parameters:
 *  p:  page to convert
 */
static void
mswap(pg)
    PAGE *pg;
{
    char *p;
 
    p = (char *)pg;
    P_32_SWAP(p);       /* magic */
    p += sizeof(u_int32_t);
    P_32_SWAP(p);       /* version */
    p += sizeof(u_int32_t);
    P_32_SWAP(p);       /* psize */
    p += sizeof(u_int32_t);
    P_32_SWAP(p);       /* free */
    p += sizeof(u_int32_t);
    P_32_SWAP(p);       /* nrecs */
    p += sizeof(u_int32_t);
    P_32_SWAP(p);       /* flags */
    p += sizeof(u_int32_t);
}