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);
}