rec_utils.c

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/*-
 * Copyright (c) 1990, 1993, 1994
 * The Regents of the University of California.  All rights reserved.
 *
 * 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[] = "@(#)rec_utils.c   8.6 (Berkeley) 7/16/94";
#endif /* LIBC_SCCS and not lint */

#include <sys/param.h>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "../include/db.h"
#include "recno.h"

/*
 * __rec_ret --
 * Build return data.
 *
 * Parameters:
 * t: tree
 * e: key/data pair to be returned
 *   nrec:  record number
 *    key:  user's key structure
 * data: user's data structure
 *
 * Returns:
 * RET_SUCCESS, RET_ERROR.
 */
int
__rec_ret(t, e, nrec, key, data)
   BTREE *t;
   EPG *e;
   recno_t nrec;
   DBT *key, *data;
{
   RLEAF *rl;
   void *p;

   if (key == NULL)
      goto dataonly;

   /* We have to copy the key, it's not on the page. */
   if (sizeof(recno_t) > t->bt_rkey.size) {
      p = (void *)(t->bt_rkey.data == NULL ?
          malloc(sizeof(recno_t)) :
          realloc(t->bt_rkey.data, sizeof(recno_t)));
      if (p == NULL)
         return (RET_ERROR);
      t->bt_rkey.data = p;
      t->bt_rkey.size = sizeof(recno_t);
   }
   memmove(t->bt_rkey.data, &nrec, sizeof(recno_t));
   key->size = sizeof(recno_t);
   key->data = t->bt_rkey.data;

dataonly:
   if (data == NULL)
      return (RET_SUCCESS);

   /*
    * We must copy big keys/data to make them contiguous.  Otherwise,
    * leave the page pinned and don't copy unless the user specified
    * concurrent access.
    */
   rl = GETRLEAF(e->page, e->index);
   if (rl->flags & P_BIGDATA) {
      if (__ovfl_get(t, rl->bytes,
          &data->size, &t->bt_rdata.data, &t->bt_rdata.size))
         return (RET_ERROR);
      data->data = t->bt_rdata.data;
   } else if (F_ISSET(t, B_DB_LOCK)) {
      /* Use +1 in case the first record retrieved is 0 length. */
      if (rl->dsize + 1 > t->bt_rdata.size) {
         p = (void *)(t->bt_rdata.data == NULL ?
             malloc(rl->dsize + 1) :
             realloc(t->bt_rdata.data, rl->dsize + 1));
         if (p == NULL)
            return (RET_ERROR);
         t->bt_rdata.data = p;
         t->bt_rdata.size = rl->dsize + 1;
      }
      memmove(t->bt_rdata.data, rl->bytes, rl->dsize);
      data->size = rl->dsize;
      data->data = t->bt_rdata.data;
   } else {
      data->size = rl->dsize;
      data->data = rl->bytes;
   }
   return (RET_SUCCESS);
}