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/* $NetBSD: rec_search.c,v 1.7 1996/05/03 21:38:52 cgd Exp $ */
/*-
* Copyright (c) 1990, 1993
* 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)
#if 0
static char sccsid[] = "@(#)rec_search.c 8.4 (Berkeley) 7/14/94";
#else
static char rcsid[] = "$NetBSD: rec_search.c,v 1.7 1996/05/03 21:38:52 cgd Exp $";
#endif
#endif /* LIBC_SCCS and not lint */
#include <sys/types.h>
#include <errno.h>
#include <stdio.h>
#include <db.h>
#include "recno.h"
/*
* __REC_SEARCH -- Search a btree for a key.
*
* Parameters:
* t: tree to search
* recno: key to find
* op: search operation
*
* Returns:
* EPG for matching record, if any, or the EPG for the location of the
* key, if it were inserted into the tree.
*
* Returns:
* The EPG for matching record, if any, or the EPG for the location
* of the key, if it were inserted into the tree, is entered into
* the bt_cur field of the tree. A pointer to the field is returned.
*/
EPG *
__rec_search(t, recno, op)
BTREE *t;
recno_t recno;
enum SRCHOP op;
{
register indx_t index;
register PAGE *h;
EPGNO *parent;
RINTERNAL *r;
pgno_t pg;
indx_t top;
recno_t total;
int sverrno;
BT_CLR(t);
for (pg = P_ROOT, total = 0;;) {
if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL)
goto err;
if (h->flags & P_RLEAF) {
t->bt_cur.page = h;
t->bt_cur.index = recno - total;
return (&t->bt_cur);
}
for (index = 0, top = NEXTINDEX(h);;) {
r = GETRINTERNAL(h, index);
if (++index == top || total + r->nrecs > recno)
break;
total += r->nrecs;
}
BT_PUSH(t, pg, index - 1);
pg = r->pgno;
switch (op) {
case SDELETE:
--GETRINTERNAL(h, (index - 1))->nrecs;
mpool_put(t->bt_mp, h, MPOOL_DIRTY);
break;
case SINSERT:
++GETRINTERNAL(h, (index - 1))->nrecs;
mpool_put(t->bt_mp, h, MPOOL_DIRTY);
break;
case SEARCH:
mpool_put(t->bt_mp, h, 0);
break;
}
}
/* Try and recover the tree. */
err: sverrno = errno;
if (op != SEARCH)
while ((parent = BT_POP(t)) != NULL) {
if ((h = mpool_get(t->bt_mp, parent->pgno, 0)) == NULL)
break;
if (op == SINSERT)
--GETRINTERNAL(h, parent->index)->nrecs;
else
++GETRINTERNAL(h, parent->index)->nrecs;
mpool_put(t->bt_mp, h, MPOOL_DIRTY);
}
errno = sverrno;
return (NULL);
}
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