[apple/libc.git] / db / recno / FreeBSD / rec_search.c

/*-
 * 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.
 * 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_search.c	8.4 (Berkeley) 7/14/94";
#endif /* LIBC_SCCS and not lint */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/lib/libc/db/recno/rec_search.c,v 1.8 2009/03/04 00:58:04 delphij Exp $");

#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(BTREE *t, recno_t recno, enum SRCHOP op)
{
	indx_t idx;
	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 (idx = 0, top = NEXTINDEX(h);;) {
			r = GETRINTERNAL(h, idx);
			if (++idx == top || total + r->nrecs > recno)
				break;
			total += r->nrecs;
		}

		BT_PUSH(t, pg, idx - 1);

		pg = r->pgno;
		switch (op) {
		case SDELETE:
			--GETRINTERNAL(h, (idx - 1))->nrecs;
			mpool_put(t->bt_mp, h, MPOOL_DIRTY);
			break;
		case SINSERT:
			++GETRINTERNAL(h, (idx - 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);
}
Commit	Line	Data
9385eb3d	1	/*-
e9ce8d39 A	2	* Copyright (c) 1990, 1993
	3	* The Regents of the University of California. All rights reserved.
	4	*
	5	* Redistribution and use in source and binary forms, with or without
	6	* modification, are permitted provided that the following conditions
	7	* are met:
	8	* 1. Redistributions of source code must retain the above copyright
	9	* notice, this list of conditions and the following disclaimer.
	10	* 2. Redistributions in binary form must reproduce the above copyright
	11	* notice, this list of conditions and the following disclaimer in the
	12	* documentation and/or other materials provided with the distribution.
e9ce8d39 A	13	* 4. Neither the name of the University nor the names of its contributors
	14	* may be used to endorse or promote products derived from this software
	15	* without specific prior written permission.
	16	*
	17	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	18	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	19	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	20	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	21	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	22	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	23	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	24	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	25	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	26	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	27	* SUCH DAMAGE.
	28	*/
	29
9385eb3d A	30	#if defined(LIBC_SCCS) && !defined(lint)
	31	static char sccsid[] = "@(#)rec_search.c 8.4 (Berkeley) 7/14/94";
	32	#endif /* LIBC_SCCS and not lint */
	33	#include <sys/cdefs.h>
1f2f436a	34	__FBSDID("$FreeBSD: src/lib/libc/db/recno/rec_search.c,v 1.8 2009/03/04 00:58:04 delphij Exp $");
e9ce8d39 A	35
	36	#include <sys/types.h>
	37
	38	#include <errno.h>
	39	#include <stdio.h>
	40
	41	#include <db.h>
	42	#include "recno.h"
	43
	44	/*
	45	* __REC_SEARCH -- Search a btree for a key.
	46	*
	47	* Parameters:
	48	* t: tree to search
	49	* recno: key to find
1f2f436a	50	* op: search operation
e9ce8d39 A	51	*
	52	* Returns:
	53	* EPG for matching record, if any, or the EPG for the location of the
	54	* key, if it were inserted into the tree.
	55	*
	56	* Returns:
	57	* The EPG for matching record, if any, or the EPG for the location
	58	* of the key, if it were inserted into the tree, is entered into
	59	* the bt_cur field of the tree. A pointer to the field is returned.
	60	*/
	61	EPG *
1f2f436a	62	__rec_search(BTREE *t, recno_t recno, enum SRCHOP op)
e9ce8d39	63	{
1f2f436a	64	indx_t idx;
9385eb3d	65	PAGE *h;
e9ce8d39 A	66	EPGNO *parent;
	67	RINTERNAL *r;
	68	pgno_t pg;
	69	indx_t top;
	70	recno_t total;
	71	int sverrno;
	72
	73	BT_CLR(t);
	74	for (pg = P_ROOT, total = 0;;) {
	75	if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL)
	76	goto err;
	77	if (h->flags & P_RLEAF) {
	78	t->bt_cur.page = h;
	79	t->bt_cur.index = recno - total;
	80	return (&t->bt_cur);
	81	}
1f2f436a A	82	for (idx = 0, top = NEXTINDEX(h);;) {
	83	r = GETRINTERNAL(h, idx);
	84	if (++idx == top \|\| total + r->nrecs > recno)
e9ce8d39 A	85	break;
	86	total += r->nrecs;
	87	}
	88
1f2f436a A	89	BT_PUSH(t, pg, idx - 1);
1f2f436a A	90
e9ce8d39 A	91	pg = r->pgno;
	92	switch (op) {
	93	case SDELETE:
1f2f436a	94	--GETRINTERNAL(h, (idx - 1))->nrecs;
e9ce8d39 A	95	mpool_put(t->bt_mp, h, MPOOL_DIRTY);
	96	break;
	97	case SINSERT:
1f2f436a	98	++GETRINTERNAL(h, (idx - 1))->nrecs;
e9ce8d39 A	99	mpool_put(t->bt_mp, h, MPOOL_DIRTY);
	100	break;
	101	case SEARCH:
	102	mpool_put(t->bt_mp, h, 0);
	103	break;
	104	}
	105
	106	}
	107	/* Try and recover the tree. */
	108	err: sverrno = errno;
	109	if (op != SEARCH)
	110	while ((parent = BT_POP(t)) != NULL) {
	111	if ((h = mpool_get(t->bt_mp, parent->pgno, 0)) == NULL)
	112	break;
	113	if (op == SINSERT)
	114	--GETRINTERNAL(h, parent->index)->nrecs;
	115	else
	116	++GETRINTERNAL(h, parent->index)->nrecs;
1f2f436a A	117	mpool_put(t->bt_mp, h, MPOOL_DIRTY);
1f2f436a A	118	}
e9ce8d39 A	119	errno = sverrno;
	120	return (NULL);
	121	}