1#pragma ident	"%Z%%M%	%I%	%E% SMI"
2
3/*-
4 * Copyright (c) 1990, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. All advertising materials mentioning features or use of this software
16 *    must display the following acknowledgement:
17 *	This product includes software developed by the University of
18 *	California, Berkeley and its contributors.
19 * 4. Neither the name of the University nor the names of its contributors
20 *    may be used to endorse or promote products derived from this software
21 *    without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36#if defined(LIBC_SCCS) && !defined(lint)
37static char sccsid[] = "@(#)rec_search.c	8.4 (Berkeley) 7/14/94";
38#endif /* LIBC_SCCS and not lint */
39
40#include <sys/types.h>
41
42#include <errno.h>
43#include <stdio.h>
44
45#include "db-int.h"
46#include "recno.h"
47
48/*
49 * __REC_SEARCH -- Search a btree for a key.
50 *
51 * Parameters:
52 *	t:	tree to search
53 *	recno:	key to find
54 *	op: 	search operation
55 *
56 * Returns:
57 *	EPG for matching record, if any, or the EPG for the location of the
58 *	key, if it were inserted into the tree.
59 *
60 * Returns:
61 *	The EPG for matching record, if any, or the EPG for the location
62 *	of the key, if it were inserted into the tree, is entered into
63 *	the bt_cur field of the tree.  A pointer to the field is returned.
64 */
65EPG *
66__rec_search(t, recno, op)
67	BTREE *t;
68	recno_t recno;
69	enum SRCHOP op;
70{
71	register indx_t idx;
72	register PAGE *h;
73	EPGNO *parent;
74	RINTERNAL *r;
75	db_pgno_t pg;
76	indx_t top;
77	recno_t total;
78	int sverrno;
79
80	BT_CLR(t);
81	for (pg = P_ROOT, total = 0;;) {
82		if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL)
83			goto err;
84		if (h->flags & P_RLEAF) {
85			t->bt_cur.page = h;
86			t->bt_cur.index = recno - total;
87			return (&t->bt_cur);
88		}
89		for (idx = 0, top = NEXTINDEX(h);;) {
90			r = GETRINTERNAL(h, idx);
91			if (++idx == top || total + r->nrecs > recno)
92				break;
93			total += r->nrecs;
94		}
95
96		BT_PUSH(t, pg, idx - 1);
97
98		pg = r->pgno;
99		switch (op) {
100		case SDELETE:
101			--GETRINTERNAL(h, (idx - 1))->nrecs;
102			mpool_put(t->bt_mp, h, MPOOL_DIRTY);
103			break;
104		case SINSERT:
105			++GETRINTERNAL(h, (idx - 1))->nrecs;
106			mpool_put(t->bt_mp, h, MPOOL_DIRTY);
107			break;
108		case SEARCH:
109			mpool_put(t->bt_mp, h, 0);
110			break;
111		}
112
113	}
114	/* Try and recover the tree. */
115err:	sverrno = errno;
116	if (op != SEARCH)
117		while  ((parent = BT_POP(t)) != NULL) {
118			if ((h = mpool_get(t->bt_mp, parent->pgno, 0)) == NULL)
119				break;
120			if (op == SINSERT)
121				--GETRINTERNAL(h, parent->index)->nrecs;
122			else
123				++GETRINTERNAL(h, parent->index)->nrecs;
124                        mpool_put(t->bt_mp, h, MPOOL_DIRTY);
125                }
126	errno = sverrno;
127	return (NULL);
128}
129