1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
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. Neither the name of the University nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#include <sys/types.h>
33
34#include <errno.h>
35#include <stdio.h>
36
37#include <db.h>
38#include "recno.h"
39
40/*
41 * __REC_SEARCH -- Search a btree for a key.
42 *
43 * Parameters:
44 *	t:	tree to search
45 *	recno:	key to find
46 *	op:	search operation
47 *
48 * Returns:
49 *	EPG for matching record, if any, or the EPG for the location of the
50 *	key, if it were inserted into the tree.
51 *
52 * Returns:
53 *	The EPG for matching record, if any, or the EPG for the location
54 *	of the key, if it were inserted into the tree, is entered into
55 *	the bt_cur field of the tree.  A pointer to the field is returned.
56 */
57EPG *
58__rec_search(BTREE *t, recno_t recno, enum SRCHOP op)
59{
60	indx_t idx;
61	PAGE *h;
62	EPGNO *parent;
63	RINTERNAL *r;
64	pgno_t pg;
65	indx_t top;
66	recno_t total;
67	int sverrno;
68
69	BT_CLR(t);
70	for (pg = P_ROOT, total = 0;;) {
71		if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL)
72			goto err;
73		if (h->flags & P_RLEAF) {
74			t->bt_cur.page = h;
75			t->bt_cur.index = recno - total;
76			return (&t->bt_cur);
77		}
78		for (idx = 0, top = NEXTINDEX(h);;) {
79			r = GETRINTERNAL(h, idx);
80			if (++idx == top || total + r->nrecs > recno)
81				break;
82			total += r->nrecs;
83		}
84
85		BT_PUSH(t, pg, idx - 1);
86
87		pg = r->pgno;
88		switch (op) {
89		case SDELETE:
90			--GETRINTERNAL(h, (idx - 1))->nrecs;
91			mpool_put(t->bt_mp, h, MPOOL_DIRTY);
92			break;
93		case SINSERT:
94			++GETRINTERNAL(h, (idx - 1))->nrecs;
95			mpool_put(t->bt_mp, h, MPOOL_DIRTY);
96			break;
97		case SEARCH:
98			mpool_put(t->bt_mp, h, 0);
99			break;
100		}
101
102	}
103	/* Try and recover the tree. */
104err:	sverrno = errno;
105	if (op != SEARCH)
106		while  ((parent = BT_POP(t)) != NULL) {
107			if ((h = mpool_get(t->bt_mp, parent->pgno, 0)) == NULL)
108				break;
109			if (op == SINSERT)
110				--GETRINTERNAL(h, parent->index)->nrecs;
111			else
112				++GETRINTERNAL(h, parent->index)->nrecs;
113			mpool_put(t->bt_mp, h, MPOOL_DIRTY);
114		}
115	errno = sverrno;
116	return (NULL);
117}
118