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 */
57 EPG *
__rec_search(BTREE * t,recno_t recno,enum SRCHOP op)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. */
104 err: 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