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)
37 static 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 */
65 EPG *
__rec_search(t,recno,op)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. */
115 err: 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