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 #if defined(LIBC_SCCS) && !defined(lint) 33 static char sccsid[] = "@(#)rec_search.c 8.4 (Berkeley) 7/14/94"; 34 #endif /* LIBC_SCCS and not lint */ 35 #include <sys/cdefs.h> 36 __FBSDID("$FreeBSD$"); 37 38 #include <sys/types.h> 39 40 #include <errno.h> 41 #include <stdio.h> 42 43 #include <db.h> 44 #include "recno.h" 45 46 /* 47 * __REC_SEARCH -- Search a btree for a key. 48 * 49 * Parameters: 50 * t: tree to search 51 * recno: key to find 52 * op: search operation 53 * 54 * Returns: 55 * EPG for matching record, if any, or the EPG for the location of the 56 * key, if it were inserted into the tree. 57 * 58 * Returns: 59 * The EPG for matching record, if any, or the EPG for the location 60 * of the key, if it were inserted into the tree, is entered into 61 * the bt_cur field of the tree. A pointer to the field is returned. 62 */ 63 EPG * 64 __rec_search(BTREE *t, recno_t recno, enum SRCHOP op) 65 { 66 indx_t idx; 67 PAGE *h; 68 EPGNO *parent; 69 RINTERNAL *r; 70 pgno_t pg; 71 indx_t top; 72 recno_t total; 73 int sverrno; 74 75 BT_CLR(t); 76 for (pg = P_ROOT, total = 0;;) { 77 if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL) 78 goto err; 79 if (h->flags & P_RLEAF) { 80 t->bt_cur.page = h; 81 t->bt_cur.index = recno - total; 82 return (&t->bt_cur); 83 } 84 for (idx = 0, top = NEXTINDEX(h);;) { 85 r = GETRINTERNAL(h, idx); 86 if (++idx == top || total + r->nrecs > recno) 87 break; 88 total += r->nrecs; 89 } 90 91 BT_PUSH(t, pg, idx - 1); 92 93 pg = r->pgno; 94 switch (op) { 95 case SDELETE: 96 --GETRINTERNAL(h, (idx - 1))->nrecs; 97 mpool_put(t->bt_mp, h, MPOOL_DIRTY); 98 break; 99 case SINSERT: 100 ++GETRINTERNAL(h, (idx - 1))->nrecs; 101 mpool_put(t->bt_mp, h, MPOOL_DIRTY); 102 break; 103 case SEARCH: 104 mpool_put(t->bt_mp, h, 0); 105 break; 106 } 107 108 } 109 /* Try and recover the tree. */ 110 err: sverrno = errno; 111 if (op != SEARCH) 112 while ((parent = BT_POP(t)) != NULL) { 113 if ((h = mpool_get(t->bt_mp, parent->pgno, 0)) == NULL) 114 break; 115 if (op == SINSERT) 116 --GETRINTERNAL(h, parent->index)->nrecs; 117 else 118 ++GETRINTERNAL(h, parent->index)->nrecs; 119 mpool_put(t->bt_mp, h, MPOOL_DIRTY); 120 } 121 errno = sverrno; 122 return (NULL); 123 } 124