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/types.h> 36 37 #include <errno.h> 38 #include <stdio.h> 39 40 #include <db.h> 41 #include "recno.h" 42 43 /* 44 * __REC_SEARCH -- Search a btree for a key. 45 * 46 * Parameters: 47 * t: tree to search 48 * recno: key to find 49 * op: search operation 50 * 51 * Returns: 52 * EPG for matching record, if any, or the EPG for the location of the 53 * key, if it were inserted into the tree. 54 * 55 * Returns: 56 * The EPG for matching record, if any, or the EPG for the location 57 * of the key, if it were inserted into the tree, is entered into 58 * the bt_cur field of the tree. A pointer to the field is returned. 59 */ 60 EPG * 61 __rec_search(BTREE *t, recno_t recno, enum SRCHOP op) 62 { 63 indx_t idx; 64 PAGE *h; 65 EPGNO *parent; 66 RINTERNAL *r; 67 pgno_t pg; 68 indx_t top; 69 recno_t total; 70 int sverrno; 71 72 BT_CLR(t); 73 for (pg = P_ROOT, total = 0;;) { 74 if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL) 75 goto err; 76 if (h->flags & P_RLEAF) { 77 t->bt_cur.page = h; 78 t->bt_cur.index = recno - total; 79 return (&t->bt_cur); 80 } 81 for (idx = 0, top = NEXTINDEX(h);;) { 82 r = GETRINTERNAL(h, idx); 83 if (++idx == top || total + r->nrecs > recno) 84 break; 85 total += r->nrecs; 86 } 87 88 BT_PUSH(t, pg, idx - 1); 89 90 pg = r->pgno; 91 switch (op) { 92 case SDELETE: 93 --GETRINTERNAL(h, (idx - 1))->nrecs; 94 mpool_put(t->bt_mp, h, MPOOL_DIRTY); 95 break; 96 case SINSERT: 97 ++GETRINTERNAL(h, (idx - 1))->nrecs; 98 mpool_put(t->bt_mp, h, MPOOL_DIRTY); 99 break; 100 case SEARCH: 101 mpool_put(t->bt_mp, h, 0); 102 break; 103 } 104 105 } 106 /* Try and recover the tree. */ 107 err: sverrno = errno; 108 if (op != SEARCH) 109 while ((parent = BT_POP(t)) != NULL) { 110 if ((h = mpool_get(t->bt_mp, parent->pgno, 0)) == NULL) 111 break; 112 if (op == SINSERT) 113 --GETRINTERNAL(h, parent->index)->nrecs; 114 else 115 ++GETRINTERNAL(h, parent->index)->nrecs; 116 mpool_put(t->bt_mp, h, MPOOL_DIRTY); 117 } 118 errno = sverrno; 119 return (NULL); 120 } 121