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 * 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