1 /*- 2 * Copyright (c) 1990, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)rec_search.c 8.4 (Berkeley) 7/14/94 30 * $FreeBSD: head/lib/libc/db/recno/rec_search.c 189327 2009-03-04 00:58:04Z delphij $ 31 */ 32 33 #include <sys/types.h> 34 35 #include <errno.h> 36 #include <stdio.h> 37 38 #include <db.h> 39 #include "recno.h" 40 41 /* 42 * __REC_SEARCH -- Search a btree for a key. 43 * 44 * Parameters: 45 * t: tree to search 46 * recno: key to find 47 * op: search operation 48 * 49 * Returns: 50 * EPG for matching record, if any, or the EPG for the location of the 51 * key, if it were inserted into the tree. 52 * 53 * Returns: 54 * The EPG for matching record, if any, or the EPG for the location 55 * of the key, if it were inserted into the tree, is entered into 56 * the bt_cur field of the tree. A pointer to the field is returned. 57 */ 58 EPG * 59 __rec_search(BTREE *t, recno_t recno, enum SRCHOP op) 60 { 61 indx_t idx; 62 PAGE *h; 63 EPGNO *parent; 64 RINTERNAL *r; 65 pgno_t pg; 66 indx_t top; 67 recno_t total; 68 int sverrno; 69 70 BT_CLR(t); 71 for (pg = P_ROOT, total = 0;;) { 72 if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL) 73 goto err; 74 if (h->flags & P_RLEAF) { 75 t->bt_cur.page = h; 76 t->bt_cur.index = recno - total; 77 return (&t->bt_cur); 78 } 79 for (idx = 0, top = NEXTINDEX(h);;) { 80 r = GETRINTERNAL(h, idx); 81 if (++idx == top || total + r->nrecs > recno) 82 break; 83 total += r->nrecs; 84 } 85 86 BT_PUSH(t, pg, idx - 1); 87 88 pg = r->pgno; 89 switch (op) { 90 case SDELETE: 91 --GETRINTERNAL(h, (idx - 1))->nrecs; 92 mpool_put(t->bt_mp, h, MPOOL_DIRTY); 93 break; 94 case SINSERT: 95 ++GETRINTERNAL(h, (idx - 1))->nrecs; 96 mpool_put(t->bt_mp, h, MPOOL_DIRTY); 97 break; 98 case SEARCH: 99 mpool_put(t->bt_mp, h, 0); 100 break; 101 } 102 103 } 104 /* Try and recover the tree. */ 105 err: sverrno = errno; 106 if (op != SEARCH) 107 while ((parent = BT_POP(t)) != NULL) { 108 if ((h = mpool_get(t->bt_mp, parent->pgno, 0)) == NULL) 109 break; 110 if (op == SINSERT) 111 --GETRINTERNAL(h, parent->index)->nrecs; 112 else 113 ++GETRINTERNAL(h, parent->index)->nrecs; 114 mpool_put(t->bt_mp, h, MPOOL_DIRTY); 115 } 116 errno = sverrno; 117 return (NULL); 118 } 119