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 30 #if defined(LIBC_SCCS) && !defined(lint) 31 static char sccsid[] = "@(#)rec_search.c 8.4 (Berkeley) 7/14/94"; 32 #endif /* LIBC_SCCS and not lint */ 33 #include <sys/cdefs.h> 34 __FBSDID("$FreeBSD$"); 35 36 #include <sys/types.h> 37 38 #include <errno.h> 39 #include <stdio.h> 40 41 #include <db.h> 42 #include "recno.h" 43 44 /* 45 * __REC_SEARCH -- Search a btree for a key. 46 * 47 * Parameters: 48 * t: tree to search 49 * recno: key to find 50 * op: search operation 51 * 52 * Returns: 53 * EPG for matching record, if any, or the EPG for the location of the 54 * key, if it were inserted into the tree. 55 * 56 * Returns: 57 * The EPG for matching record, if any, or the EPG for the location 58 * of the key, if it were inserted into the tree, is entered into 59 * the bt_cur field of the tree. A pointer to the field is returned. 60 */ 61 EPG * 62 __rec_search(BTREE *t, recno_t recno, enum SRCHOP op) 63 { 64 indx_t idx; 65 PAGE *h; 66 EPGNO *parent; 67 RINTERNAL *r; 68 pgno_t pg; 69 indx_t top; 70 recno_t total; 71 int sverrno; 72 73 BT_CLR(t); 74 for (pg = P_ROOT, total = 0;;) { 75 if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL) 76 goto err; 77 if (h->flags & P_RLEAF) { 78 t->bt_cur.page = h; 79 t->bt_cur.index = recno - total; 80 return (&t->bt_cur); 81 } 82 for (idx = 0, top = NEXTINDEX(h);;) { 83 r = GETRINTERNAL(h, idx); 84 if (++idx == top || total + r->nrecs > recno) 85 break; 86 total += r->nrecs; 87 } 88 89 BT_PUSH(t, pg, idx - 1); 90 91 pg = r->pgno; 92 switch (op) { 93 case SDELETE: 94 --GETRINTERNAL(h, (idx - 1))->nrecs; 95 mpool_put(t->bt_mp, h, MPOOL_DIRTY); 96 break; 97 case SINSERT: 98 ++GETRINTERNAL(h, (idx - 1))->nrecs; 99 mpool_put(t->bt_mp, h, MPOOL_DIRTY); 100 break; 101 case SEARCH: 102 mpool_put(t->bt_mp, h, 0); 103 break; 104 } 105 106 } 107 /* Try and recover the tree. */ 108 err: sverrno = errno; 109 if (op != SEARCH) 110 while ((parent = BT_POP(t)) != NULL) { 111 if ((h = mpool_get(t->bt_mp, parent->pgno, 0)) == NULL) 112 break; 113 if (op == SINSERT) 114 --GETRINTERNAL(h, parent->index)->nrecs; 115 else 116 ++GETRINTERNAL(h, parent->index)->nrecs; 117 mpool_put(t->bt_mp, h, MPOOL_DIRTY); 118 } 119 errno = sverrno; 120 return (NULL); 121 } 122