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. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)rec_search.c 8.4 (Berkeley) 7/14/94 34 * $DragonFly: src/lib/libc/db/recno/rec_search.c,v 1.3 2004/10/25 19:38:01 drhodus Exp $ 35 */ 36 37 #include <sys/types.h> 38 39 #include <errno.h> 40 #include <stdio.h> 41 42 #include <db.h> 43 #include "recno.h" 44 45 /* 46 * __REC_SEARCH -- Search a btree for a key. 47 * 48 * Parameters: 49 * t: tree to search 50 * recno: key to find 51 * op: search operation 52 * 53 * Returns: 54 * EPG for matching record, if any, or the EPG for the location of the 55 * key, if it were inserted into the tree. 56 * 57 * Returns: 58 * The EPG for matching record, if any, or the EPG for the location 59 * of the key, if it were inserted into the tree, is entered into 60 * the bt_cur field of the tree. A pointer to the field is returned. 61 */ 62 EPG * 63 __rec_search(t, recno, op) 64 BTREE *t; 65 recno_t recno; 66 enum SRCHOP op; 67 { 68 indx_t index; 69 PAGE *h; 70 EPGNO *parent; 71 RINTERNAL *r; 72 pgno_t pg; 73 indx_t top; 74 recno_t total; 75 int sverrno; 76 77 BT_CLR(t); 78 for (pg = P_ROOT, total = 0;;) { 79 if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL) 80 goto err; 81 if (h->flags & P_RLEAF) { 82 t->bt_cur.page = h; 83 t->bt_cur.index = recno - total; 84 return (&t->bt_cur); 85 } 86 for (index = 0, top = NEXTINDEX(h);;) { 87 r = GETRINTERNAL(h, index); 88 if (++index == top || total + r->nrecs > recno) 89 break; 90 total += r->nrecs; 91 } 92 93 BT_PUSH(t, pg, index - 1); 94 95 pg = r->pgno; 96 switch (op) { 97 case SDELETE: 98 --GETRINTERNAL(h, (index - 1))->nrecs; 99 mpool_put(t->bt_mp, h, MPOOL_DIRTY); 100 break; 101 case SINSERT: 102 ++GETRINTERNAL(h, (index - 1))->nrecs; 103 mpool_put(t->bt_mp, h, MPOOL_DIRTY); 104 break; 105 case SEARCH: 106 mpool_put(t->bt_mp, h, 0); 107 break; 108 } 109 110 } 111 /* Try and recover the tree. */ 112 err: sverrno = errno; 113 if (op != SEARCH) 114 while ((parent = BT_POP(t)) != NULL) { 115 if ((h = mpool_get(t->bt_mp, parent->pgno, 0)) == NULL) 116 break; 117 if (op == SINSERT) 118 --GETRINTERNAL(h, parent->index)->nrecs; 119 else 120 ++GETRINTERNAL(h, parent->index)->nrecs; 121 mpool_put(t->bt_mp, h, MPOOL_DIRTY); 122 } 123 errno = sverrno; 124 return (NULL); 125 } 126