1 /* $NetBSD: rec_search.c,v 1.11 2003/08/07 16:42:44 agc Exp $ */ 2 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/cdefs.h> 33 #if defined(LIBC_SCCS) && !defined(lint) 34 #if 0 35 static char sccsid[] = "@(#)rec_search.c 8.4 (Berkeley) 7/14/94"; 36 #else 37 __RCSID("$NetBSD: rec_search.c,v 1.11 2003/08/07 16:42:44 agc Exp $"); 38 #endif 39 #endif /* LIBC_SCCS and not lint */ 40 41 #include "namespace.h" 42 #include <sys/types.h> 43 44 #include <errno.h> 45 #include <stdio.h> 46 47 #include <db.h> 48 #include "recno.h" 49 50 /* 51 * __REC_SEARCH -- Search a btree for a key. 52 * 53 * Parameters: 54 * t: tree to search 55 * recno: key to find 56 * op: search operation 57 * 58 * Returns: 59 * EPG for matching record, if any, or the EPG for the location of the 60 * key, if it were inserted into the tree. 61 * 62 * Returns: 63 * The EPG for matching record, if any, or the EPG for the location 64 * of the key, if it were inserted into the tree, is entered into 65 * the bt_cur field of the tree. A pointer to the field is returned. 66 */ 67 EPG * 68 __rec_search(t, recno, op) 69 BTREE *t; 70 recno_t recno; 71 enum SRCHOP op; 72 { 73 register indx_t idx; 74 register PAGE *h; 75 EPGNO *parent; 76 RINTERNAL *r; 77 pgno_t pg; 78 indx_t top; 79 recno_t total; 80 int sverrno; 81 82 BT_CLR(t); 83 for (pg = P_ROOT, total = 0;;) { 84 if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL) 85 goto err; 86 if (h->flags & P_RLEAF) { 87 t->bt_cur.page = h; 88 t->bt_cur.index = recno - total; 89 return (&t->bt_cur); 90 } 91 for (idx = 0, top = NEXTINDEX(h);;) { 92 r = GETRINTERNAL(h, idx); 93 if (++idx == top || total + r->nrecs > recno) 94 break; 95 total += r->nrecs; 96 } 97 98 BT_PUSH(t, pg, idx - 1); 99 100 pg = r->pgno; 101 switch (op) { 102 case SDELETE: 103 --GETRINTERNAL(h, (idx - 1))->nrecs; 104 mpool_put(t->bt_mp, h, MPOOL_DIRTY); 105 break; 106 case SINSERT: 107 ++GETRINTERNAL(h, (idx - 1))->nrecs; 108 mpool_put(t->bt_mp, h, MPOOL_DIRTY); 109 break; 110 case SEARCH: 111 mpool_put(t->bt_mp, h, 0); 112 break; 113 } 114 115 } 116 /* Try and recover the tree. */ 117 err: sverrno = errno; 118 if (op != SEARCH) 119 while ((parent = BT_POP(t)) != NULL) { 120 if ((h = mpool_get(t->bt_mp, parent->pgno, 0)) == NULL) 121 break; 122 if (op == SINSERT) 123 --GETRINTERNAL(h, parent->index)->nrecs; 124 else 125 ++GETRINTERNAL(h, parent->index)->nrecs; 126 mpool_put(t->bt_mp, h, MPOOL_DIRTY); 127 } 128 errno = sverrno; 129 return (NULL); 130 } 131