1 /* $NetBSD: rec_search.c,v 1.10 2001/12/30 19:26:28 thorpej 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. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #include <sys/cdefs.h> 37 #if defined(LIBC_SCCS) && !defined(lint) 38 #if 0 39 static char sccsid[] = "@(#)rec_search.c 8.4 (Berkeley) 7/14/94"; 40 #else 41 __RCSID("$NetBSD: rec_search.c,v 1.10 2001/12/30 19:26:28 thorpej Exp $"); 42 #endif 43 #endif /* LIBC_SCCS and not lint */ 44 45 #include "namespace.h" 46 #include <sys/types.h> 47 48 #include <errno.h> 49 #include <stdio.h> 50 51 #include <db.h> 52 #include "recno.h" 53 54 /* 55 * __REC_SEARCH -- Search a btree for a key. 56 * 57 * Parameters: 58 * t: tree to search 59 * recno: key to find 60 * op: search operation 61 * 62 * Returns: 63 * EPG for matching record, if any, or the EPG for the location of the 64 * key, if it were inserted into the tree. 65 * 66 * Returns: 67 * The EPG for matching record, if any, or the EPG for the location 68 * of the key, if it were inserted into the tree, is entered into 69 * the bt_cur field of the tree. A pointer to the field is returned. 70 */ 71 EPG * 72 __rec_search(t, recno, op) 73 BTREE *t; 74 recno_t recno; 75 enum SRCHOP op; 76 { 77 register indx_t idx; 78 register PAGE *h; 79 EPGNO *parent; 80 RINTERNAL *r; 81 pgno_t pg; 82 indx_t top; 83 recno_t total; 84 int sverrno; 85 86 BT_CLR(t); 87 for (pg = P_ROOT, total = 0;;) { 88 if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL) 89 goto err; 90 if (h->flags & P_RLEAF) { 91 t->bt_cur.page = h; 92 t->bt_cur.index = recno - total; 93 return (&t->bt_cur); 94 } 95 for (idx = 0, top = NEXTINDEX(h);;) { 96 r = GETRINTERNAL(h, idx); 97 if (++idx == top || total + r->nrecs > recno) 98 break; 99 total += r->nrecs; 100 } 101 102 BT_PUSH(t, pg, idx - 1); 103 104 pg = r->pgno; 105 switch (op) { 106 case SDELETE: 107 --GETRINTERNAL(h, (idx - 1))->nrecs; 108 mpool_put(t->bt_mp, h, MPOOL_DIRTY); 109 break; 110 case SINSERT: 111 ++GETRINTERNAL(h, (idx - 1))->nrecs; 112 mpool_put(t->bt_mp, h, MPOOL_DIRTY); 113 break; 114 case SEARCH: 115 mpool_put(t->bt_mp, h, 0); 116 break; 117 } 118 119 } 120 /* Try and recover the tree. */ 121 err: sverrno = errno; 122 if (op != SEARCH) 123 while ((parent = BT_POP(t)) != NULL) { 124 if ((h = mpool_get(t->bt_mp, parent->pgno, 0)) == NULL) 125 break; 126 if (op == SINSERT) 127 --GETRINTERNAL(h, parent->index)->nrecs; 128 else 129 ++GETRINTERNAL(h, parent->index)->nrecs; 130 mpool_put(t->bt_mp, h, MPOOL_DIRTY); 131 } 132 errno = sverrno; 133 return (NULL); 134 } 135