1 /* $NetBSD: rec_search.c,v 1.12 2007/02/03 23:46:09 christos 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 1.12 2007/02/03 23:46:09 christos Exp $"); 38 #endif 39 #endif /* LIBC_SCCS and not lint */ 40 41 #include "namespace.h" 42 #include <sys/types.h> 43 44 #include <assert.h> 45 #include <errno.h> 46 #include <stdio.h> 47 48 #include <db.h> 49 #include "recno.h" 50 51 /* 52 * __REC_SEARCH -- Search a btree for a key. 53 * 54 * Parameters: 55 * t: tree to search 56 * recno: key to find 57 * op: search operation 58 * 59 * Returns: 60 * EPG for matching record, if any, or the EPG for the location of the 61 * key, if it were inserted into the tree. 62 * 63 * Returns: 64 * The EPG for matching record, if any, or the EPG for the location 65 * of the key, if it were inserted into the tree, is entered into 66 * the bt_cur field of the tree. A pointer to the field is returned. 67 */ 68 EPG * 69 __rec_search(BTREE *t, recno_t recno, enum SRCHOP op) 70 { 71 indx_t idx; 72 PAGE *h; 73 EPGNO *parent; 74 RINTERNAL *r; 75 pgno_t pg; 76 indx_t top; 77 recno_t total; 78 int sverrno; 79 80 BT_CLR(t); 81 for (pg = P_ROOT, total = 0;;) { 82 if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL) 83 goto err; 84 if (h->flags & P_RLEAF) { 85 t->bt_cur.page = h; 86 t->bt_cur.index = recno - total; 87 return (&t->bt_cur); 88 } 89 for (idx = 0, top = NEXTINDEX(h);;) { 90 r = GETRINTERNAL(h, idx); 91 if (++idx == top || total + r->nrecs > recno) 92 break; 93 total += r->nrecs; 94 } 95 96 BT_PUSH(t, pg, idx - 1); 97 98 pg = r->pgno; 99 switch (op) { 100 case SDELETE: 101 --GETRINTERNAL(h, (idx - 1))->nrecs; 102 mpool_put(t->bt_mp, h, MPOOL_DIRTY); 103 break; 104 case SINSERT: 105 ++GETRINTERNAL(h, (idx - 1))->nrecs; 106 mpool_put(t->bt_mp, h, MPOOL_DIRTY); 107 break; 108 case SEARCH: 109 mpool_put(t->bt_mp, h, 0); 110 break; 111 } 112 113 } 114 /* Try and recover the tree. */ 115 err: sverrno = errno; 116 if (op != SEARCH) 117 while ((parent = BT_POP(t)) != NULL) { 118 if ((h = mpool_get(t->bt_mp, parent->pgno, 0)) == NULL) 119 break; 120 if (op == SINSERT) 121 --GETRINTERNAL(h, parent->index)->nrecs; 122 else 123 ++GETRINTERNAL(h, parent->index)->nrecs; 124 mpool_put(t->bt_mp, h, MPOOL_DIRTY); 125 } 126 errno = sverrno; 127 return (NULL); 128 } 129