1 /* $NetBSD: rec_search.c,v 1.6 1995/02/27 13:25:17 cgd 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 #if defined(LIBC_SCCS) && !defined(lint) 37 #if 0 38 static char sccsid[] = "@(#)rec_search.c 8.3 (Berkeley) 2/21/94"; 39 #else 40 static char rcsid[] = "$NetBSD: rec_search.c,v 1.6 1995/02/27 13:25:17 cgd Exp $"; 41 #endif 42 #endif /* LIBC_SCCS and not lint */ 43 44 #include <sys/types.h> 45 46 #include <errno.h> 47 #include <stdio.h> 48 49 #include <db.h> 50 #include "recno.h" 51 52 /* 53 * __REC_SEARCH -- Search a btree for a key. 54 * 55 * Parameters: 56 * t: tree to search 57 * recno: key to find 58 * op: search operation 59 * 60 * Returns: 61 * EPG for matching record, if any, or the EPG for the location of the 62 * key, if it were inserted into the tree. 63 * 64 * Returns: 65 * The EPG for matching record, if any, or the EPG for the location 66 * of the key, if it were inserted into the tree, is entered into 67 * the bt_cur field of the tree. A pointer to the field is returned. 68 */ 69 EPG * 70 __rec_search(t, recno, op) 71 BTREE *t; 72 recno_t recno; 73 enum SRCHOP op; 74 { 75 register indx_t index; 76 register PAGE *h; 77 EPGNO *parent; 78 RINTERNAL *r; 79 pgno_t pg; 80 indx_t top; 81 recno_t total; 82 int sverrno; 83 84 BT_CLR(t); 85 for (pg = P_ROOT, total = 0;;) { 86 if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL) 87 goto err; 88 if (h->flags & P_RLEAF) { 89 t->bt_cur.page = h; 90 t->bt_cur.index = recno - total; 91 return (&t->bt_cur); 92 } 93 for (index = 0, top = NEXTINDEX(h);;) { 94 r = GETRINTERNAL(h, index); 95 if (++index == top || total + r->nrecs > recno) 96 break; 97 total += r->nrecs; 98 } 99 100 if (__bt_push(t, pg, index - 1) == RET_ERROR) 101 return (NULL); 102 103 pg = r->pgno; 104 switch (op) { 105 case SDELETE: 106 --GETRINTERNAL(h, (index - 1))->nrecs; 107 mpool_put(t->bt_mp, h, MPOOL_DIRTY); 108 break; 109 case SINSERT: 110 ++GETRINTERNAL(h, (index - 1))->nrecs; 111 mpool_put(t->bt_mp, h, MPOOL_DIRTY); 112 break; 113 case SEARCH: 114 mpool_put(t->bt_mp, h, 0); 115 break; 116 } 117 118 } 119 /* Try and recover the tree. */ 120 err: sverrno = errno; 121 if (op != SEARCH) 122 while ((parent = BT_POP(t)) != NULL) { 123 if ((h = mpool_get(t->bt_mp, parent->pgno, 0)) == NULL) 124 break; 125 if (op == SINSERT) 126 --GETRINTERNAL(h, parent->index)->nrecs; 127 else 128 ++GETRINTERNAL(h, parent->index)->nrecs; 129 mpool_put(t->bt_mp, h, MPOOL_DIRTY); 130 } 131 errno = sverrno; 132 return (NULL); 133 } 134