1 /* $NetBSD: rec_search.c,v 1.16 2016/09/24 21:31:25 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 #if HAVE_NBTOOL_CONFIG_H 33 #include "nbtool_config.h" 34 #endif 35 36 #include <sys/cdefs.h> 37 __RCSID("$NetBSD: rec_search.c,v 1.16 2016/09/24 21:31:25 christos Exp $"); 38 39 #include "namespace.h" 40 #include <sys/types.h> 41 42 #include <assert.h> 43 #include <errno.h> 44 #include <stdio.h> 45 46 #include <db.h> 47 #include "recno.h" 48 49 /* 50 * __REC_SEARCH -- Search a btree for a key. 51 * 52 * Parameters: 53 * t: tree to search 54 * recno: key to find 55 * op: search operation 56 * 57 * Returns: 58 * EPG for matching record, if any, or the EPG for the location of the 59 * key, if it were inserted into the tree. 60 * 61 * Returns: 62 * The EPG for matching record, if any, or the EPG for the location 63 * of the key, if it were inserted into the tree, is entered into 64 * the bt_cur field of the tree. A pointer to the field is returned. 65 */ 66 EPG * 67 __rec_search(BTREE *t, recno_t recno, enum SRCHOP op) 68 { 69 indx_t idx; 70 PAGE *h; 71 EPGNO *parent; 72 RINTERNAL *r; 73 pgno_t pg; 74 indx_t top; 75 recno_t total; 76 int sverrno; 77 78 BT_CLR(t); 79 for (pg = P_ROOT, total = 0;;) { 80 if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL) 81 goto err; 82 if (h->flags & P_RLEAF) { 83 t->bt_cur.page = h; 84 t->bt_cur.index = recno - total; 85 return (&t->bt_cur); 86 } 87 for (idx = 0, top = NEXTINDEX(h);;) { 88 r = GETRINTERNAL(h, idx); 89 if (++idx == top || total + r->nrecs > recno) 90 break; 91 total += r->nrecs; 92 } 93 94 BT_PUSH(t, pg, idx - 1); 95 96 pg = r->pgno; 97 switch (op) { 98 case SDELETE: 99 --GETRINTERNAL(h, (idx - 1))->nrecs; 100 mpool_put(t->bt_mp, h, MPOOL_DIRTY); 101 break; 102 case SINSERT: 103 ++GETRINTERNAL(h, (idx - 1))->nrecs; 104 mpool_put(t->bt_mp, h, MPOOL_DIRTY); 105 break; 106 case SEARCH: 107 mpool_put(t->bt_mp, h, 0); 108 break; 109 } 110 111 } 112 /* Try and recover the tree. */ 113 err: sverrno = errno; 114 if (op != SEARCH) 115 while ((parent = BT_POP(t)) != NULL) { 116 if ((h = mpool_get(t->bt_mp, parent->pgno, 0)) == NULL) 117 break; 118 if (op == SINSERT) 119 --GETRINTERNAL(h, parent->index)->nrecs; 120 else 121 ++GETRINTERNAL(h, parent->index)->nrecs; 122 mpool_put(t->bt_mp, h, MPOOL_DIRTY); 123 } 124 errno = sverrno; 125 return (NULL); 126 } 127