1 /*- 2 * Copyright (c) 1990, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 #if defined(LIBC_SCCS) && !defined(lint) 35 static char sccsid[] = "@(#)rec_search.c 8.4 (Berkeley) 7/14/94"; 36 #endif /* LIBC_SCCS and not lint */ 37 38 #include <sys/types.h> 39 40 #include <errno.h> 41 #include <stdio.h> 42 43 #include <db.h> 44 #include "recno.h" 45 46 /* 47 * __REC_SEARCH -- Search a btree for a key. 48 * 49 * Parameters: 50 * t: tree to search 51 * recno: key to find 52 * op: search operation 53 * 54 * Returns: 55 * EPG for matching record, if any, or the EPG for the location of the 56 * key, if it were inserted into the tree. 57 * 58 * Returns: 59 * The EPG for matching record, if any, or the EPG for the location 60 * of the key, if it were inserted into the tree, is entered into 61 * the bt_cur field of the tree. A pointer to the field is returned. 62 */ 63 EPG * 64 __rec_search(t, recno, op) 65 BTREE *t; 66 recno_t recno; 67 enum SRCHOP op; 68 { 69 register indx_t index; 70 register 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 (index = 0, top = NEXTINDEX(h);;) { 88 r = GETRINTERNAL(h, index); 89 if (++index == top || total + r->nrecs > recno) 90 break; 91 total += r->nrecs; 92 } 93 94 BT_PUSH(t, pg, index - 1); 95 96 pg = r->pgno; 97 switch (op) { 98 case SDELETE: 99 --GETRINTERNAL(h, (index - 1))->nrecs; 100 mpool_put(t->bt_mp, h, MPOOL_DIRTY); 101 break; 102 case SINSERT: 103 ++GETRINTERNAL(h, (index - 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