1/*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1990, 1993, 1994 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Mike Olson. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35#if defined(LIBC_SCCS) && !defined(lint) 36static char sccsid[] = "@(#)rec_delete.c 8.7 (Berkeley) 7/14/94"; 37#endif /* LIBC_SCCS and not lint */ 38#include <sys/cdefs.h> 39__FBSDID("$FreeBSD$"); 40 41#include <sys/types.h> 42 43#include <errno.h> 44#include <stdio.h> 45#include <string.h> 46 47#include <db.h> 48#include "recno.h" 49 50static int rec_rdelete(BTREE *, recno_t); 51 52/* 53 * __REC_DELETE -- Delete the item(s) referenced by a key. 54 * 55 * Parameters: 56 * dbp: pointer to access method 57 * key: key to delete 58 * flags: R_CURSOR if deleting what the cursor references 59 * 60 * Returns: 61 * RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found. 62 */ 63int 64__rec_delete(const DB *dbp, const DBT *key, u_int flags) 65{ 66 BTREE *t; 67 recno_t nrec; 68 int status; 69 70 t = dbp->internal; 71 72 /* Toss any page pinned across calls. */ 73 if (t->bt_pinned != NULL) { 74 mpool_put(t->bt_mp, t->bt_pinned, 0); 75 t->bt_pinned = NULL; 76 } 77 78 switch(flags) { 79 case 0: 80 if ((nrec = *(recno_t *)key->data) == 0) 81 goto einval; 82 if (nrec > t->bt_nrecs) 83 return (RET_SPECIAL); 84 --nrec; 85 status = rec_rdelete(t, nrec); 86 break; 87 case R_CURSOR: 88 if (!F_ISSET(&t->bt_cursor, CURS_INIT)) 89 goto einval; 90 if (t->bt_nrecs == 0) 91 return (RET_SPECIAL); 92 status = rec_rdelete(t, t->bt_cursor.rcursor - 1); 93 if (status == RET_SUCCESS) 94 --t->bt_cursor.rcursor; 95 break; 96 default: 97einval: errno = EINVAL; 98 return (RET_ERROR); 99 } 100 101 if (status == RET_SUCCESS) 102 F_SET(t, B_MODIFIED | R_MODIFIED); 103 return (status); 104} 105 106/* 107 * REC_RDELETE -- Delete the data matching the specified key. 108 * 109 * Parameters: 110 * tree: tree 111 * nrec: record to delete 112 * 113 * Returns: 114 * RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found. 115 */ 116static int 117rec_rdelete(BTREE *t, recno_t nrec) 118{ 119 EPG *e; 120 PAGE *h; 121 int status; 122 123 /* Find the record; __rec_search pins the page. */ 124 if ((e = __rec_search(t, nrec, SDELETE)) == NULL) 125 return (RET_ERROR); 126 127 /* Delete the record. */ 128 h = e->page; 129 status = __rec_dleaf(t, h, e->index); 130 if (status != RET_SUCCESS) { 131 mpool_put(t->bt_mp, h, 0); 132 return (status); 133 } 134 mpool_put(t->bt_mp, h, MPOOL_DIRTY); 135 return (RET_SUCCESS); 136} 137 138/* 139 * __REC_DLEAF -- Delete a single record from a recno leaf page. 140 * 141 * Parameters: 142 * t: tree 143 * idx: index on current page to delete 144 * 145 * Returns: 146 * RET_SUCCESS, RET_ERROR. 147 */ 148int 149__rec_dleaf(BTREE *t, PAGE *h, u_int32_t idx) 150{ 151 RLEAF *rl; 152 indx_t *ip, cnt, offset; 153 u_int32_t nbytes; 154 char *from; 155 void *to; 156 157 /* 158 * Delete a record from a recno leaf page. Internal records are never 159 * deleted from internal pages, regardless of the records that caused 160 * them to be added being deleted. Pages made empty by deletion are 161 * not reclaimed. They are, however, made available for reuse. 162 * 163 * Pack the remaining entries at the end of the page, shift the indices 164 * down, overwriting the deleted record and its index. If the record 165 * uses overflow pages, make them available for reuse. 166 */ 167 to = rl = GETRLEAF(h, idx); 168 if (rl->flags & P_BIGDATA && __ovfl_delete(t, rl->bytes) == RET_ERROR) 169 return (RET_ERROR); 170 nbytes = NRLEAF(rl); 171 172 /* 173 * Compress the key/data pairs. Compress and adjust the [BR]LEAF 174 * offsets. Reset the headers. 175 */ 176 from = (char *)h + h->upper; 177 memmove(from + nbytes, from, (char *)to - from); 178 h->upper += nbytes; 179 180 offset = h->linp[idx]; 181 for (cnt = &h->linp[idx] - (ip = &h->linp[0]); cnt--; ++ip) 182 if (ip[0] < offset) 183 ip[0] += nbytes; 184 for (cnt = &h->linp[NEXTINDEX(h)] - ip; --cnt; ++ip) 185 ip[0] = ip[1] < offset ? ip[1] + nbytes : ip[1]; 186 h->lower -= sizeof(indx_t); 187 --t->bt_nrecs; 188 return (RET_SUCCESS); 189} 190