rec_delete.c revision 1.17
1 /* $NetBSD: rec_delete.c,v 1.17 2008/09/11 12:58:00 joerg Exp $ */ 2 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 HAVE_NBTOOL_CONFIG_H 36 #include "nbtool_config.h" 37 #endif 38 39 #include <sys/cdefs.h> 40 __RCSID("$NetBSD: rec_delete.c,v 1.17 2008/09/11 12:58:00 joerg Exp $"); 41 42 #include "namespace.h" 43 #include <sys/types.h> 44 45 #include <assert.h> 46 #include <errno.h> 47 #include <stdio.h> 48 #include <string.h> 49 50 #include <db.h> 51 #include "recno.h" 52 53 static int rec_rdelete(BTREE *, recno_t); 54 55 /* 56 * __REC_DELETE -- Delete the item(s) referenced by a key. 57 * 58 * Parameters: 59 * dbp: pointer to access method 60 * key: key to delete 61 * flags: R_CURSOR if deleting what the cursor references 62 * 63 * Returns: 64 * RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found. 65 */ 66 int 67 __rec_delete(const DB *dbp, const DBT *key, u_int flags) 68 { 69 BTREE *t; 70 recno_t nrec; 71 int status; 72 73 t = dbp->internal; 74 75 /* Toss any page pinned across calls. */ 76 if (t->bt_pinned != NULL) { 77 mpool_put(t->bt_mp, t->bt_pinned, 0); 78 t->bt_pinned = NULL; 79 } 80 81 switch(flags) { 82 case 0: 83 if ((nrec = *(recno_t *)key->data) == 0) 84 goto einval; 85 if (nrec > t->bt_nrecs) 86 return (RET_SPECIAL); 87 --nrec; 88 status = rec_rdelete(t, nrec); 89 break; 90 case R_CURSOR: 91 if (!F_ISSET(&t->bt_cursor, CURS_INIT)) 92 goto einval; 93 if (t->bt_nrecs == 0) 94 return (RET_SPECIAL); 95 status = rec_rdelete(t, t->bt_cursor.rcursor - 1); 96 if (status == RET_SUCCESS) 97 --t->bt_cursor.rcursor; 98 break; 99 default: 100 einval: errno = EINVAL; 101 return (RET_ERROR); 102 } 103 104 if (status == RET_SUCCESS) 105 F_SET(t, B_MODIFIED | R_MODIFIED); 106 return (status); 107 } 108 109 /* 110 * REC_RDELETE -- Delete the data matching the specified key. 111 * 112 * Parameters: 113 * tree: tree 114 * nrec: record to delete 115 * 116 * Returns: 117 * RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found. 118 */ 119 static int 120 rec_rdelete(BTREE *t, recno_t nrec) 121 { 122 EPG *e; 123 PAGE *h; 124 int status; 125 126 /* Find the record; __rec_search pins the page. */ 127 if ((e = __rec_search(t, nrec, SDELETE)) == NULL) 128 return (RET_ERROR); 129 130 /* Delete the record. */ 131 h = e->page; 132 status = __rec_dleaf(t, h, (uint32_t)e->index); 133 if (status != RET_SUCCESS) { 134 mpool_put(t->bt_mp, h, 0); 135 return (status); 136 } 137 mpool_put(t->bt_mp, h, MPOOL_DIRTY); 138 return (RET_SUCCESS); 139 } 140 141 /* 142 * __REC_DLEAF -- Delete a single record from a recno leaf page. 143 * 144 * Parameters: 145 * t: tree 146 * index: index on current page to delete 147 * 148 * Returns: 149 * RET_SUCCESS, RET_ERROR. 150 */ 151 int 152 __rec_dleaf(BTREE *t, PAGE *h, uint32_t idx) 153 { 154 RLEAF *rl; 155 indx_t *ip, cnt, offset; 156 uint32_t nbytes; 157 char *from; 158 void *to; 159 size_t temp; 160 161 /* 162 * Delete a record from a recno leaf page. Internal records are never 163 * deleted from internal pages, regardless of the records that caused 164 * them to be added being deleted. Pages made empty by deletion are 165 * not reclaimed. They are, however, made available for reuse. 166 * 167 * Pack the remaining entries at the end of the page, shift the indices 168 * down, overwriting the deleted record and its index. If the record 169 * uses overflow pages, make them available for reuse. 170 */ 171 to = rl = GETRLEAF(h, idx); 172 if (rl->flags & P_BIGDATA && __ovfl_delete(t, rl->bytes) == RET_ERROR) 173 return (RET_ERROR); 174 nbytes = NRLEAF(rl); 175 176 /* 177 * Compress the key/data pairs. Compress and adjust the [BR]LEAF 178 * offsets. Reset the headers. 179 */ 180 from = (char *)(void *)h + h->upper; 181 memmove(from + nbytes, from, (size_t)((char *)to - from)); 182 h->upper += nbytes; 183 184 offset = h->linp[idx]; 185 temp = &h->linp[idx] - (ip = &h->linp[0]); 186 _DBFIT(temp, uint16_t); 187 for (cnt = (uint16_t)temp; cnt--; ++ip) 188 if (ip[0] < offset) 189 ip[0] += nbytes; 190 temp = &h->linp[NEXTINDEX(h)] - ip; 191 _DBFIT(temp, uint16_t); 192 for (cnt = (uint16_t)temp; --cnt; ++ip) 193 ip[0] = ip[1] < offset ? ip[1] + nbytes : ip[1]; 194 h->lower -= sizeof(indx_t); 195 --t->bt_nrecs; 196 return (RET_SUCCESS); 197 } 198
Indexes created Tue Sep 23 07:09:52 GMT 2025