rec_delete.c revision 1.13
1 /* $NetBSD: rec_delete.c,v 1.13 2003/08/07 16:42:44 agc 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 #include <sys/cdefs.h> 36 #if defined(LIBC_SCCS) && !defined(lint) 37 #if 0 38 static char sccsid[] = "@(#)rec_delete.c 8.7 (Berkeley) 7/14/94"; 39 #else 40 __RCSID("$NetBSD: rec_delete.c,v 1.13 2003/08/07 16:42:44 agc Exp $"); 41 #endif 42 #endif /* LIBC_SCCS and not lint */ 43 44 #include "namespace.h" 45 #include <sys/types.h> 46 47 #include <errno.h> 48 #include <stdio.h> 49 #include <string.h> 50 51 #include <db.h> 52 #include "recno.h" 53 54 static int rec_rdelete __P((BTREE *, recno_t)); 55 56 /* 57 * __REC_DELETE -- Delete the item(s) referenced by a key. 58 * 59 * Parameters: 60 * dbp: pointer to access method 61 * key: key to delete 62 * flags: R_CURSOR if deleting what the cursor references 63 * 64 * Returns: 65 * RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found. 66 */ 67 int 68 __rec_delete(dbp, key, flags) 69 const DB *dbp; 70 const DBT *key; 71 u_int flags; 72 { 73 BTREE *t; 74 recno_t nrec; 75 int status; 76 77 t = dbp->internal; 78 79 /* Toss any page pinned across calls. */ 80 if (t->bt_pinned != NULL) { 81 mpool_put(t->bt_mp, t->bt_pinned, 0); 82 t->bt_pinned = NULL; 83 } 84 85 switch(flags) { 86 case 0: 87 if ((nrec = *(recno_t *)key->data) == 0) 88 goto einval; 89 if (nrec > t->bt_nrecs) 90 return (RET_SPECIAL); 91 --nrec; 92 status = rec_rdelete(t, nrec); 93 break; 94 case R_CURSOR: 95 if (!F_ISSET(&t->bt_cursor, CURS_INIT)) 96 goto einval; 97 if (t->bt_nrecs == 0) 98 return (RET_SPECIAL); 99 status = rec_rdelete(t, t->bt_cursor.rcursor - 1); 100 if (status == RET_SUCCESS) 101 --t->bt_cursor.rcursor; 102 break; 103 default: 104 einval: errno = EINVAL; 105 return (RET_ERROR); 106 } 107 108 if (status == RET_SUCCESS) 109 F_SET(t, B_MODIFIED | R_MODIFIED); 110 return (status); 111 } 112 113 /* 114 * REC_RDELETE -- Delete the data matching the specified key. 115 * 116 * Parameters: 117 * tree: tree 118 * nrec: record to delete 119 * 120 * Returns: 121 * RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found. 122 */ 123 static int 124 rec_rdelete(t, nrec) 125 BTREE *t; 126 recno_t nrec; 127 { 128 EPG *e; 129 PAGE *h; 130 int status; 131 132 /* Find the record; __rec_search pins the page. */ 133 if ((e = __rec_search(t, nrec, SDELETE)) == NULL) 134 return (RET_ERROR); 135 136 /* Delete the record. */ 137 h = e->page; 138 status = __rec_dleaf(t, h, (u_int32_t)e->index); 139 if (status != RET_SUCCESS) { 140 mpool_put(t->bt_mp, h, 0); 141 return (status); 142 } 143 mpool_put(t->bt_mp, h, MPOOL_DIRTY); 144 return (RET_SUCCESS); 145 } 146 147 /* 148 * __REC_DLEAF -- Delete a single record from a recno leaf page. 149 * 150 * Parameters: 151 * t: tree 152 * index: index on current page to delete 153 * 154 * Returns: 155 * RET_SUCCESS, RET_ERROR. 156 */ 157 int 158 __rec_dleaf(t, h, idx) 159 BTREE *t; 160 PAGE *h; 161 u_int32_t idx; 162 { 163 RLEAF *rl; 164 indx_t *ip, cnt, offset; 165 u_int32_t nbytes; 166 char *from; 167 void *to; 168 169 /* 170 * Delete a record from a recno leaf page. Internal records are never 171 * deleted from internal pages, regardless of the records that caused 172 * them to be added being deleted. Pages made empty by deletion are 173 * not reclaimed. They are, however, made available for reuse. 174 * 175 * Pack the remaining entries at the end of the page, shift the indices 176 * down, overwriting the deleted record and its index. If the record 177 * uses overflow pages, make them available for reuse. 178 */ 179 to = rl = GETRLEAF(h, idx); 180 if (rl->flags & P_BIGDATA && __ovfl_delete(t, rl->bytes) == RET_ERROR) 181 return (RET_ERROR); 182 nbytes = NRLEAF(rl); 183 184 /* 185 * Compress the key/data pairs. Compress and adjust the [BR]LEAF 186 * offsets. Reset the headers. 187 */ 188 from = (char *)(void *)h + h->upper; 189 memmove(from + nbytes, from, (size_t)((char *)to - from)); 190 h->upper += nbytes; 191 192 offset = h->linp[idx]; 193 for (cnt = &h->linp[idx] - (ip = &h->linp[0]); cnt--; ++ip) 194 if (ip[0] < offset) 195 ip[0] += nbytes; 196 for (cnt = &h->linp[NEXTINDEX(h)] - ip; --cnt; ++ip) 197 ip[0] = ip[1] < offset ? ip[1] + nbytes : ip[1]; 198 h->lower -= sizeof(indx_t); 199 --t->bt_nrecs; 200 return (RET_SUCCESS); 201 } 202
Indexes created Mon Sep 22 21:09:42 GMT 2025