rec_delete.c revision 1.5
1 /*- 2 * Copyright (c) 1990, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Mike Olson. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 #if defined(LIBC_SCCS) && !defined(lint) 38 /* from: static char sccsid[] = "@(#)rec_delete.c 8.2 (Berkeley) 9/7/93"; */ 39 static char *rcsid = "$Id: rec_delete.c,v 1.5 1994/02/17 21:13:26 pk Exp $"; 40 #endif /* LIBC_SCCS and not lint */ 41 42 #include <sys/types.h> 43 44 #include <errno.h> 45 #include <stdio.h> 46 #include <string.h> 47 48 #include <db.h> 49 #include "recno.h" 50 51 static int rec_rdelete __P((BTREE *, recno_t)); 52 53 /* 54 * __REC_DELETE -- Delete the item(s) referenced by a key. 55 * 56 * Parameters: 57 * dbp: pointer to access method 58 * key: key to delete 59 * flags: R_CURSOR if deleting what the cursor references 60 * 61 * Returns: 62 * RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found. 63 */ 64 int 65 __rec_delete(dbp, key, flags) 66 const DB *dbp; 67 const DBT *key; 68 u_int flags; 69 { 70 BTREE *t; 71 recno_t nrec; 72 int status; 73 74 t = dbp->internal; 75 76 /* Toss any page pinned across calls. */ 77 if (t->bt_pinned != NULL) { 78 mpool_put(t->bt_mp, t->bt_pinned, 0); 79 t->bt_pinned = NULL; 80 } 81 82 switch(flags) { 83 case 0: 84 if ((nrec = *(recno_t *)key->data) == 0) 85 goto einval; 86 if (nrec > t->bt_nrecs) 87 return (RET_SPECIAL); 88 --nrec; 89 status = rec_rdelete(t, nrec); 90 break; 91 case R_CURSOR: 92 if (!ISSET(t, B_SEQINIT)) 93 goto einval; 94 if (t->bt_nrecs == 0) 95 return (RET_SPECIAL); 96 status = rec_rdelete(t, t->bt_rcursor - 1); 97 if (status == RET_SUCCESS) 98 --t->bt_rcursor; 99 break; 100 default: 101 einval: errno = EINVAL; 102 return (RET_ERROR); 103 } 104 105 if (status == RET_SUCCESS) 106 SET(t, B_MODIFIED | R_MODIFIED); 107 return (status); 108 } 109 110 /* 111 * REC_RDELETE -- Delete the data matching the specified key. 112 * 113 * Parameters: 114 * tree: tree 115 * nrec: record to delete 116 * 117 * Returns: 118 * RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found. 119 */ 120 static int 121 rec_rdelete(t, nrec) 122 BTREE *t; 123 recno_t nrec; 124 { 125 EPG *e; 126 PAGE *h; 127 int status; 128 129 /* Find the record; __rec_search pins the page. */ 130 if ((e = __rec_search(t, nrec, SDELETE)) == NULL) 131 return (RET_ERROR); 132 133 /* Delete the record. */ 134 h = e->page; 135 status = __rec_dleaf(t, h, e->index); 136 if (status != RET_SUCCESS) { 137 mpool_put(t->bt_mp, h, 0); 138 return (status); 139 } 140 mpool_put(t->bt_mp, h, MPOOL_DIRTY); 141 return (RET_SUCCESS); 142 } 143 144 /* 145 * __REC_DLEAF -- Delete a single record from a recno leaf page. 146 * 147 * Parameters: 148 * t: tree 149 * index: index on current page to delete 150 * 151 * Returns: 152 * RET_SUCCESS, RET_ERROR. 153 */ 154 int 155 __rec_dleaf(t, h, index) 156 BTREE *t; 157 PAGE *h; 158 int index; 159 { 160 register RLEAF *rl; 161 register indx_t *ip, offset; 162 register size_t nbytes; 163 register int cnt; 164 char *from; 165 void *to; 166 167 /* 168 * Delete a record from a recno leaf page. Internal records are never 169 * deleted from internal pages, regardless of the records that caused 170 * them to be added being deleted. Pages made empty by deletion are 171 * not reclaimed. They are, however, made available for reuse. 172 * 173 * Pack the remaining entries at the end of the page, shift the indices 174 * down, overwriting the deleted record and its index. If the record 175 * uses overflow pages, make them available for reuse. 176 */ 177 to = rl = GETRLEAF(h, index); 178 if (rl->flags & P_BIGDATA && __ovfl_delete(t, rl->bytes) == RET_ERROR) 179 return (RET_ERROR); 180 nbytes = NRLEAF(rl); 181 182 /* 183 * Compress the key/data pairs. Compress and adjust the [BR]LEAF 184 * offsets. Reset the headers. 185 */ 186 from = (char *)h + h->upper; 187 memmove(from + nbytes, from, (char *)to - from); 188 h->upper += nbytes; 189 190 offset = h->linp[index]; 191 for (cnt = &h->linp[index] - (ip = &h->linp[0]); cnt--; ++ip) 192 if (ip[0] < offset) 193 ip[0] += nbytes; 194 for (cnt = &h->linp[NEXTINDEX(h)] - ip; --cnt; ++ip) 195 ip[0] = ip[1] < offset ? ip[1] + nbytes : ip[1]; 196 h->lower -= sizeof(indx_t); 197 --t->bt_nrecs; 198 return (RET_SUCCESS); 199 } 200
Indexes created Mon Sep 22 13:09:51 GMT 2025