1 /*- 2 * Copyright (c) 1990, 1993, 1994 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 * @(#)rec_delete.c 8.7 (Berkeley) 7/14/94 37 * $DragonFly: src/lib/libc/db/recno/rec_delete.c,v 1.3 2003/11/12 20:21:23 eirikn Exp $ 38 */ 39 40 #include <sys/types.h> 41 42 #include <errno.h> 43 #include <stdio.h> 44 #include <string.h> 45 46 #include <db.h> 47 #include "recno.h" 48 49 static int rec_rdelete (BTREE *, recno_t); 50 51 /* 52 * __REC_DELETE -- Delete the item(s) referenced by a key. 53 * 54 * Parameters: 55 * dbp: pointer to access method 56 * key: key to delete 57 * flags: R_CURSOR if deleting what the cursor references 58 * 59 * Returns: 60 * RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found. 61 */ 62 int 63 __rec_delete(dbp, key, flags) 64 const DB *dbp; 65 const DBT *key; 66 u_int flags; 67 { 68 BTREE *t; 69 recno_t nrec; 70 int status; 71 72 t = dbp->internal; 73 74 /* Toss any page pinned across calls. */ 75 if (t->bt_pinned != NULL) { 76 mpool_put(t->bt_mp, t->bt_pinned, 0); 77 t->bt_pinned = NULL; 78 } 79 80 switch(flags) { 81 case 0: 82 if ((nrec = *(recno_t *)key->data) == 0) 83 goto einval; 84 if (nrec > t->bt_nrecs) 85 return (RET_SPECIAL); 86 --nrec; 87 status = rec_rdelete(t, nrec); 88 break; 89 case R_CURSOR: 90 if (!F_ISSET(&t->bt_cursor, CURS_INIT)) 91 goto einval; 92 if (t->bt_nrecs == 0) 93 return (RET_SPECIAL); 94 status = rec_rdelete(t, t->bt_cursor.rcursor - 1); 95 if (status == RET_SUCCESS) 96 --t->bt_cursor.rcursor; 97 break; 98 default: 99 einval: errno = EINVAL; 100 return (RET_ERROR); 101 } 102 103 if (status == RET_SUCCESS) 104 F_SET(t, B_MODIFIED | R_MODIFIED); 105 return (status); 106 } 107 108 /* 109 * REC_RDELETE -- Delete the data matching the specified key. 110 * 111 * Parameters: 112 * tree: tree 113 * nrec: record to delete 114 * 115 * Returns: 116 * RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found. 117 */ 118 static int 119 rec_rdelete(t, nrec) 120 BTREE *t; 121 recno_t nrec; 122 { 123 EPG *e; 124 PAGE *h; 125 int status; 126 127 /* Find the record; __rec_search pins the page. */ 128 if ((e = __rec_search(t, nrec, SDELETE)) == NULL) 129 return (RET_ERROR); 130 131 /* Delete the record. */ 132 h = e->page; 133 status = __rec_dleaf(t, h, e->index); 134 if (status != RET_SUCCESS) { 135 mpool_put(t->bt_mp, h, 0); 136 return (status); 137 } 138 mpool_put(t->bt_mp, h, MPOOL_DIRTY); 139 return (RET_SUCCESS); 140 } 141 142 /* 143 * __REC_DLEAF -- Delete a single record from a recno leaf page. 144 * 145 * Parameters: 146 * t: tree 147 * index: index on current page to delete 148 * 149 * Returns: 150 * RET_SUCCESS, RET_ERROR. 151 */ 152 int 153 __rec_dleaf(t, h, index) 154 BTREE *t; 155 PAGE *h; 156 u_int32_t index; 157 { 158 RLEAF *rl; 159 indx_t *ip, cnt, offset; 160 u_int32_t nbytes; 161 char *from; 162 void *to; 163 164 /* 165 * Delete a record from a recno leaf page. Internal records are never 166 * deleted from internal pages, regardless of the records that caused 167 * them to be added being deleted. Pages made empty by deletion are 168 * not reclaimed. They are, however, made available for reuse. 169 * 170 * Pack the remaining entries at the end of the page, shift the indices 171 * down, overwriting the deleted record and its index. If the record 172 * uses overflow pages, make them available for reuse. 173 */ 174 to = rl = GETRLEAF(h, index); 175 if (rl->flags & P_BIGDATA && __ovfl_delete(t, rl->bytes) == RET_ERROR) 176 return (RET_ERROR); 177 nbytes = NRLEAF(rl); 178 179 /* 180 * Compress the key/data pairs. Compress and adjust the [BR]LEAF 181 * offsets. Reset the headers. 182 */ 183 from = (char *)h + h->upper; 184 memmove(from + nbytes, from, (char *)to - from); 185 h->upper += nbytes; 186 187 offset = h->linp[index]; 188 for (cnt = &h->linp[index] - (ip = &h->linp[0]); cnt--; ++ip) 189 if (ip[0] < offset) 190 ip[0] += nbytes; 191 for (cnt = &h->linp[NEXTINDEX(h)] - ip; --cnt; ++ip) 192 ip[0] = ip[1] < offset ? ip[1] + nbytes : ip[1]; 193 h->lower -= sizeof(indx_t); 194 --t->bt_nrecs; 195 return (RET_SUCCESS); 196 } 197