1 #pragma ident "%Z%%M% %I% %E% SMI" 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. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 */ 38 39 #if defined(LIBC_SCCS) && !defined(lint) 40 static char sccsid[] = "@(#)rec_delete.c 8.7 (Berkeley) 7/14/94"; 41 #endif /* LIBC_SCCS and not lint */ 42 43 #include <sys/types.h> 44 45 #include <errno.h> 46 #include <stdio.h> 47 #include <string.h> 48 49 #include "db-int.h" 50 #include "recno.h" 51 52 static int rec_rdelete __P((BTREE *, recno_t)); 53 54 /* 55 * __REC_DELETE -- Delete the item(s) referenced by a key. 56 * 57 * Parameters: 58 * dbp: pointer to access method 59 * key: key to delete 60 * flags: R_CURSOR if deleting what the cursor references 61 * 62 * Returns: 63 * RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found. 64 */ 65 int 66 __rec_delete(dbp, key, flags) 67 const DB *dbp; 68 const DBT *key; 69 u_int flags; 70 { 71 BTREE *t; 72 recno_t nrec; 73 int status; 74 75 t = dbp->internal; 76 77 /* Toss any page pinned across calls. */ 78 if (t->bt_pinned != NULL) { 79 mpool_put(t->bt_mp, t->bt_pinned, 0); 80 t->bt_pinned = NULL; 81 } 82 83 switch(flags) { 84 case 0: 85 if ((nrec = *(recno_t *)key->data) == 0) 86 goto einval; 87 if (nrec > t->bt_nrecs) 88 return (RET_SPECIAL); 89 --nrec; 90 status = rec_rdelete(t, nrec); 91 break; 92 case R_CURSOR: 93 if (!F_ISSET(&t->bt_cursor, CURS_INIT)) 94 goto einval; 95 if (t->bt_nrecs == 0) 96 return (RET_SPECIAL); 97 status = rec_rdelete(t, t->bt_cursor.rcursor - 1); 98 if (status == RET_SUCCESS) 99 --t->bt_cursor.rcursor; 100 break; 101 default: 102 einval: errno = EINVAL; 103 return (RET_ERROR); 104 } 105 106 if (status == RET_SUCCESS) 107 F_SET(t, B_MODIFIED | R_MODIFIED); 108 return (status); 109 } 110 111 /* 112 * REC_RDELETE -- Delete the data matching the specified key. 113 * 114 * Parameters: 115 * tree: tree 116 * nrec: record to delete 117 * 118 * Returns: 119 * RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found. 120 */ 121 static int 122 rec_rdelete(t, nrec) 123 BTREE *t; 124 recno_t nrec; 125 { 126 EPG *e; 127 PAGE *h; 128 int status; 129 130 /* Find the record; __rec_search pins the page. */ 131 if ((e = __rec_search(t, nrec, SDELETE)) == NULL) 132 return (RET_ERROR); 133 134 /* Delete the record. */ 135 h = e->page; 136 status = __rec_dleaf(t, h, e->index); 137 if (status != RET_SUCCESS) { 138 mpool_put(t->bt_mp, h, 0); 139 return (status); 140 } 141 mpool_put(t->bt_mp, h, MPOOL_DIRTY); 142 return (RET_SUCCESS); 143 } 144 145 /* 146 * __REC_DLEAF -- Delete a single record from a recno leaf page. 147 * 148 * Parameters: 149 * t: tree 150 * idx: index on current page to delete 151 * 152 * Returns: 153 * RET_SUCCESS, RET_ERROR. 154 */ 155 int 156 __rec_dleaf(t, h, idx) 157 BTREE *t; 158 PAGE *h; 159 u_int32_t idx; 160 { 161 RLEAF *rl; 162 indx_t *ip, cnt, offset; 163 u_int32_t nbytes; 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, idx); 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[idx]; 191 for (cnt = &h->linp[idx] - (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