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91b5c9e5 | 1 | /*- |
fd88f5c5 | 2 | * Copyright (c) 1990, 1993, 1994 |
64c2209a | 3 | * The Regents of the University of California. All rights reserved. |
91b5c9e5 KB |
4 | * |
5 | * This code is derived from software contributed to Berkeley by | |
6 | * Mike Olson. | |
7 | * | |
ad787160 C |
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. | |
91b5c9e5 KB |
35 | */ |
36 | ||
37 | #if defined(LIBC_SCCS) && !defined(lint) | |
fd88f5c5 | 38 | static char sccsid[] = "@(#)rec_delete.c 8.7 (Berkeley) 7/14/94"; |
91b5c9e5 KB |
39 | #endif /* LIBC_SCCS and not lint */ |
40 | ||
41 | #include <sys/types.h> | |
cc740374 | 42 | |
cc740374 | 43 | #include <errno.h> |
91b5c9e5 KB |
44 | #include <stdio.h> |
45 | #include <string.h> | |
cc740374 | 46 | |
94ac72c5 | 47 | #include <db.h> |
3c86d21d | 48 | #include "recno.h" |
91b5c9e5 KB |
49 | |
50 | static int rec_rdelete __P((BTREE *, recno_t)); | |
51 | ||
52 | /* | |
53 | * __REC_DELETE -- Delete the item(s) referenced by a key. | |
54 | * | |
55 | * Parameters: | |
56 | * dbp: pointer to access method | |
57 | * key: key to delete | |
58 | * flags: R_CURSOR if deleting what the cursor references | |
59 | * | |
60 | * Returns: | |
61 | * RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found. | |
62 | */ | |
63 | int | |
64 | __rec_delete(dbp, key, flags) | |
65 | const DB *dbp; | |
66 | const DBT *key; | |
67 | u_int flags; | |
68 | { | |
69 | BTREE *t; | |
70 | recno_t nrec; | |
71 | int status; | |
72 | ||
91b5c9e5 | 73 | t = dbp->internal; |
19f5c4f5 KB |
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 | ||
91b5c9e5 KB |
81 | switch(flags) { |
82 | case 0: | |
cc740374 KB |
83 | if ((nrec = *(recno_t *)key->data) == 0) |
84 | goto einval; | |
3c86d21d KB |
85 | if (nrec > t->bt_nrecs) |
86 | return (RET_SPECIAL); | |
87 | --nrec; | |
91b5c9e5 KB |
88 | status = rec_rdelete(t, nrec); |
89 | break; | |
90 | case R_CURSOR: | |
fd88f5c5 | 91 | if (!F_ISSET(&t->bt_cursor, CURS_INIT)) |
cc740374 KB |
92 | goto einval; |
93 | if (t->bt_nrecs == 0) | |
3c86d21d | 94 | return (RET_SPECIAL); |
fd88f5c5 | 95 | status = rec_rdelete(t, t->bt_cursor.rcursor - 1); |
cc740374 | 96 | if (status == RET_SUCCESS) |
fd88f5c5 | 97 | --t->bt_cursor.rcursor; |
91b5c9e5 KB |
98 | break; |
99 | default: | |
cc740374 | 100 | einval: errno = EINVAL; |
91b5c9e5 KB |
101 | return (RET_ERROR); |
102 | } | |
103 | ||
5e36b7ba | 104 | if (status == RET_SUCCESS) |
fd88f5c5 | 105 | F_SET(t, B_MODIFIED | R_MODIFIED); |
91b5c9e5 KB |
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(t, nrec) | |
121 | BTREE *t; | |
122 | recno_t nrec; | |
123 | { | |
124 | EPG *e; | |
91b5c9e5 | 125 | PAGE *h; |
3c86d21d | 126 | int status; |
91b5c9e5 | 127 | |
3c86d21d | 128 | /* Find the record; __rec_search pins the page. */ |
c6591310 | 129 | if ((e = __rec_search(t, nrec, SDELETE)) == NULL) |
3c86d21d | 130 | return (RET_ERROR); |
91b5c9e5 KB |
131 | |
132 | /* Delete the record. */ | |
133 | h = e->page; | |
134 | status = __rec_dleaf(t, h, e->index); | |
3c86d21d | 135 | if (status != RET_SUCCESS) { |
91b5c9e5 KB |
136 | mpool_put(t->bt_mp, h, 0); |
137 | return (status); | |
138 | } | |
3c86d21d | 139 | mpool_put(t->bt_mp, h, MPOOL_DIRTY); |
91b5c9e5 KB |
140 | return (RET_SUCCESS); |
141 | } | |
142 | ||
143 | /* | |
144 | * __REC_DLEAF -- Delete a single record from a recno leaf page. | |
145 | * | |
146 | * Parameters: | |
147 | * t: tree | |
148 | * index: index on current page to delete | |
149 | * | |
150 | * Returns: | |
151 | * RET_SUCCESS, RET_ERROR. | |
152 | */ | |
153 | int | |
154 | __rec_dleaf(t, h, index) | |
155 | BTREE *t; | |
156 | PAGE *h; | |
fd88f5c5 | 157 | u_int32_t index; |
91b5c9e5 | 158 | { |
fd88f5c5 C |
159 | RLEAF *rl; |
160 | indx_t *ip, cnt, offset; | |
161 | u_int32_t nbytes; | |
91b5c9e5 KB |
162 | char *from; |
163 | void *to; | |
164 | ||
165 | /* | |
166 | * Delete a record from a recno leaf page. Internal records are never | |
167 | * deleted from internal pages, regardless of the records that caused | |
168 | * them to be added being deleted. Pages made empty by deletion are | |
169 | * not reclaimed. They are, however, made available for reuse. | |
170 | * | |
171 | * Pack the remaining entries at the end of the page, shift the indices | |
172 | * down, overwriting the deleted record and its index. If the record | |
173 | * uses overflow pages, make them available for reuse. | |
174 | */ | |
175 | to = rl = GETRLEAF(h, index); | |
176 | if (rl->flags & P_BIGDATA && __ovfl_delete(t, rl->bytes) == RET_ERROR) | |
177 | return (RET_ERROR); | |
178 | nbytes = NRLEAF(rl); | |
179 | ||
180 | /* | |
181 | * Compress the key/data pairs. Compress and adjust the [BR]LEAF | |
182 | * offsets. Reset the headers. | |
183 | */ | |
184 | from = (char *)h + h->upper; | |
1911b5bf | 185 | memmove(from + nbytes, from, (char *)to - from); |
91b5c9e5 KB |
186 | h->upper += nbytes; |
187 | ||
188 | offset = h->linp[index]; | |
189 | for (cnt = &h->linp[index] - (ip = &h->linp[0]); cnt--; ++ip) | |
190 | if (ip[0] < offset) | |
191 | ip[0] += nbytes; | |
192 | for (cnt = &h->linp[NEXTINDEX(h)] - ip; --cnt; ++ip) | |
193 | ip[0] = ip[1] < offset ? ip[1] + nbytes : ip[1]; | |
93a5373b | 194 | h->lower -= sizeof(indx_t); |
5e36b7ba | 195 | --t->bt_nrecs; |
91b5c9e5 KB |
196 | return (RET_SUCCESS); |
197 | } |