1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
|
/*-
* Copyright (c) 1990, 1993, 1994
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Mike Olson.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)rec_delete.c 8.7 (Berkeley) 7/14/94";
#endif /* LIBC_SCCS and not lint */
#include <sys/types.h>
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <db.h>
#include "recno.h"
static int rec_rdelete __P((BTREE *, recno_t));
/*
* __REC_DELETE -- Delete the item(s) referenced by a key.
*
* Parameters:
* dbp: pointer to access method
* key: key to delete
* flags: R_CURSOR if deleting what the cursor references
*
* Returns:
* RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found.
*/
int
__rec_delete(dbp, key, flags)
const DB *dbp;
const DBT *key;
u_int flags;
{
BTREE *t;
recno_t nrec;
int status;
t = dbp->internal;
/* Toss any page pinned across calls. */
if (t->bt_pinned != NULL) {
mpool_put(t->bt_mp, t->bt_pinned, 0);
t->bt_pinned = NULL;
}
switch(flags) {
case 0:
if ((nrec = *(recno_t *)key->data) == 0)
goto einval;
if (nrec > t->bt_nrecs)
return (RET_SPECIAL);
--nrec;
status = rec_rdelete(t, nrec);
break;
case R_CURSOR:
if (!F_ISSET(&t->bt_cursor, CURS_INIT))
goto einval;
if (t->bt_nrecs == 0)
return (RET_SPECIAL);
status = rec_rdelete(t, t->bt_cursor.rcursor - 1);
if (status == RET_SUCCESS)
--t->bt_cursor.rcursor;
break;
default:
einval: errno = EINVAL;
return (RET_ERROR);
}
if (status == RET_SUCCESS)
F_SET(t, B_MODIFIED | R_MODIFIED);
return (status);
}
/*
* REC_RDELETE -- Delete the data matching the specified key.
*
* Parameters:
* tree: tree
* nrec: record to delete
*
* Returns:
* RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found.
*/
static int
rec_rdelete(t, nrec)
BTREE *t;
recno_t nrec;
{
EPG *e;
PAGE *h;
int status;
/* Find the record; __rec_search pins the page. */
if ((e = __rec_search(t, nrec, SDELETE)) == NULL)
return (RET_ERROR);
/* Delete the record. */
h = e->page;
status = __rec_dleaf(t, h, e->index);
if (status != RET_SUCCESS) {
mpool_put(t->bt_mp, h, 0);
return (status);
}
mpool_put(t->bt_mp, h, MPOOL_DIRTY);
return (RET_SUCCESS);
}
/*
* __REC_DLEAF -- Delete a single record from a recno leaf page.
*
* Parameters:
* t: tree
* index: index on current page to delete
*
* Returns:
* RET_SUCCESS, RET_ERROR.
*/
int
__rec_dleaf(t, h, index)
BTREE *t;
PAGE *h;
u_int32_t index;
{
RLEAF *rl;
indx_t *ip, cnt, offset;
u_int32_t nbytes;
char *from;
void *to;
/*
* Delete a record from a recno leaf page. Internal records are never
* deleted from internal pages, regardless of the records that caused
* them to be added being deleted. Pages made empty by deletion are
* not reclaimed. They are, however, made available for reuse.
*
* Pack the remaining entries at the end of the page, shift the indices
* down, overwriting the deleted record and its index. If the record
* uses overflow pages, make them available for reuse.
*/
to = rl = GETRLEAF(h, index);
if (rl->flags & P_BIGDATA && __ovfl_delete(t, rl->bytes) == RET_ERROR)
return (RET_ERROR);
nbytes = NRLEAF(rl);
/*
* Compress the key/data pairs. Compress and adjust the [BR]LEAF
* offsets. Reset the headers.
*/
from = (char *)h + h->upper;
memmove(from + nbytes, from, (char *)to - from);
h->upper += nbytes;
offset = h->linp[index];
for (cnt = &h->linp[index] - (ip = &h->linp[0]); cnt--; ++ip)
if (ip[0] < offset)
ip[0] += nbytes;
for (cnt = &h->linp[NEXTINDEX(h)] - ip; --cnt; ++ip)
ip[0] = ip[1] < offset ? ip[1] + nbytes : ip[1];
h->lower -= sizeof(indx_t);
--t->bt_nrecs;
return (RET_SUCCESS);
}
|
