Asterisk - The Open Source Telephony Project GIT-master-2de1a68
rec_delete.c
Go to the documentation of this file.
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
37#if defined(LIBC_SCCS) && !defined(lint)
38static char sccsid[] = "@(#)rec_delete.c 8.7 (Berkeley) 7/14/94";
39#endif /* LIBC_SCCS and not lint */
40
41#include <sys/types.h>
42
43#include <errno.h>
44#include <stdio.h>
45#include <string.h>
46
47#include "../include/db.h"
48#include "recno.h"
49
50static 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 */
63int
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
73 t = dbp->internal;
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
81 switch(flags) {
82 case 0:
83 if ((nrec = *(recno_t *)key->data) == 0)
84 goto einval;
85 if (nrec > t->bt_nrecs)
86 return (RET_SPECIAL);
87 --nrec;
88 status = rec_rdelete(t, nrec);
89 break;
90 case R_CURSOR:
91 if (!F_ISSET(&t->bt_cursor, CURS_INIT))
92 goto einval;
93 if (t->bt_nrecs == 0)
94 return (RET_SPECIAL);
96 if (status == RET_SUCCESS)
97 --t->bt_cursor.rcursor;
98 break;
99 default:
100einval: errno = EINVAL;
101 return (RET_ERROR);
102 }
103
104 if (status == RET_SUCCESS)
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 */
119static int
121 BTREE *t;
122 recno_t nrec;
123{
124 EPG *e;
125 PAGE *h;
126 int status;
127
128 /* Find the record; __rec_search pins the page. */
129 if ((e = __rec_search(t, nrec, SDELETE)) == NULL)
130 return (RET_ERROR);
131
132 /* Delete the record. */
133 h = e->page;
134 status = __rec_dleaf(t, h, e->index);
135 if (status != RET_SUCCESS) {
136 mpool_put(t->bt_mp, h, 0);
137 return (status);
138 }
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 */
153int
154__rec_dleaf(t, h, idx)
155 BTREE *t;
156 PAGE *h;
157 u_int32_t idx;
158{
159 RLEAF *rl;
160 indx_t *ip, cnt, offset;
161 u_int32_t nbytes;
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, idx);
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;
185 memmove(from + nbytes, from, (char *)to - from);
186 h->upper += nbytes;
187
188 offset = h->linp[idx];
189 for (cnt = &h->linp[idx] - (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];
194 h->lower -= sizeof(indx_t);
195 --t->bt_nrecs;
196 return (RET_SUCCESS);
197}
jack_status_t status
Definition: app_jack.c:146
int __ovfl_delete(BTREE *t, void *p)
Definition: bt_overflow.c:193
#define F_ISSET(p, f)
Definition: btree.h:42
#define B_MODIFIED
Definition: btree.h:370
#define NRLEAF(p)
Definition: btree.h:224
#define NEXTINDEX(p)
Definition: btree.h:98
#define R_MODIFIED
Definition: btree.h:382
#define P_BIGDATA
Definition: btree.h:131
#define CURS_INIT
Definition: btree.h:291
#define F_SET(p, f)
Definition: btree.h:40
#define GETRLEAF(pg, indx)
Definition: btree.h:220
u_int16_t indx_t
Definition: db.h:80
#define R_CURSOR
Definition: db.h:91
#define RET_SUCCESS
Definition: db.h:52
u_int32_t recno_t
Definition: db.h:82
#define RET_ERROR
Definition: db.h:51
#define RET_SPECIAL
Definition: db.h:53
static DB * dbp
Definition: hsearch.c:49
unsigned int u_int32_t
int errno
int mpool_put(MPOOL *mp, void *page, u_int flags)
Definition: mpool.c:251
#define MPOOL_DIRTY
Definition: mpool.h:61
int __rec_delete(DB *dbp, const DBT *key, u_int flags) const
Definition: rec_delete.c:64
static int rec_rdelete __P((BTREE *, recno_t))
static int rec_rdelete(BTREE *t, recno_t nrec)
Definition: rec_delete.c:120
int __rec_dleaf(BTREE *t, PAGE *h, u_int32_t idx)
Definition: rec_delete.c:154
EPG * __rec_search(BTREE *t, recno_t recno, enum SRCHOP op)
Definition: rec_search.c:64
@ SDELETE
Definition: recno.h:36
#define NULL
Definition: resample.c:96
Definition: db.h:85
void * data
Definition: db.h:86
Definition: db.h:129
void * internal
Definition: db.h:137
Definition: btree.h:312
CURSOR bt_cursor
Definition: btree.h:320
MPOOL * bt_mp
Definition: btree.h:313
PAGE * bt_pinned
Definition: btree.h:318
recno_t bt_nrecs
Definition: btree.h:360
recno_t rcursor
Definition: btree.h:286
Definition: btree.h:254
indx_t index
Definition: btree.h:256
PAGE * page
Definition: btree.h:255
Definition: btree.h:75
indx_t lower
Definition: btree.h:89
indx_t upper
Definition: btree.h:90
indx_t linp[1]
Definition: btree.h:91
Definition: btree.h:213
u_char flags
Definition: btree.h:215
char bytes[1]
Definition: btree.h:216