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/* $OpenBSD: rec_delete.c,v 1.7 2003/06/02 20:18:34 millert Exp $ */
/*-
* 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. 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)
#if 0
static char sccsid[] = "@(#)rec_delete.c 8.7 (Berkeley) 7/14/94";
#else
static const char rcsid[] = "$OpenBSD: rec_delete.c,v 1.7 2003/06/02 20:18:34 millert Exp $";
#endif
#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(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);
}
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