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/*-
* Copyright (c) 1990, 1993, 1994
* The Regents of the University of California. All rights reserved.
*
* 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[] = "@(#)bt_page.c 8.3 (Berkeley) 7/14/94";
#endif /* LIBC_SCCS and not lint */
#include <sys/types.h>
#include <stdio.h>
#include <db.h>
#include "btree.h"
/*
* __bt_free --
* Put a page on the freelist.
*
* Parameters:
* t: tree
* h: page to free
*
* Returns:
* RET_ERROR, RET_SUCCESS
*
* Side-effect:
* mpool_put's the page.
*/
int
__bt_free(t, h)
BTREE *t;
PAGE *h;
{
/* Insert the page at the head of the free list. */
h->prevpg = P_INVALID;
h->nextpg = t->bt_free;
t->bt_free = h->pgno;
/* Make sure the page gets written back. */
return (mpool_put(t->bt_mp, h, MPOOL_DIRTY));
}
/*
* __bt_new --
* Get a new page, preferably from the freelist.
*
* Parameters:
* t: tree
* npg: storage for page number.
*
* Returns:
* Pointer to a page, NULL on error.
*/
PAGE *
__bt_new(t, npg)
BTREE *t;
pgno_t *npg;
{
PAGE *h;
if (t->bt_free != P_INVALID &&
(h = mpool_get(t->bt_mp, t->bt_free, 0)) != NULL) {
*npg = t->bt_free;
t->bt_free = h->nextpg;
return (h);
}
return (mpool_new(t->bt_mp, npg));
}
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