bt_page.c revision 2
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster/*-
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster * Copyright (c) 1990, 1993, 1994
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster * The Regents of the University of California. All rights reserved.
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster *
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster * Redistribution and use in source and binary forms, with or without
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster * modification, are permitted provided that the following conditions
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster * are met:
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster * 1. Redistributions of source code must retain the above copyright
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster * notice, this list of conditions and the following disclaimer.
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster * 2. Redistributions in binary form must reproduce the above copyright
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster * notice, this list of conditions and the following disclaimer in the
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster * documentation and/or other materials provided with the distribution.
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster * 3. All advertising materials mentioning features or use of this software
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster * must display the following acknowledgement:
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster * This product includes software developed by the University of
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster * California, Berkeley and its contributors.
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster * 4. Neither the name of the University nor the names of its contributors
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster * may be used to endorse or promote products derived from this software
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster * without specific prior written permission.
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster *
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
f948ca04a28ccfeed9633bf4b0fb0d2c59c37478David Luna * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster * SUCH DAMAGE.
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster */
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster#if defined(LIBC_SCCS) && !defined(lint)
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Fosterstatic char sccsid[] = "@(#)bt_page.c 8.4 (Berkeley) 11/2/95";
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster#endif /* LIBC_SCCS and not lint */
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster#include <sys/types.h>
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster#include <stdio.h>
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster
f948ca04a28ccfeed9633bf4b0fb0d2c59c37478David Luna#include "db-int.h"
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster#include "btree.h"
f948ca04a28ccfeed9633bf4b0fb0d2c59c37478David Luna
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster/*
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster * __bt_free --
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster * Put a page on the freelist.
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster *
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster * Parameters:
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster * t: tree
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster * h: page to free
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster *
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster * Returns:
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster * RET_ERROR, RET_SUCCESS
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster *
a688bcbb4bcff5398fdd29b86f83450257dc0df4Allan Foster * 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;
F_SET(t, B_METADIRTY);
/* 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;
db_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;
F_SET(t, B_METADIRTY);
return (h);
}
return (mpool_new(t->bt_mp, npg, MPOOL_PAGE_NEXT));
}