156500Sbostic /*-
261196Sbostic * Copyright (c) 1990, 1993
361196Sbostic * The Regents of the University of California. All rights reserved.
456500Sbostic *
556500Sbostic * %sccs.include.redist.c%
656500Sbostic */
756500Sbostic
856500Sbostic #if defined(LIBC_SCCS) && !defined(lint)
9*66192Sbostic static char sccsid[] = "@(#)bt_page.c 8.2 (Berkeley) 02/21/94";
1056500Sbostic #endif /* LIBC_SCCS and not lint */
1156500Sbostic
1256500Sbostic #include <sys/types.h>
1356739Sbostic
1456500Sbostic #include <stdio.h>
1556500Sbostic
1657932Sbostic #include <db.h>
1756500Sbostic #include "btree.h"
1856500Sbostic
1956500Sbostic /*
2056500Sbostic * __BT_FREE -- Put a page on the freelist.
2156500Sbostic *
2256500Sbostic * Parameters:
2356500Sbostic * t: tree
2456500Sbostic * h: page to free
2556500Sbostic *
2656500Sbostic * Returns:
2756500Sbostic * RET_ERROR, RET_SUCCESS
2856500Sbostic */
2956500Sbostic int
__bt_free(t,h)3056500Sbostic __bt_free(t, h)
3156500Sbostic BTREE *t;
3256500Sbostic PAGE *h;
3356500Sbostic {
3456500Sbostic /* Insert the page at the start of the free list. */
3556500Sbostic h->prevpg = P_INVALID;
3656500Sbostic h->nextpg = t->bt_free;
3756500Sbostic t->bt_free = h->pgno;
3856500Sbostic
3956500Sbostic /* Make sure the page gets written back. */
4056500Sbostic return (mpool_put(t->bt_mp, h, MPOOL_DIRTY));
4156500Sbostic }
4256500Sbostic
4356500Sbostic /*
4456500Sbostic * __BT_NEW -- Get a new page, preferably from the freelist.
4556500Sbostic *
4656500Sbostic * Parameters:
4756500Sbostic * t: tree
4856500Sbostic * npg: storage for page number.
4956500Sbostic *
5056500Sbostic * Returns:
5156500Sbostic * Pointer to a page, NULL on error.
5256500Sbostic */
5356500Sbostic PAGE *
__bt_new(t,npg)5456500Sbostic __bt_new(t, npg)
5556500Sbostic BTREE *t;
5656500Sbostic pgno_t *npg;
5756500Sbostic {
5856500Sbostic PAGE *h;
5956500Sbostic
6056500Sbostic if (t->bt_free != P_INVALID &&
6156500Sbostic (h = mpool_get(t->bt_mp, t->bt_free, 0)) != NULL) {
6256500Sbostic *npg = t->bt_free;
6356500Sbostic t->bt_free = h->nextpg;
6456500Sbostic return (h);
6556500Sbostic }
6656500Sbostic return (mpool_new(t->bt_mp, npg));
6756500Sbostic }
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