1 /*-
2 * Copyright (c) 1990, 1993, 1994
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34 #if defined(LIBC_SCCS) && !defined(lint)
35 static char sccsid[] = "@(#)bt_page.c 8.4 (Berkeley) 11/2/95";
36 #endif /* LIBC_SCCS and not lint */
37
38 #include <sys/types.h>
39
40 #include <stdio.h>
41
42 #include "db-int.h"
43 #include "btree.h"
44
45 /*
46 * __bt_free --
47 * Put a page on the freelist.
48 *
49 * Parameters:
50 * t: tree
51 * h: page to free
52 *
53 * Returns:
54 * RET_ERROR, RET_SUCCESS
55 *
56 * Side-effect:
57 * mpool_put's the page.
58 */
59 int
__bt_free(t,h)60 __bt_free(t, h)
61 BTREE *t;
62 PAGE *h;
63 {
64 /* Insert the page at the head of the free list. */
65 h->prevpg = P_INVALID;
66 h->nextpg = t->bt_free;
67 t->bt_free = h->pgno;
68 F_SET(t, B_METADIRTY);
69
70 /* Make sure the page gets written back. */
71 return (mpool_put(t->bt_mp, h, MPOOL_DIRTY));
72 }
73
74 /*
75 * __bt_new --
76 * Get a new page, preferably from the freelist.
77 *
78 * Parameters:
79 * t: tree
80 * npg: storage for page number.
81 *
82 * Returns:
83 * Pointer to a page, NULL on error.
84 */
85 PAGE *
__bt_new(t,npg)86 __bt_new(t, npg)
87 BTREE *t;
88 db_pgno_t *npg;
89 {
90 PAGE *h;
91
92 if (t->bt_free != P_INVALID &&
93 (h = mpool_get(t->bt_mp, t->bt_free, 0)) != NULL) {
94 *npg = t->bt_free;
95 t->bt_free = h->nextpg;
96 F_SET(t, B_METADIRTY);
97 return (h);
98 }
99 return (mpool_new(t->bt_mp, npg, MPOOL_PAGE_NEXT));
100 }
101