1 #pragma ident "%Z%%M% %I% %E% SMI"
2
3 /*-
4 * Copyright (c) 1990, 1993, 1994
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. All advertising materials mentioning features or use of this software
16 * must display the following acknowledgement:
17 * This product includes software developed by the University of
18 * California, Berkeley and its contributors.
19 * 4. Neither the name of the University nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36 #if defined(LIBC_SCCS) && !defined(lint)
37 static char sccsid[] = "@(#)bt_page.c 8.4 (Berkeley) 11/2/95";
38 #endif /* LIBC_SCCS and not lint */
39
40 #include <sys/types.h>
41
42 #include <stdio.h>
43
44 #include "db-int.h"
45 #include "btree.h"
46
47 /*
48 * __bt_free --
49 * Put a page on the freelist.
50 *
51 * Parameters:
52 * t: tree
53 * h: page to free
54 *
55 * Returns:
56 * RET_ERROR, RET_SUCCESS
57 *
58 * Side-effect:
59 * mpool_put's the page.
60 */
61 int
__bt_free(t,h)62 __bt_free(t, h)
63 BTREE *t;
64 PAGE *h;
65 {
66 /* Insert the page at the head of the free list. */
67 h->prevpg = P_INVALID;
68 h->nextpg = t->bt_free;
69 t->bt_free = h->pgno;
70 F_SET(t, B_METADIRTY);
71
72 /* Make sure the page gets written back. */
73 return (mpool_put(t->bt_mp, h, MPOOL_DIRTY));
74 }
75
76 /*
77 * __bt_new --
78 * Get a new page, preferably from the freelist.
79 *
80 * Parameters:
81 * t: tree
82 * npg: storage for page number.
83 *
84 * Returns:
85 * Pointer to a page, NULL on error.
86 */
87 PAGE *
__bt_new(t,npg)88 __bt_new(t, npg)
89 BTREE *t;
90 db_pgno_t *npg;
91 {
92 PAGE *h;
93
94 if (t->bt_free != P_INVALID &&
95 (h = mpool_get(t->bt_mp, t->bt_free, 0)) != NULL) {
96 *npg = t->bt_free;
97 t->bt_free = h->nextpg;
98 F_SET(t, B_METADIRTY);
99 return (h);
100 }
101 return (mpool_new(t->bt_mp, npg, MPOOL_PAGE_NEXT));
102 }
103