Asterisk - The Open Source Telephony Project  GIT-master-a1fa8df
bt_page.c
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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 8.3 (Berkeley) 7/14/94";
36 #endif /* LIBC_SCCS and not lint */
37 
38 #include <sys/types.h>
39 
40 #include <stdio.h>
41 
42 #include "../include/db.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
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 *
86 __bt_new(t, npg)
87  BTREE *t;
88  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));
100 }
Definition: btree.h:75
pgno_t pgno
Definition: btree.h:76
#define F_SET(p, f)
Definition: btree.h:40
int mpool_put(MPOOL *mp, void *page, u_int flags)
Definition: mpool.c:251
#define NULL
Definition: resample.c:96
Definition: btree.h:312
#define MPOOL_DIRTY
Definition: mpool.h:61
void * mpool_get(MPOOL *mp, pgno_t pgno, u_int flags)
Definition: mpool.c:165
int __bt_free(BTREE *t, PAGE *h)
Definition: bt_page.c:60
MPOOL * bt_mp
Definition: btree.h:313
u_int32_t pgno_t
Definition: db.h:78
pgno_t nextpg
Definition: btree.h:78
pgno_t prevpg
Definition: btree.h:77
#define B_METADIRTY
Definition: btree.h:369
#define P_INVALID
Definition: btree.h:63
void * mpool_new(MPOOL *mp, pgno_t *pgnoaddr)
Definition: mpool.c:130
PAGE * __bt_new(BTREE *t, pgno_t *npg)
Definition: bt_page.c:86
pgno_t bt_free
Definition: btree.h:337