xref: /minix/lib/libc/db/btree/bt_get.c (revision 00b67f09)
1 /*	$NetBSD: bt_get.c,v 1.13 2008/09/11 12:58:00 joerg Exp $	*/
2 
3 /*-
4  * Copyright (c) 1990, 1993, 1994
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * This code is derived from software contributed to Berkeley by
8  * Mike Olson.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 
35 #if HAVE_NBTOOL_CONFIG_H
36 #include "nbtool_config.h"
37 #endif
38 
39 #include <sys/cdefs.h>
40 __RCSID("$NetBSD: bt_get.c,v 1.13 2008/09/11 12:58:00 joerg Exp $");
41 
42 #include "namespace.h"
43 #include <sys/types.h>
44 
45 #include <assert.h>
46 #include <errno.h>
47 #include <stddef.h>
48 #include <stdio.h>
49 
50 #include <db.h>
51 #include "btree.h"
52 
53 /*
54  * __BT_GET -- Get a record from the btree.
55  *
56  * Parameters:
57  *	dbp:	pointer to access method
58  *	key:	key to find
59  *	data:	data to return
60  *	flag:	currently unused
61  *
62  * Returns:
63  *	RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found.
64  */
65 int
66 __bt_get(const DB *dbp, const DBT *key, DBT *data, u_int flags)
67 {
68 	BTREE *t;
69 	EPG *e;
70 	int exact, status;
71 
72 	t = dbp->internal;
73 
74 	/* Toss any page pinned across calls. */
75 	if (t->bt_pinned != NULL) {
76 		mpool_put(t->bt_mp, t->bt_pinned, 0);
77 		t->bt_pinned = NULL;
78 	}
79 
80 	/* Get currently doesn't take any flags. */
81 	if (flags) {
82 		errno = EINVAL;
83 		return (RET_ERROR);
84 	}
85 
86 	if ((e = __bt_search(t, key, &exact)) == NULL)
87 		return (RET_ERROR);
88 	if (!exact) {
89 		mpool_put(t->bt_mp, e->page, 0);
90 		return (RET_SPECIAL);
91 	}
92 
93 	status = __bt_ret(t, e, NULL, NULL, data, &t->bt_rdata, 0);
94 
95 	/*
96 	 * If the user is doing concurrent access, we copied the
97 	 * key/data, toss the page.
98 	 */
99 	if (F_ISSET(t, B_DB_LOCK))
100 		mpool_put(t->bt_mp, e->page, 0);
101 	else
102 		t->bt_pinned = e->page;
103 	return (status);
104 }
105