Home | History | Annotate | Line # | Download | only in btree
bt_get.c revision 1.10 
      1 /*	$NetBSD: bt_get.c,v 1.10 2003/08/07 16:42:41 agc 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 #include <sys/cdefs.h>
     36 #if defined(LIBC_SCCS) && !defined(lint)
     37 #if 0
     38 static char sccsid[] = "@(#)bt_get.c	8.6 (Berkeley) 7/20/94";
     39 #else
     40 __RCSID("$NetBSD: bt_get.c,v 1.10 2003/08/07 16:42:41 agc Exp $");
     41 #endif
     42 #endif /* LIBC_SCCS and not lint */
     43 
     44 #include "namespace.h"
     45 #include <sys/types.h>
     46 
     47 #include <errno.h>
     48 #include <stddef.h>
     49 #include <stdio.h>
     50 
     51 #include <db.h>
     52 #include "btree.h"
     53 
     54 /*
     55  * __BT_GET -- Get a record from the btree.
     56  *
     57  * Parameters:
     58  *	dbp:	pointer to access method
     59  *	key:	key to find
     60  *	data:	data to return
     61  *	flag:	currently unused
     62  *
     63  * Returns:
     64  *	RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found.
     65  */
     66 int
     67 __bt_get(dbp, key, data, flags)
     68 	const DB *dbp;
     69 	const DBT *key;
     70 	DBT *data;
     71 	u_int flags;
     72 {
     73 	BTREE *t;
     74 	EPG *e;
     75 	int exact, status;
     76 
     77 	t = dbp->internal;
     78 
     79 	/* Toss any page pinned across calls. */
     80 	if (t->bt_pinned != NULL) {
     81 		mpool_put(t->bt_mp, t->bt_pinned, 0);
     82 		t->bt_pinned = NULL;
     83 	}
     84 
     85 	/* Get currently doesn't take any flags. */
     86 	if (flags) {
     87 		errno = EINVAL;
     88 		return (RET_ERROR);
     89 	}
     90 
     91 	if ((e = __bt_search(t, key, &exact)) == NULL)
     92 		return (RET_ERROR);
     93 	if (!exact) {
     94 		mpool_put(t->bt_mp, e->page, 0);
     95 		return (RET_SPECIAL);
     96 	}
     97 
     98 	status = __bt_ret(t, e, NULL, NULL, data, &t->bt_rdata, 0);
     99 
    100 	/*
    101 	 * If the user is doing concurrent access, we copied the
    102 	 * key/data, toss the page.
    103 	 */
    104 	if (F_ISSET(t, B_DB_LOCK))
    105 		mpool_put(t->bt_mp, e->page, 0);
    106 	else
    107 		t->bt_pinned = e->page;
    108 	return (status);
    109 }
    110