bt_get.c

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/*-
 * Copyright (c) 1990, 1993, 1994
 *  The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Mike Olson.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *  This product includes software developed by the University of
 *  California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */
 
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)bt_get.c    8.6 (Berkeley) 7/20/94";
#endif /* LIBC_SCCS and not lint */
 
#include <sys/types.h>
 
#include <errno.h>
#include <stddef.h>
#include <stdio.h>
 
#include "../include/db.h"
#include "btree.h"
 
/*
 * __BT_GET -- Get a record from the btree.
 *
 * Parameters:
 *  dbp:    pointer to access method
 *  key:    key to find
 *  data:   data to return
 *  flag:   currently unused
 *
 * Returns:
 *  RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found.
 */
int
__bt_get(dbp, key, data, flags)
    const DB *dbp;
    const DBT *key;
    DBT *data;
    u_int flags;
{
    BTREE *t;
    EPG *e;
    int exact, status;
 
    t = dbp->internal;
 
    /* Toss any page pinned across calls. */
    if (t->bt_pinned != NULL) {
        mpool_put(t->bt_mp, t->bt_pinned, 0);
        t->bt_pinned = NULL;
    }
 
    /* Get currently doesn't take any flags. */
    if (flags) {
        errno = EINVAL;
        return (RET_ERROR);
    }
 
    if ((e = __bt_search(t, key, &exact)) == NULL)
        return (RET_ERROR);
    if (!exact) {
        mpool_put(t->bt_mp, e->page, 0);
        return (RET_SPECIAL);
    }
 
    status = __bt_ret(t, e, NULL, NULL, data, &t->bt_rdata, 0);
 
    /*
     * If the user is doing concurrent access, we copied the
     * key/data, toss the page.
     */
    if (F_ISSET(t, B_DB_LOCK))
        mpool_put(t->bt_mp, e->page, 0);
    else
        t->bt_pinned = e->page;
    return (status);
}