94 lines
2.8 KiB
C
94 lines
2.8 KiB
C
/*-
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* Copyright (c) 1990, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#if defined(LIBC_SCCS) && !defined(lint)
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static char sccsid[] = "@(#)bt_page.c 8.2 (Berkeley) 2/21/94";
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#endif /* LIBC_SCCS and not lint */
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#include <sys/types.h>
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#include <stdio.h>
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#include <db.h>
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#include "btree.h"
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/*
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* __BT_FREE -- Put a page on the freelist.
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*
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* Parameters:
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* t: tree
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* h: page to free
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*
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* Returns:
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* RET_ERROR, RET_SUCCESS
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*/
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int
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__bt_free(t, h)
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BTREE *t;
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PAGE *h;
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{
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/* Insert the page at the start of the free list. */
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h->prevpg = P_INVALID;
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h->nextpg = t->bt_free;
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t->bt_free = h->pgno;
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/* Make sure the page gets written back. */
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return (mpool_put(t->bt_mp, h, MPOOL_DIRTY));
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}
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/*
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* __BT_NEW -- Get a new page, preferably from the freelist.
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*
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* Parameters:
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* t: tree
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* npg: storage for page number.
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*
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* Returns:
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* Pointer to a page, NULL on error.
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*/
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PAGE *
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__bt_new(t, npg)
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BTREE *t;
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pgno_t *npg;
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{
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PAGE *h;
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if (t->bt_free != P_INVALID &&
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(h = mpool_get(t->bt_mp, t->bt_free, 0)) != NULL) {
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*npg = t->bt_free;
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t->bt_free = h->nextpg;
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return (h);
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}
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return (mpool_new(t->bt_mp, npg));
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}
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