93 lines
3.2 KiB
C
93 lines
3.2 KiB
C
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/*-
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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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* This code is derived from software contributed to Berkeley by
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* Mike Olson.
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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_stack.c 8.3 (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 <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <db.h>
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#include "btree.h"
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/*
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* When a page splits, a new record has to be inserted into its parent page.
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* This page may have to split as well, all the way up to the root. Since
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* parent pointers in each page would be expensive, we maintain a stack of
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* parent pages as we descend the tree.
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*
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* XXX
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* This is a concurrency problem -- if user a builds a stack, then user b
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* splits the tree, then user a tries to split the tree, there's a new level
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* in the tree that user a doesn't know about.
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*/
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/*
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* __BT_PUSH -- Push parent page info onto the stack (LIFO).
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*
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* Parameters:
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* t: tree
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* pgno: page
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* index: page index
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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_push(t, pgno, index)
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BTREE *t;
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pgno_t pgno;
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indx_t index;
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{
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if (t->bt_sp == t->bt_maxstack) {
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t->bt_maxstack += 50;
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if ((t->bt_stack = (EPGNO *)realloc(t->bt_stack,
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t->bt_maxstack * sizeof(EPGNO))) == NULL) {
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t->bt_maxstack -= 50;
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return (RET_ERROR);
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}
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}
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t->bt_stack[t->bt_sp].pgno = pgno;
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t->bt_stack[t->bt_sp].index = index;
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++t->bt_sp;
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return (RET_SUCCESS);
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}
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