* Copyright (c) 1990, 1993
* The Regents of the University of California. All rights reserved.
* This code is derived from software contributed to Berkeley by
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* 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
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid
[] = "@(#)bt_stack.c 8.1 (Berkeley) 6/4/93";
#endif /* LIBC_SCCS and not lint */
* When a page splits, a new record has to be inserted into its parent page.
* This page may have to split as well, all the way up to the root. Since
* parent pointers in each page would be expensive, we maintain a stack of
* parent pages as we descend the tree.
* This is a concurrency problem -- if user a builds a stack, then user b
* splits the tree, then user a tries to split the tree, there's a new level
* in the tree that user a doesn't know about.
* __BT_PUSH -- Push parent page info onto the stack (LIFO).
__bt_push(t
, pgno
, index
)
if (t
->bt_sp
== t
->bt_maxstack
) {
if ((t
->bt_stack
= realloc(t
->bt_stack
,
t
->bt_maxstack
* sizeof(EPGNO
))) == NULL
) {
t
->bt_stack
[t
->bt_sp
].pgno
= pgno
;
t
->bt_stack
[t
->bt_sp
].index
= index
;