665 lines
15 KiB
C
665 lines
15 KiB
C
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/*-
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* Copyright (c) 1990 The Regents of the University of California.
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* 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[] = "@(#)storage.c 5.2 (Berkeley) 2/22/91";
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#endif /* LIBC_SCCS and not lint */
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#include <sys/param.h>
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#include <db.h>
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#include <errno.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include "btree.h"
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/*
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* BT_GETPAGE -- Make pgno the current page of the btree.
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*
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* This routine is just a wrapper that decides whether to call the
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* memory or disk-based routine to do the work.
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*
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* Parameters:
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* t -- btree in which to get page
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* pgno -- page number to get
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*
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* Returns:
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* RET_SUCCESS or RET_ERROR.
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*/
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int
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_bt_getpage(t, pgno)
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BTREE_P t;
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pgno_t pgno;
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{
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#ifdef DEBUG
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if (pgno == P_NONE)
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_punt();
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#endif /* DEBUG */
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/* see if we can get away without doing any work */
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if (t->bt_curpage != (BTHEADER *) NULL) {
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if (t->bt_curpage->h_pgno == pgno)
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return (RET_SUCCESS);
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}
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if (t->bt_fname == (char *) NULL)
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return (_bt_getmpage(t, pgno));
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else
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return (_bt_getdpage(t, pgno));
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}
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/*
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* _BT_GETMPAGE -- Make pgno the current page of the btree.
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*
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* This routine gets pages for in-memory btrees.
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*
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* Parameters:
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* t -- btree in which to get page
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* pgno -- page number to get
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*
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* Returns:
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* RET_SUCCESS or RET_ERROR.
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*/
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int
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_bt_getmpage(t, pgno)
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register BTREE_P t;
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pgno_t pgno;
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{
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int htindex;
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BTHEADER *h;
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HTBUCKET *b;
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if (t->bt_curpage == (BTHEADER *) NULL) {
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if (pgno != P_ROOT) {
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errno = EBADF;
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return (RET_ERROR);
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}
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t->bt_npages++;
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h = (BTHEADER *) malloc((unsigned) t->bt_psize);
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if (h == (BTHEADER *) NULL)
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return (RET_ERROR);
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h->h_pgno = P_ROOT;
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h->h_flags = F_LEAF;
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h->h_lower = (index_t)
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(((char *) &(h->h_linp[0])) - ((char *) h));
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h->h_upper = t->bt_psize;
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h->h_prevpg = h->h_nextpg = P_NONE;
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t->bt_curpage = h;
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/* get the root page into the hash table */
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if (_bt_write(t, h, RELEASE) == RET_ERROR)
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return (RET_ERROR);
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}
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htindex = HASHKEY(pgno);
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for (b = t->bt_s.bt_ht[htindex];
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b != (HTBUCKET *) NULL;
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b = b->ht_next) {
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if (b->ht_pgno == pgno) {
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t->bt_curpage = b->ht_page;
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return (RET_SUCCESS);
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}
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}
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return (RET_ERROR);
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}
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/*
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* _BT_GETDPAGE -- Make pgno the current page of the btree.
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*
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* This routine gets pages for disk btrees.
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*
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* Because disk btree pages must be readable across machine architectures,
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* the btree code writes integers out in network format. This routine
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* converts them back to host format before returning the page.
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*
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* Parameters:
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* t -- btree in which to get page
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* pgno -- page number to get
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*
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* Returns:
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* RET_SUCCESS, RET_ERROR.
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*/
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int
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_bt_getdpage(t, pgno)
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register BTREE_P t;
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pgno_t pgno;
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{
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BTHEADER *h;
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char *cache;
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long pos;
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int n, nbytes;
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/* if we have an lru cache, let the cache code do the work */
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if (ISCACHE(t)) {
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cache = t->bt_s.bt_d.d_cache;
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/* release the old page */
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if (t->bt_curpage != (BTHEADER *) NULL) {
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pgno_t opgno = t->bt_curpage->h_pgno;
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t->bt_curpage->h_flags &= ~F_DIRTY;
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if (lruwrite(cache, (int) opgno) < 0)
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return (RET_ERROR);
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if (lrurelease(cache, (int) opgno) < 0)
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return (RET_ERROR);
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}
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if (pgno > t->bt_npages) {
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if ((h = (BTHEADER *) lrugetnew(cache, (int)pgno, &nbytes))
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== (BTHEADER *) NULL)
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return (RET_ERROR);
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t->bt_npages = pgno;
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} else {
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if ((h = (BTHEADER *) lruget(cache, (int)pgno, &nbytes))
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== (BTHEADER *) NULL)
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return (RET_ERROR);
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}
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/* init this page, if necessary */
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if (nbytes == 0) {
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h->h_pgno = pgno;
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h->h_flags = F_LEAF;
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h->h_lower = (index_t)
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(((char *) &(h->h_linp[0])) - ((char *) h));
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h->h_upper = t->bt_psize;
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h->h_prevpg = h->h_nextpg = P_NONE;
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}
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t->bt_curpage = h;
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return (RET_SUCCESS);
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}
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/* sync the current page, if necessary */
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if (t->bt_curpage != (BTHEADER *) NULL) {
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if (t->bt_curpage->h_flags & F_DIRTY)
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if (_bt_write(t, t->bt_curpage, RELEASE) == RET_ERROR)
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return (RET_ERROR);
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} else {
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if (t->bt_npages == 0)
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t->bt_npages = 1;
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/* if no current page, get space for one */
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if ((t->bt_curpage = (BTHEADER *) malloc((unsigned) t->bt_psize))
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== (BTHEADER *) NULL) {
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return (RET_ERROR);
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}
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}
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n = t->bt_psize;
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pos = (long) (pgno * n);
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/* seek to correct location in file */
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if (lseek(t->bt_s.bt_d.d_fd, pos, L_SET) != pos) {
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return (RET_ERROR);
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}
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/* read the page */
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if ((nbytes = read(t->bt_s.bt_d.d_fd, t->bt_curpage, n)) < n) {
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/*
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* If we didn't get a full page, we must have gotten no
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* data at all -- in which case we're trying to read a
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* root page that doesn't exist yet. This is the only
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* case in which this is okay. If this happens, construct
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* an empty root page by hand.
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*/
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if (nbytes != 0 || pgno != P_ROOT) {
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errno = EBADF;
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return (RET_ERROR);
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}
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h = (BTHEADER *) t->bt_curpage;
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h->h_pgno = pgno;
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h->h_flags = F_LEAF;
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h->h_lower = (index_t)
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(((char *) &(h->h_linp[0])) - ((char *) h));
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h->h_upper = t->bt_psize;
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h->h_prevpg = h->h_nextpg = P_NONE;
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} else
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(void) _bt_pgin(t->bt_curpage, (char *) t->bt_lorder);
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return (RET_SUCCESS);
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}
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/*
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* _BT_PGOUT, _BT_PGIN -- Convert host-specific number layout to/from
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* the host-independent format stored on disk.
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*
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* Parameters:
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* h -- page to convert
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* _lorder -- byte order for pages (stored as a char * in the
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* cache, and passed around as a magic cookie).
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*
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* Returns:
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* RET_SUCCESS (lru code requires a return value).
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*
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* Side Effects:
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* Layout of tree metadata on the page is changed in place.
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*
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* Warnings:
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* Everywhere else in the code, the types pgno_t and index_t
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* are opaque. These two routines know what they really
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* are.
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*/
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int
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_bt_pgout(h, _lorder)
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BTHEADER *h;
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char *_lorder;
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{
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int i;
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int top;
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int lorder;
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DATUM *d;
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IDATUM *id;
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size_t chain;
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lorder = (int) _lorder;
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if (lorder == BYTE_ORDER)
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return (RET_SUCCESS);
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if (h->h_flags & F_LEAF) {
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if (h->h_flags & F_CONT) {
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if (h->h_prevpg == P_NONE) {
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size_t longsz;
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(void) bcopy((char *) &(h->h_linp[0]),
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(char *) &longsz,
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sizeof(longsz));
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BLSWAP(longsz);
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(void) bcopy((char *) &longsz,
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(char *) &(h->h_linp[0]),
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sizeof(longsz));
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}
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} else {
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top = NEXTINDEX(h);
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for (i = 0; i < top; i++) {
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d = (DATUM *) GETDATUM(h, i);
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if (d->d_flags & D_BIGKEY) {
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(void) bcopy((char *) &(d->d_bytes[0]),
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(char *) &chain,
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sizeof(chain));
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BLSWAP(chain);
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(void) bcopy((char *) &chain,
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(char *) &(d->d_bytes[0]),
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sizeof(chain));
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}
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if (d->d_flags & D_BIGDATA) {
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(void) bcopy((char *) &(d->d_bytes[d->d_ksize]),
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(char *) &chain,
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sizeof(chain));
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BLSWAP(chain);
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(void) bcopy((char *) &chain,
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(char *) &(d->d_bytes[d->d_ksize]),
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sizeof(chain));
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}
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BLSWAP(d->d_dsize);
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BLSWAP(d->d_ksize);
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BLSWAP(d->d_flags);
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BLSWAP(h->h_linp[i]);
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}
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}
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} else {
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top = NEXTINDEX(h);
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for (i = 0; i < top; i++) {
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id = (IDATUM *) GETDATUM(h, i);
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BLSWAP(id->i_size);
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BLSWAP(id->i_pgno);
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BLSWAP(id->i_flags);
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if (id->i_flags & D_BIGKEY) {
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(void) bcopy((char *) &(id->i_bytes[0]),
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(char *) &chain,
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sizeof(chain));
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BLSWAP(chain);
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(void) bcopy((char *) &chain,
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(char *) &(id->i_bytes[0]),
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sizeof(chain));
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}
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BLSWAP(h->h_linp[i]);
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}
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}
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BLSWAP(h->h_flags);
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BLSWAP(h->h_pgno);
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BLSWAP(h->h_prevpg);
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BLSWAP(h->h_nextpg);
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BLSWAP(h->h_lower);
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BLSWAP(h->h_upper);
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return (RET_SUCCESS);
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}
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int
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_bt_pgin(h, _lorder)
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BTHEADER *h;
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char *_lorder;
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{
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int i;
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int top;
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int lorder;
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DATUM *d;
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IDATUM *id;
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size_t chain;
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/*
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* If btree pages are to be stored in the host byte order, don't
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* bother swapping.
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*/
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lorder = (int) _lorder;
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if (lorder == BYTE_ORDER)
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return (RET_SUCCESS);
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BLSWAP(h->h_upper);
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BLSWAP(h->h_lower);
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BLSWAP(h->h_nextpg);
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BLSWAP(h->h_prevpg);
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BLSWAP(h->h_pgno);
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BLSWAP(h->h_flags);
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if (h->h_flags & F_LEAF) {
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if (h->h_flags & F_CONT) {
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if (h->h_prevpg == P_NONE) {
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size_t longsz;
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(void) bcopy((char *) &(h->h_linp[0]),
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(char *) &longsz,
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sizeof(longsz));
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BLSWAP(longsz);
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(void) bcopy((char *) &longsz,
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(char *) &(h->h_linp[0]),
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sizeof(longsz));
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}
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} else {
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top = NEXTINDEX(h);
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for (i = 0; i < top; i++) {
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BLSWAP(h->h_linp[i]);
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d = (DATUM *) GETDATUM(h, i);
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BLSWAP(d->d_dsize);
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BLSWAP(d->d_ksize);
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BLSWAP(d->d_flags);
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if (d->d_flags & D_BIGKEY) {
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(void) bcopy((char *) &(d->d_bytes[0]),
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(char *) &chain,
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sizeof(chain));
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BLSWAP(chain);
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(void) bcopy((char *) &chain,
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(char *) &(d->d_bytes[0]),
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sizeof(chain));
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}
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if (d->d_flags & D_BIGDATA) {
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(void) bcopy((char *) &(d->d_bytes[d->d_ksize]),
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(char *) &chain,
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sizeof(chain));
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BLSWAP(chain);
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(void) bcopy((char *) &chain,
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||
|
(char *) &(d->d_bytes[d->d_ksize]),
|
||
|
sizeof(chain));
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
} else {
|
||
|
top = NEXTINDEX(h);
|
||
|
for (i = 0; i < top; i++) {
|
||
|
BLSWAP(h->h_linp[i]);
|
||
|
id = (IDATUM *) GETDATUM(h, i);
|
||
|
BLSWAP(id->i_size);
|
||
|
BLSWAP(id->i_pgno);
|
||
|
BLSWAP(id->i_flags);
|
||
|
if (id->i_flags & D_BIGKEY) {
|
||
|
(void) bcopy((char *) &(id->i_bytes[0]),
|
||
|
(char *) &chain,
|
||
|
sizeof(chain));
|
||
|
BLSWAP(chain);
|
||
|
(void) bcopy((char *) &chain,
|
||
|
(char *) &(id->i_bytes[0]),
|
||
|
sizeof(chain));
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
return (RET_SUCCESS);
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* _BT_ALLOCPG -- allocate a new page in the btree.
|
||
|
*
|
||
|
* This is called when we split a page, to get space to do the split.
|
||
|
* For disk btrees, these pages are released when the split is done.
|
||
|
* For memory btrees, they are not.
|
||
|
*
|
||
|
* Parameters:
|
||
|
* t -- tree in which to do split
|
||
|
*
|
||
|
* Returns:
|
||
|
* Pointer to the newly-allocated page
|
||
|
*/
|
||
|
|
||
|
BTHEADER *
|
||
|
_bt_allocpg(t)
|
||
|
BTREE_P t;
|
||
|
{
|
||
|
BTHEADER *h = t->bt_curpage;
|
||
|
BTHEADER *nh;
|
||
|
int nbytes;
|
||
|
|
||
|
/* if we have a cache, let the cache code do the work */
|
||
|
if (ISDISK(t) && ISCACHE(t)) {
|
||
|
nh = (BTHEADER *) lrugetnew(t->bt_s.bt_d.d_cache,
|
||
|
(int) (t->bt_npages + 1),
|
||
|
&nbytes);
|
||
|
} else {
|
||
|
nh = (BTHEADER *) malloc((unsigned) t->bt_psize);
|
||
|
}
|
||
|
|
||
|
if (nh != (BTHEADER *) NULL) {
|
||
|
nh->h_pgno = nh->h_prevpg = nh->h_nextpg = P_NONE;
|
||
|
nh->h_flags = h->h_flags;
|
||
|
nh->h_lower = (index_t)
|
||
|
(((char *) &(nh->h_linp[0])) - ((char *) nh));
|
||
|
nh->h_upper = t->bt_psize;
|
||
|
}
|
||
|
|
||
|
return (nh);
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* _BT_WRITE -- Write a specific page to a btree file.
|
||
|
*
|
||
|
* Parameters:
|
||
|
* t -- btree to get the page
|
||
|
* h -- page to write
|
||
|
* relflag -- (int) this page may/may not be released
|
||
|
*
|
||
|
* Returns:
|
||
|
* RET_SUCCESS, RET_ERROR.
|
||
|
*
|
||
|
* Side Effects:
|
||
|
* Writes a metadata page if none has been written yet.
|
||
|
*/
|
||
|
|
||
|
int
|
||
|
_bt_write(t, h, relflag)
|
||
|
BTREE_P t;
|
||
|
BTHEADER *h;
|
||
|
int relflag;
|
||
|
{
|
||
|
long pos;
|
||
|
int htindex;
|
||
|
HTBUCKET *b;
|
||
|
char *cache;
|
||
|
pgno_t pgno;
|
||
|
|
||
|
h->h_flags &= ~F_DIRTY;
|
||
|
if (ISDISK(t)) {
|
||
|
|
||
|
/* if we haven't done so yet, write the metadata */
|
||
|
if (!(t->bt_flags & BTF_METAOK)) {
|
||
|
if (_bt_wrtmeta(t) == RET_ERROR)
|
||
|
return (RET_ERROR);
|
||
|
}
|
||
|
|
||
|
pgno = h->h_pgno;
|
||
|
|
||
|
|
||
|
/* if we have a cache, let the cache code do the work */
|
||
|
if ((cache = t->bt_s.bt_d.d_cache) != (char *) NULL) {
|
||
|
if (lruwrite(cache, (int) pgno) < 0)
|
||
|
return (RET_ERROR);
|
||
|
if (relflag && lrurelease(cache, (int) pgno) < 0)
|
||
|
return (RET_ERROR);
|
||
|
|
||
|
} else {
|
||
|
(void) _bt_pgout(h, (char *) t->bt_lorder);
|
||
|
/* now write the current page */
|
||
|
pos = (long) (pgno * t->bt_psize);
|
||
|
if (lseek(t->bt_s.bt_d.d_fd, pos, L_SET) != pos)
|
||
|
return (RET_ERROR);
|
||
|
if (write(t->bt_s.bt_d.d_fd, (char *) h, (int) t->bt_psize)
|
||
|
< t->bt_psize)
|
||
|
return (RET_ERROR);
|
||
|
if (!relflag)
|
||
|
(void) _bt_pgin(h, (char *) t->bt_lorder);
|
||
|
}
|
||
|
} else {
|
||
|
/* in-memory btree */
|
||
|
htindex = HASHKEY(h->h_pgno);
|
||
|
|
||
|
/* see if we need to overwrite existing entry */
|
||
|
for (b = t->bt_s.bt_ht[htindex];
|
||
|
b != (HTBUCKET *) NULL;
|
||
|
b = b->ht_next) {
|
||
|
if (b->ht_pgno == h->h_pgno) {
|
||
|
b->ht_page = h;
|
||
|
return (RET_SUCCESS);
|
||
|
}
|
||
|
}
|
||
|
|
||
|
/* new entry, write it */
|
||
|
b = (HTBUCKET *) malloc((unsigned) sizeof (HTBUCKET));
|
||
|
if (b == (HTBUCKET *) NULL)
|
||
|
return (RET_ERROR);
|
||
|
|
||
|
b->ht_pgno = h->h_pgno;
|
||
|
b->ht_page = h;
|
||
|
b->ht_next = t->bt_s.bt_ht[htindex];
|
||
|
t->bt_s.bt_ht[htindex] = b;
|
||
|
}
|
||
|
return (RET_SUCCESS);
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* _BT_RELEASE -- Release a locked-down cache page
|
||
|
*
|
||
|
* During page splits, we want to force pages out to the cache
|
||
|
* before we actually release them, in some cases. This routine
|
||
|
* releases such a page when it is no longer needed.
|
||
|
*
|
||
|
* Parameters:
|
||
|
* t -- btree in which to release page
|
||
|
* h -- page to release
|
||
|
*
|
||
|
* Returns:
|
||
|
* RET_SUCCESS, RET_ERROR.
|
||
|
*
|
||
|
* Side Effects:
|
||
|
* None.
|
||
|
*/
|
||
|
|
||
|
int
|
||
|
_bt_release(t, h)
|
||
|
BTREE_P t;
|
||
|
BTHEADER *h;
|
||
|
{
|
||
|
if (ISDISK(t) && ISCACHE(t)) {
|
||
|
if (lrurelease(t->bt_s.bt_d.d_cache, (int) (h->h_pgno)) < 0)
|
||
|
return (RET_ERROR);
|
||
|
}
|
||
|
return (RET_SUCCESS);
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* _BT_WRTMETA -- Write metadata to the btree.
|
||
|
*
|
||
|
* Parameters:
|
||
|
* t -- tree to which to write
|
||
|
*
|
||
|
* Returns:
|
||
|
* RET_SUCCESS, RET_ERROR.
|
||
|
*/
|
||
|
|
||
|
int
|
||
|
_bt_wrtmeta(t)
|
||
|
BTREE_P t;
|
||
|
{
|
||
|
BTMETA m;
|
||
|
|
||
|
if (lseek(t->bt_s.bt_d.d_fd, 0l, L_SET) != 0l)
|
||
|
return (RET_ERROR);
|
||
|
|
||
|
/* lorder has to be in host-independent format */
|
||
|
m.m_lorder = (u_long) htonl((long) t->bt_lorder);
|
||
|
|
||
|
m.m_magic = BTREEMAGIC;
|
||
|
m.m_version = BTREEVERSION;
|
||
|
m.m_psize = t->bt_psize;
|
||
|
m.m_free = t->bt_free;
|
||
|
m.m_flags = t->bt_flags & BTF_NODUPS;
|
||
|
|
||
|
if (t->bt_lorder != BYTE_ORDER) {
|
||
|
BLSWAP(m.m_magic);
|
||
|
BLSWAP(m.m_version);
|
||
|
BLSWAP(m.m_psize);
|
||
|
BLSWAP(m.m_free);
|
||
|
BLSWAP(m.m_flags);
|
||
|
}
|
||
|
|
||
|
if (write(t->bt_s.bt_d.d_fd, (char *) &m, sizeof(m))
|
||
|
!= sizeof(m)) {
|
||
|
return (RET_ERROR);
|
||
|
}
|
||
|
|
||
|
t->bt_flags |= BTF_METAOK;
|
||
|
|
||
|
return (RET_SUCCESS);
|
||
|
}
|