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405 lines
10 KiB
405 lines
10 KiB
/*-
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* See the file LICENSE for redistribution information.
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*
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* Copyright (c) 1996, 1997, 1998, 1999
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* Sleepycat Software. All rights reserved.
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*/
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/*
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* Copyright (c) 1990, 1993, 1994, 1995, 1996
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* Keith Bostic. All rights reserved.
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*/
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/*
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* Copyright (c) 1990, 1993, 1994, 1995
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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. 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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#include "db_config.h"
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#ifndef lint
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static const char sccsid[] = "@(#)db_overflow.c 11.2 (Sleepycat) 9/9/99";
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#endif /* not lint */
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#ifndef NO_SYSTEM_INCLUDES
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#include <sys/types.h>
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#include <errno.h>
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#include <string.h>
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#endif
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#include "db_int.h"
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#include "db_page.h"
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#include "db_am.h"
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/*
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* Big key/data code.
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*
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* Big key and data entries are stored on linked lists of pages. The initial
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* reference is a structure with the total length of the item and the page
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* number where it begins. Each entry in the linked list contains a pointer
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* to the next page of data, and so on.
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*/
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/*
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* CDB___db_goff --
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* Get an offpage item.
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*
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* PUBLIC: int CDB___db_goff __P((DB *, DBT *,
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* PUBLIC: u_int32_t, db_pgno_t, void **, u_int32_t *));
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*/
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int
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CDB___db_goff(dbp, dbt, tlen, pgno, bpp, bpsz)
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DB *dbp;
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DBT *dbt;
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u_int32_t tlen;
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db_pgno_t pgno;
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void **bpp;
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u_int32_t *bpsz;
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{
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PAGE *h;
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db_indx_t bytes;
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u_int32_t curoff, needed, start;
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u_int8_t *p, *src;
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int ret;
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/*
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* Check if the buffer is big enough; if it is not and we are
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* allowed to malloc space, then we'll malloc it. If we are
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* not (DB_DBT_USERMEM), then we'll set the dbt and return
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* appropriately.
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*/
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if (F_ISSET(dbt, DB_DBT_PARTIAL)) {
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start = dbt->doff;
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needed = dbt->dlen;
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} else {
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start = 0;
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needed = tlen;
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}
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/* Allocate any necessary memory. */
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if (F_ISSET(dbt, DB_DBT_USERMEM)) {
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if (needed > dbt->ulen) {
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dbt->size = needed;
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return (ENOMEM);
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}
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} else if (F_ISSET(dbt, DB_DBT_MALLOC)) {
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if ((ret =
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CDB___os_malloc(needed, dbp->db_malloc, &dbt->data)) != 0)
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return (ret);
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} else if (F_ISSET(dbt, DB_DBT_REALLOC)) {
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if ((ret =
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CDB___os_realloc(needed, dbp->db_realloc, &dbt->data)) != 0)
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return (ret);
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} else if (*bpsz == 0 || *bpsz < needed) {
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if ((ret = CDB___os_realloc(needed, NULL, bpp)) != 0)
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return (ret);
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*bpsz = needed;
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dbt->data = *bpp;
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} else
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dbt->data = *bpp;
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/*
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* Step through the linked list of pages, copying the data on each
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* one into the buffer. Never copy more than the total data length.
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*/
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dbt->size = needed;
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for (curoff = 0, p = dbt->data; pgno != P_INVALID && needed > 0;) {
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if ((ret = CDB_memp_fget(dbp->mpf, &pgno, 0, &h)) != 0) {
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(void)CDB___db_pgerr(dbp, pgno);
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return (ret);
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}
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/* Check if we need any bytes from this page. */
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if (curoff + OV_LEN(h) >= start) {
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src = (u_int8_t *)h + P_OVERHEAD;
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bytes = OV_LEN(h);
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if (start > curoff) {
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src += start - curoff;
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bytes -= start - curoff;
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}
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if (bytes > needed)
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bytes = needed;
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memcpy(p, src, bytes);
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p += bytes;
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needed -= bytes;
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}
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curoff += OV_LEN(h);
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pgno = h->next_pgno;
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CDB_memp_fput(dbp->mpf, h, 0);
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}
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return (0);
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}
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/*
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* CDB___db_poff --
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* Put an offpage item.
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*
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* PUBLIC: int CDB___db_poff __P((DBC *, const DBT *, db_pgno_t *));
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*/
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int
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CDB___db_poff(dbc, dbt, pgnop)
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DBC *dbc;
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const DBT *dbt;
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db_pgno_t *pgnop;
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{
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DB *dbp;
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PAGE *pagep, *lastp;
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DB_LSN new_lsn, null_lsn;
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DBT tmp_dbt;
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db_indx_t pagespace;
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u_int32_t sz;
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u_int8_t *p;
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int ret;
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/*
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* Allocate pages and copy the key/data item into them. Calculate the
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* number of bytes we get for pages we fill completely with a single
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* item.
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*/
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dbp = dbc->dbp;
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pagespace = P_MAXSPACE(dbp->pgsize);
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lastp = NULL;
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for (p = dbt->data,
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sz = dbt->size; sz > 0; p += pagespace, sz -= pagespace) {
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/*
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* Reduce pagespace so we terminate the loop correctly and
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* don't copy too much data.
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*/
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if (sz < pagespace)
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pagespace = sz;
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/*
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* Allocate and initialize a new page and copy all or part of
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* the item onto the page. If sz is less than pagespace, we
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* have a partial record.
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*/
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if ((ret = CDB___db_new(dbc, P_OVERFLOW, &pagep)) != 0)
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return (ret);
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if (DB_LOGGING(dbc)) {
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tmp_dbt.data = p;
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tmp_dbt.size = pagespace;
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ZERO_LSN(null_lsn);
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if ((ret = CDB___db_big_log(dbp->dbenv, dbc->txn,
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&new_lsn, 0, DB_ADD_BIG, dbp->log_fileid,
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PGNO(pagep), lastp ? PGNO(lastp) : PGNO_INVALID,
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PGNO_INVALID, &tmp_dbt, &LSN(pagep),
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lastp == NULL ? &null_lsn : &LSN(lastp),
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&null_lsn)) != 0)
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return (ret);
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/* Move lsn onto page. */
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if (lastp)
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LSN(lastp) = new_lsn;
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LSN(pagep) = new_lsn;
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}
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P_INIT(pagep, dbp->pgsize,
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PGNO(pagep), PGNO_INVALID, PGNO_INVALID, 0, P_OVERFLOW);
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OV_LEN(pagep) = pagespace;
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OV_REF(pagep) = 1;
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memcpy((u_int8_t *)pagep + P_OVERHEAD, p, pagespace);
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/*
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* If this is the first entry, update the user's info.
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* Otherwise, update the entry on the last page filled
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* in and release that page.
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*/
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if (lastp == NULL)
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*pgnop = PGNO(pagep);
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else {
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lastp->next_pgno = PGNO(pagep);
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pagep->prev_pgno = PGNO(lastp);
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(void)CDB_memp_fput(dbp->mpf, lastp, DB_MPOOL_DIRTY);
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}
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lastp = pagep;
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}
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(void)CDB_memp_fput(dbp->mpf, lastp, DB_MPOOL_DIRTY);
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return (0);
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}
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/*
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* CDB___db_ovref --
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* Increment/decrement the reference count on an overflow page.
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*
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* PUBLIC: int CDB___db_ovref __P((DBC *, db_pgno_t, int32_t));
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*/
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int
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CDB___db_ovref(dbc, pgno, adjust)
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DBC *dbc;
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db_pgno_t pgno;
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int32_t adjust;
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{
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DB *dbp;
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PAGE *h;
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int ret;
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dbp = dbc->dbp;
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if ((ret = CDB_memp_fget(dbp->mpf, &pgno, 0, &h)) != 0) {
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(void)CDB___db_pgerr(dbp, pgno);
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return (ret);
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}
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if (DB_LOGGING(dbc))
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if ((ret = CDB___db_ovref_log(dbp->dbenv, dbc->txn,
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&LSN(h), 0, dbp->log_fileid, h->pgno, adjust,
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&LSN(h))) != 0)
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return (ret);
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OV_REF(h) += adjust;
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(void)CDB_memp_fput(dbp->mpf, h, DB_MPOOL_DIRTY);
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return (0);
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}
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/*
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* CDB___db_doff --
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* Delete an offpage chain of overflow pages.
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*
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* PUBLIC: int CDB___db_doff __P((DBC *, db_pgno_t));
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*/
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int
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CDB___db_doff(dbc, pgno)
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DBC *dbc;
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db_pgno_t pgno;
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{
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DB *dbp;
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PAGE *pagep;
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DB_LSN null_lsn;
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DBT tmp_dbt;
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int ret;
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dbp = dbc->dbp;
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do {
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if ((ret = CDB_memp_fget(dbp->mpf, &pgno, 0, &pagep)) != 0) {
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(void)CDB___db_pgerr(dbp, pgno);
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return (ret);
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}
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/*
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* If it's an overflow page and it's referenced by more than
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* one key/data item, decrement the reference count and return.
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*/
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if (TYPE(pagep) == P_OVERFLOW && OV_REF(pagep) > 1) {
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(void)CDB_memp_fput(dbp->mpf, pagep, 0);
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return (CDB___db_ovref(dbc, pgno, -1));
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}
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if (DB_LOGGING(dbc)) {
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tmp_dbt.data = (u_int8_t *)pagep + P_OVERHEAD;
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tmp_dbt.size = OV_LEN(pagep);
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ZERO_LSN(null_lsn);
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if ((ret = CDB___db_big_log(dbp->dbenv, dbc->txn,
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&LSN(pagep), 0, DB_REM_BIG, dbp->log_fileid,
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PGNO(pagep), PREV_PGNO(pagep), NEXT_PGNO(pagep),
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&tmp_dbt, &LSN(pagep), &null_lsn, &null_lsn)) != 0)
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return (ret);
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}
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pgno = pagep->next_pgno;
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if ((ret = CDB___db_free(dbc, pagep)) != 0)
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return (ret);
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} while (pgno != PGNO_INVALID);
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return (0);
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}
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/*
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* CDB___db_moff --
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* Match on overflow pages.
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*
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* Given a starting page number and a key, return <0, 0, >0 to indicate if the
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* key on the page is less than, equal to or greater than the key specified.
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* We optimize this by doing chunk at a time comparison unless the user has
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* specified a comparison function. In this case, we need to materialize
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* the entire object and call their comparison routine.
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*
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* PUBLIC: int CDB___db_moff __P((DB *, const DBT *, db_pgno_t, u_int32_t,
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* PUBLIC: int (*)(const DBT *, const DBT *), int *));
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*/
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int
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CDB___db_moff(dbp, dbt, pgno, tlen, cmpfunc, cmpp)
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DB *dbp;
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const DBT *dbt;
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db_pgno_t pgno;
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u_int32_t tlen;
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int (*cmpfunc) __P((const DBT *, const DBT *)), *cmpp;
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{
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PAGE *pagep;
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DBT local_dbt;
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void *buf;
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u_int32_t bufsize, cmp_bytes, key_left;
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u_int8_t *p1, *p2;
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int ret;
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/*
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* If there is a user-specified comparison function, build a
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* contiguous copy of the key, and call it.
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*/
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if (cmpfunc != NULL) {
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memset(&local_dbt, 0, sizeof(local_dbt));
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buf = NULL;
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bufsize = 0;
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if ((ret = CDB___db_goff(dbp,
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&local_dbt, tlen, pgno, &buf, &bufsize)) != 0)
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return (ret);
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*cmpp = cmpfunc(&local_dbt, dbt);
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CDB___os_free(buf, bufsize);
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return (0);
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}
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/* While there are both keys to compare. */
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for (*cmpp = 0, p1 = dbt->data,
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key_left = dbt->size; key_left > 0 && pgno != PGNO_INVALID;) {
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if ((ret = CDB_memp_fget(dbp->mpf, &pgno, 0, &pagep)) != 0)
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return (ret);
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cmp_bytes = OV_LEN(pagep) < key_left ? OV_LEN(pagep) : key_left;
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tlen -= cmp_bytes;
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key_left -= cmp_bytes;
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for (p2 =
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(u_int8_t *)pagep + P_OVERHEAD; cmp_bytes-- > 0; ++p1, ++p2)
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if (*p1 != *p2) {
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*cmpp = (long)*p1 - (long)*p2;
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break;
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}
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pgno = NEXT_PGNO(pagep);
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if ((ret = CDB_memp_fput(dbp->mpf, pagep, 0)) != 0)
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return (ret);
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if (*cmpp != 0)
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return (0);
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}
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if (key_left > 0) /* DBT is longer than the page key. */
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*cmpp = -1;
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else if (tlen > 0) /* DBT is shorter than the page key. */
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*cmpp = 1;
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else
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*cmpp = 0;
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return (0);
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}
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