132 lines
3.8 KiB
C
132 lines
3.8 KiB
C
/*-
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* Copyright (c) 1991, 1993, 1994
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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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#ifndef lint
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static char sccsid[] = "@(#)rec_seq.c 8.3 (Berkeley) 7/14/94";
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#endif /* not lint */
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#include <sys/types.h>
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#include <errno.h>
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#include <limits.h>
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#include <stdio.h>
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#include <string.h>
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#include <db.h>
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#include "recno.h"
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/*
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* __REC_SEQ -- Recno sequential scan interface.
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*
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* Parameters:
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* dbp: pointer to access method
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* key: key for positioning and return value
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* data: data return value
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* flags: R_CURSOR, R_FIRST, R_LAST, R_NEXT, R_PREV.
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*
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* Returns:
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* RET_ERROR, RET_SUCCESS or RET_SPECIAL if there's no next key.
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*/
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int
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__rec_seq(dbp, key, data, flags)
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const DB *dbp;
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DBT *key, *data;
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u_int flags;
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{
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BTREE *t;
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EPG *e;
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recno_t nrec;
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int status;
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t = dbp->internal;
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/* Toss any page pinned across calls. */
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if (t->bt_pinned != NULL) {
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mpool_put(t->bt_mp, t->bt_pinned, 0);
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t->bt_pinned = NULL;
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}
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switch(flags) {
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case R_CURSOR:
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if ((nrec = *(recno_t *)key->data) == 0)
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goto einval;
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break;
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case R_NEXT:
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if (F_ISSET(&t->bt_cursor, CURS_INIT)) {
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nrec = t->bt_cursor.rcursor + 1;
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break;
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}
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/* FALLTHROUGH */
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case R_FIRST:
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nrec = 1;
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break;
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case R_PREV:
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if (F_ISSET(&t->bt_cursor, CURS_INIT)) {
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if ((nrec = t->bt_cursor.rcursor - 1) == 0)
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return (RET_SPECIAL);
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break;
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}
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/* FALLTHROUGH */
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case R_LAST:
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if (!F_ISSET(t, R_EOF | R_INMEM) &&
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t->bt_irec(t, MAX_REC_NUMBER) == RET_ERROR)
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return (RET_ERROR);
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nrec = t->bt_nrecs;
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break;
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default:
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einval: errno = EINVAL;
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return (RET_ERROR);
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}
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if (t->bt_nrecs == 0 || nrec > t->bt_nrecs) {
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if (!F_ISSET(t, R_EOF | R_INMEM) &&
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(status = t->bt_irec(t, nrec)) != RET_SUCCESS)
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return (status);
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if (t->bt_nrecs == 0 || nrec > t->bt_nrecs)
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return (RET_SPECIAL);
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}
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if ((e = __rec_search(t, nrec - 1, SEARCH)) == NULL)
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return (RET_ERROR);
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F_SET(&t->bt_cursor, CURS_INIT);
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t->bt_cursor.rcursor = nrec;
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status = __rec_ret(t, e, nrec, key, data);
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if (F_ISSET(t, B_DB_LOCK))
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mpool_put(t->bt_mp, e->page, 0);
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else
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t->bt_pinned = e->page;
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return (status);
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}
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