diff options
Diffstat (limited to 'db/recno/rec_seq.c')
| -rw-r--r-- | db/recno/rec_seq.c | 131 |
1 files changed, 131 insertions, 0 deletions
diff --git a/db/recno/rec_seq.c b/db/recno/rec_seq.c new file mode 100644 index 0000000000..f80992c598 --- /dev/null +++ b/db/recno/rec_seq.c @@ -0,0 +1,131 @@ +/*- + * Copyright (c) 1991, 1993, 1994 + * The Regents of the University of California. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 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 + * SUCH DAMAGE. + */ + +#ifndef lint +static char sccsid[] = "@(#)rec_seq.c 8.3 (Berkeley) 7/14/94"; +#endif /* not lint */ + +#include <sys/types.h> + +#include <errno.h> +#include <limits.h> +#include <stdio.h> +#include <string.h> + +#include <db.h> +#include "recno.h" + +/* + * __REC_SEQ -- Recno sequential scan interface. + * + * Parameters: + * dbp: pointer to access method + * key: key for positioning and return value + * data: data return value + * flags: R_CURSOR, R_FIRST, R_LAST, R_NEXT, R_PREV. + * + * Returns: + * RET_ERROR, RET_SUCCESS or RET_SPECIAL if there's no next key. + */ +int +__rec_seq(dbp, key, data, flags) + const DB *dbp; + DBT *key, *data; + u_int flags; +{ + BTREE *t; + EPG *e; + recno_t nrec; + int status; + + t = dbp->internal; + + /* Toss any page pinned across calls. */ + if (t->bt_pinned != NULL) { + mpool_put(t->bt_mp, t->bt_pinned, 0); + t->bt_pinned = NULL; + } + + switch(flags) { + case R_CURSOR: + if ((nrec = *(recno_t *)key->data) == 0) + goto einval; + break; + case R_NEXT: + if (F_ISSET(&t->bt_cursor, CURS_INIT)) { + nrec = t->bt_cursor.rcursor + 1; + break; + } + /* FALLTHROUGH */ + case R_FIRST: + nrec = 1; + break; + case R_PREV: + if (F_ISSET(&t->bt_cursor, CURS_INIT)) { + if ((nrec = t->bt_cursor.rcursor - 1) == 0) + return (RET_SPECIAL); + break; + } + /* FALLTHROUGH */ + case R_LAST: + if (!F_ISSET(t, R_EOF | R_INMEM) && + t->bt_irec(t, MAX_REC_NUMBER) == RET_ERROR) + return (RET_ERROR); + nrec = t->bt_nrecs; + break; + default: +einval: errno = EINVAL; + return (RET_ERROR); + } + + if (t->bt_nrecs == 0 || nrec > t->bt_nrecs) { + if (!F_ISSET(t, R_EOF | R_INMEM) && + (status = t->bt_irec(t, nrec)) != RET_SUCCESS) + return (status); + if (t->bt_nrecs == 0 || nrec > t->bt_nrecs) + return (RET_SPECIAL); + } + + if ((e = __rec_search(t, nrec - 1, SEARCH)) == NULL) + return (RET_ERROR); + + F_SET(&t->bt_cursor, CURS_INIT); + t->bt_cursor.rcursor = nrec; + + status = __rec_ret(t, e, nrec, key, data); + if (F_ISSET(t, B_DB_LOCK)) + mpool_put(t->bt_mp, e->page, 0); + else + t->bt_pinned = e->page; + return (status); +} |