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rec_seq.c revision 1.10 
      1 /*	$NetBSD: rec_seq.c,v 1.10 2000/09/13 22:32:27 msaitoh Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1991, 1993, 1994
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *	This product includes software developed by the University of
     18  *	California, Berkeley and its contributors.
     19  * 4. Neither the name of the University nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  */
     35 
     36 #include <sys/cdefs.h>
     37 #if defined(LIBC_SCCS) && !defined(lint)
     38 #if 0
     39 static char sccsid[] = "@(#)rec_seq.c	8.3 (Berkeley) 7/14/94";
     40 #else
     41 __RCSID("$NetBSD: rec_seq.c,v 1.10 2000/09/13 22:32:27 msaitoh Exp $");
     42 #endif
     43 #endif /* LIBC_SCCS and not lint */
     44 
     45 #include "namespace.h"
     46 #include <sys/types.h>
     47 
     48 #include <errno.h>
     49 #include <limits.h>
     50 #include <stdio.h>
     51 #include <string.h>
     52 
     53 #include <db.h>
     54 #include "recno.h"
     55 
     56 /*
     57  * __REC_SEQ -- Recno sequential scan interface.
     58  *
     59  * Parameters:
     60  *	dbp:	pointer to access method
     61  *	key:	key for positioning and return value
     62  *	data:	data return value
     63  *	flags:	R_CURSOR, R_FIRST, R_LAST, R_NEXT, R_PREV.
     64  *
     65  * Returns:
     66  *	RET_ERROR, RET_SUCCESS or RET_SPECIAL if there's no next key.
     67  */
     68 int
     69 __rec_seq(dbp, key, data, flags)
     70 	const DB *dbp;
     71 	DBT *key, *data;
     72 	u_int flags;
     73 {
     74 	BTREE *t;
     75 	EPG *e;
     76 	recno_t nrec;
     77 	int status;
     78 
     79 	t = dbp->internal;
     80 
     81 	/* Toss any page pinned across calls. */
     82 	if (t->bt_pinned != NULL) {
     83 		mpool_put(t->bt_mp, t->bt_pinned, 0);
     84 		t->bt_pinned = NULL;
     85 	}
     86 
     87 	switch(flags) {
     88 	case R_CURSOR:
     89 		if ((nrec = *(recno_t *)key->data) == 0)
     90 			goto einval;
     91 		break;
     92 	case R_NEXT:
     93 		if (F_ISSET(&t->bt_cursor, CURS_INIT)) {
     94 			nrec = t->bt_cursor.rcursor + 1;
     95 			break;
     96 		}
     97 		/* FALLTHROUGH */
     98 	case R_FIRST:
     99 		nrec = 1;
    100 		break;
    101 	case R_PREV:
    102 		if (F_ISSET(&t->bt_cursor, CURS_INIT)) {
    103 			if ((nrec = t->bt_cursor.rcursor - 1) == 0)
    104 				return (RET_SPECIAL);
    105 			break;
    106 		}
    107 		/* FALLTHROUGH */
    108 	case R_LAST:
    109 		if (!F_ISSET(t, R_EOF | R_INMEM) &&
    110 		    t->bt_irec(t, MAX_REC_NUMBER) == RET_ERROR)
    111 			return (RET_ERROR);
    112 		nrec = t->bt_nrecs;
    113 		break;
    114 	default:
    115 einval:		errno = EINVAL;
    116 		return (RET_ERROR);
    117 	}
    118 
    119 	if (t->bt_nrecs == 0 || nrec > t->bt_nrecs) {
    120 		if (!F_ISSET(t, R_EOF | R_INMEM) &&
    121 		    (status = t->bt_irec(t, nrec)) != RET_SUCCESS)
    122 			return (status);
    123 		if (t->bt_nrecs == 0 || nrec > t->bt_nrecs)
    124 			return (RET_SPECIAL);
    125 	}
    126 
    127 	if ((e = __rec_search(t, nrec - 1, SEARCH)) == NULL)
    128 		return (RET_ERROR);
    129 
    130 	F_SET(&t->bt_cursor, CURS_INIT);
    131 	t->bt_cursor.rcursor = nrec;
    132 
    133 	status = __rec_ret(t, e, nrec, key, data);
    134 	if (F_ISSET(t, B_DB_LOCK))
    135 		mpool_put(t->bt_mp, e->page, 0);
    136 	else
    137 		t->bt_pinned = e->page;
    138 	return (status);
    139 }
    140