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      1 /*	$NetBSD: rec_seq.c,v 1.14 2008/09/11 12:58:00 joerg 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. Neither the name of the University nor the names of its contributors
     16  *    may be used to endorse or promote products derived from this software
     17  *    without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  */
     31 
     32 #if HAVE_NBTOOL_CONFIG_H
     33 #include "nbtool_config.h"
     34 #endif
     35 
     36 #include <sys/cdefs.h>
     37 __RCSID("$NetBSD: rec_seq.c,v 1.14 2008/09/11 12:58:00 joerg Exp $");
     38 
     39 #include "namespace.h"
     40 #include <sys/types.h>
     41 
     42 #include <assert.h>
     43 #include <errno.h>
     44 #include <limits.h>
     45 #include <stdio.h>
     46 #include <string.h>
     47 
     48 #include <db.h>
     49 #include "recno.h"
     50 
     51 /*
     52  * __REC_SEQ -- Recno sequential scan interface.
     53  *
     54  * Parameters:
     55  *	dbp:	pointer to access method
     56  *	key:	key for positioning and return value
     57  *	data:	data return value
     58  *	flags:	R_CURSOR, R_FIRST, R_LAST, R_NEXT, R_PREV.
     59  *
     60  * Returns:
     61  *	RET_ERROR, RET_SUCCESS or RET_SPECIAL if there's no next key.
     62  */
     63 int
     64 __rec_seq(const DB *dbp, DBT *key, DBT *data, u_int flags)
     65 {
     66 	BTREE *t;
     67 	EPG *e;
     68 	recno_t nrec;
     69 	int status;
     70 
     71 	t = dbp->internal;
     72 
     73 	/* Toss any page pinned across calls. */
     74 	if (t->bt_pinned != NULL) {
     75 		mpool_put(t->bt_mp, t->bt_pinned, 0);
     76 		t->bt_pinned = NULL;
     77 	}
     78 
     79 	switch(flags) {
     80 	case R_CURSOR:
     81 		if ((nrec = *(recno_t *)key->data) == 0)
     82 			goto einval;
     83 		break;
     84 	case R_NEXT:
     85 		if (F_ISSET(&t->bt_cursor, CURS_INIT)) {
     86 			nrec = t->bt_cursor.rcursor + 1;
     87 			break;
     88 		}
     89 		/* FALLTHROUGH */
     90 	case R_FIRST:
     91 		nrec = 1;
     92 		break;
     93 	case R_PREV:
     94 		if (F_ISSET(&t->bt_cursor, CURS_INIT)) {
     95 			if ((nrec = t->bt_cursor.rcursor - 1) == 0)
     96 				return (RET_SPECIAL);
     97 			break;
     98 		}
     99 		/* FALLTHROUGH */
    100 	case R_LAST:
    101 		if (!F_ISSET(t, R_EOF | R_INMEM) &&
    102 		    t->bt_irec(t, MAX_REC_NUMBER) == RET_ERROR)
    103 			return (RET_ERROR);
    104 		nrec = t->bt_nrecs;
    105 		break;
    106 	default:
    107 einval:		errno = EINVAL;
    108 		return (RET_ERROR);
    109 	}
    110 
    111 	if (t->bt_nrecs == 0 || nrec > t->bt_nrecs) {
    112 		if (!F_ISSET(t, R_EOF | R_INMEM) &&
    113 		    (status = t->bt_irec(t, nrec)) != RET_SUCCESS)
    114 			return (status);
    115 		if (t->bt_nrecs == 0 || nrec > t->bt_nrecs)
    116 			return (RET_SPECIAL);
    117 	}
    118 
    119 	if ((e = __rec_search(t, nrec - 1, SEARCH)) == NULL)
    120 		return (RET_ERROR);
    121 
    122 	F_SET(&t->bt_cursor, CURS_INIT);
    123 	t->bt_cursor.rcursor = nrec;
    124 
    125 	status = __rec_ret(t, e, nrec, key, data);
    126 	if (F_ISSET(t, B_DB_LOCK))
    127 		mpool_put(t->bt_mp, e->page, 0);
    128 	else
    129 		t->bt_pinned = e->page;
    130 	return (status);
    131 }
    132