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rec_seq.c revision 1.7.2.1 
      1 /*	$NetBSD: rec_seq.c,v 1.7.2.1 1996/09/16 18:40:08 jtc 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 #ifndef lint
     37 #if 0
     38 static char sccsid[] = "@(#)rec_seq.c	8.3 (Berkeley) 7/14/94";
     39 #else
     40 static char rcsid[] = "$NetBSD: rec_seq.c,v 1.7.2.1 1996/09/16 18:40:08 jtc Exp $";
     41 #endif
     42 #endif /* not lint */
     43 
     44 #include "namespace.h"
     45 #include <sys/types.h>
     46 
     47 #include <errno.h>
     48 #include <limits.h>
     49 #include <stdio.h>
     50 #include <string.h>
     51 
     52 #include <db.h>
     53 #include "recno.h"
     54 
     55 /*
     56  * __REC_SEQ -- Recno sequential scan interface.
     57  *
     58  * Parameters:
     59  *	dbp:	pointer to access method
     60  *	key:	key for positioning and return value
     61  *	data:	data return value
     62  *	flags:	R_CURSOR, R_FIRST, R_LAST, R_NEXT, R_PREV.
     63  *
     64  * Returns:
     65  *	RET_ERROR, RET_SUCCESS or RET_SPECIAL if there's no next key.
     66  */
     67 int
     68 __rec_seq(dbp, key, data, flags)
     69 	const DB *dbp;
     70 	DBT *key, *data;
     71 	u_int flags;
     72 {
     73 	BTREE *t;
     74 	EPG *e;
     75 	recno_t nrec;
     76 	int status;
     77 
     78 	t = dbp->internal;
     79 
     80 	/* Toss any page pinned across calls. */
     81 	if (t->bt_pinned != NULL) {
     82 		mpool_put(t->bt_mp, t->bt_pinned, 0);
     83 		t->bt_pinned = NULL;
     84 	}
     85 
     86 	switch(flags) {
     87 	case R_CURSOR:
     88 		if ((nrec = *(recno_t *)key->data) == 0)
     89 			goto einval;
     90 		break;
     91 	case R_NEXT:
     92 		if (F_ISSET(&t->bt_cursor, CURS_INIT)) {
     93 			nrec = t->bt_cursor.rcursor + 1;
     94 			break;
     95 		}
     96 		/* FALLTHROUGH */
     97 	case R_FIRST:
     98 		nrec = 1;
     99 		break;
    100 	case R_PREV:
    101 		if (F_ISSET(&t->bt_cursor, CURS_INIT)) {
    102 			if ((nrec = t->bt_cursor.rcursor - 1) == 0)
    103 				return (RET_SPECIAL);
    104 			break;
    105 		}
    106 		/* FALLTHROUGH */
    107 	case R_LAST:
    108 		if (!F_ISSET(t, R_EOF | R_INMEM) &&
    109 		    t->bt_irec(t, MAX_REC_NUMBER) == RET_ERROR)
    110 			return (RET_ERROR);
    111 		nrec = t->bt_nrecs;
    112 		break;
    113 	default:
    114 einval:		errno = EINVAL;
    115 		return (RET_ERROR);
    116 	}
    117 
    118 	if (t->bt_nrecs == 0 || nrec > t->bt_nrecs) {
    119 		if (!F_ISSET(t, R_EOF | R_INMEM) &&
    120 		    (status = t->bt_irec(t, nrec)) != RET_SUCCESS)
    121 			return (status);
    122 		if (t->bt_nrecs == 0 || nrec > t->bt_nrecs)
    123 			return (RET_SPECIAL);
    124 	}
    125 
    126 	if ((e = __rec_search(t, nrec - 1, SEARCH)) == NULL)
    127 		return (RET_ERROR);
    128 
    129 	F_SET(&t->bt_cursor, CURS_INIT);
    130 	t->bt_cursor.rcursor = nrec;
    131 
    132 	status = __rec_ret(t, e, nrec, key, data);
    133 	if (F_ISSET(t, B_DB_LOCK))
    134 		mpool_put(t->bt_mp, e->page, 0);
    135 	else
    136 		t->bt_pinned = e->page;
    137 	return (status);
    138 }
    139