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rec_seq.c revision 1.13 
      1 /*	$NetBSD: rec_seq.c,v 1.13 2008/09/10 17:52:36 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 #include <sys/cdefs.h>
     33 __RCSID("$NetBSD: rec_seq.c,v 1.13 2008/09/10 17:52:36 joerg Exp $");
     34 
     35 #include "namespace.h"
     36 #include <sys/types.h>
     37 
     38 #include <assert.h>
     39 #include <errno.h>
     40 #include <limits.h>
     41 #include <stdio.h>
     42 #include <string.h>
     43 
     44 #include <db.h>
     45 #include "recno.h"
     46 
     47 /*
     48  * __REC_SEQ -- Recno sequential scan interface.
     49  *
     50  * Parameters:
     51  *	dbp:	pointer to access method
     52  *	key:	key for positioning and return value
     53  *	data:	data return value
     54  *	flags:	R_CURSOR, R_FIRST, R_LAST, R_NEXT, R_PREV.
     55  *
     56  * Returns:
     57  *	RET_ERROR, RET_SUCCESS or RET_SPECIAL if there's no next key.
     58  */
     59 int
     60 __rec_seq(const DB *dbp, DBT *key, DBT *data, u_int flags)
     61 {
     62 	BTREE *t;
     63 	EPG *e;
     64 	recno_t nrec;
     65 	int status;
     66 
     67 	t = dbp->internal;
     68 
     69 	/* Toss any page pinned across calls. */
     70 	if (t->bt_pinned != NULL) {
     71 		mpool_put(t->bt_mp, t->bt_pinned, 0);
     72 		t->bt_pinned = NULL;
     73 	}
     74 
     75 	switch(flags) {
     76 	case R_CURSOR:
     77 		if ((nrec = *(recno_t *)key->data) == 0)
     78 			goto einval;
     79 		break;
     80 	case R_NEXT:
     81 		if (F_ISSET(&t->bt_cursor, CURS_INIT)) {
     82 			nrec = t->bt_cursor.rcursor + 1;
     83 			break;
     84 		}
     85 		/* FALLTHROUGH */
     86 	case R_FIRST:
     87 		nrec = 1;
     88 		break;
     89 	case R_PREV:
     90 		if (F_ISSET(&t->bt_cursor, CURS_INIT)) {
     91 			if ((nrec = t->bt_cursor.rcursor - 1) == 0)
     92 				return (RET_SPECIAL);
     93 			break;
     94 		}
     95 		/* FALLTHROUGH */
     96 	case R_LAST:
     97 		if (!F_ISSET(t, R_EOF | R_INMEM) &&
     98 		    t->bt_irec(t, MAX_REC_NUMBER) == RET_ERROR)
     99 			return (RET_ERROR);
    100 		nrec = t->bt_nrecs;
    101 		break;
    102 	default:
    103 einval:		errno = EINVAL;
    104 		return (RET_ERROR);
    105 	}
    106 
    107 	if (t->bt_nrecs == 0 || nrec > t->bt_nrecs) {
    108 		if (!F_ISSET(t, R_EOF | R_INMEM) &&
    109 		    (status = t->bt_irec(t, nrec)) != RET_SUCCESS)
    110 			return (status);
    111 		if (t->bt_nrecs == 0 || nrec > t->bt_nrecs)
    112 			return (RET_SPECIAL);
    113 	}
    114 
    115 	if ((e = __rec_search(t, nrec - 1, SEARCH)) == NULL)
    116 		return (RET_ERROR);
    117 
    118 	F_SET(&t->bt_cursor, CURS_INIT);
    119 	t->bt_cursor.rcursor = nrec;
    120 
    121 	status = __rec_ret(t, e, nrec, key, data);
    122 	if (F_ISSET(t, B_DB_LOCK))
    123 		mpool_put(t->bt_mp, e->page, 0);
    124 	else
    125 		t->bt_pinned = e->page;
    126 	return (status);
    127 }
    128