1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
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/types.h>
33
34#include <errno.h>
35#include <limits.h>
36#include <stdio.h>
37#include <string.h>
38
39#include <db.h>
40#include "recno.h"
41
42/*
43 * __REC_SEQ -- Recno sequential scan interface.
44 *
45 * Parameters:
46 *	dbp:	pointer to access method
47 *	key:	key for positioning and return value
48 *	data:	data return value
49 *	flags:	R_CURSOR, R_FIRST, R_LAST, R_NEXT, R_PREV.
50 *
51 * Returns:
52 *	RET_ERROR, RET_SUCCESS or RET_SPECIAL if there's no next key.
53 */
54int
55__rec_seq(const DB *dbp, DBT *key, DBT *data, u_int flags)
56{
57	BTREE *t;
58	EPG *e;
59	recno_t nrec;
60	int status;
61
62	t = dbp->internal;
63
64	/* Toss any page pinned across calls. */
65	if (t->bt_pinned != NULL) {
66		mpool_put(t->bt_mp, t->bt_pinned, 0);
67		t->bt_pinned = NULL;
68	}
69
70	switch(flags) {
71	case R_CURSOR:
72		if ((nrec = *(recno_t *)key->data) == 0)
73			goto einval;
74		break;
75	case R_NEXT:
76		if (F_ISSET(&t->bt_cursor, CURS_INIT)) {
77			nrec = t->bt_cursor.rcursor + 1;
78			break;
79		}
80		/* FALLTHROUGH */
81	case R_FIRST:
82		nrec = 1;
83		break;
84	case R_PREV:
85		if (F_ISSET(&t->bt_cursor, CURS_INIT)) {
86			if ((nrec = t->bt_cursor.rcursor - 1) == 0)
87				return (RET_SPECIAL);
88			break;
89		}
90		/* FALLTHROUGH */
91	case R_LAST:
92		if (!F_ISSET(t, R_EOF | R_INMEM) &&
93		    t->bt_irec(t, MAX_REC_NUMBER) == RET_ERROR)
94			return (RET_ERROR);
95		nrec = t->bt_nrecs;
96		break;
97	default:
98einval:		errno = EINVAL;
99		return (RET_ERROR);
100	}
101
102	if (t->bt_nrecs == 0 || nrec > t->bt_nrecs) {
103		if (!F_ISSET(t, R_EOF | R_INMEM) &&
104		    (status = t->bt_irec(t, nrec)) != RET_SUCCESS)
105			return (status);
106		if (t->bt_nrecs == 0 || nrec > t->bt_nrecs)
107			return (RET_SPECIAL);
108	}
109
110	if ((e = __rec_search(t, nrec - 1, SEARCH)) == NULL)
111		return (RET_ERROR);
112
113	F_SET(&t->bt_cursor, CURS_INIT);
114	t->bt_cursor.rcursor = nrec;
115
116	status = __rec_ret(t, e, nrec, key, data);
117	if (F_ISSET(t, B_DB_LOCK))
118		mpool_put(t->bt_mp, e->page, 0);
119	else
120		t->bt_pinned = e->page;
121	return (status);
122}
123