rec_seq.c revision 111010 
1/*-
2 * Copyright (c) 1991, 1993, 1994
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#include <sys/cdefs.h>
35#ifndef lint
36/* XXX use __SCCSID */
37static char sccsid[] __unused = "@(#)rec_seq.c	8.3 (Berkeley) 7/14/94";
38#endif /* not lint */
39__FBSDID("$FreeBSD: head/lib/libc/db/recno/rec_seq.c 111010 2003-02-16 17:29:11Z nectar $");
40
41#include <sys/types.h>
42
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 */
63int
64__rec_seq(dbp, key, data, flags)
65	const DB *dbp;
66	DBT *key, *data;
67	u_int flags;
68{
69	BTREE *t;
70	EPG *e;
71	recno_t nrec;
72	int status;
73
74	t = dbp->internal;
75
76	/* Toss any page pinned across calls. */
77	if (t->bt_pinned != NULL) {
78		mpool_put(t->bt_mp, t->bt_pinned, 0);
79		t->bt_pinned = NULL;
80	}
81
82	switch(flags) {
83	case R_CURSOR:
84		if ((nrec = *(recno_t *)key->data) == 0)
85			goto einval;
86		break;
87	case R_NEXT:
88		if (F_ISSET(&t->bt_cursor, CURS_INIT)) {
89			nrec = t->bt_cursor.rcursor + 1;
90			break;
91		}
92		/* FALLTHROUGH */
93	case R_FIRST:
94		nrec = 1;
95		break;
96	case R_PREV:
97		if (F_ISSET(&t->bt_cursor, CURS_INIT)) {
98			if ((nrec = t->bt_cursor.rcursor - 1) == 0)
99				return (RET_SPECIAL);
100			break;
101		}
102		/* FALLTHROUGH */
103	case R_LAST:
104		if (!F_ISSET(t, R_EOF | R_INMEM) &&
105		    t->bt_irec(t, MAX_REC_NUMBER) == RET_ERROR)
106			return (RET_ERROR);
107		nrec = t->bt_nrecs;
108		break;
109	default:
110einval:		errno = EINVAL;
111		return (RET_ERROR);
112	}
113
114	if (t->bt_nrecs == 0 || nrec > t->bt_nrecs) {
115		if (!F_ISSET(t, R_EOF | R_INMEM) &&
116		    (status = t->bt_irec(t, nrec)) != RET_SUCCESS)
117			return (status);
118		if (t->bt_nrecs == 0 || nrec > t->bt_nrecs)
119			return (RET_SPECIAL);
120	}
121
122	if ((e = __rec_search(t, nrec - 1, SEARCH)) == NULL)
123		return (RET_ERROR);
124
125	F_SET(&t->bt_cursor, CURS_INIT);
126	t->bt_cursor.rcursor = nrec;
127
128	status = __rec_ret(t, e, nrec, key, data);
129	if (F_ISSET(t, B_DB_LOCK))
130		mpool_put(t->bt_mp, e->page, 0);
131	else
132		t->bt_pinned = e->page;
133	return (status);
134}
135