xref: /freebsd/lib/libc/db/recno/rec_seq.c (revision 1e413cf93298b5b97441a21d9a50fdcd0ee9945e)
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  * 4. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #include <sys/cdefs.h>
31 #ifndef lint
32 /* XXX use __SCCSID */
33 static char sccsid[] __unused = "@(#)rec_seq.c	8.3 (Berkeley) 7/14/94";
34 #endif /* not lint */
35 __FBSDID("$FreeBSD$");
36 
37 #include <sys/types.h>
38 
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(dbp, key, data, flags)
61 	const DB *dbp;
62 	DBT *key, *data;
63 	u_int flags;
64 {
65 	BTREE *t;
66 	EPG *e;
67 	recno_t nrec;
68 	int status;
69 
70 	t = dbp->internal;
71 
72 	/* Toss any page pinned across calls. */
73 	if (t->bt_pinned != NULL) {
74 		mpool_put(t->bt_mp, t->bt_pinned, 0);
75 		t->bt_pinned = NULL;
76 	}
77 
78 	switch(flags) {
79 	case R_CURSOR:
80 		if ((nrec = *(recno_t *)key->data) == 0)
81 			goto einval;
82 		break;
83 	case R_NEXT:
84 		if (F_ISSET(&t->bt_cursor, CURS_INIT)) {
85 			nrec = t->bt_cursor.rcursor + 1;
86 			break;
87 		}
88 		/* FALLTHROUGH */
89 	case R_FIRST:
90 		nrec = 1;
91 		break;
92 	case R_PREV:
93 		if (F_ISSET(&t->bt_cursor, CURS_INIT)) {
94 			if ((nrec = t->bt_cursor.rcursor - 1) == 0)
95 				return (RET_SPECIAL);
96 			break;
97 		}
98 		/* FALLTHROUGH */
99 	case R_LAST:
100 		if (!F_ISSET(t, R_EOF | R_INMEM) &&
101 		    t->bt_irec(t, MAX_REC_NUMBER) == RET_ERROR)
102 			return (RET_ERROR);
103 		nrec = t->bt_nrecs;
104 		break;
105 	default:
106 einval:		errno = EINVAL;
107 		return (RET_ERROR);
108 	}
109 
110 	if (t->bt_nrecs == 0 || nrec > t->bt_nrecs) {
111 		if (!F_ISSET(t, R_EOF | R_INMEM) &&
112 		    (status = t->bt_irec(t, nrec)) != RET_SUCCESS)
113 			return (status);
114 		if (t->bt_nrecs == 0 || nrec > t->bt_nrecs)
115 			return (RET_SPECIAL);
116 	}
117 
118 	if ((e = __rec_search(t, nrec - 1, SEARCH)) == NULL)
119 		return (RET_ERROR);
120 
121 	F_SET(&t->bt_cursor, CURS_INIT);
122 	t->bt_cursor.rcursor = nrec;
123 
124 	status = __rec_ret(t, e, nrec, key, data);
125 	if (F_ISSET(t, B_DB_LOCK))
126 		mpool_put(t->bt_mp, e->page, 0);
127 	else
128 		t->bt_pinned = e->page;
129 	return (status);
130 }
131