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