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