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
__rec_seq(dbp,key,data,flags)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