1 /*-
2 * Copyright (c) 1991 The Regents of the University of California.
3 * 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 #ifndef lint
35 static char sccsid[] = "@(#)rec_seq.c 5.9 (Berkeley) 5/16/93";
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.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 switch(flags) {
73 case R_CURSOR:
74 if ((nrec = *(recno_t *)key->data) == 0)
75 goto einval;
76 break;
77 case R_NEXT:
78 if (ISSET(t, B_SEQINIT)) {
79 nrec = t->bt_rcursor + 1;
80 break;
81 }
82 /* FALLTHROUGH */
83 case R_FIRST:
84 nrec = 1;
85 break;
86 case R_PREV:
87 if (ISSET(t, B_SEQINIT)) {
88 if ((nrec = t->bt_rcursor - 1) == 0)
89 return (RET_SPECIAL);
90 break;
91 }
92 /* FALLTHROUGH */
93 case R_LAST:
94 if (!ISSET(t, R_EOF | R_INMEM) &&
95 t->bt_irec(t, MAX_REC_NUMBER) == RET_ERROR)
96 return (RET_ERROR);
97 nrec = t->bt_nrecs;
98 break;
99 default:
100 einval: errno = EINVAL;
101 return (RET_ERROR);
102 }
103
104 if (t->bt_nrecs == 0 || nrec > t->bt_nrecs) {
105 if (!ISSET(t, R_EOF | R_INMEM) &&
106 (status = t->bt_irec(t, nrec)) != RET_SUCCESS)
107 return (status);
108 if (t->bt_nrecs == 0 || nrec > t->bt_nrecs)
109 return (RET_SPECIAL);
110 }
111
112 if ((e = __rec_search(t, nrec - 1, SEARCH)) == NULL)
113 return (RET_ERROR);
114
115 SET(t, B_SEQINIT);
116 t->bt_rcursor = nrec;
117
118 status = __rec_ret(t, e, nrec, key, data);
119
120 mpool_put(t->bt_mp, e->page, 0);
121 return (status);
122 }
123