db/recno/FreeBSD/rec_seq.c

   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: src/lib/libc/db/recno/rec_seq.c,v 1.8 2009/03/04 00:58:04 delphij Exp $");
  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(const DB *dbp, DBT *key, DBT *data, u_int flags)
  61 {
  62         BTREE *t;
  63         EPG *e;
  64         recno_t nrec;
  65         int status;
  66
  67         t = dbp->internal;
  68
  69         /* Toss any page pinned across calls. */
  70         if (t->bt_pinned != NULL) {
  71                 mpool_put(t->bt_mp, t->bt_pinned, 0);
  72                 t->bt_pinned = NULL;
  73         }
  74
  75         switch(flags) {
  76         case R_CURSOR:
  77                 if ((nrec = *(recno_t *)key->data) == 0)
  78                         goto einval;
  79                 break;
  80         case R_NEXT:
  81                 if (F_ISSET(&t->bt_cursor, CURS_INIT)) {
  82                         nrec = t->bt_cursor.rcursor + 1;
  83                         break;
  84                 }
  85                 /* FALLTHROUGH */
  86         case R_FIRST:
  87                 nrec = 1;
  88                 break;
  89         case R_PREV:
  90                 if (F_ISSET(&t->bt_cursor, CURS_INIT)) {
  91                         if ((nrec = t->bt_cursor.rcursor - 1) == 0)
  92                                 return (RET_SPECIAL);
  93                         break;
  94                 }
  95                 /* FALLTHROUGH */
  96         case R_LAST:
  97                 if (!F_ISSET(t, R_EOF | R_INMEM) &&
  98                     t->bt_irec(t, MAX_REC_NUMBER) == RET_ERROR)
  99                         return (RET_ERROR);
 100                 nrec = t->bt_nrecs;
 101                 break;
 102         default:
 103 einval:         errno = EINVAL;
 104                 return (RET_ERROR);
 105         }
 106
 107         if (t->bt_nrecs == 0 || nrec > t->bt_nrecs) {
 108                 if (!F_ISSET(t, R_EOF | R_INMEM) &&
 109                     (status = t->bt_irec(t, nrec)) != RET_SUCCESS)
 110                         return (status);
 111                 if (t->bt_nrecs == 0 || nrec > t->bt_nrecs)
 112                         return (RET_SPECIAL);
 113         }
 114
 115         if ((e = __rec_search(t, nrec - 1, SEARCH)) == NULL)
 116                 return (RET_ERROR);
 117
 118         F_SET(&t->bt_cursor, CURS_INIT);
 119         t->bt_cursor.rcursor = nrec;
 120
 121         status = __rec_ret(t, e, nrec, key, data);
 122         if (F_ISSET(t, B_DB_LOCK))
 123                 mpool_put(t->bt_mp, e->page, 0);
 124         else
 125                 t->bt_pinned = e->page;
 126         return (status);
 127 }