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  * 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 #include <sys/cdefs.h>
  35 #ifndef lint
  36 /* XXX use __SCCSID */
  37 static char sccsid[] __unused = "@(#)rec_seq.c  8.3 (Berkeley) 7/14/94";
  38 #endif /* not lint */
  39 __FBSDID("$FreeBSD: src/lib/libc/db/recno/rec_seq.c,v 1.5 2003/02/16 17:29:09 nectar Exp $");
  40
  41 #include <sys/types.h>
  42
  43 #include <errno.h>
  44 #include <limits.h>
  45 #include <stdio.h>
  46 #include <string.h>
  47
  48 #include <db.h>
  49 #include "recno.h"
  50
  51 /*
  52  * __REC_SEQ -- Recno sequential scan interface.
  53  *
  54  * Parameters:
  55  *      dbp:    pointer to access method
  56  *      key:    key for positioning and return value
  57  *      data:   data return value
  58  *      flags:  R_CURSOR, R_FIRST, R_LAST, R_NEXT, R_PREV.
  59  *
  60  * Returns:
  61  *      RET_ERROR, RET_SUCCESS or RET_SPECIAL if there's no next key.
  62  */
  63 int
  64 __rec_seq(dbp, key, data, flags)
  65         const DB *dbp;
  66         DBT *key, *data;
  67         u_int flags;
  68 {
  69         BTREE *t;
  70         EPG *e;
  71         recno_t nrec;
  72         int status;
  73
  74         t = dbp->internal;
  75
  76         /* Toss any page pinned across calls. */
  77         if (t->bt_pinned != NULL) {
  78                 mpool_put(t->bt_mp, t->bt_pinned, 0);
  79                 t->bt_pinned = NULL;
  80         }
  81
  82         switch(flags) {
  83         case R_CURSOR:
  84                 if ((nrec = *(recno_t *)key->data) == 0)
  85                         goto einval;
  86                 break;
  87         case R_NEXT:
  88                 if (F_ISSET(&t->bt_cursor, CURS_INIT)) {
  89                         nrec = t->bt_cursor.rcursor + 1;
  90                         break;
  91                 }
  92                 /* FALLTHROUGH */
  93         case R_FIRST:
  94                 nrec = 1;
  95                 break;
  96         case R_PREV:
  97                 if (F_ISSET(&t->bt_cursor, CURS_INIT)) {
  98                         if ((nrec = t->bt_cursor.rcursor - 1) == 0)
  99                                 return (RET_SPECIAL);
 100                         break;
 101                 }
 102                 /* FALLTHROUGH */
 103         case R_LAST:
 104                 if (!F_ISSET(t, R_EOF | R_INMEM) &&
 105                     t->bt_irec(t, MAX_REC_NUMBER) == RET_ERROR)
 106                         return (RET_ERROR);
 107                 nrec = t->bt_nrecs;
 108                 break;
 109         default:
 110 einval:         errno = EINVAL;
 111                 return (RET_ERROR);
 112         }
 113
 114         if (t->bt_nrecs == 0 || nrec > t->bt_nrecs) {
 115                 if (!F_ISSET(t, R_EOF | R_INMEM) &&
 116                     (status = t->bt_irec(t, nrec)) != RET_SUCCESS)
 117                         return (status);
 118                 if (t->bt_nrecs == 0 || nrec > t->bt_nrecs)
 119                         return (RET_SPECIAL);
 120         }
 121
 122         if ((e = __rec_search(t, nrec - 1, SEARCH)) == NULL)
 123                 return (RET_ERROR);
 124
 125         F_SET(&t->bt_cursor, CURS_INIT);
 126         t->bt_cursor.rcursor = nrec;
 127
 128         status = __rec_ret(t, e, nrec, key, data);
 129         if (F_ISSET(t, B_DB_LOCK))
 130                 mpool_put(t->bt_mp, e->page, 0);
 131         else
 132                 t->bt_pinned = e->page;
 133         return (status);
 134 }