os_brew/os_seek.c

   1 /*-
   2  * See the file LICENSE for redistribution information.
   3  *
   4  * Copyright (c) 1997-2009 Oracle.  All rights reserved.
   5  *
   6  * $Id$
   7  */
   8
   9 #include "db_config.h"
  10
  11 #include "db_int.h"
  12
  13 /*
  14  * __os_seek --
  15  *      Seek to a page/byte offset in the file.
  16  */
  17 int
  18 __os_seek(env, fhp, pgno, pgsize, relative)
  19         ENV *env;
  20         DB_FH *fhp;
  21         db_pgno_t pgno;
  22         u_int32_t pgsize;
  23         u_int32_t relative;
  24 {
  25         off_t offset;
  26         int ret;
  27
  28 #if defined(HAVE_STATISTICS)
  29         ++fhp->seek_count;
  30 #endif
  31
  32         offset = (off_t)pgsize * pgno + relative;
  33
  34         /*
  35          * Use BREW's lseek function IFILE_Seek.  If the seek fails, the source
  36          * returns EBADSEEKPOS.
  37          */
  38         ret = IFILE_Seek(fhp->ifp, _SEEK_START, offset);
  39
  40         if (ret == SUCCESS) {
  41                 fhp->pgsize = pgsize;
  42                 fhp->pgno = pgno;
  43                 fhp->offset = relative;
  44                 ret = 0;
  45         } else {
  46                 __db_syserr(env, ret,
  47                     "seek: %lu: (%lu * %lu) + %lu", (u_long)offset,
  48                     (u_long)pgno, (u_long)pgsize, (u_long)relative);
  49                 ret = __os_posix_err(ret);
  50         }
  51
  52         return (ret);
  53 }