db2/os/os_seek.c

   1 /*-
   2  * See the file LICENSE for redistribution information.
   3  *
   4  * Copyright (c) 1997, 1998
   5  *      Sleepycat Software.  All rights reserved.
   6  */
   7
   8 #include "config.h"
   9
  10 #ifndef lint
  11 static const char sccsid[] = "@(#)os_seek.c     10.9 (Sleepycat) 4/19/98";
  12 #endif /* not lint */
  13
  14 #ifndef NO_SYSTEM_INCLUDES
  15 #include <sys/types.h>
  16
  17 #include <errno.h>
  18 #include <unistd.h>
  19 #endif
  20
  21 #include "db_int.h"
  22
  23 /*
  24  * __os_seek --
  25  *      Seek to a page/byte offset in the file.
  26  *
  27  * PUBLIC: int __os_seek __P((int, size_t, db_pgno_t, u_int32_t, int, int));
  28  */
  29 int
  30 __os_seek(fd, pgsize, pageno, relative, isrewind, whence)
  31         int fd;
  32         size_t pgsize;
  33         db_pgno_t pageno;
  34         u_int32_t relative;
  35         int isrewind, whence;
  36 {
  37         off_t offset;
  38
  39         offset = (off_t)pgsize * pageno + relative;
  40         if (isrewind)
  41                 offset = -offset;
  42
  43         return (lseek(fd, offset, whence) == -1 ? errno : 0);
  44 }