usr/src/cmd/sendmail/db/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     10.11 (Sleepycat) 10/12/98";
  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 #include "os_jump.h"
  23
  24 /*
  25  * __os_seek --
  26  *      Seek to a page/byte offset in the file.
  27  *
  28  * PUBLIC: int __os_seek __P((int, size_t, db_pgno_t, u_int32_t, int, int));
  29  */
  30 int
  31 __os_seek(fd, pgsize, pageno, relative, isrewind, whence)
  32         int fd;
  33         size_t pgsize;
  34         db_pgno_t pageno;
  35         u_int32_t relative;
  36         int isrewind, whence;
  37 {
  38         off_t offset;
  39         int ret;
  40
  41         if (__db_jump.j_seek != NULL)
  42                 ret = __db_jump.j_seek(fd,
  43                     pgsize, pageno, relative, isrewind, whence);
  44         else {
  45                 offset = (off_t)pgsize * pageno + relative;
  46                 if (isrewind)
  47                         offset = -offset;
  48
  49                 ret = lseek(fd, offset, whence);
  50         }
  51         return (ret == -1 ? errno : 0);
  52 }