usr/src/lib/libast/common/dir/seekdir.c

   1 /***********************************************************************
   2 *                                                                      *
   3 *               This software is part of the ast package               *
   4 *          Copyright (c) 1985-2010 AT&T Intellectual Property          *
   5 *                      and is licensed under the                       *
   6 *                  Common Public License, Version 1.0                  *
   7 *                    by AT&T Intellectual Property                     *
   8 *                                                                      *
   9 *                A copy of the License is available at                 *
  10 *            http://www.opensource.org/licenses/cpl1.0.txt             *
  11 *         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
  12 *                                                                      *
  13 *              Information and Software Systems Research               *
  14 *                            AT&T Research                             *
  15 *                           Florham Park NJ                            *
  16 *                                                                      *
  17 *                 Glenn Fowler <gsf@research.att.com>                  *
  18 *                  David Korn <dgk@research.att.com>                   *
  19 *                   Phong Vo <kpv@research.att.com>                    *
  20 *                                                                      *
  21 ***********************************************************************/
  22 #pragma prototyped
  23
  24 /*
  25  * seekdir
  26  *
  27  * seek on directory stream
  28  * this is not optimal because there aren't portable
  29  * semantics for directory seeks
  30  */
  31
  32 #include "dirlib.h"
  33
  34 #if _dir_ok
  35
  36 NoN(seekdir)
  37
  38 #else
  39
  40 void
  41 seekdir(register DIR* dirp, long loc)
  42 {
  43         off_t   base;           /* file location of block */
  44         off_t   offset;         /* offset within block */
  45
  46         if (telldir(dirp) != loc)
  47         {
  48                 lseek(dirp->dd_fd, 0L, SEEK_SET);
  49                 dirp->dd_loc = dirp->dd_size = 0;
  50                 while (telldir(dirp) != loc)
  51                         if (!readdir(dirp))
  52                                 break;  /* "can't happen" */
  53         }
  54 }
  55
  56 #endif