diplodocus.org Git - nmh/blob - docs/historical/mh-6.8.5/miscellany/libndir/seekdir.c

   1 static char sccsid[] = "@(#)seekdir.c 4.9 3/25/83";
   2
   3 #include <sys/param.h>
   4 #include <dir.h>
   5
   6 /*
   7  * seek to an entry in a directory.
   8  * Only values returned by "telldir" should be passed to seekdir.
   9  */
  10 void
  11 seekdir(dirp, loc)
  12         register DIR *dirp;
  13         long loc;
  14 {
  15         long curloc, base, offset;
  16         struct direct *dp;
  17         extern long lseek();
  18
  19         curloc = telldir(dirp);
  20         if (loc == curloc)
  21                 return;
  22         base = loc & ~(DIRBLKSIZ - 1);
  23         offset = loc & (DIRBLKSIZ - 1);
  24         (void) lseek(dirp->dd_fd, base, 0);
  25         dirp->dd_loc = 0;
  26         while (dirp->dd_loc < offset) {
  27                 dp = readdir(dirp);
  28                 if (dp == NULL)
  29                         return;
  30         }
  31 }