ualarm

[unix-history] / usr / src / lib / libc / gen / seekdir.c

/*
* Copyright (c) 1983 Regents of the University of California.
* All rights reserved.  The Berkeley software License Agreement
* specifies the terms and conditions for redistribution.
*/

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)seekdir.c   5.2 (Berkeley) %G%";
#endif LIBC_SCCS and not lint

#include <sys/param.h>
#include <sys/dir.h>

/*
* seek to an entry in a directory.
* Only values returned by "telldir" should be passed to seekdir.
*/
void
seekdir(dirp, loc)
       register DIR *dirp;
       long loc;
{
       long curloc, base, offset;
       struct direct *dp;
       extern long lseek();

       curloc = telldir(dirp);
       if (loc == curloc)
               return;
       base = loc & ~(DIRBLKSIZ - 1);
       offset = loc & (DIRBLKSIZ - 1);
       (void) lseek(dirp->dd_fd, base, 0);
       dirp->dd_loc = 0;
       while (dirp->dd_loc < offset) {
               dp = readdir(dirp);
               if (dp == NULL)
                       return;
       }
}