usr/src/lib/libc/gen/seekdir.c

#ifndef lint
static char sccsid[] = "@(#)seekdir.c   4.10 (Berkeley) %G%";
#endif

#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;
        }
}