xref: /csrg-svn/lib/libc/gen/seekdir.c (revision 26583)
121358Sdist /*
221358Sdist  * Copyright (c) 1983 Regents of the University of California.
321358Sdist  * All rights reserved.  The Berkeley software License Agreement
421358Sdist  * specifies the terms and conditions for redistribution.
521358Sdist  */
621358Sdist 
7*26583Sdonn #if defined(LIBC_SCCS) && !defined(lint)
8*26583Sdonn static char sccsid[] = "@(#)seekdir.c	5.2 (Berkeley) 03/09/86";
9*26583Sdonn #endif LIBC_SCCS and not lint
105752Smckusick 
116370Smckusic #include <sys/param.h>
1213582Ssam #include <sys/dir.h>
135752Smckusick 
145752Smckusick /*
155928Smckusic  * seek to an entry in a directory.
1611636Smckusick  * Only values returned by "telldir" should be passed to seekdir.
175752Smckusick  */
185752Smckusick void
195928Smckusic seekdir(dirp, loc)
205928Smckusic 	register DIR *dirp;
215928Smckusic 	long loc;
225752Smckusick {
235947Smckusic 	long curloc, base, offset;
245947Smckusic 	struct direct *dp;
2511718Smckusick 	extern long lseek();
265947Smckusic 
275947Smckusic 	curloc = telldir(dirp);
285947Smckusic 	if (loc == curloc)
295947Smckusic 		return;
305947Smckusic 	base = loc & ~(DIRBLKSIZ - 1);
315947Smckusic 	offset = loc & (DIRBLKSIZ - 1);
3211718Smckusick 	(void) lseek(dirp->dd_fd, base, 0);
335947Smckusic 	dirp->dd_loc = 0;
345947Smckusic 	while (dirp->dd_loc < offset) {
355947Smckusic 		dp = readdir(dirp);
365947Smckusic 		if (dp == NULL)
375947Smckusic 			return;
385947Smckusic 	}
395752Smckusick }
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