* Copyright (c) 1983 Regents of the University of California.
* %sccs.include.redist.c%
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid
[] = "@(#)telldir.c 5.8 (Berkeley) %G%";
#endif /* LIBC_SCCS and not lint */
* The option SINGLEUSE may be defined to say that a telldir
* cookie may be used only once before it is freed. This option
* is used to avoid having memory usage grow without bound.
* One of these structures is malloced to describe the current directory
* position each time telldir is called. It records the current magic
* cookie returned by getdirentries and the offset within the buffer
* associated with that return value.
struct ddloc
*loc_next
;/* next structure in list */
long loc_index
; /* key associated with structure */
long loc_seek
; /* magic cookie returned by getdirentries */
long loc_loc
; /* offset of entry in buffer */
#define NDIRHASH 32 /* Num of hash lists, must be a power of 2 */
#define LOCHASH(i) ((i)&(NDIRHASH-1))
static long dd_loccnt
; /* Index of entry for sequential readdir's */
static struct ddloc
*dd_hash
[NDIRHASH
]; /* Hash list heads for ddlocs */
* return a pointer into a directory
register struct ddloc
*lp
;
if ((lp
= (struct ddloc
*)malloc(sizeof(struct ddloc
))) == NULL
)
lp
->loc_seek
= dirp
->dd_seek
;
lp
->loc_loc
= dirp
->dd_loc
;
lp
->loc_next
= dd_hash
[LOCHASH(index
)];
dd_hash
[LOCHASH(index
)] = lp
;
* seek to an entry in a directory.
* Only values returned by "telldir" should be passed to seekdir.
register struct ddloc
*lp
;
register struct ddloc
**prevlp
;
prevlp
= &dd_hash
[LOCHASH(loc
)];
if (lp
->loc_index
== loc
)
if (lp
->loc_loc
== dirp
->dd_loc
&& lp
->loc_seek
== dirp
->dd_seek
)
(void) lseek(dirp
->dd_fd
, lp
->loc_seek
, 0);
dirp
->dd_seek
= lp
->loc_seek
;
while (dirp
->dd_loc
< lp
->loc_loc
) {