2 * Copyright (c) 1983, 1993
3 * The Regents of the University of California. All rights reserved.
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15 * This product includes software developed by the University of
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33 * $FreeBSD: src/lib/libc/gen/telldir.c,v 1.4.12.1 2001/03/05 09:39:59 obrien Exp $
34 * $DragonFly: src/lib/libcr/gen/Attic/telldir.c,v 1.2 2003/06/17 04:26:42 dillon Exp $
36 * @(#)telldir.c 8.1 (Berkeley) 6/4/93
39 #include <sys/param.h>
45 * The option SINGLEUSE may be defined to say that a telldir
46 * cookie may be used only once before it is freed. This option
47 * is used to avoid having memory usage grow without bound.
52 * One of these structures is malloced to describe the current directory
53 * position each time telldir is called. It records the current magic
54 * cookie returned by getdirentries and the offset within the buffer
55 * associated with that return value.
58 struct ddloc *loc_next;/* next structure in list */
59 long loc_index; /* key associated with structure */
60 long loc_seek; /* magic cookie returned by getdirentries */
61 long loc_loc; /* offset of entry in buffer */
62 const DIR* loc_dirp; /* directory which used this entry */
65 #define NDIRHASH 32 /* Num of hash lists, must be a power of 2 */
66 #define LOCHASH(i) ((i)&(NDIRHASH-1))
68 static long dd_loccnt; /* Index of entry for sequential readdir's */
69 static struct ddloc *dd_hash[NDIRHASH]; /* Hash list heads for ddlocs */
72 * return a pointer into a directory
81 if ((lp = (struct ddloc *)malloc(sizeof(struct ddloc))) == NULL)
84 lp->loc_index = index;
85 lp->loc_seek = dirp->dd_seek;
86 lp->loc_loc = dirp->dd_loc;
88 lp->loc_next = dd_hash[LOCHASH(index)];
89 dd_hash[LOCHASH(index)] = lp;
94 * seek to an entry in a directory.
95 * Only values returned by "telldir" should be passed to seekdir.
103 struct ddloc **prevlp;
106 prevlp = &dd_hash[LOCHASH(loc)];
109 if (lp->loc_index == loc)
111 prevlp = &lp->loc_next;
116 if (lp->loc_loc == dirp->dd_loc && lp->loc_seek == dirp->dd_seek)
118 (void) lseek(dirp->dd_fd, (off_t)lp->loc_seek, SEEK_SET);
119 dirp->dd_seek = lp->loc_seek;
121 while (dirp->dd_loc < lp->loc_loc) {
128 *prevlp = lp->loc_next;
134 * Reclaim memory for telldir cookies which weren't used.
137 _reclaim_telldir(dirp)
141 struct ddloc **prevlp;
144 for (i = 0; i < NDIRHASH; i++) {
145 prevlp = &dd_hash[i];
148 if (lp->loc_dirp == dirp) {
149 *prevlp = lp->loc_next;
154 prevlp = &lp->loc_next;