1 files changed, 93 insertions, 0 deletions
diff --git a/sysdeps/unix/bsd/telldir.c b/sysdeps/unix/bsd/telldir.c
new file mode 100644
index 0000000000..0321f954b8
--- /dev/null
+++ b/sysdeps/unix/bsd/telldir.c
@@ -0,0 +1,93 @@
+/* Copyright (C) 1994 Free Software Foundation, Inc.
+This file is part of the GNU C Library.
+
+The GNU C Library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Library General Public License as
+published by the Free Software Foundation; either version 2 of the
+License, or (at your option) any later version.
+
+The GNU C Library is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB.  If
+not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA.  */
+
+#include <ansidecl.h>
+#include <errno.h>
+#include <stddef.h>
+#include <dirent.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <stdlib.h>
+
+/* Internal data structure for telldir and seekdir.  */
+struct record
+  {
+    struct record *next; /* Link in chain.  */
+    off_t cookie;		/* Value returned by `telldir'.  */
+    off_t pos;
+    size_t offset;
+  };
+#define NBUCKETS 32
+static struct record *records[32];
+static off_t lastpos;
+
+
+/* Return the current position of DIRP.  */
+off_t
+DEFUN(telldir, (dirp), DIR *dirp)
+{
+  struct record *new;
+
+  new = malloc (sizeof *new);
+  if (new == NULL)
+    return (off_t) -1;
+
+  new->pos = dirp->__pos;
+  new->offset = dirp->__offset;
+  new->cookie = ++lastpos;
+  new->next = records[new->cookie % NBUCKETS];
+  records[new->cookie % NBUCKETS] = new;
+
+  return new->cookie;
+}
+
+
+
+/* Seek to position POS in DIRP.  */
+void
+DEFUN(seekdir, (dirp, pos), DIR *dirp AND __off_t pos)
+{
+  struct record *r, **prevr;
+
+  for (prevr = &records[pos % NBUCKETS], r = *prevr;
+       r != NULL;
+       prevr = &r->next, r = r->next)
+    if (r->cookie == pos)
+      {
+	if (dirp->__pos != r->pos || dirp->__offset != r->offset)
+	  {
+	    dirp->__size = 0;	/* Must read a fresh buffer.  */
+	    /* Move to the saved position.  */
+	    __lseek (dirp->__fd, r->pos, SEEK_SET);
+	    dirp->__pos = r->pos;
+	    dirp->__offset = 0;
+	    /* Read entries until we reach the saved offset.  */
+	    while (dirp->__offset < r->offset)
+	      if (readdir (dirp) == NULL)
+		break;
+	  }
+
+	/* To prevent leaking memory, cookies returned from telldir
+	   can only be used once.  So free this one's record now.  */
+	*prevr = r->next;
+	free (r);
+	return;
+      }
+
+  /* We lost, but have no way to indicate it.  Oh well.  */
+}