vlc_tdestroy: safe replacement for GNU tdestroy()

[vlc] / src / extras / tdestroy.c

diff --git a/src/extras/tdestroy.c b/src/extras/tdestroy.c
new file mode 100644 (file)
index 0000000..aeb43bb
--- /dev/null
+++ b/src/extras/tdestroy.c
@@ -0,0 +1,117 @@
+/**
+ * @file tdestroy.c
+ * @brief replacement for GNU tdestroy()
+ */
+/*****************************************************************************
+ * Copyright (C) 2009 Rémi Denis-Courmont
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2.1 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
+ *****************************************************************************/
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <stdlib.h>
+#include <assert.h>
+
+#include <vlc_common.h>
+
+#ifdef HAVE_TDESTROY
+void vlc_tdestroy (void *root, void (*freenode) (void *))
+{
+    (void) root;
+    assert (freenode != NULL);
+    abort ();
+}
+
+#else
+#include <search.h>
+
+static struct
+{
+    const void **tab;
+    size_t count;
+    vlc_mutex_t lock;
+} list = { NULL, 0, VLC_STATIC_MUTEX };
+
+static void list_nodes (const void *node, const VISIT which, const int depth)
+{
+    (void) depth;
+
+    if (which != postorder && which != leaf)
+        return;
+
+    const void **tab = realloc (list.tab, sizeof (*tab) * (list.count + 1));
+    if (unlikely(tab == NULL))
+        abort ();
+
+    tab[list.count] = *(const void **)node;
+    list.tab = tab;
+    list.count++;
+}
+
+static struct
+{
+    const void *node;
+    vlc_mutex_t lock;
+} smallest = { NULL, VLC_STATIC_MUTEX };
+
+static int cmp_smallest (const void *a, const void *b)
+{
+    if (a == b)
+        return 0;
+    if (a == smallest.node)
+        return -1;
+    if (likely(b == smallest.node))
+        return +1;
+    abort ();
+}
+
+void vlc_tdestroy (void *root, void (*freenode) (void *))
+{
+    const void **tab;
+    size_t count;
+
+    assert (freenode != NULL);
+
+    /* Enumerate nodes in order */
+    vlc_mutex_lock (&list.lock);
+    assert (list.count == 0);
+    twalk (root, list_nodes);
+    tab = list.tab;
+    count = list.count;
+    list.tab = NULL;
+    list.count = 0;
+    vlc_mutex_unlock (&list.lock);
+
+    /* Destroy the tree */
+    vlc_mutex_lock (&smallest.lock);
+    for (size_t i = 0; i < count; i++)
+    {
+         smallest.node = tab[i];
+         if (tdelete (smallest.node, &root, cmp_smallest) == NULL)
+             abort ();
+    }
+    vlc_mutex_unlock (&smallest.lock);
+    assert (root == NULL);
+
+    /* Destroy the nodes */
+    for (size_t i = 0; i < count; i++)
+         freenode ((void *)(tab[i]));
+    free (tab);
+}
+
+#endif