kern: add radix tree library

Import a radix tree library from Richard Braun's librbraun.

* Makefile.am (clib_routines): Steal `__ffsdi2'.
* Makefrag.am (libkernel_a_SOURCES): Add new files.
* kern/rdxtree.c: New file.
* kern/rdxtree.h: Likewise.
* kern/rdxtree_i.h: Likewise.
* kern/startup.c (setup_main): Initialize radix tree library.

1 files changed, 66 insertions, 0 deletions

diff --git a/kern/rdxtree_i.h b/kern/rdxtree_i.h
new file mode 100644
index 00000000..1bd1f64a
--- /dev/null
+++ b/kern/rdxtree_i.h
@@ -0,0 +1,66 @@
+/*
+ * Copyright (c) 2013-2015 Richard Braun.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 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 General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *
+ * Upstream site with license notes :
+ * http://git.sceen.net/rbraun/librbraun.git/
+ */
+
+#ifndef _RDXTREE_I_H
+#define _RDXTREE_I_H
+
+/*
+ * Radix tree.
+ */
+struct rdxtree {
+    unsigned int height;
+    void *root;
+};
+
+/*
+ * Radix tree iterator.
+ *
+ * The node member refers to the node containing the current pointer, if any.
+ * The key member refers to the current pointer, and is valid if and only if
+ * rdxtree_walk() has been called at least once on the iterator.
+ */
+struct rdxtree_iter {
+    void *node;
+    rdxtree_key_t key;
+};
+
+/*
+ * Initialize an iterator.
+ */
+static inline void
+rdxtree_iter_init(struct rdxtree_iter *iter)
+{
+    iter->node = NULL;
+    iter->key = (rdxtree_key_t)-1;
+}
+
+int rdxtree_insert_common(struct rdxtree *tree, rdxtree_key_t key,
+                          void *ptr, void ***slotp);
+
+int rdxtree_insert_alloc_common(struct rdxtree *tree, void *ptr,
+                                rdxtree_key_t *keyp, void ***slotp);
+
+void * rdxtree_lookup_common(const struct rdxtree *tree, rdxtree_key_t key,
+                             int get_slot);
+
+void * rdxtree_walk(struct rdxtree *tree, struct rdxtree_iter *iter);
+
+#endif /* _RDXTREE_I_H */