Add a very simple red-black tree implementation

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

1 files changed, 63 insertions, 0 deletions

diff --git a/include/rbtree.h b/include/rbtree.h
new file mode 100644
index 0000000..7fe1752
--- /dev/null
+++ b/include/rbtree.h
@@ -0,0 +1,63 @@
+/* SPDX-License-Identifier: LGPL-3.0-or-later */
+/*
+ * rbtree.h
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#ifndef SQFS_RBTREE_H
+#define SQFS_RBTREE_H
+
+#include "config.h"
+#include "sqfs/predef.h"
+#include "compat.h"
+
+#include <stddef.h>
+
+typedef struct rbtree_node_t {
+	struct rbtree_node_t *left;
+	struct rbtree_node_t *right;
+	sqfs_u32 value_offset;
+	sqfs_u32 is_red : 1;
+	sqfs_u32 pad0 : 31;
+
+	sqfs_u8 data[];
+} rbtree_node_t;
+
+typedef struct rbtree_t {
+	rbtree_node_t *root;
+
+	int (*key_compare)(const void *lhs, const void *hrs);
+
+	size_t key_size;
+	size_t key_size_padded;
+
+	size_t value_size;
+} rbtree_t;
+
+static SQFS_INLINE void *rbtree_node_key(rbtree_node_t *n)
+{
+	return n->data;
+}
+
+static SQFS_INLINE void *rbtree_node_value(rbtree_node_t *n)
+{
+	return n->data + n->value_offset;
+}
+
+SQFS_INTERNAL int rbtree_init(rbtree_t *tree, size_t keysize, size_t valuesize,
+			      int(*key_compare)(const void *, const void *));
+
+SQFS_INTERNAL void rbtree_cleanup(rbtree_t *tree);
+
+SQFS_INTERNAL int rbtree_insert(rbtree_t *tree, const void *key,
+				const void *value);
+
+SQFS_INTERNAL rbtree_node_t *rbtree_lookup(const rbtree_t *tree,
+					   const void *key);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* TOOLS_RBTREE_H */
+