Implemented AVL tree insertion

sandbox/btree/btree.c

@@ -1,15 +1,135 @@
-#include "include/socks/btree.h"
-#include <socks/bree.h>
+#include <socks/btree.h>
+#include <stddef.h>
+#include <stdlib.h>
 
-static void insert_fixup(btree_t *tree, btree_node_t *node)
+#define MAX(a, b) ((a) > (b) ? (a) : (b))
+#define MIN(a, b) ((a) < (b) ? (a) : (b))
+
+#define IS_LEFT_CHILD(p, c) ((p) && (c) && ((p)->b_left == (c)))
+#define IS_RIGHT_CHILD(p, c) ((p) && (c) && ((p)->b_right == (c)))
+
+static void rotate_left(btree_t *tree, btree_node_t *x)
 {
+	btree_node_t *y = x->b_right;
+	btree_node_t *p = x->b_parent;
 
+	if (y->b_left) {
+		y->b_left->b_parent = x;
+	}
+
+	x->b_right = y->b_left;
+
+	if (!p) {
+		tree->b_root = y;
+	} else if (x == p->b_left) {
+		p->b_left = y;
+	} else {
+		p->b_right = y;
+	}
+
+	x->b_parent = y;
+	y->b_left = x;
+	y->b_parent = p;
+
+	x->b_bfactor = x->b_bfactor - 1 - MAX(y->b_bfactor, 0);
+
+	p = y;
+
+	while (p) {
+	    p->b_bfactor = p->b_bfactor - 1 + MIN(y->b_bfactor, 0);
+	    x = p;
+	    p = p->b_parent;
+	}
+}
+
+static void rotate_right(btree_t *tree, btree_node_t *y)
+{
+	btree_node_t *x = y->b_left;
+	btree_node_t *p = y->b_parent;
+
+	if (x->b_right) {
+		x->b_right->b_parent = y;
+	}
+
+	y->b_left = x->b_right;
+
+	if (!p) {
+		tree->b_root = x;
+	} else if (x == p->b_left) {
+		p->b_left = x;
+	} else {
+		p->b_right = x;
+	}
+
+	y->b_parent = x;
+	x->b_right = y;
+	x->b_parent = p;
+
+	y->b_bfactor = y->b_bfactor + 1 - MIN(x->b_bfactor, 0);
+
+	p = x;
+	while (p) {
+	    p->b_bfactor = x->b_bfactor + 1 + MAX(y->b_bfactor, 0);
+	    y = p;
+	}
+}
+
+static void rotate_double_left(btree_t *tree, btree_node_t *z)
+{
+	btree_node_t *x = z->b_right;
+	btree_node_t *y = x->b_left;
+
+	rotate_right(tree, x);
+	rotate_left(tree, z);
+}
+
+static void rotate_double_right(btree_t *tree, btree_node_t *z)
+{
+	btree_node_t *x = z->b_left;
+	btree_node_t *y = x->b_right;
+
+	rotate_left(tree, x);
+	rotate_right(tree, z);
+}
+
+static void insert_fixup(btree_t *tree, btree_node_t *w)
+{
+	btree_node_t *z = NULL, *y = NULL, *x = NULL;
+	
+	z = w;
+	while (z) {
+		if (z->b_bfactor >= -1 && z->b_bfactor <= 1) {
+			goto next_ancestor;
+		}
+
+
+		if (IS_LEFT_CHILD(z, y)) {
+			if (IS_LEFT_CHILD(y, x)) {
+			    rotate_right(tree, z);
+			} else {
+			    rotate_double_right(tree, z);
+			}
+		} else {
+			if (IS_LEFT_CHILD(y, x)) {
+			    rotate_double_left(tree, z);
+			} else {
+			    rotate_left(tree, z);
+			}
+		}
+
+
+next_ancestor:
+		x = y;
+		y = z;
+		z = z->b_parent;
+	}
 }
 
 void btree_insert(btree_t *tree, btree_node_t *node)
 {
 	if (!tree->b_root) {
 		tree->b_root = node;
+		node->b_parent = NULL;
 		return;
 	}
 
@@ -17,21 +137,31 @@ void btree_insert(btree_t *tree, btree_node_t *node)
 	while (1) {
 		btree_node_t **nextp = NULL;
 		
+		int bfactor_diff = 0;
 		if (node->b_key >= cur->b_key) {
 			nextp = &cur->b_right;
+			bfactor_diff = 1;
 		} else {
 			nextp = &cur->b_left;
+			bfactor_diff = -1;
 		}
 
+		cur->b_bfactor = cur->b_bfactor + bfactor_diff;
+
 		if (*nextp) {
 			cur = *nextp;
 		} else {
+			node->b_parent = cur;
 			*nextp = node;
 			break;
 		}
 	}
 
+	node->b_bfactor = 0;
 	insert_fixup(tree, node);
 }
 
-void btree_delete(btree_t *tree, btree_node_t *node) {}
+void btree_delete(btree_t *tree, btree_node_t *node)
+{
+  
+}

sandbox/btree/include/socks/btree.h

@@ -6,7 +6,7 @@
 typedef uint64_t btree_key_t;
 
 typedef struct btree_node {
-	struct btree_node *b_left, *b_right;
+	struct btree_node *b_parent, *b_left, *b_right;
 	signed char b_bfactor;
 	btree_key_t b_key;
 } btree_node_t;