Changeset 296cc1b in mainline for generic/src/adt/btree.c

Timestamp:

2006-03-30T18:39:21Z (19 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

ca687ad

Parents:

ff75d34

Message:

Change B+-tree from 2-3-4 tree to 2-3-4-5 tree by adding space for the fourth key.
This should make key removal easier.

File:

• generic/src/adt/btree.c (modified) (3 diffs)

generic/src/adt/btree.c

@@ -29 +29 @@
 /*
  * This B-tree has the following properties:
- * - it is a ballanced 2-3-4 tree (i.e. BTREE_M = 4)
+ * - it is a ballanced 2-3-4-5 tree (i.e. BTREE_M = 5)
  * - values (i.e. pointers to values) are stored only in leaves
  * - leaves are linked in a list
@@ -61 +61 @@
 #define INDEX_NODE(n)           ((n)->subtree[0] != NULL)
 #define LEAF_NODE(n)            ((n)->subtree[0] == NULL)
+
+#define FILL_FACTOR             ((BTREE_M-1)/2)
 
 #define MEDIAN_LOW_INDEX(n)     (((n)->keys-1)/2)
@@ -172 +174 @@
 }
 
-/* TODO */
-void btree_remove(btree_t *t, __native key)
-{
+/** Remove B-tree node.
+ *
+ * @param B-tree.
+ * @param key Key to be removed from the B-tree along with its associated value.
+ * @param leaf_node If not NULL, pointer to the leaf node where the key is found.
+ */
+void btree_remove(btree_t *t, __native key, btree_node_t *leaf_node)
+{
+        btree_node_t *lnode;
+        
+        lnode = leaf_node;
+        if (!lnode) {
+                if (!btree_search(t, key, &lnode)) {
+                        panic("B-tree %P does not contain key %d\n", t, key);
+                }
+        }
+        
+        /* TODO */
+
 }