Redblack: Added search_up

diff --git a/ucw/redblack.h b/ucw/redblack.h
index ece0d079304c42c17bb0e658dc245f23f31e4294..a77ee777e24ee74c58bd07b91928f9f1bad80d9e 100644 (file)
--- a/ucw/redblack.h
+++ b/ucw/redblack.h
@@ -71,6 +71,9 @@
  *  TREE_WANT_SEARCH_DOWN node *search_down(key) -- find either the node with
  *                      specified value, or if it does not exist, the node
  *                      with nearest smaller value.
+ *  TREE_WANT_SEARCH_UP        node *search_up(key) -- find either the node with
+ *                      specified value, or if it does not exist, the node
+ *                      with nearest greater value.
  *  TREE_WANT_BOUNDARY node *boundary(uint direction) -- finds smallest
  *                     (direction==0) or largest (direction==1) node.
  *  TREE_WANT_ADJACENT node *adjacent(node *, uint direction) -- finds next
@@ -480,6 +483,29 @@ TREE_STATIC P(node) * P(search_down) (T *t, TREE_KEY_DECL)
 }
 #endif
 
+#ifdef TREE_WANT_SEARCH_UP
+TREE_STATIC P(node) * P(search_up) (T *t, TREE_KEY_DECL)
+{
+       P(node) *last_left=NULL;
+       P(bucket) *node=t->root;
+       while(node)
+       {
+               int cmp;
+               cmp = P(cmp) (TREE_KEY(), TREE_KEY(node->n.));
+               if (cmp == 0)
+                       return &node->n;
+               else if (cmp > 0)
+                       node=P(tree_son) (node, 1);
+               else
+               {
+                       last_left=&node->n;
+                       node=P(tree_son) (node, 0);
+               }
+       }
+       return last_left;
+}
+#endif
+
 #ifdef TREE_WANT_BOUNDARY
 TREE_STATIC P(node) * P(boundary) (T *t, uint direction)
 {
@@ -1053,6 +1079,7 @@ do                                                                                        \
 #undef TREE_WANT_FIND_NEXT
 #undef TREE_WANT_SEARCH
 #undef TREE_WANT_SEARCH_DOWN
+#undef TREE_WANT_SEARCH_UP
 #undef TREE_WANT_BOUNDARY
 #undef TREE_WANT_ADJACENT
 #undef TREE_WANT_NEW