# HG changeset patch
# Parent ff6ad274f8ecb1715d366ddb53ecafd422252660
do not insert new node if the whole range was shifted

diff -r ff6ad274f8ec include/mdds/flat_segment_tree_def.inl
--- misc/mdds_0.3.0/inc/mdds/flat_segment_tree.hpp	Thu Mar 24 14:54:16 2011 +0100
+++ misc/build/mdds_0.3.0/inc/mdds/flat_segment_tree.hpp	Thu Mar 24 14:55:26 2011 +0100
@@ -430,16 +430,25 @@
 
         if (m_left_leaf->value_leaf.value != m_init_val)
         {
-            // The leftmost leaf node has a non-initial value.  We need to
-            // insert a new node to carry that value after the shift.
-            node_ptr new_node(new node(true));
-            new_node->value_leaf.key = pos + size;
-            new_node->value_leaf.value = m_left_leaf->value_leaf.value;
-            m_left_leaf->value_leaf.value = m_init_val;
-            new_node->left = m_left_leaf;
-            new_node->right = m_left_leaf->right;
-            m_left_leaf->right->left = new_node;
-            m_left_leaf->right = new_node;
+            if (size < m_right_leaf->value_leaf.key - m_left_leaf->value_leaf.key)
+            {
+                // The leftmost leaf node has a non-initial value.  We need to
+                // insert a new node to carry that value after the shift.
+                node_ptr new_node(new node(true));
+                new_node->value_leaf.key = pos + size;
+                new_node->value_leaf.value = m_left_leaf->value_leaf.value;
+                m_left_leaf->value_leaf.value = m_init_val;
+                new_node->left = m_left_leaf;
+                new_node->right = m_left_leaf->right;
+                m_left_leaf->right->left = new_node;
+                m_left_leaf->right = new_node;
+            }
+            else
+            {
+                // We shifted out the whole range, so there would be no new
+                // node inserted. Just set default value.
+                m_left_leaf->value_leaf.value = m_init_val;
+            }
         }
 
         m_valid_tree = false;