create a common function for the many places where all nodes in the table
[platform/upstream/glib.git] / glib / gtree.c
index aeeb467..8ae5e98 100644 (file)
  * MT safe
  */
 
+#include "config.h"
+
 #include "glib.h"
+#include "galias.h"
+
+#undef G_TREE_DEBUG
 
+#define MAX_GTREE_HEIGHT 40
 
-typedef struct _GRealTree  GRealTree;
 typedef struct _GTreeNode  GTreeNode;
 
-struct _GRealTree
+struct _GTree
 {
-  GTreeNode *root;
-  GCompareFuncData key_compare;
-  gpointer key_compare_data;
+  GTreeNode        *root;
+  GCompareDataFunc  key_compare;
+  GDestroyNotify    key_destroy_func;
+  GDestroyNotify    value_destroy_func;
+  gpointer          key_compare_data;
+  guint             nnodes;
 };
 
 struct _GTreeNode
 {
-  gint balance;      /* height (left) - height (right) */
-  GTreeNode *left;   /* left subtree */
-  GTreeNode *right;  /* right subtree */
-  gpointer key;      /* key for this node */
-  gpointer value;    /* value stored at this node */
+  gpointer   key;         /* key for this node */
+  gpointer   value;       /* value stored at this node */
+  GTreeNode *left;        /* left subtree */
+  GTreeNode *right;       /* right subtree */
+  gint8      balance;     /* height (left) - height (right) */
+  guint8     left_child;  
+  guint8     right_child;
 };
 
 
-static GTreeNode* g_tree_node_new                   (gpointer        key,
-                                                    gpointer        value);
-static void       g_tree_node_destroy               (GTreeNode      *node);
-static GTreeNode* g_tree_node_insert                (GTreeNode      *node,
-                                                    GCompareFuncData compare,
-                                                    gpointer        comp_data,
-                                                    gpointer        key,
-                                                    gpointer        value,
-                                                    gint           *inserted);
-static GTreeNode* g_tree_node_remove                (GTreeNode      *node,
-                                                    GCompareFuncData compare,
-                                                    gpointer        comp_data,
-                                                    gconstpointer   key);
-static GTreeNode* g_tree_node_balance               (GTreeNode      *node);
-static GTreeNode* g_tree_node_remove_leftmost       (GTreeNode      *node,
-                                                    GTreeNode     **leftmost);
-static GTreeNode* g_tree_node_restore_left_balance  (GTreeNode      *node,
-                                                    gint            old_balance);
-static GTreeNode* g_tree_node_restore_right_balance (GTreeNode      *node,
-                                                    gint            old_balance);
-static gpointer   g_tree_node_lookup                (GTreeNode      *node,
-                                                    GCompareFuncData compare,
-                                                    gpointer        comp_data,
-                                                    gconstpointer   key);
-static gint       g_tree_node_count                 (GTreeNode      *node);
-static gint       g_tree_node_pre_order             (GTreeNode      *node,
-                                                    GTraverseFunc   traverse_func,
-                                                    gpointer        data);
-static gint       g_tree_node_in_order              (GTreeNode      *node,
-                                                    GTraverseFunc   traverse_func,
-                                                    gpointer        data);
-static gint       g_tree_node_post_order            (GTreeNode      *node,
-                                                    GTraverseFunc   traverse_func,
-                                                    gpointer        data);
-static gpointer   g_tree_node_search                (GTreeNode      *node,
-                                                    GCompareFunc    search_func,
-                                                    gconstpointer   data);
-static gint       g_tree_node_height                (GTreeNode      *node);
-static GTreeNode* g_tree_node_rotate_left           (GTreeNode      *node);
-static GTreeNode* g_tree_node_rotate_right          (GTreeNode      *node);
-static void       g_tree_node_check                 (GTreeNode      *node);
-
-
-G_LOCK_DEFINE_STATIC (g_tree_global);
-static GMemChunk *node_mem_chunk = NULL;
-static GTreeNode *node_free_list = NULL;
+static GTreeNode* g_tree_node_new                   (gpointer       key,
+                                                    gpointer       value);
+static void       g_tree_insert_internal            (GTree         *tree,
+                                                    gpointer       key,
+                                                    gpointer       value,
+                                                    gboolean       replace);
+static gboolean   g_tree_remove_internal            (GTree         *tree,
+                                                    gconstpointer  key,
+                                                    gboolean       steal);
+static GTreeNode* g_tree_node_balance               (GTreeNode     *node);
+static GTreeNode *g_tree_find_node                  (GTree         *tree,
+                                                    gconstpointer  key);
+static gint       g_tree_node_pre_order             (GTreeNode     *node,
+                                                    GTraverseFunc  traverse_func,
+                                                    gpointer       data);
+static gint       g_tree_node_in_order              (GTreeNode     *node,
+                                                    GTraverseFunc  traverse_func,
+                                                    gpointer       data);
+static gint       g_tree_node_post_order            (GTreeNode     *node,
+                                                    GTraverseFunc  traverse_func,
+                                                    gpointer       data);
+static gpointer   g_tree_node_search                (GTreeNode     *node,
+                                                    GCompareFunc   search_func,
+                                                    gconstpointer  data);
+static GTreeNode* g_tree_node_rotate_left           (GTreeNode     *node);
+static GTreeNode* g_tree_node_rotate_right          (GTreeNode     *node);
+#ifdef G_TREE_DEBUG
+static void       g_tree_node_check                 (GTreeNode     *node);
+#endif
 
 
 static GTreeNode*
 g_tree_node_new (gpointer key,
                 gpointer value)
 {
-  GTreeNode *node;
-
-  G_LOCK (g_tree_global);
-  if (node_free_list)
-    {
-      node = node_free_list;
-      node_free_list = node->right;
-    }
-  else
-    {
-      if (!node_mem_chunk)
-       node_mem_chunk = g_mem_chunk_new ("GLib GTreeNode mem chunk",
-                                         sizeof (GTreeNode),
-                                         1024,
-                                         G_ALLOC_ONLY);
-
-      node = g_chunk_new (GTreeNode, node_mem_chunk);
-   }
-  G_UNLOCK (g_tree_global);
+  GTreeNode *node = g_slice_new (GTreeNode);
 
   node->balance = 0;
   node->left = NULL;
   node->right = NULL;
+  node->left_child = FALSE;
+  node->right_child = FALSE;
   node->key = key;
   node->value = value;
 
   return node;
 }
 
-static void
-g_tree_node_destroy (GTreeNode *node)
+/**
+ * g_tree_new:
+ * @key_compare_func: the function used to order the nodes in the #GTree.
+ *   It should return values similar to the standard strcmp() function -
+ *   0 if the two arguments are equal, a negative value if the first argument 
+ *   comes before the second, or a positive value if the first argument comes 
+ *   after the second.
+ * 
+ * Creates a new #GTree.
+ * 
+ * Return value: a new #GTree.
+ **/
+GTree*
+g_tree_new (GCompareFunc key_compare_func)
 {
-  if (node)
-    {
-      g_tree_node_destroy (node->right);
-      g_tree_node_destroy (node->left);
-
-#ifdef ENABLE_GC_FRIENDLY
-      node->left = NULL;
-      node->key = NULL;
-      node->value = NULL;
-#endif /* ENABLE_GC_FRIENDLY */
+  g_return_val_if_fail (key_compare_func != NULL, NULL);
 
-      G_LOCK (g_tree_global);
-      node->right = node_free_list;
-      node_free_list = node;
-      G_UNLOCK (g_tree_global);
-   }
+  return g_tree_new_full ((GCompareDataFunc) key_compare_func, NULL,
+                          NULL, NULL);
 }
 
-GTree*  g_tree_new_udata(GCompareFuncData key_compare_func,
-                          gpointer        key_compare_data)
+/**
+ * g_tree_new_with_data:
+ * @key_compare_func: qsort()-style comparison function.
+ * @key_compare_data: data to pass to comparison function.
+ * 
+ * Creates a new #GTree with a comparison function that accepts user data.
+ * See g_tree_new() for more details.
+ * 
+ * Return value: a new #GTree.
+ **/
+GTree*
+g_tree_new_with_data (GCompareDataFunc key_compare_func,
+                     gpointer         key_compare_data)
 {
-  GRealTree *rtree;
+  g_return_val_if_fail (key_compare_func != NULL, NULL);
+  
+  return g_tree_new_full (key_compare_func, key_compare_data, 
+                         NULL, NULL);
+}
 
+/**
+ * g_tree_new_full:
+ * @key_compare_func: qsort()-style comparison function.
+ * @key_compare_data: data to pass to comparison function.
+ * @key_destroy_func: a function to free the memory allocated for the key 
+ *   used when removing the entry from the #GTree or %NULL if you don't
+ *   want to supply such a function.
+ * @value_destroy_func: a function to free the memory allocated for the 
+ *   value used when removing the entry from the #GTree or %NULL if you 
+ *   don't want to supply such a function.
+ * 
+ * Creates a new #GTree like g_tree_new() and allows to specify functions 
+ * to free the memory allocated for the key and value that get called when 
+ * removing the entry from the #GTree.
+ * 
+ * Return value: a new #GTree.
+ **/
+GTree*  
+g_tree_new_full (GCompareDataFunc key_compare_func,
+                gpointer         key_compare_data,              
+                 GDestroyNotify   key_destroy_func,
+                GDestroyNotify   value_destroy_func)
+{
+  GTree *tree;
+  
   g_return_val_if_fail (key_compare_func != NULL, NULL);
+  
+  tree = g_new (GTree, 1);
+  tree->root               = NULL;
+  tree->key_compare        = key_compare_func;
+  tree->key_destroy_func   = key_destroy_func;
+  tree->value_destroy_func = value_destroy_func;
+  tree->key_compare_data   = key_compare_data;
+  tree->nnodes             = 0;
+  
+  return tree;
+}
 
-  rtree = g_new (GRealTree, 1);
-  rtree->root = NULL;
-  rtree->key_compare = key_compare_func;
-  rtree->key_compare_data = key_compare_data;
+static inline GTreeNode *
+g_tree_first_node (GTree *tree)
+{
+  GTreeNode *tmp;
 
-  return (GTree*) rtree;
-}
+  if (!tree->root)
+    return NULL;
 
-GTree*
-g_tree_new (GCompareFunc key_compare_func)
+  tmp = tree->root;
+
+  while (tmp->left_child)
+    tmp = tmp->left;
+
+  return tmp;
+} 
+
+static inline GTreeNode *
+g_tree_node_previous (GTreeNode *node)
 {
-  return g_tree_new_udata ((GCompareFuncData) key_compare_func, NULL);
+  GTreeNode *tmp;
+
+  tmp = node->left;
+
+  if (node->left_child)
+    while (tmp->right_child)
+      tmp = tmp->right;
+
+  return tmp;
 }
+                 
+static inline GTreeNode *
+g_tree_node_next (GTreeNode *node)
+{
+  GTreeNode *tmp;
+
+  tmp = node->right;
 
+  if (node->right_child)
+    while (tmp->left_child)
+      tmp = tmp->left;
 
+  return tmp;
+}
+                 
+/**
+ * g_tree_destroy:
+ * @tree: a #GTree.
+ * 
+ * Destroys the #GTree. If keys and/or values are dynamically allocated, you 
+ * should either free them first or create the #GTree using g_tree_new_full().
+ * In the latter case the destroy functions you supplied will be called on 
+ * all keys and values before destroying the #GTree.
+ **/
 void
 g_tree_destroy (GTree *tree)
 {
-  GRealTree *rtree;
+  GTreeNode *node;
+  GTreeNode *next;
 
   g_return_if_fail (tree != NULL);
 
-  rtree = (GRealTree*) tree;
+  node = g_tree_first_node (tree);
+  
+  while (node)
+    {
+      next = g_tree_node_next (node);
 
-  g_tree_node_destroy (rtree->root);
-  g_free (rtree);
+      if (tree->key_destroy_func)
+       tree->key_destroy_func (node->key);
+      if (tree->value_destroy_func)
+       tree->value_destroy_func (node->value);
+      g_slice_free (GTreeNode, node);
+
+      node = next;
+    }
+
+  g_free (tree);
 }
 
+/**
+ * g_tree_insert:
+ * @tree: a #GTree.
+ * @key: the key to insert.
+ * @value: the value corresponding to the key.
+ * 
+ * Inserts a key/value pair into a #GTree. If the given key already exists 
+ * in the #GTree its corresponding value is set to the new value. If you 
+ * supplied a value_destroy_func when creating the #GTree, the old value is 
+ * freed using that function. If you supplied a @key_destroy_func when 
+ * creating the #GTree, the passed key is freed using that function.
+ *
+ * The tree is automatically 'balanced' as new key/value pairs are added,
+ * so that the distance from the root to every leaf is as small as possible.
+ **/
 void
 g_tree_insert (GTree    *tree,
               gpointer  key,
               gpointer  value)
 {
-  GRealTree *rtree;
-  gint inserted;
-
   g_return_if_fail (tree != NULL);
 
-  rtree = (GRealTree*) tree;
+  g_tree_insert_internal (tree, key, value, FALSE);
 
-  inserted = FALSE;
-  rtree->root = g_tree_node_insert (rtree->root, rtree->key_compare,
-                                   rtree->key_compare_data,
-                                   key, value, &inserted);
+#ifdef G_TREE_DEBUG
+  g_tree_node_check (tree->root);
+#endif
 }
 
+/**
+ * g_tree_replace:
+ * @tree: a #GTree.
+ * @key: the key to insert.
+ * @value: the value corresponding to the key.
+ * 
+ * Inserts a new key and value into a #GTree similar to g_tree_insert(). 
+ * The difference is that if the key already exists in the #GTree, it gets 
+ * replaced by the new key. If you supplied a @value_destroy_func when 
+ * creating the #GTree, the old value is freed using that function. If you 
+ * supplied a @key_destroy_func when creating the #GTree, the old key is 
+ * freed using that function. 
+ *
+ * The tree is automatically 'balanced' as new key/value pairs are added,
+ * so that the distance from the root to every leaf is as small as possible.
+ **/
 void
+g_tree_replace (GTree    *tree,
+               gpointer  key,
+               gpointer  value)
+{
+  g_return_if_fail (tree != NULL);
+
+  g_tree_insert_internal (tree, key, value, TRUE);
+
+#ifdef G_TREE_DEBUG
+  g_tree_node_check (tree->root);
+#endif
+}
+
+/* internal insert routine */
+static void
+g_tree_insert_internal (GTree    *tree,
+                        gpointer  key,
+                        gpointer  value,
+                        gboolean  replace)
+{
+  GTreeNode *node;
+  GTreeNode *path[MAX_GTREE_HEIGHT];
+  int idx;
+
+  g_return_if_fail (tree != NULL);
+
+  if (!tree->root)
+    {
+      tree->root = g_tree_node_new (key, value);
+      tree->nnodes++;
+      return;
+    }
+
+  idx = 0;
+  path[idx++] = NULL;
+  node = tree->root;
+
+  while (1)
+    {
+      int cmp = tree->key_compare (key, node->key, tree->key_compare_data);
+      
+      if (cmp == 0)
+        {
+          if (tree->value_destroy_func)
+            tree->value_destroy_func (node->value);
+
+          node->value = value;
+
+          if (replace)
+            {
+              if (tree->key_destroy_func)
+                tree->key_destroy_func (node->key);
+
+              node->key = key;
+            }
+          else
+            {
+              /* free the passed key */
+              if (tree->key_destroy_func)
+                tree->key_destroy_func (key);
+            }
+
+          return;
+        }
+      else if (cmp < 0)
+        {
+          if (node->left_child)
+            {
+              path[idx++] = node;
+              node = node->left;
+            }
+          else
+            {
+              GTreeNode *child = g_tree_node_new (key, value);
+
+              child->left = node->left;
+              child->right = node;
+              node->left = child;
+              node->left_child = TRUE;
+              node->balance -= 1;
+
+             tree->nnodes++;
+
+              break;
+            }
+        }
+      else
+        {
+          if (node->right_child)
+            {
+              path[idx++] = node;
+              node = node->right;
+            }
+          else
+            {
+              GTreeNode *child = g_tree_node_new (key, value);
+
+              child->right = node->right;
+              child->left = node;
+              node->right = child;
+              node->right_child = TRUE;
+              node->balance += 1;
+
+             tree->nnodes++;
+
+              break;
+            }
+        }
+    }
+
+  /* restore balance. This is the goodness of a non-recursive
+     implementation, when we are done with balancing we 'break'
+     the loop and we are done. */
+  while (1)
+    {
+      GTreeNode *bparent = path[--idx];
+      gboolean left_node = (bparent && node == bparent->left);
+      g_assert (!bparent || bparent->left == node || bparent->right == node);
+
+      if (node->balance < -1 || node->balance > 1)
+        {
+          node = g_tree_node_balance (node);
+          if (bparent == NULL)
+            tree->root = node;
+          else if (left_node)
+            bparent->left = node;
+          else
+            bparent->right = node;
+        }
+
+      if (node->balance == 0 || bparent == NULL)
+        break;
+      
+      if (left_node)
+        bparent->balance -= 1;
+      else
+        bparent->balance += 1;
+
+      node = bparent;
+    }
+}
+
+/**
+ * g_tree_remove:
+ * @tree: a #GTree.
+ * @key: the key to remove.
+ * 
+ * Removes a key/value pair from a #GTree.
+ *
+ * If the #GTree was created using g_tree_new_full(), the key and value 
+ * are freed using the supplied destroy functions, otherwise you have to 
+ * make sure that any dynamically allocated values are freed yourself.
+ * If the key does not exist in the #GTree, the function does nothing.
+ *
+ * Returns: %TRUE if the key was found (prior to 2.8, this function returned 
+ *   nothing)
+ **/
+gboolean
 g_tree_remove (GTree         *tree,
               gconstpointer  key)
 {
-  GRealTree *rtree;
+  gboolean removed;
 
-  g_return_if_fail (tree != NULL);
+  g_return_val_if_fail (tree != NULL, FALSE);
+
+  removed = g_tree_remove_internal (tree, key, FALSE);
 
-  rtree = (GRealTree*) tree;
+#ifdef G_TREE_DEBUG
+  g_tree_node_check (tree->root);
+#endif
 
-  rtree->root = g_tree_node_remove (rtree->root, rtree->key_compare,
-                                    rtree->key_compare_data, key);
+  return removed;
 }
 
+/**
+ * g_tree_steal:
+ * @tree: a #GTree.
+ * @key: the key to remove.
+ * 
+ * Removes a key and its associated value from a #GTree without calling 
+ * the key and value destroy functions.
+ *
+ * If the key does not exist in the #GTree, the function does nothing.
+ *
+ * Returns: %TRUE if the key was found (prior to 2.8, this function returned 
+ *    nothing)
+ **/
+gboolean
+g_tree_steal (GTree         *tree,
+              gconstpointer  key)
+{
+  gboolean removed;
+
+  g_return_val_if_fail (tree != NULL, FALSE);
+
+  removed = g_tree_remove_internal (tree, key, TRUE);
+
+#ifdef G_TREE_DEBUG
+  g_tree_node_check (tree->root);
+#endif
+
+  return removed;
+}
+
+/* internal remove routine */
+static gboolean
+g_tree_remove_internal (GTree         *tree,
+                        gconstpointer  key,
+                        gboolean       steal)
+{
+  GTreeNode *node, *parent, *balance;
+  GTreeNode *path[MAX_GTREE_HEIGHT];
+  int idx;
+  gboolean left_node;
+
+  g_return_val_if_fail (tree != NULL, FALSE);
+
+  if (!tree->root)
+    return FALSE;
+
+  idx = 0;
+  path[idx++] = NULL;
+  node = tree->root;
+
+  while (1)
+    {
+      int cmp = tree->key_compare (key, node->key, tree->key_compare_data);
+      
+      if (cmp == 0)
+        break;
+      else if (cmp < 0)
+        {
+          if (!node->left_child)
+            return FALSE;
+         
+         path[idx++] = node;
+         node = node->left;
+        }
+      else
+        {
+          if (!node->right_child)
+            return FALSE;
+         
+         path[idx++] = node;
+         node = node->right;
+        }
+    }
+
+  /* the following code is almost equal to g_tree_remove_node,
+     except that we do not have to call g_tree_node_parent. */
+  balance = parent = path[--idx];
+  g_assert (!parent || parent->left == node || parent->right == node);
+  left_node = (parent && node == parent->left);
+
+  if (!node->left_child)
+    {
+      if (!node->right_child)
+        {
+          if (!parent)
+            tree->root = NULL;
+          else if (left_node)
+            {
+              parent->left_child = FALSE;
+              parent->left = node->left;
+              parent->balance += 1;
+            }
+          else
+            {
+              parent->right_child = FALSE;
+              parent->right = node->right;
+              parent->balance -= 1;
+            }
+        }
+      else /* node has a right child */
+        {
+          GTreeNode *tmp = g_tree_node_next (node);
+         tmp->left = node->left;
+
+          if (!parent)
+            tree->root = node->right;
+          else if (left_node)
+            {
+              parent->left = node->right;
+              parent->balance += 1;
+            }
+          else
+            {
+              parent->right = node->right;
+              parent->balance -= 1;
+            }
+        }
+    }
+  else /* node has a left child */
+    {
+      if (!node->right_child)
+        {
+          GTreeNode *tmp = g_tree_node_previous (node);
+          tmp->right = node->right;
+         
+          if (parent == NULL)
+            tree->root = node->left;
+          else if (left_node)
+            {
+              parent->left = node->left;
+              parent->balance += 1;
+            }
+          else
+            {
+              parent->right = node->left;
+              parent->balance -= 1;
+            }
+        }
+      else /* node has a both children (pant, pant!) */
+        {
+         GTreeNode *prev = node->left;
+         GTreeNode *next = node->right;
+         GTreeNode *nextp = node;
+         int old_idx = idx + 1;
+         idx++;
+         
+         /* path[idx] == parent */
+         /* find the immediately next node (and its parent) */
+         while (next->left_child)
+            {
+             path[++idx] = nextp = next;
+             next = next->left;
+            }
+         
+         path[old_idx] = next;
+         balance = path[idx];
+         
+         /* remove 'next' from the tree */
+         if (nextp != node)
+           {
+             if (next->right_child)
+               nextp->left = next->right;
+             else
+               nextp->left_child = FALSE;
+             nextp->balance += 1;
+             
+             next->right_child = TRUE;
+             next->right = node->right;
+           }
+         else
+           node->balance -= 1;
+           
+         /* set the prev to point to the right place */
+         while (prev->right_child)
+           prev = prev->right;
+         prev->right = next;
+           
+         /* prepare 'next' to replace 'node' */
+         next->left_child = TRUE;
+         next->left = node->left;
+         next->balance = node->balance;
+         
+         if (!parent)
+           tree->root = next;
+         else if (left_node)
+           parent->left = next;
+         else
+           parent->right = next;
+        }
+    }
+  
+  /* restore balance */
+  if (balance)
+    while (1)
+      {
+       GTreeNode *bparent = path[--idx];
+       g_assert (!bparent || bparent->left == balance || bparent->right == balance);
+       left_node = (bparent && balance == bparent->left);
+                             
+       if(balance->balance < -1 || balance->balance > 1)
+         {
+           balance = g_tree_node_balance (balance);
+           if (!bparent)
+             tree->root = balance;
+           else if (left_node)
+             bparent->left = balance;
+           else
+             bparent->right = balance;
+         }
+       
+       if (balance->balance != 0 || !bparent)
+         break;
+       
+       if (left_node)
+         bparent->balance += 1;
+       else
+         bparent->balance -= 1;
+       
+       balance = bparent;
+      }
+  
+  if (!steal)
+    {
+      if (tree->key_destroy_func)
+        tree->key_destroy_func (node->key);
+      if (tree->value_destroy_func)
+        tree->value_destroy_func (node->value);
+    }
+
+  g_slice_free (GTreeNode, node);
+
+  tree->nnodes--;
+
+  return TRUE;
+}
+
+/**
+ * g_tree_lookup:
+ * @tree: a #GTree.
+ * @key: the key to look up.
+ * 
+ * Gets the value corresponding to the given key. Since a #GTree is 
+ * automatically balanced as key/value pairs are added, key lookup is very 
+ * fast.
+ *
+ * Return value: the value corresponding to the key, or %NULL if the key was
+ * not found.
+ **/
 gpointer
 g_tree_lookup (GTree         *tree,
               gconstpointer  key)
 {
-  GRealTree *rtree;
+  GTreeNode *node;
 
   g_return_val_if_fail (tree != NULL, NULL);
 
-  rtree = (GRealTree*) tree;
+  node = g_tree_find_node (tree, key);
+  
+  return node ? node->value : NULL;
+}
+
+/**
+ * g_tree_lookup_extended:
+ * @tree: a #GTree.
+ * @lookup_key: the key to look up.
+ * @orig_key: returns the original key.
+ * @value: returns the value associated with the key.
+ * 
+ * Looks up a key in the #GTree, returning the original key and the
+ * associated value and a #gboolean which is %TRUE if the key was found. This 
+ * is useful if you need to free the memory allocated for the original key, 
+ * for example before calling g_tree_remove().
+ * 
+ * Return value: %TRUE if the key was found in the #GTree.
+ **/
+gboolean
+g_tree_lookup_extended (GTree         *tree,
+                        gconstpointer  lookup_key,
+                        gpointer      *orig_key,
+                        gpointer      *value)
+{
+  GTreeNode *node;
+  
+  g_return_val_if_fail (tree != NULL, FALSE);
+  
+  node = g_tree_find_node (tree, lookup_key);
+  
+  if (node)
+    {
+      if (orig_key)
+        *orig_key = node->key;
+      if (value)
+        *value = node->value;
+      return TRUE;
+    }
+  else
+    return FALSE;
+}
+
+/**
+ * g_tree_foreach:
+ * @tree: a #GTree.
+ * @func: the function to call for each node visited. If this function
+ *   returns %TRUE, the traversal is stopped.
+ * @user_data: user data to pass to the function.
+ * 
+ * Calls the given function for each of the key/value pairs in the #GTree.
+ * The function is passed the key and value of each pair, and the given
+ * @data parameter. The tree is traversed in sorted order.
+ *
+ * The tree may not be modified while iterating over it (you can't 
+ * add/remove items). To remove all items matching a predicate, you need 
+ * to add each item to a list in your #GTraverseFunc as you walk over 
+ * the tree, then walk the list and remove each item.
+ **/
+void
+g_tree_foreach (GTree         *tree,
+                GTraverseFunc  func,
+                gpointer       user_data)
+{
+  GTreeNode *node;
 
-  return g_tree_node_lookup (rtree->root, rtree->key_compare, 
-                             rtree->key_compare_data, key);
+  g_return_if_fail (tree != NULL);
+  
+  if (!tree->root)
+    return;
+
+  node = g_tree_first_node (tree);
+  
+  while (node)
+    {
+      if ((*func) (node->key, node->value, user_data))
+       break;
+      
+      node = g_tree_node_next (node);
+    }
 }
 
+/**
+ * g_tree_traverse:
+ * @tree: a #GTree.
+ * @traverse_func: the function to call for each node visited. If this 
+ *   function returns %TRUE, the traversal is stopped.
+ * @traverse_type: the order in which nodes are visited, one of %G_IN_ORDER,
+ *   %G_PRE_ORDER and %G_POST_ORDER.
+ * @user_data: user data to pass to the function.
+ * 
+ * Calls the given function for each node in the #GTree. 
+ *
+ * Deprecated:2.2: The order of a balanced tree is somewhat arbitrary. If you 
+ * just want to visit all nodes in sorted order, use g_tree_foreach() 
+ * instead. If you really need to visit nodes in a different order, consider
+ * using an <link linkend="glib-N-ary-Trees">N-ary Tree</link>.
+ **/
 void
 g_tree_traverse (GTree         *tree,
                 GTraverseFunc  traverse_func,
                 GTraverseType  traverse_type,
-                gpointer       data)
+                gpointer       user_data)
 {
-  GRealTree *rtree;
-
   g_return_if_fail (tree != NULL);
 
-  rtree = (GRealTree*) tree;
-
-  if (!rtree->root)
+  if (!tree->root)
     return;
 
   switch (traverse_type)
     {
     case G_PRE_ORDER:
-      g_tree_node_pre_order (rtree->root, traverse_func, data);
+      g_tree_node_pre_order (tree->root, traverse_func, user_data);
       break;
 
     case G_IN_ORDER:
-      g_tree_node_in_order (rtree->root, traverse_func, data);
+      g_tree_node_in_order (tree->root, traverse_func, user_data);
       break;
 
     case G_POST_ORDER:
-      g_tree_node_post_order (rtree->root, traverse_func, data);
+      g_tree_node_post_order (tree->root, traverse_func, user_data);
       break;
     
     case G_LEVEL_ORDER:
@@ -269,189 +872,89 @@ g_tree_traverse (GTree         *tree,
     }
 }
 
+/**
+ * g_tree_search:
+ * @tree: a #GTree.
+ * @search_func: a function used to search the #GTree. 
+ * @user_data: the data passed as the second argument to the @search_func 
+ * function.
+ * 
+ * Searches a #GTree using @search_func.
+ *
+ * The @search_func is called with a pointer to the key of a key/value pair in 
+ * the tree, and the passed in @user_data. If @search_func returns 0 for a 
+ * key/value pair, then g_tree_search_func() will return the value of that 
+ * pair. If @search_func returns -1,  searching will proceed among the 
+ * key/value pairs that have a smaller key; if @search_func returns 1, 
+ * searching will proceed among the key/value pairs that have a larger key.
+ *
+ * Return value: the value corresponding to the found key, or %NULL if the key 
+ * was not found.
+ **/
 gpointer
-g_tree_search (GTree            *tree,
-              GCompareFunc      search_func,
-              gconstpointer     data)
+g_tree_search (GTree         *tree,
+              GCompareFunc   search_func,
+              gconstpointer  user_data)
 {
-  GRealTree *rtree;
-
   g_return_val_if_fail (tree != NULL, NULL);
 
-  rtree = (GRealTree*) tree;
-
-  if (rtree->root)
-    return g_tree_node_search (rtree->root, search_func, data);
+  if (tree->root)
+    return g_tree_node_search (tree->root, search_func, user_data);
   else
     return NULL;
 }
 
+/**
+ * g_tree_height:
+ * @tree: a #GTree.
+ * 
+ * Gets the height of a #GTree.
+ *
+ * If the #GTree contains no nodes, the height is 0.
+ * If the #GTree contains only one root node the height is 1.
+ * If the root node has children the height is 2, etc.
+ * 
+ * Return value: the height of the #GTree.
+ **/
 gint
 g_tree_height (GTree *tree)
 {
-  GRealTree *rtree;
-
-  g_return_val_if_fail (tree != NULL, 0);
-
-  rtree = (GRealTree*) tree;
-
-  if (rtree->root)
-    return g_tree_node_height (rtree->root);
-  else
-    return 0;
-}
-
-gint
-g_tree_nnodes (GTree *tree)
-{
-  GRealTree *rtree;
+  GTreeNode *node;
+  gint height;
 
   g_return_val_if_fail (tree != NULL, 0);
 
-  rtree = (GRealTree*) tree;
-
-  if (rtree->root)
-    return g_tree_node_count (rtree->root);
-  else
+  if (!tree->root)
     return 0;
-}
-
-static GTreeNode*
-g_tree_node_insert (GTreeNode      *node,
-                   GCompareFuncData compare,
-                   gpointer        compare_data,
-                   gpointer        key,
-                   gpointer        value,
-                   gint           *inserted)
-{
-  gint old_balance;
-  gint cmp;
-
-  if (!node)
-    {
-      *inserted = TRUE;
-      return g_tree_node_new (key, value);
-    }
 
-  cmp = (* compare) (key, node->key, compare_data);
-  if (cmp == 0)
-    {
-      *inserted = FALSE;
-      node->value = value;
-      return node;
-    }
-
-  if (cmp < 0)
-    {
-      if (node->left)
-       {
-         old_balance = node->left->balance;
-         node->left = g_tree_node_insert (node->left, compare, compare_data,
-                                          key, value, inserted);
+  height = 0;
+  node = tree->root;
 
-         if ((old_balance != node->left->balance) && node->left->balance)
-           node->balance -= 1;
-       }
-      else
-       {
-         *inserted = TRUE;
-         node->left = g_tree_node_new (key, value);
-         node->balance -= 1;
-       }
-    }
-  else if (cmp > 0)
+  while (1)
     {
-      if (node->right)
-       {
-         old_balance = node->right->balance;
-         node->right = g_tree_node_insert (node->right, compare, compare_data,
-                                           key, value, inserted);
+      height += 1 + MAX(node->balance, 0);
 
-         if ((old_balance != node->right->balance) && node->right->balance)
-           node->balance += 1;
-       }
-      else
-       {
-         *inserted = TRUE;
-         node->right = g_tree_node_new (key, value);
-         node->balance += 1;
-       }
-    }
-
-  if (*inserted)
-    {
-      if ((node->balance < -1) || (node->balance > 1))
-       node = g_tree_node_balance (node);
+      if (!node->left_child)
+       return height;
+      
+      node = node->left;
     }
-
-  return node;
 }
 
-static GTreeNode*
-g_tree_node_remove (GTreeNode      *node,
-                   GCompareFuncData compare,
-                   gpointer        compare_data,
-                   gconstpointer   key)
+/**
+ * g_tree_nnodes:
+ * @tree: a #GTree.
+ * 
+ * Gets the number of nodes in a #GTree.
+ * 
+ * Return value: the number of nodes in the #GTree.
+ **/
+gint
+g_tree_nnodes (GTree *tree)
 {
-  GTreeNode *new_root;
-  gint old_balance;
-  gint cmp;
-
-  if (!node)
-    return NULL;
-
-  cmp = (* compare) (key, node->key, compare_data);
-  if (cmp == 0)
-    {
-      GTreeNode *garbage;
-
-      garbage = node;
-
-      if (!node->right)
-       {
-         node = node->left;
-       }
-      else
-       {
-         old_balance = node->right->balance;
-         node->right = g_tree_node_remove_leftmost (node->right, &new_root);
-         new_root->left = node->left;
-         new_root->right = node->right;
-         new_root->balance = node->balance;
-         node = g_tree_node_restore_right_balance (new_root, old_balance);
-       }
-
-#ifdef ENABLE_GC_FRIENDLY
-      garbage->left = NULL;
-      garbage->key = NULL;
-      garbage->value = NULL;
-#endif /* ENABLE_GC_FRIENDLY */
-
-      G_LOCK (g_tree_global);
-      garbage->right = node_free_list;
-      node_free_list = garbage;
-      G_UNLOCK (g_tree_global);
-   }
-  else if (cmp < 0)
-    {
-      if (node->left)
-       {
-         old_balance = node->left->balance;
-         node->left = g_tree_node_remove (node->left, compare, compare_data, key);
-         node = g_tree_node_restore_left_balance (node, old_balance);
-       }
-    }
-  else if (cmp > 0)
-    {
-      if (node->right)
-       {
-         old_balance = node->right->balance;
-         node->right = g_tree_node_remove (node->right, compare, compare_data, key);
-         node = g_tree_node_restore_right_balance (node, old_balance);
-       }
-    }
+  g_return_val_if_fail (tree != NULL, 0);
 
-  return node;
+  return tree->nnodes;
 }
 
 static GTreeNode*
@@ -473,94 +976,37 @@ g_tree_node_balance (GTreeNode *node)
   return node;
 }
 
-static GTreeNode*
-g_tree_node_remove_leftmost (GTreeNode  *node,
-                            GTreeNode **leftmost)
-{
-  gint old_balance;
-
-  if (!node->left)
-    {
-      *leftmost = node;
-      return node->right;
-    }
-
-  old_balance = node->left->balance;
-  node->left = g_tree_node_remove_leftmost (node->left, leftmost);
-  return g_tree_node_restore_left_balance (node, old_balance);
-}
-
-static GTreeNode*
-g_tree_node_restore_left_balance (GTreeNode *node,
-                                 gint       old_balance)
-{
-  if (!node->left)
-    node->balance += 1;
-  else if ((node->left->balance != old_balance) &&
-          (node->left->balance == 0))
-    node->balance += 1;
-
-  if (node->balance > 1)
-    return g_tree_node_balance (node);
-  return node;
-}
-
-static GTreeNode*
-g_tree_node_restore_right_balance (GTreeNode *node,
-                                  gint       old_balance)
-{
-  if (!node->right)
-    node->balance -= 1;
-  else if ((node->right->balance != old_balance) &&
-          (node->right->balance == 0))
-    node->balance -= 1;
-
-  if (node->balance < -1)
-    return g_tree_node_balance (node);
-  return node;
-}
-
-static gpointer
-g_tree_node_lookup (GTreeNode      *node,
-                   GCompareFuncData compare,
-                   gpointer        compare_data,
-                   gconstpointer   key)
+static GTreeNode *
+g_tree_find_node (GTree        *tree,
+                 gconstpointer key)
 {
+  GTreeNode *node;
   gint cmp;
 
+  node = tree->root;
   if (!node)
     return NULL;
 
-  cmp = (* compare) (key, node->key, compare_data);
-  if (cmp == 0)
-    return node->value;
-
-  if (cmp < 0)
-    {
-      if (node->left)
-       return g_tree_node_lookup (node->left, compare, compare_data, key);
-    }
-  else if (cmp > 0)
+  while (1)
     {
-      if (node->right)
-       return g_tree_node_lookup (node->right, compare, compare_data, key);
-    }
-
-  return NULL;
-}
-
-static gint
-g_tree_node_count (GTreeNode *node)
-{
-  gint count;
+      cmp = tree->key_compare (key, node->key, tree->key_compare_data);
+      if (cmp == 0)
+       return node;
+      else if (cmp < 0)
+       {
+         if (!node->left_child)
+           return NULL;
 
-  count = 1;
-  if (node->left)
-    count += g_tree_node_count (node->left);
-  if (node->right)
-    count += g_tree_node_count (node->right);
+         node = node->left;
+       }
+      else
+       {
+         if (!node->right_child)
+           return NULL;
 
-  return count;
+         node = node->right;
+       }
+    }
 }
 
 static gint
@@ -570,12 +1016,14 @@ g_tree_node_pre_order (GTreeNode     *node,
 {
   if ((*traverse_func) (node->key, node->value, data))
     return TRUE;
-  if (node->left)
+
+  if (node->left_child)
     {
       if (g_tree_node_pre_order (node->left, traverse_func, data))
        return TRUE;
     }
-  if (node->right)
+
+  if (node->right_child)
     {
       if (g_tree_node_pre_order (node->right, traverse_func, data))
        return TRUE;
@@ -589,19 +1037,21 @@ g_tree_node_in_order (GTreeNode     *node,
                      GTraverseFunc  traverse_func,
                      gpointer       data)
 {
-  if (node->left)
+  if (node->left_child)
     {
       if (g_tree_node_in_order (node->left, traverse_func, data))
        return TRUE;
     }
+
   if ((*traverse_func) (node->key, node->value, data))
     return TRUE;
-  if (node->right)
+
+  if (node->right_child)
     {
       if (g_tree_node_in_order (node->right, traverse_func, data))
        return TRUE;
     }
-
+  
   return FALSE;
 }
 
@@ -610,16 +1060,18 @@ g_tree_node_post_order (GTreeNode     *node,
                        GTraverseFunc  traverse_func,
                        gpointer       data)
 {
-  if (node->left)
+  if (node->left_child)
     {
       if (g_tree_node_post_order (node->left, traverse_func, data))
        return TRUE;
     }
-  if (node->right)
+
+  if (node->right_child)
     {
       if (g_tree_node_post_order (node->right, traverse_func, data))
        return TRUE;
     }
+
   if ((*traverse_func) (node->key, node->value, data))
     return TRUE;
 
@@ -636,41 +1088,26 @@ g_tree_node_search (GTreeNode     *node,
   if (!node)
     return NULL;
 
-  do {
-    dir = (* search_func) (node->key, data);
-    if (dir == 0)
-      return node->value;
-
-    if (dir < 0)
-      node = node->left;
-    else if (dir > 0)
-      node = node->right;
-  } while (node && (dir != 0));
-
-  return NULL;
-}
-
-static gint
-g_tree_node_height (GTreeNode *node)
-{
-  gint left_height;
-  gint right_height;
-
-  if (node)
+  while (1) 
     {
-      left_height = 0;
-      right_height = 0;
+      dir = (* search_func) (node->key, data);
+      if (dir == 0)
+       return node->value;
+      else if (dir < 0) 
+       { 
+         if (!node->left_child)
+           return NULL;
 
-      if (node->left)
-       left_height = g_tree_node_height (node->left);
-
-      if (node->right)
-       right_height = g_tree_node_height (node->right);
-
-      return MAX (left_height, right_height) + 1;
+         node = node->left;
+       }
+      else
+       {
+         if (!node->right_child)
+           return NULL;
+         
+         node = node->right;
+       }
     }
-
-  return 0;
 }
 
 static GTreeNode*
@@ -682,7 +1119,14 @@ g_tree_node_rotate_left (GTreeNode *node)
 
   right = node->right;
 
-  node->right = right->left;
+  if (right->left_child)
+    node->right = right->left;
+  else
+    {
+      node->right_child = FALSE;
+      node->right = right;
+      right->left_child = TRUE;
+    }
   right->left = node;
 
   a_bal = node->balance;
@@ -717,7 +1161,14 @@ g_tree_node_rotate_right (GTreeNode *node)
 
   left = node->left;
 
-  node->left = left->right;
+  if (left->right_child)
+    node->left = left->right;
+  else
+    {
+      node->left_child = FALSE;
+      node->left = left;
+      left->right_child = TRUE;
+    }
   left->right = node;
 
   a_bal = node->balance;
@@ -743,32 +1194,97 @@ g_tree_node_rotate_right (GTreeNode *node)
   return left;
 }
 
+#ifdef G_TREE_DEBUG
+static gint
+g_tree_node_height (GTreeNode *node)
+{
+  gint left_height;
+  gint right_height;
+
+  if (node)
+    {
+      left_height = 0;
+      right_height = 0;
+
+      if (node->left_child)
+       left_height = g_tree_node_height (node->left);
+
+      if (node->right_child)
+       right_height = g_tree_node_height (node->right);
+
+      return MAX (left_height, right_height) + 1;
+    }
+
+  return 0;
+}
+
 static void
 g_tree_node_check (GTreeNode *node)
 {
   gint left_height;
   gint right_height;
   gint balance;
-  
+  GTreeNode *tmp;
+
   if (node)
     {
+      if (node->left_child)
+       {
+         tmp = g_tree_node_previous (node);
+         g_assert (tmp->right == node);
+       }
+
+      if (node->right_child)
+       {
+         tmp = g_tree_node_next (node);
+         g_assert (tmp->left == node);
+       }
+
       left_height = 0;
       right_height = 0;
       
-      if (node->left)
+      if (node->left_child)
        left_height = g_tree_node_height (node->left);
-      if (node->right)
+      if (node->right_child)
        right_height = g_tree_node_height (node->right);
       
       balance = right_height - left_height;
-      if (balance != node->balance)
-       g_log (g_log_domain_glib, G_LOG_LEVEL_INFO,
-              "g_tree_node_check: failed: %d ( %d )\n",
-              balance, node->balance);
+      g_assert (balance == node->balance);
       
-      if (node->left)
+      if (node->left_child)
        g_tree_node_check (node->left);
-      if (node->right)
+      if (node->right_child)
        g_tree_node_check (node->right);
     }
 }
+
+static void
+g_tree_node_dump (GTreeNode *node, 
+                 gint       indent)
+{
+  g_print ("%*s%c\n", indent, "", *(char *)node->key);
+
+  if (node->left_child)
+    g_tree_node_dump (node->left, indent + 2);
+  else if (node->left)
+    g_print ("%*s<%c\n", indent + 2, "", *(char *)node->left->key);
+
+  if (node->right_child)
+    g_tree_node_dump (node->right, indent + 2);
+  else if (node->right)
+    g_print ("%*s>%c\n", indent + 2, "", *(char *)node->right->key);
+}
+
+
+void
+g_tree_dump (GTree *tree)
+{
+  if (tree->root)
+    g_tree_node_dump (tree->root, 0);
+}
+#endif
+
+
+#define __G_TREE_C__
+#include "galiasdef.c"
+