Checked in initial draft of the new tree widget.

2000-10-04    <jrb@redhat.com>

	* gtk/gtk{tree,cell}?*.[ch]: Checked in initial draft of the new
	tree widget.

1 files changed, 994 insertions, 0 deletions

diff --git a/gtk/gtkrbtree.c b/gtk/gtkrbtree.c
new file mode 100644
index 0000000000..92b170d1ff
--- /dev/null
+++ b/gtk/gtkrbtree.c
@@ -0,0 +1,994 @@
+/* gtkrbtree.c
+ * Copyright (C) 2000  Red Hat, Inc.,  Jonathan Blandford <jrb@redhat.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#include "gtkrbtree.h"
+
+static void       _gtk_rbnode_validate_allocator (GAllocator *allocator);
+static GtkRBNode *_gtk_rbnode_new                (GtkRBTree  *tree,
+						  gint        height);
+static void       _gtk_rbnode_free               (GtkRBNode  *node);
+static void       _gtk_rbnode_rotate_left        (GtkRBTree  *tree,
+						  GtkRBNode  *node);
+static void       _gtk_rbnode_rotate_left        (GtkRBTree  *tree,
+						  GtkRBNode  *node);
+static void       _gtk_rbtree_insert_fixup       (GtkRBTree  *tree,
+						  GtkRBNode  *node);
+static void       _gtk_rbtree_remove_node_fixup  (GtkRBTree  *tree,
+						  GtkRBNode  *node);
+static gint       _count_nodes                   (GtkRBTree  *tree,
+						  GtkRBNode  *node);
+
+
+/* node allocation
+ */
+struct _GAllocator /* from gmem.c */
+{
+  gchar      *name;
+  guint16     n_preallocs;
+  guint       is_unused : 1;
+  guint       type : 4;
+  GAllocator *last;
+  GMemChunk  *mem_chunk;
+  GtkRBNode  *free_nodes; /* implementation specific */
+};
+
+
+G_LOCK_DEFINE_STATIC (current_allocator);
+static GAllocator *current_allocator = NULL;
+
+/* HOLDS: current_allocator_lock */
+static void
+_gtk_rbnode_validate_allocator (GAllocator *allocator)
+{
+  g_return_if_fail (allocator != NULL);
+  g_return_if_fail (allocator->is_unused == TRUE);
+
+  if (allocator->type != G_ALLOCATOR_NODE)
+    {
+      allocator->type = G_ALLOCATOR_NODE;
+      if (allocator->mem_chunk)
+	{
+	  g_mem_chunk_destroy (allocator->mem_chunk);
+	  allocator->mem_chunk = NULL;
+	}
+    }
+
+  if (!allocator->mem_chunk)
+    {
+      allocator->mem_chunk = g_mem_chunk_new (allocator->name,
+					      sizeof (GtkRBNode),
+					      sizeof (GtkRBNode) * allocator->n_preallocs,
+					      G_ALLOC_ONLY);
+      allocator->free_nodes = NULL;
+    }
+
+  allocator->is_unused = FALSE;
+}
+
+static GtkRBNode *
+_gtk_rbnode_new (GtkRBTree *tree,
+		 gint       height)
+{
+  GtkRBNode *node;
+
+  G_LOCK (current_allocator);
+  if (!current_allocator)
+    {
+      GAllocator *allocator = g_allocator_new ("GTK+ default GtkRBNode allocator",
+					       128);
+      _gtk_rbnode_validate_allocator (allocator);
+      allocator->last = NULL;
+      current_allocator = allocator;
+    }
+  if (!current_allocator->free_nodes)
+    node = g_chunk_new (GtkRBNode, current_allocator->mem_chunk);
+  else
+    {
+      node = current_allocator->free_nodes;
+      current_allocator->free_nodes = node->left;
+    }
+  G_UNLOCK (current_allocator);
+
+  node->left = tree->nil;
+  node->right = tree->nil;
+  node->parent = tree->nil;
+  node->flags = GTK_RBNODE_RED;
+  node->count = 1;
+  node->children = NULL;
+  node->offset = height;
+  return node;
+}
+
+static void
+_gtk_rbnode_free (GtkRBNode *node)
+{
+  G_LOCK (current_allocator);
+  node->left = current_allocator->free_nodes;
+  current_allocator->free_nodes = node;
+  G_UNLOCK (current_allocator);
+}
+
+static void
+_gtk_rbnode_rotate_left (GtkRBTree *tree,
+			 GtkRBNode *node)
+{
+  gint node_height, right_height;
+  GtkRBNode *right = node->right;
+
+  g_return_if_fail (node != tree->nil);
+
+  node_height = node->offset -
+    (node->left?node->left->offset:0) -
+    (node->right?node->right->offset:0) -
+    (node->children?node->children->root->offset:0);
+  right_height = right->offset -
+    (right->left?right->left->offset:0) -
+    (right->right?right->right->offset:0) -
+    (right->children?right->children->root->offset:0);
+
+  node->right = right->left;
+  if (right->left != tree->nil)
+    right->left->parent = node;
+
+  if (right != tree->nil)
+    right->parent = node->parent;
+  if (node->parent != tree->nil)
+    {
+      if (node == node->parent->left)
+	node->parent->left = right;
+      else
+	node->parent->right = right;
+    } else {
+      tree->root = right;
+    }
+
+  right->left = node;
+  if (node != tree->nil)
+    node->parent = right;
+
+  node->count = 1 + (node->left?node->left->count:0) +
+    (node->right?node->right->count:0);
+  right->count = 1 + (right->left?right->left->count:0) +
+    (right->right?right->right->count:0);
+  node->offset = node_height +
+    (node->left?node->left->offset:0) +
+    (node->right?node->right->offset:0) +
+    (node->children?node->children->root->offset:0);
+  right->offset = right_height +
+    (right->left?right->left->offset:0) +
+    (right->right?right->right->offset:0) +
+    (right->children?right->children->root->offset:0);
+}
+
+static void
+_gtk_rbnode_rotate_right (GtkRBTree *tree,
+			  GtkRBNode *node)
+{
+  gint node_height, left_height;
+  GtkRBNode *left = node->left;
+
+  g_return_if_fail (node != tree->nil);
+
+  node_height = node->offset -
+    (node->left?node->left->offset:0) -
+    (node->right?node->right->offset:0) -
+    (node->children?node->children->root->offset:0);
+  left_height = left->offset -
+    (left->left?left->left->offset:0) -
+    (left->right?left->right->offset:0) -
+    (left->children?left->children->root->offset:0);
+
+  node->left = left->right;
+  if (left->right != tree->nil)
+    left->right->parent = node;
+
+  if (left != tree->nil)
+    left->parent = node->parent;
+  if (node->parent != tree->nil)
+    {
+      if (node == node->parent->right)
+	node->parent->right = left;
+      else
+	node->parent->left = left;
+    }
+  else
+    {
+      tree->root = left;
+    }
+
+  /* link node and left */
+  left->right = node;
+  if (node != tree->nil)
+    node->parent = left;
+
+  node->count = 1 + (node->left?node->left->count:0) +
+    (node->right?node->right->count:0);
+  left->count = 1 + (left->left?left->left->count:0) +
+    (left->right?left->right->count:0);
+  node->offset = node_height +
+    (node->left?node->left->offset:0) +
+    (node->right?node->right->offset:0) +
+    (node->children?node->children->root->offset:0);
+  left->offset = left_height +
+    (left->left?left->left->offset:0) +
+    (left->right?left->right->offset:0) +
+    (left->children?left->children->root->offset:0);
+}
+
+static void
+_gtk_rbtree_insert_fixup (GtkRBTree *tree,
+			  GtkRBNode *node)
+{
+
+  /* check Red-Black properties */
+  while (node != tree->root && GTK_RBNODE_GET_COLOR (node->parent) == GTK_RBNODE_RED)
+    {
+      /* we have a violation */
+      if (node->parent == node->parent->parent->left)
+	{
+	  GtkRBNode *y = node->parent->parent->right;
+	  if (GTK_RBNODE_GET_COLOR (y) == GTK_RBNODE_RED)
+	    {
+				/* uncle is GTK_RBNODE_RED */
+	      GTK_RBNODE_SET_COLOR (node->parent, GTK_RBNODE_BLACK);
+	      GTK_RBNODE_SET_COLOR (y, GTK_RBNODE_BLACK);
+	      GTK_RBNODE_SET_COLOR (node->parent->parent, GTK_RBNODE_RED);
+	      node = node->parent->parent;
+	    }
+	  else
+	    {
+				/* uncle is GTK_RBNODE_BLACK */
+	      if (node == node->parent->right)
+		{
+		  /* make node a left child */
+		  node = node->parent;
+		  _gtk_rbnode_rotate_left (tree, node);
+		}
+
+				/* recolor and rotate */
+	      GTK_RBNODE_SET_COLOR (node->parent, GTK_RBNODE_BLACK);
+	      GTK_RBNODE_SET_COLOR (node->parent->parent, GTK_RBNODE_RED);
+	      _gtk_rbnode_rotate_right(tree, node->parent->parent);
+	    }
+	}
+      else
+	{
+	  /* mirror image of above code */
+	  GtkRBNode *y = node->parent->parent->left;
+	  if (GTK_RBNODE_GET_COLOR (y) == GTK_RBNODE_RED)
+	    {
+				/* uncle is GTK_RBNODE_RED */
+	      GTK_RBNODE_SET_COLOR (node->parent, GTK_RBNODE_BLACK);
+	      GTK_RBNODE_SET_COLOR (y, GTK_RBNODE_BLACK);
+	      GTK_RBNODE_SET_COLOR (node->parent->parent, GTK_RBNODE_RED);
+	      node = node->parent->parent;
+	    }
+	  else
+	    {
+				/* uncle is GTK_RBNODE_BLACK */
+	      if (node == node->parent->left)
+		{
+		  node = node->parent;
+		  _gtk_rbnode_rotate_right (tree, node);
+		}
+	      GTK_RBNODE_SET_COLOR (node->parent, GTK_RBNODE_BLACK);
+	      GTK_RBNODE_SET_COLOR (node->parent->parent, GTK_RBNODE_RED);
+	      _gtk_rbnode_rotate_left (tree, node->parent->parent);
+	    }
+	}
+    }
+  GTK_RBNODE_SET_COLOR (tree->root, GTK_RBNODE_BLACK);
+}
+
+static void
+_gtk_rbtree_remove_node_fixup (GtkRBTree *tree,
+			       GtkRBNode *node)
+{
+  while (node != tree->root && GTK_RBNODE_GET_COLOR (node) == GTK_RBNODE_BLACK)
+    {
+      if (node == node->parent->left)
+	{
+	  GtkRBNode *w = node->parent->right;
+	  if (GTK_RBNODE_GET_COLOR (w) == GTK_RBNODE_RED)
+	    {
+	      GTK_RBNODE_SET_COLOR (w, GTK_RBNODE_BLACK);
+	      GTK_RBNODE_SET_COLOR (node->parent, GTK_RBNODE_RED);
+	      _gtk_rbnode_rotate_left (tree, node->parent);
+	      w = node->parent->right;
+	    }
+	  if (GTK_RBNODE_GET_COLOR (w->left) == GTK_RBNODE_BLACK && GTK_RBNODE_GET_COLOR (w->right) == GTK_RBNODE_BLACK)
+	    {
+	      GTK_RBNODE_SET_COLOR (w, GTK_RBNODE_RED);
+	      node = node->parent;
+	    }
+	  else
+	    {
+	      if (GTK_RBNODE_GET_COLOR (w->right) == GTK_RBNODE_BLACK)
+		{
+		  GTK_RBNODE_SET_COLOR (w->left, GTK_RBNODE_BLACK);
+		  GTK_RBNODE_SET_COLOR (w, GTK_RBNODE_RED);
+		  _gtk_rbnode_rotate_right (tree, w);
+		  w = node->parent->right;
+		}
+	      GTK_RBNODE_SET_COLOR (w, GTK_RBNODE_GET_COLOR (node->parent));
+	      GTK_RBNODE_SET_COLOR (node->parent, GTK_RBNODE_BLACK);
+	      GTK_RBNODE_SET_COLOR (w->right, GTK_RBNODE_BLACK);
+	      _gtk_rbnode_rotate_left (tree, node->parent);
+	      node = tree->root;
+	    }
+	}
+      else
+	{
+	  GtkRBNode *w = node->parent->left;
+	  if (GTK_RBNODE_GET_COLOR (w) == GTK_RBNODE_RED)
+	    {
+	      GTK_RBNODE_SET_COLOR (w, GTK_RBNODE_BLACK);
+	      GTK_RBNODE_SET_COLOR (node->parent, GTK_RBNODE_RED);
+	      _gtk_rbnode_rotate_right (tree, node->parent);
+	      w = node->parent->left;
+	    }
+	  if (GTK_RBNODE_GET_COLOR (w->right) == GTK_RBNODE_BLACK && GTK_RBNODE_GET_COLOR (w->left) == GTK_RBNODE_BLACK)
+	    {
+	      GTK_RBNODE_SET_COLOR (w, GTK_RBNODE_RED);
+	      node = node->parent;
+	    }
+	  else
+	    {
+	      if (GTK_RBNODE_GET_COLOR (w->left) == GTK_RBNODE_BLACK)
+		{
+		  GTK_RBNODE_SET_COLOR (w->right, GTK_RBNODE_BLACK);
+		  GTK_RBNODE_SET_COLOR (w, GTK_RBNODE_RED);
+		  _gtk_rbnode_rotate_left (tree, w);
+		  w = node->parent->left;
+		}
+	      GTK_RBNODE_SET_COLOR (w, GTK_RBNODE_GET_COLOR (node->parent));
+	      GTK_RBNODE_SET_COLOR (node->parent, GTK_RBNODE_BLACK);
+	      GTK_RBNODE_SET_COLOR (w->left, GTK_RBNODE_BLACK);
+	      _gtk_rbnode_rotate_right (tree, node->parent);
+	      node = tree->root;
+	    }
+	}
+    }
+  GTK_RBNODE_SET_COLOR (node, GTK_RBNODE_BLACK);
+}
+
+/* Public functions */
+void
+_gtk_rbnode_push_allocator (GAllocator *allocator)
+{
+  G_LOCK (current_allocator);
+  _gtk_rbnode_validate_allocator ( allocator );
+  allocator->last = current_allocator;
+  current_allocator = allocator;
+  G_UNLOCK (current_allocator);
+}
+
+void
+_gtk_rbnode_pop_allocator (void)
+{
+  G_LOCK (current_allocator);
+  if (current_allocator)
+    {
+      GAllocator *allocator;
+
+      allocator = current_allocator;
+      current_allocator = allocator->last;
+      allocator->last = NULL;
+      allocator->is_unused = TRUE;
+    }
+  G_UNLOCK (current_allocator);
+}
+
+GtkRBTree *
+_gtk_rbtree_new (void)
+{
+  GtkRBTree *retval;
+
+  retval = (GtkRBTree *) g_new (GtkRBTree, 1);
+  retval->parent_tree = NULL;
+  retval->parent_node = NULL;
+
+  retval->nil = g_new0 (GtkRBNode, 1);
+  retval->nil->left = NULL;
+  retval->nil->right = NULL;
+  retval->nil->parent = NULL;
+  retval->nil->flags = GTK_RBNODE_BLACK;
+  retval->nil->count = 0;
+  retval->nil->offset = 0;
+
+  retval->root = retval->nil;
+  return retval;
+}
+
+static void
+_gtk_rbtree_free_helper (GtkRBTree  *tree,
+			 GtkRBNode  *node,
+			 gpointer    data)
+{
+  if (node->children)
+    _gtk_rbtree_free (node->children);
+
+  _gtk_rbnode_free (node);
+}
+
+void
+_gtk_rbtree_free (GtkRBTree *tree)
+{
+  _gtk_rbtree_traverse (tree,
+			tree->root,
+			G_POST_ORDER,
+			_gtk_rbtree_free_helper,
+			NULL);
+
+  if (tree->parent_node &&
+      tree->parent_node->children == tree)
+    tree->parent_node->children = NULL;
+  _gtk_rbnode_free (tree->nil);
+  g_free (tree);
+}
+
+void
+_gtk_rbtree_remove (GtkRBTree *tree)
+{
+  GtkRBTree *tmp_tree;
+  GtkRBNode *tmp_node;
+
+  gint height = tree->root->offset;
+  tmp_tree = tree->parent_tree;
+  tmp_node = tree->parent_node;
+
+  while (tmp_tree && tmp_node && tmp_node != tmp_tree->nil)
+    {
+      tmp_node->offset -= height;
+      tmp_node = tmp_node->parent;
+      if (tmp_node == tmp_tree->nil)
+	{
+	  tmp_node = tmp_tree->parent_node;
+	  tmp_tree = tmp_tree->parent_tree;
+	}
+    }
+  _gtk_rbtree_free (tree);
+}
+
+
+GtkRBNode *
+_gtk_rbtree_insert_after (GtkRBTree  *tree,
+			  GtkRBNode  *current,
+			  gint        height)
+{
+  GtkRBNode *node;
+  gboolean right = TRUE;
+  GtkRBNode *tmp_node;
+  GtkRBTree *tmp_tree;
+
+  if (current != NULL && current->right != tree->nil)
+    {
+      current = current->right;
+      while (current->left != tree->nil)
+	current = current->left;
+      right = FALSE;
+    }
+
+  /* setup new node */
+  node = _gtk_rbnode_new (tree, height);
+  node->parent = (current?current:tree->nil);
+
+  /* insert node in tree */
+  if (current)
+    {
+      if (right)
+	current->right = node;
+      else
+	current->left = node;
+      tmp_node = node->parent;
+      tmp_tree = tree;
+    }
+  else
+    {
+      tree->root = node;
+      tmp_node = tree->parent_node;
+      tmp_tree = tree->parent_tree;
+    }
+
+  while (tmp_tree && tmp_node && tmp_node != tmp_tree->nil)
+    {
+      /* We only want to propagate the count if we are in the tree we
+       * started in. */
+      if (tmp_tree == tree)
+	tmp_node->count++;
+      tmp_node->offset += height;
+      tmp_node = tmp_node->parent;
+      if (tmp_node == tmp_tree->nil)
+	{
+	  tmp_node = tmp_tree->parent_node;
+	  tmp_tree = tmp_tree->parent_tree;
+	}
+    }
+  _gtk_rbtree_insert_fixup (tree, node);
+
+  return node;
+}
+
+GtkRBNode *
+_gtk_rbtree_insert_before (GtkRBTree  *tree,
+			   GtkRBNode  *current,
+			   gint        height)
+{
+  GtkRBNode *node;
+  gboolean left = TRUE;
+  GtkRBNode *tmp_node;
+  GtkRBTree *tmp_tree;
+
+  if (current != NULL && current->left != tree->nil)
+    {
+      current = current->left;
+      while (current->right != tree->nil)
+	current = current->right;
+      left = FALSE;
+    }
+
+  /* setup new node */
+  node = _gtk_rbnode_new (tree, height);
+  node->parent = (current?current:tree->nil);
+
+  /* insert node in tree */
+  if (current)
+    {
+      if (left)
+	current->left = node;
+      else
+	current->right = node;
+      tmp_node = node->parent;
+      tmp_tree = tree;
+    }
+  else
+    {
+      tree->root = node;
+      tmp_node = tree->parent_node;
+      tmp_tree = tree->parent_tree;
+    }
+
+  while (tmp_tree && tmp_node && tmp_node != tmp_tree->nil)
+    {
+      /* We only want to propagate the count if we are in the tree we
+       * started in. */
+      if (tmp_tree == tree)
+	tmp_node->count++;
+      tmp_node->offset += height;
+      tmp_node = tmp_node->parent;
+      if (tmp_node == tmp_tree->nil)
+	{
+	  tmp_node = tmp_tree->parent_node;
+	  tmp_tree = tmp_tree->parent_tree;
+	}
+    }
+  _gtk_rbtree_insert_fixup (tree, node);
+
+  return node;
+}
+
+GtkRBNode *
+_gtk_rbtree_find_count (GtkRBTree *tree,
+			gint       count)
+{
+  GtkRBNode *node;
+
+  node = tree->root;
+  while (node != tree->nil && (node->left->count + 1 != count))
+    {
+      if (node->left->count >= count)
+	node = node->left;
+      else
+	{
+	  count -= (node->left->count + 1);
+	  node = node->right;
+	}
+    }
+  if (node == tree->nil)
+    return NULL;
+  return node;
+}
+
+void
+_gtk_rbtree_node_set_height (GtkRBTree *tree,
+			     GtkRBNode *node,
+			     gint       height)
+{
+  gint diff = height - GTK_RBNODE_GET_HEIGHT (node);
+  GtkRBNode *tmp_node = node;
+  GtkRBTree *tmp_tree = tree;
+
+  if (diff == 0)
+    return;
+
+  while (tmp_tree && tmp_node && tmp_node != tmp_tree->nil)
+    {
+      tmp_node->offset += diff;
+      tmp_node = tmp_node->parent;
+      if (tmp_node == tmp_tree->nil)
+	{
+	  tmp_node = tmp_tree->parent_node;
+	  tmp_tree = tmp_tree->parent_tree;
+	}
+    }
+}
+
+gint
+_gtk_rbtree_node_find_offset (GtkRBTree *tree,
+			      GtkRBNode *node)
+{
+  GtkRBNode *last;
+  gint retval = node->left->offset;
+
+  while (tree && node && node != tree->nil)
+    {
+      last = node;
+      node = node->parent;
+      if (node->right == last)
+	retval += node->left->offset + GTK_RBNODE_GET_HEIGHT (node);
+      if (node == tree->nil)
+	{
+	  node = tree->parent_node;
+	  tree = tree->parent_tree;
+	  if (node)
+	    retval += node->left->offset;
+	}
+    }
+  return retval;
+}
+
+gint
+_gtk_rbtree_find_offset (GtkRBTree  *tree,
+			 gint        height,
+			 GtkRBTree **new_tree,
+			 GtkRBNode **new_node)
+{
+  GtkRBNode *tmp_node;
+
+  tmp_node = tree->root;
+  while (tmp_node != tree->nil &&
+	 (tmp_node->left->offset > height ||
+	  (tmp_node->offset - tmp_node->right->offset) < height))
+    {
+      if (tmp_node->left->offset > height)
+	tmp_node = tmp_node->left;
+      else
+	{
+	  height -= (tmp_node->offset - tmp_node->right->offset);
+	  tmp_node = tmp_node->right;
+	}
+    }
+  if (tmp_node == tree->nil)
+    {
+      *new_tree = NULL;
+      *new_node = NULL;
+      return 0;
+    }
+  if (tmp_node->children)
+    {
+      if ((tmp_node->offset -
+	   tmp_node->right->offset -
+	   tmp_node->children->root->offset) > height)
+	{
+	  *new_tree = tree;
+	  *new_node = tmp_node;
+	  return (height - tmp_node->left->offset);
+	}
+      return _gtk_rbtree_find_offset (tmp_node->children,
+				      height - tmp_node->left->offset -
+				      (tmp_node->offset -
+				       tmp_node->left->offset -
+				       tmp_node->right->offset -
+				       tmp_node->children->root->offset),
+				      new_tree,
+				      new_node);
+    }
+  *new_tree = tree;
+  *new_node = tmp_node;
+  return (height - tmp_node->left->offset);
+}
+
+
+void
+_gtk_rbtree_remove_node (GtkRBTree *tree,
+			 GtkRBNode *node)
+{
+  GtkRBNode *x, *y;
+
+  g_return_if_fail (tree != NULL);
+  g_return_if_fail (node != NULL);
+  /* make sure we're deleting a node that's actually in the tree */
+  for (x = node; x->parent != tree->nil; x = x->parent)
+    ;
+  g_return_if_fail (x == tree->root);
+
+  if (node->left == tree->nil || node->right == tree->nil)
+    {
+      y = node;
+    }
+  else
+    {
+      y = node->right;
+
+      while (y->left != tree->nil)
+	y = y->left;
+    }
+  for (x = y; x != tree->nil; x = x->parent)
+    x->count--;
+  y->count = node->count;
+  /* x is y's only child */
+  if (y->left != tree->nil)
+    x = y->left;
+  else
+    x = y->right;
+
+  /* remove y from the parent chain */
+  x->parent = y->parent;
+  if (y->parent != tree->nil)
+    if (y == y->parent->left)
+      y->parent->left = x;
+    else
+      y->parent->right = x;
+  else
+    tree->root = x;
+
+  if (y != node)
+    node->children = y->children;
+
+  if (GTK_RBNODE_GET_COLOR (y) == GTK_RBNODE_BLACK)
+    _gtk_rbtree_remove_node_fixup (tree, x);
+
+  G_LOCK (current_allocator);
+  y->left = current_allocator->free_nodes;
+  current_allocator->free_nodes = y;
+  G_UNLOCK (current_allocator);
+}
+
+GtkRBNode *
+_gtk_rbtree_next (GtkRBTree *tree,
+		  GtkRBNode *node)
+{
+  g_return_val_if_fail (tree != NULL, NULL);
+  g_return_val_if_fail (node != NULL, NULL);
+
+  /* Case 1: the node's below us. */
+  if (node->right != tree->nil)
+    {
+      node = node->right;
+      while (node->left != tree->nil)
+	node = node->left;
+      return node;
+    }
+
+  /* Case 2: it's an ancestor */
+  while (node->parent != tree->nil)
+    {
+      if (node->parent->right == node)
+	node = node->parent;
+      else
+	return (node->parent);
+    }
+
+  /* Case 3: There is no next node */
+  return NULL;
+}
+
+GtkRBNode *
+_gtk_rbtree_prev (GtkRBTree *tree,
+		  GtkRBNode *node)
+{
+  g_return_val_if_fail (tree != NULL, NULL);
+  g_return_val_if_fail (node != NULL, NULL);
+
+  /* Case 1: the node's below us. */
+  if (node->left != tree->nil)
+    {
+      node = node->left;
+      while (node->right != tree->nil)
+	node = node->right;
+      return node;
+    }
+
+  /* Case 2: it's an ancestor */
+  while (node->parent != tree->nil)
+    {
+      if (node->parent->left == node)
+	node = node->parent;
+      else
+	return (node->parent);
+    }
+
+  /* Case 3: There is no next node */
+  return NULL;
+}
+
+void
+_gtk_rbtree_next_full (GtkRBTree  *tree,
+		       GtkRBNode  *node,
+		       GtkRBTree **new_tree,
+		       GtkRBNode **new_node)
+{
+  g_return_if_fail (tree != NULL);
+  g_return_if_fail (node != NULL);
+  g_return_if_fail (new_tree != NULL);
+  g_return_if_fail (new_node != NULL);
+
+  if (node->children)
+    {
+      *new_tree = node->children;
+      *new_node = (*new_tree)->root;
+      while ((*new_node)->left != (*new_tree)->nil)
+	*new_node = (*new_node)->left;
+      return;
+    }
+
+  *new_tree = tree;
+  *new_node = _gtk_rbtree_next (tree, node);
+
+  while ((*new_node == NULL) &&
+	 (*new_tree != NULL))
+    {
+      *new_node = (*new_tree)->parent_node;
+      *new_tree = (*new_tree)->parent_tree;
+      if (*new_tree)
+	*new_node = _gtk_rbtree_next (*new_tree, *new_node);
+    }
+}
+
+void
+_gtk_rbtree_prev_full (GtkRBTree  *tree,
+		       GtkRBNode  *node,
+		       GtkRBTree **new_tree,
+		       GtkRBNode **new_node)
+{
+  g_return_if_fail (tree != NULL);
+  g_return_if_fail (node != NULL);
+  g_return_if_fail (new_tree != NULL);
+  g_return_if_fail (new_node != NULL);
+
+  *new_tree = tree;
+  *new_node = _gtk_rbtree_prev (tree, node);
+
+  if (*new_node == NULL)
+    {
+      *new_node = (*new_tree)->parent_node;
+      *new_tree = (*new_tree)->parent_tree;
+    }
+  else
+    {
+      while ((*new_node)->children)
+	{
+	  *new_tree = (*new_node)->children;
+	  *new_node = (*new_tree)->root;
+	  while ((*new_node)->right != (*new_tree)->nil)
+	    *new_node = (*new_node)->right;
+	}
+    }
+}
+
+static void
+_gtk_rbtree_traverse_pre_order (GtkRBTree             *tree,
+				GtkRBNode             *node,
+				GtkRBTreeTraverseFunc  func,
+				gpointer               data)
+{
+  if (node == tree->nil)
+    return;
+
+  (* func) (tree, node, data);
+  _gtk_rbtree_traverse_pre_order (tree, node->left, func, data);
+  _gtk_rbtree_traverse_pre_order (tree, node->right, func, data);
+}
+
+static void
+_gtk_rbtree_traverse_post_order (GtkRBTree             *tree,
+				 GtkRBNode             *node,
+				 GtkRBTreeTraverseFunc  func,
+				 gpointer               data)
+{
+  if (node == tree->nil)
+    return;
+
+  _gtk_rbtree_traverse_post_order (tree, node->left, func, data);
+  _gtk_rbtree_traverse_post_order (tree, node->right, func, data);
+  (* func) (tree, node, data);
+}
+
+void
+_gtk_rbtree_traverse (GtkRBTree             *tree,
+		      GtkRBNode             *node,
+		      GTraverseType          order,
+		      GtkRBTreeTraverseFunc  func,
+		      gpointer               data)
+{
+  g_return_if_fail (tree != NULL);
+  g_return_if_fail (node != NULL);
+  g_return_if_fail (func != NULL);
+  g_return_if_fail (order <= G_LEVEL_ORDER);
+
+  switch (order)
+    {
+    case G_PRE_ORDER:
+      _gtk_rbtree_traverse_pre_order (tree, node, func, data);
+      break;
+    case G_POST_ORDER:
+      _gtk_rbtree_traverse_post_order (tree, node, func, data);
+      break;
+    case G_IN_ORDER:
+    case G_LEVEL_ORDER:
+    default:
+      g_warning ("unsupported traversal order.");
+      break;
+    }
+}
+
+static gint
+_count_nodes (GtkRBTree *tree,
+	      GtkRBNode *node)
+{
+  gint res;
+  if (node == tree->nil)
+    return 0;
+
+  res = (_count_nodes (tree, node->left) +
+	 _count_nodes (tree, node->right) + 1);
+
+  if (res != node->count)
+    g_print ("Tree failed\n");
+  return res;
+}
+
+void
+_gtk_rbtree_test (GtkRBTree *tree)
+{
+  if ((_count_nodes (tree, tree->root->left) +
+       _count_nodes (tree, tree->root->right) + 1) == tree->root->count)
+    g_print ("Tree passed\n");
+  else
+    g_print ("Tree failed\n");
+
+}
+
+static void
+_gtk_rbtree_test_height_helper (GtkRBTree *tree,
+				GtkRBNode *node,
+				gint       height)
+{
+  if (node == tree->nil)
+    return;
+
+  if (node->offset -
+      (node->left?node->left->offset:0) -
+      (node->right?node->right->offset:0) -
+      (node->children?node->children->root->offset:0) != height)
+    g_error ("tree failed\n");
+
+  _gtk_rbtree_test_height_helper (tree, node->left, height);
+  _gtk_rbtree_test_height_helper (tree, node->right, height);
+  if (node->children)
+    _gtk_rbtree_test_height_helper (node->children, node->children->root, height);
+
+}
+
+void
+_gtk_rbtree_test_height (GtkRBTree *tree,
+			 gint       height)
+{
+  _gtk_rbtree_test_height_helper (tree, tree->root, height);
+}