/* GLIB - Library of useful routines for C programming
 * Copyright (C) 1995-1997  Peter Mattis, Spencer Kimball and Josh MacDonald
 *
 * GNode: N-way tree implementation.
 * Copyright (C) 1998 Tim Janik
 *
 * 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.
 */

/* 
 * MT safe
 */

#include "glib.h"

/* node allocation
 */
struct _GAllocator /* from gmem.c */
{
  gchar         *name;
  guint16        n_preallocs;
  guint          is_unused : 1;
  guint          type : 4;
  GAllocator    *last;
  GMemChunk     *mem_chunk;
  GNode         *free_nodes; /* implementation specific */
};

G_LOCK_DECLARE_STATIC (current_allocator);
static GAllocator *current_allocator = NULL;

/* HOLDS: current_allocator_lock */
static void
g_node_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 (GNode),
					      sizeof (GNode) * allocator->n_preallocs,
					      G_ALLOC_ONLY);
      allocator->free_nodes = NULL;
    }

  allocator->is_unused = FALSE;
}

void
g_node_push_allocator (GAllocator *allocator)
{
  G_LOCK (current_allocator);
  g_node_validate_allocator ( allocator );
  allocator->last = current_allocator;
  current_allocator = allocator;
  G_UNLOCK (current_allocator);
}

void
g_node_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);
}


/* --- functions --- */
GNode*
g_node_new (gpointer data)
{
  GNode *node;

  G_LOCK (current_allocator);
  if (!current_allocator)
    {
       GAllocator *allocator = g_allocator_new ("GLib default GNode allocator",
						1024);
       g_node_validate_allocator (allocator);
       allocator->last = NULL;
       current_allocator = allocator;
    }
  if (!current_allocator->free_nodes)
    node = g_chunk_new (GNode, current_allocator->mem_chunk);
  else
    {
      node = current_allocator->free_nodes;
      current_allocator->free_nodes = node->next;
    }
  G_UNLOCK (current_allocator);
  
  node->data = data;
  node->next = NULL;
  node->prev = NULL;
  node->parent = NULL;
  node->children = NULL;
  
  return node;
}

static void
g_nodes_free (GNode *node)
{
  GNode *parent;

  parent = node;
  while (1)
    {
      if (parent->children)
	g_nodes_free (parent->children);
      if (parent->next)
	parent = parent->next;
      else
	break;
    }
  
  G_LOCK (current_allocator);
  parent->next = current_allocator->free_nodes;
  current_allocator->free_nodes = node;
  G_UNLOCK (current_allocator);
}

void
g_node_destroy (GNode *root)
{
  g_return_if_fail (root != NULL);
  
  if (!G_NODE_IS_ROOT (root))
    g_node_unlink (root);
  
  g_nodes_free (root);
}

void
g_node_unlink (GNode *node)
{
  g_return_if_fail (node != NULL);
  
  if (node->prev)
    node->prev->next = node->next;
  else if (node->parent)
    node->parent->children = node->next;
  node->parent = NULL;
  if (node->next)
    {
      node->next->prev = node->prev;
      node->next = NULL;
    }
  node->prev = NULL;
}

GNode*
g_node_insert (GNode *parent,
	       gint   position,
	       GNode *node)
{
  g_return_val_if_fail (parent != NULL, node);
  g_return_val_if_fail (node != NULL, node);
  g_return_val_if_fail (G_NODE_IS_ROOT (node), node);
  
  if (position > 0)
    return g_node_insert_before (parent,
				 g_node_nth_child (parent, position),
				 node);
  else if (position == 0)
    return g_node_prepend (parent, node);
  else /* if (position < 0) */
    return g_node_append (parent, node);
}

GNode*
g_node_insert_before (GNode *parent,
		      GNode *sibling,
		      GNode *node)
{
  g_return_val_if_fail (parent != NULL, node);
  g_return_val_if_fail (node != NULL, node);
  g_return_val_if_fail (G_NODE_IS_ROOT (node), node);
  if (sibling)
    g_return_val_if_fail (sibling->parent == parent, node);
  
  node->parent = parent;
  
  if (sibling)
    {
      if (sibling->prev)
	{
	  node->prev = sibling->prev;
	  node->prev->next = node;
	  node->next = sibling;
	  sibling->prev = node;
	}
      else
	{
	  node->parent->children = node;
	  node->next = sibling;
	  sibling->prev = node;
	}
    }
  else
    {
      if (parent->children)
	{
	  sibling = parent->children;
	  while (sibling->next)
	    sibling = sibling->next;
	  node->prev = sibling;
	  sibling->next = node;
	}
      else
	node->parent->children = node;
    }

  return node;
}

GNode*
g_node_prepend (GNode *parent,
		GNode *node)
{
  g_return_val_if_fail (parent != NULL, node);
  
  return g_node_insert_before (parent, parent->children, node);
}

GNode*
g_node_get_root (GNode *node)
{
  g_return_val_if_fail (node != NULL, NULL);
  
  while (node->parent)
    node = node->parent;
  
  return node;
}

gboolean
g_node_is_ancestor (GNode *node,
		    GNode *descendant)
{
  g_return_val_if_fail (node != NULL, FALSE);
  g_return_val_if_fail (descendant != NULL, FALSE);
  
  while (descendant)
    {
      if (descendant->parent == node)
	return TRUE;
      
      descendant = descendant->parent;
    }
  
  return FALSE;
}

/* returns 1 for root, 2 for first level children,
 * 3 for children's children...
 */
guint
g_node_depth (GNode *node)
{
  register guint depth = 0;
  
  while (node)
    {
      depth++;
      node = node->parent;
    }
  
  return depth;
}

void
g_node_reverse_children (GNode *node)
{
  GNode *child;
  GNode *last;
  
  g_return_if_fail (node != NULL);
  
  child = node->children;
  last = NULL;
  while (child)
    {
      last = child;
      child = last->next;
      last->next = last->prev;
      last->prev = child;
    }
  node->children = last;
}

guint
g_node_max_height (GNode *root)
{
  register GNode *child;
  register guint max_height = 0;
  
  if (!root)
    return 0;
  
  child = root->children;
  while (child)
    {
      register guint tmp_height;
      
      tmp_height = g_node_max_height (child);
      if (tmp_height > max_height)
	max_height = tmp_height;
      child = child->next;
    }
  
  return max_height + 1;
}

static gboolean
g_node_traverse_pre_order (GNode	    *node,
			   GTraverseFlags    flags,
			   GNodeTraverseFunc func,
			   gpointer	     data)
{
  if (node->children)
    {
      GNode *child;
      
      if ((flags & G_TRAVERSE_NON_LEAFS) &&
	  func (node, data))
	return TRUE;
      
      child = node->children;
      while (child)
	{
	  register GNode *current;
	  
	  current = child;
	  child = current->next;
	  if (g_node_traverse_pre_order (current, flags, func, data))
	    return TRUE;
	}
    }
  else if ((flags & G_TRAVERSE_LEAFS) &&
	   func (node, data))
    return TRUE;
  
  return FALSE;
}

static gboolean
g_node_depth_traverse_pre_order (GNode		  *node,
				 GTraverseFlags	   flags,
				 guint		   depth,
				 GNodeTraverseFunc func,
				 gpointer	   data)
{
  if (node->children)
    {
      GNode *child;
      
      if ((flags & G_TRAVERSE_NON_LEAFS) &&
	  func (node, data))
	return TRUE;
      
      depth--;
      if (!depth)
	return FALSE;
      
      child = node->children;
      while (child)
	{
	  register GNode *current;
	  
	  current = child;
	  child = current->next;
	  if (g_node_depth_traverse_pre_order (current, flags, depth, func, data))
	    return TRUE;
	}
    }
  else if ((flags & G_TRAVERSE_LEAFS) &&
	   func (node, data))
    return TRUE;
  
  return FALSE;
}

static gboolean
g_node_traverse_post_order (GNode	     *node,
			    GTraverseFlags    flags,
			    GNodeTraverseFunc func,
			    gpointer	      data)
{
  if (node->children)
    {
      GNode *child;
      
      child = node->children;
      while (child)
	{
	  register GNode *current;
	  
	  current = child;
	  child = current->next;
	  if (g_node_traverse_post_order (current, flags, func, data))
	    return TRUE;
	}
      
      if ((flags & G_TRAVERSE_NON_LEAFS) &&
	  func (node, data))
	return TRUE;
      
    }
  else if ((flags & G_TRAVERSE_LEAFS) &&
	   func (node, data))
    return TRUE;
  
  return FALSE;
}

static gboolean
g_node_depth_traverse_post_order (GNode		   *node,
				  GTraverseFlags    flags,
				  guint		    depth,
				  GNodeTraverseFunc func,
				  gpointer	    data)
{
  if (node->children)
    {
      depth--;
      if (depth)
	{
	  GNode *child;
	  
	  child = node->children;
	  while (child)
	    {
	      register GNode *current;
	      
	      current = child;
	      child = current->next;
	      if (g_node_depth_traverse_post_order (current, flags, depth, func, data))
		return TRUE;
	    }
	}
      
      if ((flags & G_TRAVERSE_NON_LEAFS) &&
	  func (node, data))
	return TRUE;
      
    }
  else if ((flags & G_TRAVERSE_LEAFS) &&
	   func (node, data))
    return TRUE;
  
  return FALSE;
}

static gboolean
g_node_traverse_in_order (GNode		   *node,
			  GTraverseFlags    flags,
			  GNodeTraverseFunc func,
			  gpointer	    data)
{
  if (node->children)
    {
      GNode *child;
      register GNode *current;
      
      child = node->children;
      current = child;
      child = current->next;
      
      if (g_node_traverse_in_order (current, flags, func, data))
	return TRUE;
      
      if ((flags & G_TRAVERSE_NON_LEAFS) &&
	  func (node, data))
	return TRUE;
      
      while (child)
	{
	  current = child;
	  child = current->next;
	  if (g_node_traverse_in_order (current, flags, func, data))
	    return TRUE;
	}
    }
  else if ((flags & G_TRAVERSE_LEAFS) &&
	   func (node, data))
    return TRUE;
  
  return FALSE;
}

static gboolean
g_node_depth_traverse_in_order (GNode		 *node,
				GTraverseFlags	  flags,
				guint		  depth,
				GNodeTraverseFunc func,
				gpointer	  data)
{
  if (node->children)
    {
      depth--;
      if (depth)
	{
	  GNode *child;
	  register GNode *current;
	  
	  child = node->children;
	  current = child;
	  child = current->next;
	  
	  if (g_node_depth_traverse_in_order (current, flags, depth, func, data))
	    return TRUE;
	  
	  if ((flags & G_TRAVERSE_NON_LEAFS) &&
	      func (node, data))
	    return TRUE;
	  
	  while (child)
	    {
	      current = child;
	      child = current->next;
	      if (g_node_depth_traverse_in_order (current, flags, depth, func, data))
		return TRUE;
	    }
	}
      else if ((flags & G_TRAVERSE_NON_LEAFS) &&
	       func (node, data))
	return TRUE;
    }
  else if ((flags & G_TRAVERSE_LEAFS) &&
	   func (node, data))
    return TRUE;
  
  return FALSE;
}

static gboolean
g_node_traverse_children (GNode		    *node,
			  GTraverseFlags     flags,
			  GNodeTraverseFunc  func,
			  gpointer	     data)
{
  GNode *child;
  
  child = node->children;
  
  while (child)
    {
      register GNode *current;
      
      current = child;
      child = current->next;
      
      if (current->children)
	{
	  if ((flags & G_TRAVERSE_NON_LEAFS) &&
	      func (current, data))
	    return TRUE;
	}
      else if ((flags & G_TRAVERSE_LEAFS) &&
	       func (current, data))
	return TRUE;
    }
  
  child = node->children;
  
  while (child)
    {
      register GNode *current;
      
      current = child;
      child = current->next;
      
      if (current->children &&
	  g_node_traverse_children (current, flags, func, data))
	return TRUE;
    }
  
  return FALSE;
}

static gboolean
g_node_depth_traverse_children (GNode		 *node,
				GTraverseFlags	  flags,
				guint		  depth,
				GNodeTraverseFunc func,
				gpointer	  data)
{
  GNode *child;
  
  child = node->children;
  
  while (child)
    {
      register GNode *current;
      
      current = child;
      child = current->next;
      
      if (current->children)
	{
	  if ((flags & G_TRAVERSE_NON_LEAFS) &&
	      func (current, data))
	    return TRUE;
	}
      else if ((flags & G_TRAVERSE_LEAFS) &&
	       func (current, data))
	return TRUE;
    }
  
  depth--;
  if (!depth)
    return FALSE;
  
  child = node->children;
  
  while (child)
    {
      register GNode *current;
      
      current = child;
      child = current->next;
      
      if (current->children &&
	  g_node_depth_traverse_children (current, flags, depth, func, data))
	return TRUE;
    }
  
  return FALSE;
}

void
g_node_traverse (GNode		  *root,
		 GTraverseType	   order,
		 GTraverseFlags	   flags,
		 gint		   depth,
		 GNodeTraverseFunc func,
		 gpointer	   data)
{
  g_return_if_fail (root != NULL);
  g_return_if_fail (func != NULL);
  g_return_if_fail (order <= G_LEVEL_ORDER);
  g_return_if_fail (flags <= G_TRAVERSE_MASK);
  g_return_if_fail (depth == -1 || depth > 0);
  
  switch (order)
    {
    case G_PRE_ORDER:
      if (depth < 0)
	g_node_traverse_pre_order (root, flags, func, data);
      else
	g_node_depth_traverse_pre_order (root, flags, depth, func, data);
      break;
    case G_POST_ORDER:
      if (depth < 0)
	g_node_traverse_post_order (root, flags, func, data);
      else
	g_node_depth_traverse_post_order (root, flags, depth, func, data);
      break;
    case G_IN_ORDER:
      if (depth < 0)
	g_node_traverse_in_order (root, flags, func, data);
      else
	g_node_depth_traverse_in_order (root, flags, depth, func, data);
      break;
    case G_LEVEL_ORDER:
      if (root->children)
	{
	  if (!((flags & G_TRAVERSE_NON_LEAFS) &&
		func (root, data)))
	    {
	      if (depth < 0)
		g_node_traverse_children (root, flags, func, data);
	      else
		{
		  depth--;
		  if (depth)
		    g_node_depth_traverse_children (root, flags, depth, func, data);
		}
	    }
	}
      else if (flags & G_TRAVERSE_LEAFS)
	func (root, data);
      break;
    }
}

static gboolean
g_node_find_func (GNode	  *node,
		  gpointer data)
{
  register gpointer *d = data;
  
  if (*d != node->data)
    return FALSE;
  
  *(++d) = node;
  
  return TRUE;
}

GNode*
g_node_find (GNode	       *root,
	     GTraverseType	order,
	     GTraverseFlags	flags,
	     gpointer		data)
{
  gpointer d[2];
  
  g_return_val_if_fail (root != NULL, NULL);
  g_return_val_if_fail (order <= G_LEVEL_ORDER, NULL);
  g_return_val_if_fail (flags <= G_TRAVERSE_MASK, NULL);
  
  d[0] = data;
  d[1] = NULL;
  
  g_node_traverse (root, order, flags, -1, g_node_find_func, d);
  
  return d[1];
}

static void
g_node_count_func (GNode	 *node,
		   GTraverseFlags flags,
		   guint	 *n)
{
  if (node->children)
    {
      GNode *child;
      
      if (flags & G_TRAVERSE_NON_LEAFS)
	(*n)++;
      
      child = node->children;
      while (child)
	{
	  g_node_count_func (child, flags, n);
	  child = child->next;
	}
    }
  else if (flags & G_TRAVERSE_LEAFS)
    (*n)++;
}

guint
g_node_n_nodes (GNode	      *root,
		GTraverseFlags flags)
{
  guint n = 0;
  
  g_return_val_if_fail (root != NULL, 0);
  g_return_val_if_fail (flags <= G_TRAVERSE_MASK, 0);
  
  g_node_count_func (root, flags, &n);
  
  return n;
}

GNode*
g_node_last_child (GNode *node)
{
  g_return_val_if_fail (node != NULL, NULL);
  
  node = node->children;
  if (node)
    while (node->next)
      node = node->next;
  
  return node;
}

GNode*
g_node_nth_child (GNode *node,
		  guint	 n)
{
  g_return_val_if_fail (node != NULL, NULL);
  
  node = node->children;
  if (node)
    while ((n-- > 0) && node)
      node = node->next;
  
  return node;
}

guint
g_node_n_children (GNode *node)
{
  guint n = 0;
  
  g_return_val_if_fail (node != NULL, 0);
  
  node = node->children;
  while (node)
    {
      n++;
      node = node->next;
    }
  
  return n;
}

GNode*
g_node_find_child (GNode	 *node,
		   GTraverseFlags flags,
		   gpointer	  data)
{
  g_return_val_if_fail (node != NULL, NULL);
  g_return_val_if_fail (flags <= G_TRAVERSE_MASK, NULL);
  
  node = node->children;
  while (node)
    {
      if (node->data == data)
	{
	  if (G_NODE_IS_LEAF (node))
	    {
	      if (flags & G_TRAVERSE_LEAFS)
		return node;
	    }
	  else
	    {
	      if (flags & G_TRAVERSE_NON_LEAFS)
		return node;
	    }
	}
      node = node->next;
    }
  
  return NULL;
}

gint
g_node_child_position (GNode *node,
		       GNode *child)
{
  register guint n = 0;
  
  g_return_val_if_fail (node != NULL, -1);
  g_return_val_if_fail (child != NULL, -1);
  g_return_val_if_fail (child->parent == node, -1);
  
  node = node->children;
  while (node)
    {
      if (node == child)
	return n;
      n++;
      node = node->next;
    }
  
  return -1;
}

gint
g_node_child_index (GNode   *node,
		    gpointer data)
{
  register guint n = 0;
  
  g_return_val_if_fail (node != NULL, -1);
  
  node = node->children;
  while (node)
    {
      if (node->data == data)
	return n;
      n++;
      node = node->next;
    }
  
  return -1;
}

GNode*
g_node_first_sibling (GNode *node)
{
  g_return_val_if_fail (node != NULL, NULL);
  
  while (node->prev)
    node = node->prev;
  
  return node;
}

GNode*
g_node_last_sibling (GNode *node)
{
  g_return_val_if_fail (node != NULL, NULL);
  
  while (node->next)
    node = node->next;
  
  return node;
}

void
g_node_children_foreach (GNode		 *node,
			 GTraverseFlags	  flags,
			 GNodeForeachFunc func,
			 gpointer	  data)
{
  g_return_if_fail (node != NULL);
  g_return_if_fail (flags <= G_TRAVERSE_MASK);
  g_return_if_fail (func != NULL);
  
  node = node->children;
  while (node)
    {
      register GNode *current;
      
      current = node;
      node = current->next;
      if (G_NODE_IS_LEAF (current))
	{
	  if (flags & G_TRAVERSE_LEAFS)
	    func (current, data);
	}
      else
	{
	  if (flags & G_TRAVERSE_NON_LEAFS)
	    func (current, data);
	}
    }
}