tree.h

/* Copyright (C) 2000 MySQL AB

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; version 2 of the License.

   This program 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 General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA */

#pragma once

#include <unistd.h>

#include <drizzled/base.h>    // for 'enum ha_rkey_function'
#include <drizzled/memory/root.h>
#include <drizzled/qsort_cmp.h>

namespace drizzled
{

// Worst case tree is half full. This gives us 2^(MAX_TREE_HEIGHT/2) leaves
static const int MAX_TREE_HEIGHT= 64;

static const int TREE_NO_DUPS= 1;

typedef enum { left_root_right, right_root_left } TREE_WALK;
typedef int (*tree_walk_action)(void *,uint32_t,void *);

typedef enum { free_init, free_free, free_end } TREE_FREE;
typedef void (*tree_element_free)(void*, TREE_FREE, void *);


class Tree_Element
{
public:
  Tree_Element *left,*right;
  uint32_t count:31,
       colour:1;      /* black is marked as 1 */
};

static const int TREE_ELEMENT_EXTRA_SIZE= (sizeof(Tree_Element) + sizeof(void*));

class Tree
{
private:
  Tree_Element *root, null_element;
  void *custom_arg;
  Tree_Element **parents[MAX_TREE_HEIGHT];
  uint32_t offset_to_key, elements_in_tree, size_of_element;
  size_t memory_limit;
  size_t allocated;
  qsort_cmp2 compare;
  memory::Root mem_root;
  bool with_delete;
  tree_element_free free;
  uint32_t flag;

public:
  void* getCustomArg() {
    return custom_arg;
  }
  Tree_Element* getRoot() {
    return root;
  }
  void setRoot(Tree_Element* root_arg) {
    root = root_arg;
  }
  uint32_t getElementsInTree() {
    return elements_in_tree;
  }
  // tree methods
  void init_tree(size_t default_alloc_size, uint32_t memory_limit,
           uint32_t size, qsort_cmp2 compare, bool with_delete,
           tree_element_free free_element, void *custom_arg);
  bool is_inited()
  {
    return this->root != 0;
  }
  void delete_tree();
  void reset_tree();

  // element methods
  Tree_Element *tree_insert(void *key, uint32_t key_size, void *custom_arg);
  int tree_walk(tree_walk_action action, void *argument, TREE_WALK visit);

private:
  void free_tree(myf free_flags);

  void* element_key(Tree_Element* element);
  void delete_tree_element(Tree_Element* element);
  int tree_walk_left_root_right(Tree_Element* element, tree_walk_action action, void* argument);
  int tree_walk_right_root_left(Tree_Element* element, tree_walk_action action, void* argument);

  void left_rotate(Tree_Element **parent,Tree_Element *element);
  void right_rotate(Tree_Element **parent, Tree_Element *element);
  void rb_insert(Tree_Element ***parent, Tree_Element *element);
};

} /* namespace drizzled */