~drizzle-trunk/drizzle/development

/* -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-

 *  vim:expandtab:shiftwidth=2:tabstop=2:smarttab:

 *

 *  Copyright (C) 2008-2009 Sun Microsystems, Inc.

 *

 *  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

 */

#include <config.h>

#include <drizzled/sql_base.h>

#include <drizzled/sql_select.h>

#include <drizzled/memory/sql_alloc.h>

#include <drizzled/optimizer/range.h>

#include <drizzled/optimizer/range_param.h>

#include <drizzled/optimizer/sel_arg.h>

#include <drizzled/optimizer/sel_tree.h>

#include <drizzled/optimizer/sel_imerge.h>

using namespace std;

using namespace drizzled;

optimizer::SEL_IMERGE::SEL_IMERGE() 

  :

    trees(&trees_prealloced[0]),

    trees_next(trees),

    trees_end(trees + PREALLOCED_TREES)

{}

int optimizer::SEL_IMERGE::or_sel_tree(optimizer::RangeParameter *param, optimizer::SEL_TREE *tree)

{

  if (trees_next == trees_end)

  {

    const int realloc_ratio= 2;		/* Double size for next round */

    uint32_t old_elements= (trees_end - trees);

    uint32_t old_size= sizeof(optimizer::SEL_TREE**) * old_elements;

    uint32_t new_size= old_size * realloc_ratio;

    optimizer::SEL_TREE **new_trees= NULL;

    if (! (new_trees= (optimizer::SEL_TREE**) param->mem_root->alloc_root(new_size)))

      return -1;

    memcpy(new_trees, trees, old_size);

    trees= new_trees;

    trees_next= trees + old_elements;

    trees_end= trees + old_elements * realloc_ratio;

  }

  *(trees_next++)= tree;

  return 0;

}

int optimizer::SEL_IMERGE::or_sel_tree_with_checks(optimizer::RangeParameter *param, optimizer::SEL_TREE *new_tree)

{

  for (optimizer::SEL_TREE** tree = trees;

       tree != trees_next;

       tree++)

  {

    if (sel_trees_can_be_ored(*tree, new_tree, param))

    {

      *tree = tree_or(param, *tree, new_tree);

      if (!*tree)

        return 1;

      if (((*tree)->type == optimizer::SEL_TREE::MAYBE) ||

          ((*tree)->type == optimizer::SEL_TREE::ALWAYS))

        return 1;

      /* optimizer::SEL_TREE::IMPOSSIBLE is impossible here */

      return 0;

    }

  }

  /* New tree cannot be combined with any of existing trees. */

  return or_sel_tree(param, new_tree);

}

int optimizer::SEL_IMERGE::or_sel_imerge_with_checks(optimizer::RangeParameter *param, optimizer::SEL_IMERGE* imerge)

{

  for (optimizer::SEL_TREE** tree= imerge->trees;

       tree != imerge->trees_next;

       tree++)

  {

    if (or_sel_tree_with_checks(param, *tree))

      return 1;

  }

  return 0;

}