sel_imerge.cc

/* -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-
 *  vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
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 *  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)
{}


void optimizer::SEL_IMERGE::or_sel_tree(optimizer::RangeParameter *param, optimizer::SEL_TREE *tree)
{
  if (trees_next == trees_end)
  {
    uint32_t old_elements= trees_end - trees;
    optimizer::SEL_TREE** new_trees= new (*param->mem_root) optimizer::SEL_TREE*[2 * old_elements];
    memcpy(new_trees, trees, sizeof(optimizer::SEL_TREE**) * old_elements);
    trees= new_trees;
    trees_next= trees + old_elements;
    trees_end= trees + 2 * old_elements;
  }
  *(trees_next++)= tree;
}


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 == SEL_TREE::MAYBE) ||
          ((*tree)->type == SEL_TREE::ALWAYS))
        return 1;
      /* optimizer::SEL_TREE::IMPOSSIBLE is impossible here */
      return 0;
    }
  }

  /* New tree cannot be combined with any of existing trees. */
  or_sel_tree(&param, &new_tree);
  return 0;
}


int optimizer::SEL_IMERGE::or_sel_imerge_with_checks(RangeParameter& param, SEL_IMERGE& imerge)
{
  for (SEL_TREE** tree= imerge.trees; tree != imerge.trees_next; tree++)
  {
    if (or_sel_tree_with_checks(param, **tree))
      return 1;
  }
  return 0;
}