/* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */
/*
 *  Main authors:
 *     Christian Schulte <schulte@gecode.org>
 *
 *  Copyright:
 *     Christian Schulte, 2009
 *
 *  Last modified:
 *     $Date: 2009-05-12 22:21:02 +1000 (Tue, 12 May 2009) $ by $Author: schulte $
 *     $Revision: 9063 $
 *
 *  This file is part of Gecode, the generic constraint
 *  development environment:
 *     http://www.gecode.org
 *
 *  Permission is hereby granted, free of charge, to any person obtaining
 *  a copy of this software and associated documentation files (the
 *  "Software"), to deal in the Software without restriction, including
 *  without limitation the rights to use, copy, modify, merge, publish,
 *  distribute, sublicense, and/or sell copies of the Software, and to
 *  permit persons to whom the Software is furnished to do so, subject to
 *  the following conditions:
 *
 *  The above copyright notice and this permission notice shall be
 *  included in all copies or substantial portions of the Software.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 *  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 *  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 *  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 */

#ifndef __GECODE_SEARCH_SEQUENTIAL_RESTART_HH__
#define __GECODE_SEARCH_SEQUENTIAL_RESTART_HH__

#include <gecode/search/sequential/dfs.hh>

namespace Gecode { namespace Search { namespace Sequential {

  /// Depth-first restart best solution search engine implementation
  class Restart : public DFS {
  protected:
    /// Root node
    Space* root;
    /// So-far best solution
    Space* best;
  public:
    /// Initialize engine for space \a s (with size \a sz) and options \a o
    Restart(Space* s, size_t sz, const Search::Options& o);
    /// Return next better solution (NULL, if none exists or search has been stopped)
    Space* next(void);
    /// Destructor
    ~Restart(void);
  };

  forceinline 
  Restart::Restart(Space* s, size_t sz, const Search::Options& o) :
    DFS(s,sz,o),
    root(s->status() == SS_FAILED ? NULL : s->clone()), best(NULL) {}

  forceinline Space*
  Restart::next(void) {
    if (best != NULL) {
      root->constrain(*best);
      root = reset(root);
    }
    if (root == NULL)
      return NULL;
    delete best;
    best = DFS::next();
    return (best != NULL) ? best->clone() : NULL;
  }

  forceinline 
  Restart::~Restart(void) {
    delete best;
    delete root;
  }

}}}

#endif

// STATISTICS: search-sequential