Trail.hxx

Go to the documentation of this file.

#ifndef TRAIL_HXX
#define TRAIL_HXX

/**************************************************************************
 *
 * Copyright (C) 2008, Johns Hopkins University.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or
 * without modification, are permitted provided that the following
 * conditions are met:
 *
 *   - Redistributions of source code must contain the above 
 *     copyright notice, this list of conditions, and the following
 *     disclaimer. 
 *
 *   - Redistributions in binary form must reproduce the above
 *     copyright notice, this list of conditions, and the following
 *     disclaimer in the documentation and/or other materials 
 *     provided with the distribution.
 *
 *   - Neither the names of the copyright holders nor the names of any
 *     of any contributors may be used to endorse or promote products
 *     derived from this software without specific prior written
 *     permission. 
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 **************************************************************************/

#include <stdlib.h>
#include <iostream>
#include <string>

struct Type;

struct Trail {
  std::vector<boost::shared_ptr<Type> > vec;
  
  Trail() 
  {
  }
  
  static inline boost::shared_ptr<Trail>
  make() {
    Trail *tmp = new Trail;
    return boost::shared_ptr<Trail>(tmp);
  }

  size_t snapshot() const { return vec.size(); }
  
  // Substitution works on Type Variables only
  void subst(boost::shared_ptr<Type> from, boost::shared_ptr<Type> to);
  // Generic Link
  void link(boost::shared_ptr<Type> from, boost::shared_ptr<Type> to);
  void rollBack(const size_t upto=0);
  
  void release(const size_t n, boost::shared_ptr<Type> rel);  
};

#endif /* TRAIL_HXX */

---