dfa_bin.h

/*
 * ASTL - the Automaton Standard Template Library.
 * C++ generic components for Finite State Automata handling.
 * Copyright (C) 2000-2003 Vincent Le Maout (vincent.lemaout@chello.fr).
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library 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
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#ifndef ASTL_DFA_BIN_H
#define ASTL_DFA_BIN_H


#include <dfa_base.h>
#include <vector>
#include <algorithm>    // lower_bound()
#include <utility>      // pair<>
#include <functional>

namespace astl {

template <class Sigma_ = plain, 
          class Tag_   = empty_tag>
class DFA_bin 
  : public DFA_base<Sigma_, Tag_, 
                    vector<pair<typename Sigma_::char_type, unsigned int> > >
{
public:
  typedef DFA_base<Sigma_, Tag_, vector<pair<typename Sigma_::char_type, 
                                             unsigned int> > > super;
  typedef DFA_bin                    self;
  typedef Sigma_                     char_traits;
  typedef Tag_                       tag_type;
  typedef typename Sigma_::char_type char_type;
  typedef unsigned int               state_type;
  using super::null_state;
  
  // Backward compatibility
  typedef char_traits Sigma;
  typedef char_type   Alphabet;
  typedef tag_type    Tag;
  typedef state_type  State;

protected:
  typedef vector<pair<typename Sigma_::char_type, 
                      unsigned int> > transition_container;
  mutable pair<char_type, unsigned int> p;  // optimization
        
public:
  class edges_type
  {
    friend class DFA_bin;
  protected:
    const transition_container *container;

  public:
    typedef char_type                 key_type;
    typedef state_type                data_type;
    typedef pair<key_type, data_type> value_type;
    typedef value_type*               pointer;
    typedef const value_type*         const_pointer;
    typedef value_type&               reference;
    typedef const value_type&         const_reference;
    typedef unsigned int              size_type;
    typedef int                       difference_type;

    struct key_compare : public binary_function<key_type, key_type, bool>
    {
      bool operator () (const key_type &x, const key_type &y) const {
        return char_traits::lt(x, y);
      }
    }; 
    
    struct value_compare : public binary_function<value_type, value_type, bool>
    {
      bool operator () (const value_type &x, const value_type &y) const {
        return self::char_traits::lt(x.first, y.first);
      }
    }; 

    typedef typename transition_container::const_iterator         
    const_iterator ;
    typedef typename transition_container::const_reverse_iterator 
    const_reverse_iterator ;

    // allocation/deallocation:
    edges_type(const transition_container *c = NULL)
      : container(c) 
    { }
    
    const_iterator begin() const { 
      return container->begin(); 
    }
    const_iterator end() const { 
      return container->end(); 
    }

    const_reverse_iterator rbegin() const { 
      return container->rbegin(); 
    }
    const_reverse_iterator rend() const { 
      return container->rend(); 
    }

    bool empty() const { 
      return container->empty(); 
    }

    size_type size() const { 
      return container->size(); 
    }

    size_type max_size() const { 
      return container->max_size(); 
    }
    
    // map operations:
    key_compare key_comp() const {
      return key_compare();
    }

    value_compare value_comp() const {
      return value_compare();
    }

    const_iterator find(const key_type& x) const { 
      typename transition_container::const_iterator i = 
        std::lower_bound(container->begin(), container->end(), 
                         make_pair(x, 0), value_compare());

      if (i == container->end() || (*i).first != x)
        return container->end();
      else
        return i;
    }

    size_type count(const key_type& x) const { 
      return find(x) == end() ? 0 : 1;
    }

    const_iterator lower_bound(const key_type& x) const {
      return std::lower_bound(container->begin(), container->end(), 
                              make_pair(x, 0), value_compare()); 
    }

    const_iterator upper_bound(const key_type& x) const { 
      return std::upper_bound(container->begin(), container->end(), 
                              make_pair(x, 0), value_compare());
    }

    pair<const_iterator, const_iterator> equal_range(const key_type& x) const {
      return std::equal_range(container->begin(), container->end(),
                              make_pair(x, 0), value_compare());
    }
    
    friend bool operator == (const edges_type& x, const edges_type& y) {
      return x.container == y.container || *x.container == *y.container;
    }
  };

  typedef edges_type Edges;

  void set_trans(state_type s, const char_type &a, state_type aim)
  {
    p.first = a;
    p.second = aim;
    Q[s]->edges().insert(lower_bound(Q[s]->edges().begin(), 
                                     Q[s]->edges().end(), p, 
                                     typename edges_type::value_compare()), p);
    ++trans_count_;
  }

  void del_trans(state_type s, const char_type &a)
  {
    p.first = a;
    Q[s]->edges().erase(lower_bound(Q[s]->edges().begin(), 
                                    Q[s]->edges().end(), p, 
                                    typename edges_type::value_compare()));
    --trans_count_;
  }

  void change_trans(state_type s, const char_type &a, state_type new_aim) {
    p.first = a;
    (*lower_bound(Q[s]->edges().begin(), Q[s]->edges().end(), 
                  p, typename edges_type::value_compare())).second = new_aim;
  }

  state_type delta1(state_type s, const char_type &a) const
  {
    p.first = a;
    typename transition_container::const_iterator i = 
      lower_bound(Q[s]->edges().begin(), Q[s]->edges().end(), 
                  p, typename edges_type::value_compare());

    return (i == Q[s]->edges().end() || 
            !((*i).first == a)) ? null_state : (*i).second;
  }

  edges_type delta2(state_type s) const {
    return edges_type(&Q[s]->edges()); 
  }

  DFA_bin(unsigned long n = 0)
    : super(n)
  {}

protected:
  using super::Q;
  using super::trans_count_;
};

} // namespace astl

#endif

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