WeightGen.hpp

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#ifndef wali_nwa_WeightGen_GUARD
#define wali_nwa_WeightGen_GUARD 1

/**
 * @author Amanda Burton
 */

#include "opennwa/ClientInfo.hpp"
#include "wali/Reach.hpp"
#include "wali/ShortestPathSemiring.hpp"


namespace opennwa
{
  using wali::Key; // TODO remove
  using wali::sem_elem_t;
  
    /**
     *
     * This class is used in NWA::NWAtoPDS and NWA::NWAtoBackwardsPDS.  It is used to
     * compute the weights for the rules added to the WPDS and must be extended to 
     * incorporate the desired semiring in order to use either of these methods.
     *  
     */
    //TODO: we may want to split getWeight into getCallWeight/getInternalWeight/getReturnWeight
    class WeightGen
    {
    public:
      //The kinds of edges that need to be considered.
      //  INTRA:  corresponds to an Internal transition in the NWA
      //  CALL_TO_ENTRY:  corresponds to a Call transition in the NWA
      //  EXIT_TO_RET:  corresponds to the exit-to-return part of a Return transition in the NWA
      //  CALL_TO_RET:  corresponds to the call-to-return part of a Return transition in the NWA
      enum Kind {INTRA, CALL_TO_ENTRY, EXIT_TO_RET, CALL_TO_RET}; 
      typedef ref_ptr<ClientInfo> ClientInfoRefPtr;
      
      //
      // Methods
      //
      
    public:
      
      //Constructors and Destructor
      WeightGen( ) { }
      virtual ~WeightGen() {}
        
      /**
       *  
       * @brief access the One of the desired semiring
       *
       * This method returns the One of the desired semiring.  
       *
       * @return the One of the desired semiring
       *
       */
      virtual sem_elem_t getOne( ) const  = 0;

      /**
       *
       * @brief computes the weight(in the desired semiring) for a rule of the WPDS from 
       *        the given edge
       *
       * This method computes the weight(in the desired semiring) for a WPDS rule from 
       * the (kind) edge between 'src' and 'tgt' labeled with symbol 'sym'.
       * Note: The kind will never be CALL_TO_RET, this case is never needed.
       *
       * @param - src: the source of the edge
       * @param - srcInfo: the clientInfo associated with src
       * @param - sym: the symbol labeling the edge
       * @param - kind: the variety of edge
       * @param - tgt: the target of the edge
       * @param - tgtInfo: the clientInfo associated with tgt
       * @return the weight to put on the rule corresponding to the given edge
       *         
       */
      virtual sem_elem_t getWeight( Key src, ClientInfoRefPtr srcInfo, Key sym, Kind kind, Key tgt, ClientInfoRefPtr tgtInfo ) const
      {
        (void) src;
        (void) srcInfo;
        (void) sym;
        (void) kind;
        (void) tgt;
        (void) tgtInfo;
        return getOne();
      }
        
      /** 
       * 
       * @brief computes the weight(in the desired semiring) for the return rule of the 
       *        WPDS associated with the given exit
       *
       * This method computes the weight(in the desired semiring) for the return rule of
       * the WPDS corresponding to the exit 'src'.
       * Note: This value is generally the same as getOne().
       * 
       * @param - src: the source of the exit edge
       * @param - srcInfo: the clientInfo associated with src
       * @return the weight to put on the return rule corresponding to the given exit 
       *
       */
      virtual sem_elem_t getExitWeight( Key src, ClientInfoRefPtr srcInfo ) const
      {
        (void) src;
        (void) srcInfo;
        return getOne();
      }

      /**
       *
       * @brief computes the weight(in the desired semiring) for a rule when the symbol
       *        labeling the corresponding edge in the NWA is the wild symbol
       *
       * This method computes the weight(in the desired semiring) for a WPDS rule from 
       * the edge between 'src' and 'tgt' labeled with the wild symbol.
       *
       * @param - src: the source of the edge
       * @param - srcInfo: the clientInfo associated with src
       * @param - tgt: the target of the edge
       * @param - tgtInfo: the clientInfo associated with tgt
       * @return the weight to put on the rule corresponding to the given edge
       *
       */
      virtual sem_elem_t getWildWeight( Key src, ClientInfoRefPtr srcInfo, Key tgt, ClientInfoRefPtr tgtInfo ) const
      {
        (void) src;
        (void) srcInfo;
        (void) tgt;
        (void) tgtInfo;
        return getOne();
      }
    };



    class ReachGen : public WeightGen
    {
    public:
      //
      // Methods
      //
          
    public:
      sem_elem_t getOne( ) const
      {
        static const Reach r(true);
        return r.one();
      }
    };
  

    class ShortestPathGen : public WeightGen
    {
    public:
      sem_elem_t getOne( ) const
      {
        static const wali::ShortestPathSemiring r;
        return r.one();
      }


      sem_elem_t getUnitWeight() const
      {
        static const sem_elem_t r = new wali::ShortestPathSemiring(1);
        return r;
      }

      virtual sem_elem_t getWeight( Key src, ClientInfoRefPtr srcInfo, Key sym, Kind kind, Key tgt, ClientInfoRefPtr tgtInfo ) const
      {
        (void) src;
        (void) srcInfo;
        (void) sym;
        (void) kind;
        (void) tgt;
        (void) tgtInfo;
        return getUnitWeight();
      }
        
      virtual sem_elem_t getExitWeight( Key src, ClientInfoRefPtr srcInfo ) const
      {
        (void) src;
        (void) srcInfo;
        return getUnitWeight();
      }

      virtual sem_elem_t getWildWeight( Key src, ClientInfoRefPtr srcInfo, Key tgt, ClientInfoRefPtr tgtInfo ) const
      {
        (void) src;
        (void) srcInfo;
        (void) tgt;
        (void) tgtInfo;
        return getUnitWeight();
      }
      
    };


    class ShortestWordGen : public WeightGen
    {
    public:
      // Semiring 1 is length 0
      sem_elem_t getOne( ) const
      {
        static const wali::ShortestPathSemiring r;
        return r.one();
      }


      sem_elem_t getUnitWeight() const
      {
        static const sem_elem_t r = new wali::ShortestPathSemiring(1);
        return r;
      }

      virtual sem_elem_t getWeight( Key src, ClientInfoRefPtr srcInfo, Key sym, Kind kind, Key tgt, ClientInfoRefPtr tgtInfo ) const
      {
        (void) src;
        (void) srcInfo;
        (void) kind;
        (void) tgt;
        (void) tgtInfo;
        if (sym != EPSILON) {
          return getUnitWeight();
        }
        else {
          return getOne();
        }
      }
        
      virtual sem_elem_t getExitWeight( Key src, ClientInfoRefPtr srcInfo ) const
      {
        (void) src;
        (void) srcInfo;
        return getUnitWeight();
      }

      virtual sem_elem_t getWildWeight( Key src, ClientInfoRefPtr srcInfo, Key tgt, ClientInfoRefPtr tgtInfo ) const
      {
        (void) src;
        (void) srcInfo;
        (void) tgt;
        (void) tgtInfo;
        return getUnitWeight();
      }
      
    };
    
}

// Yo, Emacs!
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#endif