/* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */
/*
 *  Main authors:
 *     Guido Tack <tack@gecode.org>
 *
 *  Contributing authors:
 *     Christian Schulte <schulte@gecode.org>
 *
 *  Copyright:
 *     Guido Tack, 2007
 *     Christian Schulte, 2007
 *
 *  Last modified:
 *     $Date: 2008-07-11 09:32:27 +0200 (Fri, 11 Jul 2008) $ by $Author: tack $
 *     $Revision: 7289 $
 *
 *  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.
 *
 */

#include <iostream>

namespace Gecode { namespace Support {
  
  /** \brief Immutable Symbols
    *
    */
  class GECODE_SUPPORT_EXPORT Symbol {
  private:
    
    /** \brief Reference-counted Symbol objects
      *
      */
    class SO {
    public:
      /// Duplicate string \a s
      static char* strdup(const char* s);
      /// The reference count
      unsigned int use_cnt;
      /// Reference counting: cancel subscription
      bool cancel(void);
      /// Reference counting: subscribe to an SO
      void subscribe(void);

      /// The actual Symbol
      char* s;
      /// Whether the SO owns the Symbol
      bool own;

      /// Construct from a given Symbol \a s0, which is copied if \a copy is true.
      SO(const char* s0, bool copy);
      /// Append \a s0
      void append(SO* s0);
      /// Compare with \a other for equality
      bool eq(const SO* other) const;
      /// Compare with \a other for equality
      bool eq(const char* other) const;
      /// Return size of the Symbol
      unsigned int size(void) const;
      /// Hash value according to modulo \a M
      int hash(int m) const;
      /// Output to \a os
      std::ostream& print(std::ostream& os) const;
      /// Allocate memory from heap
      static void* operator new(size_t s);
      /// Free memory allocated from heap
      static void  operator delete(void* p);
    };

    /// The Symbol object
    SO* so;
  public:
    /// Construct empty Symbol
    Symbol(void);
    /// Construct Symbol from \a s0, make a copy if \a copy is true.
    Symbol(const char* s0, bool copy = false);
    /// Construct Symbol from \a i
    Symbol(int i);
    /// Construct Symbol from \a i
    Symbol(unsigned int i);
    /// Copy constructor
    Symbol(const Symbol& s0);
    /// Assignment operator
    const Symbol& operator=(const Symbol& s0);
    /// Test if this Symbol is equal to \a s0
    bool operator==(const Symbol& s0) const;
    /// Test if this Symbol is equal to \a s0
    bool operator==(const char* s0) const;
    /// Return if Symbol is empty
    bool empty(void) const;
    /// Return a copy
    Symbol copy(void) const;
    /// Concatenate with \a s
    Symbol& operator+=(const Symbol& s);
    /// Hash value according to modulo \a M
    int hash(int m) const;
    /// Print this Symbol to \a os
    std::ostream& print(std::ostream& os) const;    
    /// Return the Symbol as string
    std::string toString(void) const;
    /// Destructor
    GECODE_MSC_VIRTUAL ~Symbol(void);
  };
  
}}

forceinline
std::ostream&
operator<<(std::ostream& os, const Gecode::Support::Symbol& x) {
  return x.print(os);
}

// STATISTICS: support-any