Flags.hxx

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/*
 * Copyright (c) 2001-2004 MUSIC TECHNOLOGY GROUP (MTG)
 *                         UNIVERSITAT POMPEU FABRA
 *
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#ifndef _Flags_hxx_
#define _Flags_hxx_

#include <bitset>
#include <string>
#include <iosfwd>
#include "Component.hxx"
// TODO: This is provisional to share the IllegalValue exception
#include "Enum.hxx"

namespace CLAM {


class FlagsBase : public Component {
// Internal Types
public:
        typedef unsigned int tValue;
        typedef struct {tValue value; const char*name;} tFlagValue;

// Attributes
protected:
        const tFlagValue * mFlagValues;

// Operations
public:
        virtual unsigned int GetNFlags() const=0;
        virtual void SetFlag(unsigned int whichOne, bool value)=0;
        virtual bool IsSetFlag(unsigned int whichOne) const =0;
        std::string GetFlagString(unsigned int whichOne) const throw (IllegalValue);

        unsigned int GetFlagPosition(const std::string & whichOne) const throw (IllegalValue);

        /*
         * Stores component's subitems on the given Storage
         * @param store The given storage where the subitem will be stored
         * @see Storage
         * @todo TODO: This method can throw and IllegalValue exception
         */
        virtual void StoreOn (Storage & storage) const;

        /*
         * Loads component's subitems from the given Storage
         * @param store The given storage where the subitem will be stored
         * @see Storage
         * @todo TODO: This method can throw and IllegalValue exception
         */
        virtual void LoadFrom (Storage & storage);

// Debug
public:
        inline bool CheckInvariant();
};

std::istream & operator >> (std::istream & is, FlagsBase & f);
std::ostream & operator << (std::ostream & os, const FlagsBase & f);

template <unsigned int N> class Flags : public FlagsBase, public std::bitset<N>
{
// Construction/Destruction
protected:
        Flags(tFlagValue * names) : std::bitset<N>() {
                mFlagValues=names;
        };
        Flags(tFlagValue * names, const Flags<N> &t) : std::bitset<N>() {
                mFlagValues=names;
        };
        template <class T> Flags(tFlagValue * names,const T &t) : std::bitset<N>(t) {
                mFlagValues=names;
        };
        template <class T1, class T2> Flags(tFlagValue * names,const T1 &t1,const T2 &t2) : 
                std::bitset<N>(t1, t2)
        {
                mFlagValues=names;
        };
public:
        virtual ~Flags ()  {};

        const char * GetClassName() const {return NULL;}

// Operators
public:
        virtual unsigned int GetNFlags () const {
                return N;
        }
protected:
        virtual bool IsSetFlag(unsigned int whichOne) const {
                return std::bitset<N>::test(whichOne);
        }
        virtual void SetFlag(unsigned int whichOne, bool value=true) {
                this->set(whichOne, value);
        }

// Component Protocol
public:
        virtual Component * Species () const = 0;

        virtual Component * DeepCopy () const {
                Flags<N> * pe = (Flags<N>*)Species();
                *pe=*this;
                return pe;
        }

        virtual Component * ShallowCopy () const {
                Flags<N> * pe = (Flags<N>*)Species();
                *pe=*this;
                return pe;
        }

};

//MRJ: Why this? There exists a fairly well known issue about
//VC6 support of template base classes, where polymorphism usual assumptions
//don't hold. In this case we introduce two proxy methods that
//just "inform" the compiler about what it has to do next... to promote
//the references to the derived class object into references to the
//base class. Sad but true. In discharge of MS guys this seems to be no
//longer needed in VC++ 7.1. We could have implemented the body of the methods
//inline on the header, but would have prevented us from using the compile-time
//saving usage of the <iosfwd> header.

#ifdef _MSC_VER
template <unsigned int N>
std::istream & operator >> (std::istream & is, Flags<N> & f) {
        return (is >>  static_cast<FlagsBase&>(f) );
}

template <unsigned int N>
std::ostream & operator << (std::ostream & os, const Flags<N> & f){
        return (os << static_cast<const FlagsBase&>(f));
}
#endif //_MSC_VER

}

#endif//_Flags_hxx_