WritingRegion.hxx

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/*
 * Copyright (c) 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 __WritingRegion_hxx__
#define __WritingRegion_hxx__

#include "ReadingRegion.hxx"
#include "StreamImpl.hxx"

#include <iostream> // TODO: remove

namespace CLAM
{

template< typename Token, template <class> class DataStructure = PhantomBuffer>
class WritingRegion : public Region
{
public:
        typedef StreamImpl< Token, DataStructure > ProperStream;
        typedef Token ProperToken;
        typedef ReadingRegion< WritingRegion<Token,DataStructure> > ProperReadingRegion;

        WritingRegion();
        virtual ~WritingRegion();

        Region::ReadingRegionsIterator BeginReaders();
        Region::ReadingRegionsIterator EndReaders();
        void LinkRegions( ProperReadingRegion &  reader);
        void RemoveRegion( Region & region );

        void CenterEvenRegions();

        ProperStream& Stream();

        int RearmostReadingPos();
        
        bool CanProduce();
        void Produce();

        Token& operator[](int offset);  // TODO decide if operator[0] is the best option to get the data chunk  
        bool FulfilsInvariant();
        int LogicalStreamSize();
        Region* ProducerRegion();

        void ClearData();


        /*
         * Synchronizes Follower Region and returns last written Tokens
         */
        Token & GetLastWrittenData( int offset = 0);
private:
        WritingRegion(const WritingRegion<Token>& original){}
        void SizeChanged(const int & newSize);
        int GetGreatestReaderRegionSize();

        /*
         * This method checks that all the regions have even size and are located at the correct position (the beginning of the buffer )
         */
        void CheckRegionsAreEven();
        void CenterReadingRegions( int centralIndex );

        /*
         *  Synchronizes the follower region with the last zone written, with the same size and hop than the writer.
         */     
        void SyncFollowerRegion();

        ReadingRegionsList mReadingRegions;
        ProperStream  mStream;
        ProperReadingRegion mFollowerRegion;
};


template< typename Token, template <class> class DataStructure>
WritingRegion< Token, DataStructure >::WritingRegion()
{
        SizeChanged( Size() );
}

template< typename Token, template <class> class DataStructure>
WritingRegion< Token, DataStructure >::~WritingRegion()
{       
        ReadingRegionsIterator it;
        for(it=BeginReaders(); it!=EndReaders(); it++)  
                (*it)->RemoveProducer();
        mReadingRegions.clear();
}

template< typename Token, template <class> class DataStructure>
Region::ReadingRegionsIterator WritingRegion< Token, DataStructure >::BeginReaders()
{
        return mReadingRegions.begin();
}

template< typename Token, template <class> class DataStructure>
Region::ReadingRegionsIterator WritingRegion< Token, DataStructure >::EndReaders()
{
        return mReadingRegions.end();
}

template< typename Token, template <class> class DataStructure>
void WritingRegion< Token, DataStructure >::LinkRegions( ProperReadingRegion &  reader)
{
        mReadingRegions.push_back(&reader);
        reader.LinkProducerRegion(*this);
        reader.LinkAndNotifySizeToStream( Stream() );
}

template< typename Token, template <class> class DataStructure>
int WritingRegion< Token, DataStructure >::GetGreatestReaderRegionSize()
{
        int maxSize = 0;
        
        ReadingRegionsIterator it;
        for(it=BeginReaders(); it!=EndReaders(); it++)
        {
                if(((*it)->Size())>maxSize) 
                        maxSize = (*it)->Size();
        }

        return maxSize;
}

template< typename Token, template <class> class DataStructure>
void WritingRegion<Token, DataStructure >::CheckRegionsAreEven()
{
        //TODO: writer must be even?    
        CLAM_ASSERT( Size()%2==0, "WritingRegion::CheckRegionsAreEven - Writer's size must be even for centering." );
        
        ReadingRegionsIterator it;
        for(it=BeginReaders(); it!=EndReaders(); it++)
        {
                CLAM_ASSERT( (*it)->Size()%2==0, "WritingRegion::CheckRegionsAreEven - Reader's size must be even for centering.");
        }

}
        
template< typename Token, template <class> class DataStructure>
void WritingRegion< Token, DataStructure >::ClearData()
{
        for( int i=0; i<Size(); i++ )           
                operator[](i) = Token();
}

template< typename Token, template <class> class DataStructure>
void WritingRegion< Token, DataStructure >::CenterReadingRegions( int centralIndex )
{
        ReadingRegionsIterator it;
        for(it=BeginReaders(); it!=EndReaders(); it++)
        {
                int hopToMove = centralIndex - (*it)->Size()/2; 
                (*it)->Pos( hopToMove );
                (*it)->BeginDistance( hopToMove );
        }
}

template< typename Token, template <class> class DataStructure>
void WritingRegion< Token, DataStructure >::CenterEvenRegions()
{
        CheckRegionsAreEven();
        int centralIndex = GetGreatestReaderRegionSize()/2;

        Pos( 0 );
        BeginDistance( 0);

        int currentHop = Hop();
        int currentSize = Size();

        Size( centralIndex);    
        Hop( centralIndex );

        ClearData();
        

        CenterReadingRegions( centralIndex );

        Produce();
        Size( currentSize );
        Hop( currentHop );

        

}

template< typename Token, template <class> class DataStructure>
void WritingRegion< Token, DataStructure >::RemoveRegion( Region & region )
{
        CLAM_ASSERT( region.ProducerRegion()==this, "Region::RemoveRegion() - Trying to remove an unlinked region");

        mReadingRegions.remove( &region );
        region.RemoveProducer();
}

template< typename Token, template <class> class DataStructure>
typename WritingRegion< Token, DataStructure>::ProperStream& WritingRegion< Token, DataStructure >::Stream()
{
        return mStream;
}

template< typename Token, template <class> class DataStructure>
int WritingRegion< Token, DataStructure >::RearmostReadingPos()
{
        int result = Pos();
        ReadingRegionsIterator it;
        for(it=mReadingRegions.begin(); it!=mReadingRegions.end(); it++)
                if( (*it)->Pos() < result) result = (*it)->Pos();

        return result;
}

template< typename Token, template <class> class DataStructure>
bool WritingRegion< Token, DataStructure >::CanProduce()
{
        CLAM_DEBUG_ASSERT( FulfilsInvariant(), "WritingRegion::canProduce() - fulfils invariant checking failed" );
        return !mStream.ExistsCircularOverlap( RearmostReadingPos(), Pos()+Size() );
}

template< typename Token, template <class> class DataStructure>
void WritingRegion< Token, DataStructure >::Produce()
{
        CLAM_DEBUG_ASSERT( CanProduce(), "WritingRegion::produce() - WritingRegion can't produce" );
        Pos( Pos() + Hop());
        // reserve stream tokens for next position
        mStream.WriterHasAdvanced( *this );
}

template< typename Token, template <class> class DataStructure>
Token& WritingRegion< Token, DataStructure >::operator[](int offset) 
{

        CLAM_DEBUG_ASSERT(0 <= offset && offset < Size(), "WritingRegion::operator [] - Index out of bounds" ); 
        int physicalIndex = BeginDistance() + offset;

        if (offset==0)
                return mStream.Read(physicalIndex, Size());
        return mStream[physicalIndex];
}

template< typename Token, template <class> class DataStructure>
bool WritingRegion< Token, DataStructure >::FulfilsInvariant()
{
        ReadingRegionsIterator it;
        for(it=mReadingRegions.begin(); it!=mReadingRegions.end(); it++)
                if( (*it)->Pos() >= Pos()+Size() )
                        return false;
        return true;
}

template< typename Token, template <class> class DataStructure>
int WritingRegion< Token, DataStructure >::LogicalStreamSize()
{
        return mStream.LogicalSize();
}

template< typename Token, template <class> class DataStructure>
Region* WritingRegion< Token, DataStructure >::ProducerRegion()
{
        return 0;
}

template< typename Token, template <class> class DataStructure>
void WritingRegion< Token, DataStructure >::SizeChanged(const int & newSize)
{
        mStream.NewWritingRegionSize( *this );
}

template< typename Token, template <class> class DataStructure>
void WritingRegion< Token, DataStructure >::SyncFollowerRegion()
{
        mFollowerRegion.LinkProducerRegion(*this);
        mFollowerRegion.Size( Size() );
        mFollowerRegion.Hop( Hop() );   
        mFollowerRegion.LinkAndNotifySizeToStream( Stream() );

        mFollowerRegion.Pos( Pos() - Hop() );
        mFollowerRegion.BeginDistance( BeginDistance() - Hop() );
        if(mFollowerRegion.BeginDistance() < 0 )
                mFollowerRegion.BeginDistance( mFollowerRegion.BeginDistance() + mStream.LogicalSize() );
}

template< typename Token, template <class> class DataStructure>
Token & WritingRegion< Token, DataStructure >::GetLastWrittenData( int offset)
{
        SyncFollowerRegion();
        int physicalIndex = mFollowerRegion.BeginDistance() + offset;
//      CLAM_ASSERT( physicalIndex < mStream.LogicalSize(), "WritingRegion GetLastWrittenData - Out of bounds access"  );
        return mStream.operator[]( physicalIndex );
}

} // namespace CLAM

#endif // __WritingRegion_hxx__