StreamImpl.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 StreamImpl_hxx
#define StreamImpl_hxx

#include "Region.hxx"
#include <list>
#include <vector>
#include "PhantomBuffer.hxx"
namespace CLAM
{

template <typename T>
class StdList : public std::list<T>
{};

template <typename T>
class StdVector : public std::vector<T>
{};



template< typename Token, template <class> class DataStructure >
class StreamImpl
{

public: 
        void NewWritingRegionSize( Region& writer );
        void NewReadingRegionSize( Region& );
        void WriterHasAdvanced( Region& writer );
        void ReaderHasAdvanced( Region& reader );
        Token& Read(int physicalIndex, int size);
        Token& operator[](int physicalIndex);
        int LogicalSize() const;
        bool ExistsCircularOverlap(int rear, int writingHead) const;

private:
        void RegionHasAdvanced( Region& region );
        
        DataStructure<Token> mDataImpl;
};


template< typename Token, template <class> class DataStructure >
void StreamImpl<Token,DataStructure>::NewWritingRegionSize( Region& writer  )
{
        if ( writer.Size() <= LogicalSize() ) return;
        int newTokens = writer.Size() - LogicalSize();
        for( int i=0; i<newTokens; i++)
                mDataImpl.push_back(Token());
}
        
template< typename Token, template <class> class DataStructure >
void StreamImpl<Token,DataStructure>::RegionHasAdvanced( Region& region ) 
{
        region.BeginDistance( region.BeginDistance() +  region.Hop() );

        if (region.BeginDistance() >= LogicalSize() ) // circular movement
                region.BeginDistance( region.BeginDistance() - LogicalSize() );
}

template< typename Token, template <class> class DataStructure >
void StreamImpl<Token,DataStructure>::NewReadingRegionSize( Region& )
{
}

template< typename Token, template <class> class DataStructure >
void StreamImpl<Token,DataStructure>::WriterHasAdvanced( Region& writer )
{
        for( int i=0; i<writer.Hop(); i++)
                mDataImpl.push_back(Token());

        RegionHasAdvanced( writer );
}

template< typename Token, template <class> class DataStructure >
void StreamImpl<Token,DataStructure>::ReaderHasAdvanced( Region& reader )
{
        // TODO: discard old tokens
        RegionHasAdvanced( reader);
}

template< typename Token, template <class> class DataStructure >
Token& StreamImpl<Token,DataStructure>::Read(int physicalIndex, int size)
{
        return operator[](physicalIndex);
}

template< typename Token, template <class> class DataStructure >
Token& StreamImpl<Token,DataStructure>::operator[](int physicalIndex)
{
        CLAM_DEBUG_ASSERT( physicalIndex < int(mDataImpl.size()), "StreamImpl operator[] - Index out of bounds" );
        typename DataStructure<Token>::iterator it;
        int i;
        for(i=0, it = mDataImpl.begin(); i<physicalIndex; it++, i++);
        return (*it);
}

template< typename Token, template <class> class DataStructure >
int StreamImpl<Token,DataStructure>::LogicalSize() const
{
        return int(mDataImpl.size());
}

template< typename Token, template <class> class DataStructure >
bool StreamImpl<Token,DataStructure>::ExistsCircularOverlap(int rear, int writingHead) const
{
        return false;
}

//---------------------------------------------------------------------------------

template< typename Token >
class StreamImpl<Token, PhantomBuffer>
{

public:
        void NewWritingRegionSize( Region& writer );
        void NewReadingRegionSize( Region& reader );
        void WriterHasAdvanced( Region& writer );
        void ReaderHasAdvanced( Region& reader );
        
        Token& Read(int physicalIndex, int size);
        Token& operator[](int physicalIndex);
        int LogicalSize() const;
        int PhantomSize();
        bool ExistsCircularOverlap(int rear, int writingHead) const;
private:
        int ExponentOfClosestGreaterPowerOfTwo( int newSize);
        void CommonNewRegionSize( Region& anyRegion );  
        bool ReaderAffectedByInsertion( Region & reader, Region & writer ) const;
        void UpdateBeginDistanceOfReadingRegions( Region & writer, int tokensInserted );        
        void RegionHasAdvanced( Region& region );

        PhantomBuffer<Token> mDataImpl;
};


template< typename Token >
void StreamImpl<Token, PhantomBuffer>::NewWritingRegionSize( Region& writer )
{
        CLAM_DEBUG_ASSERT( writer.Size()>0, "StreamImpl::newWritingRegionSize() - size must be greater than 0" );
        CLAM_DEBUG_ASSERT( !writer.ProducerRegion(), "StreamImpl::newWritingRegionSize() - region must be a WritingRegion" );
        CommonNewRegionSize( writer );  
}

template< typename Token >
void StreamImpl<Token, PhantomBuffer>::NewReadingRegionSize( Region& reader )
{
        CLAM_DEBUG_ASSERT( reader.ProducerRegion(), "StreamImpl::newReadingRegionSize() - region must be a ReadingRegion" );
        CommonNewRegionSize(reader);
}

template< typename Token >
void StreamImpl<Token, PhantomBuffer>::CommonNewRegionSize( Region& anyRegion )
{
        int newLogicalSize;
        int newPhantomSize;

        if(anyRegion.Size()==1)
        {
                newLogicalSize = anyRegion.Size();
                newPhantomSize = 0;
        }
        else
        {       
                int logicalSizeCandidate = anyRegion.Size()*2;
                newLogicalSize = 1 << ExponentOfClosestGreaterPowerOfTwo(logicalSizeCandidate);
                newPhantomSize = anyRegion.Size()-1;
        }

        if(newLogicalSize <= LogicalSize())
                return;

        CLAM_DEBUG_ASSERT(newLogicalSize > LogicalSize(), "StreamImpl::commonNewRegionSize() - new logical size"
                                                        "must be greater than the older logical size" ); 

        Region & producer = anyRegion.ProducerRegion() ? (*anyRegion.ProducerRegion()) : anyRegion;
        int insertionPos = producer.BeginDistance();

        int tokensToInsert = newLogicalSize - LogicalSize();

        mDataImpl.Resize( 
                        newLogicalSize, 
                        std::max(newPhantomSize,PhantomSize()), // phantom buffer size
                        insertionPos );
        
        UpdateBeginDistanceOfReadingRegions( producer, tokensToInsert );
}

template< typename Token >
bool StreamImpl<Token, PhantomBuffer>::ReaderAffectedByInsertion( Region & reader, Region & writer ) const
{
        // a reader will be affected by the insertion of new tokens due a writer's resize if:
        
        // a) the reader is physically positioned (beginDistance) at the rear of the writer.
        if (reader.BeginDistance() > writer.BeginDistance()) 
                return true;
        
        // b) the reader is physically positioned (beginDistance) at the same position than the writer AND
        // is logically position (pos) after the writer. It means that the writer is exactly at
        // LogicalSize() positions before the reader.
        if( reader.BeginDistance()==writer.BeginDistance() && reader.Pos() < writer.Pos() )
                return true;
        return false;
}

template< typename Token >
void StreamImpl<Token, PhantomBuffer>::UpdateBeginDistanceOfReadingRegions( Region & writer, int tokensInserted )
{
        Region::ReadingRegionsIterator actualReader;

        for ( actualReader=writer.BeginReaders(); actualReader!=writer.EndReaders(); actualReader++)
                if( ReaderAffectedByInsertion(**actualReader, writer) )
                        (*actualReader)->BeginDistance( (*actualReader)->BeginDistance() + tokensInserted );
}

template< typename Token >
void StreamImpl<Token, PhantomBuffer>::RegionHasAdvanced( Region& region ) 
{
        region.BeginDistance( region.BeginDistance() + region.Hop());
        if (region.BeginDistance() >= LogicalSize() ) // circular movement
                region.BeginDistance( region.BeginDistance() -  LogicalSize());
}

template< typename Token >
void StreamImpl<Token, PhantomBuffer>::WriterHasAdvanced( Region& writer )      
{
        mDataImpl.Touch( writer.BeginDistance(), writer.Size() );
        RegionHasAdvanced( writer );
}

template< typename Token >
void StreamImpl<Token, PhantomBuffer>::ReaderHasAdvanced( Region& reader )
{
        RegionHasAdvanced( reader );            
}

template< typename Token >              
Token& StreamImpl<Token, PhantomBuffer>::Read(int physicalIndex, int size)
{
        return *mDataImpl.Read( physicalIndex, size );
}

template< typename Token >
Token& StreamImpl<Token, PhantomBuffer>::operator[](int physicalIndex)
{
        CLAM_DEBUG_ASSERT( physicalIndex < LogicalSize()+PhantomSize(), "StreamImpl::operator[] - Index out of bounds" );
        return Read( physicalIndex, 1);
}

template< typename Token >
int StreamImpl<Token, PhantomBuffer>::LogicalSize() const
{
        return mDataImpl.LogicalSize();
}

template< typename Token >
int StreamImpl<Token, PhantomBuffer>::PhantomSize()
{
        return mDataImpl.PhantomSize();
}

template< typename Token >
bool StreamImpl<Token, PhantomBuffer>::ExistsCircularOverlap(int rear, int writingHead) const
{
        return writingHead - rear > LogicalSize(); 
}

template< typename Token >
int StreamImpl<Token, PhantomBuffer>::ExponentOfClosestGreaterPowerOfTwo( int newSize)
{
        int newLogicalSize = 1;
        int power = 0;
        while( newLogicalSize < newSize )
        {
                newLogicalSize <<= 1;
                power++;
        }
        return power;
}

} // namespace CLAM

#endif // StreamImpl_hxx