ArrayPartDataSource.hpp

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/***************************************************************************
  tag: The SourceWorks  Tue Sep 7 00:55:18 CEST 2010  ArrayPartDataSource.hpp

                        ArrayPartDataSource.hpp -  description
                           -------------------
    begin                : Tue September 07 2010
    copyright            : (C) 2010 The SourceWorks
    email                : peter@thesourceworks.com

 ***************************************************************************
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#ifndef ORO_ARRAYPARTDATASOURCE_HPP_
#define ORO_ARRAYPARTDATASOURCE_HPP_

#include "DataSource.hpp"
#include "NA.hpp"

namespace RTT
{
    namespace internal
    {
        template<typename T>
        class ArrayPartDataSource
        : public AssignableDataSource<T>
        {
            // a reference to a value_t
            typename AssignableDataSource<T>::value_t* mref;
            // [] index
            DataSource<unsigned int>::shared_ptr mindex;
            // parent data source, for updating after set().
            base::DataSourceBase::shared_ptr mparent;
            // safety: all indexes must be smaller than this.
            unsigned int mmax;
        public:
            ~ArrayPartDataSource() {}

            typedef boost::intrusive_ptr<ArrayPartDataSource<T> > shared_ptr;

            ArrayPartDataSource( typename AssignableDataSource<T>::reference_t ref,
                                    DataSource<unsigned int>::shared_ptr index,
                                    base::DataSourceBase::shared_ptr parent, unsigned int max )
                : mref(&ref), mindex(index), mparent(parent), mmax(max)
            {
            }

            typename DataSource<T>::result_t get() const
            {
                unsigned int i = mindex->get();
                if (i >= mmax)
                    return internal::NA<T>::na();
                return mref[ i ];
            }

            typename DataSource<T>::result_t value() const
            {
                unsigned int i = mindex->get();
                if (i >= mmax)
                    return internal::NA<T>::na();
                return mref[ i ];
            }

            void set( typename AssignableDataSource<T>::param_t t )
            {
                unsigned int i = mindex->get();
                if (i >= mmax)
                    return;
                mref[ i ] = t;
                updated();
            }

            typename AssignableDataSource<T>::reference_t set()
            {
                unsigned int i = mindex->get();
                if (i >= mmax)
                    return internal::NA<typename AssignableDataSource<T>::reference_t>::na();
                return mref[ i ];
            }

            typename AssignableDataSource<T>::const_reference_t rvalue() const
            {
                unsigned int i = mindex->get();
                if (i >= mmax)
                    return internal::NA<typename AssignableDataSource<T>::const_reference_t>::na();
                return mref[ i ];
            }

            void updated() {
                if (mparent) mparent->updated();
            }

            virtual ArrayPartDataSource<T>* clone() const {
                return new ArrayPartDataSource<T>( *mref, mindex, mparent, mmax);
            }

            virtual ArrayPartDataSource<T>* copy( std::map<const base::DataSourceBase*, base::DataSourceBase*>& replace ) const {
                // if somehow a copy exists, return the copy, otherwise return this (see Attribute copy)
                if ( replace[this] != 0 ) {
                    assert ( dynamic_cast<ArrayPartDataSource<T>*>( replace[this] ) == static_cast<ArrayPartDataSource<T>*>( replace[this] ) );
                    return static_cast<ArrayPartDataSource<T>*>( replace[this] );
                }

                // Both this and mparent are copied, but the part must also copy reference mref from the new parent !
                assert( mparent->getRawPointer() != 0 && "Can't copy part of rvalue datasource.");
                if ( mparent->getRawPointer() == 0 )
                    throw std::runtime_error("PartDataSource.hpp: Can't copy part of rvalue datasource.");
                base::DataSourceBase::shared_ptr mparent_copy =  mparent->copy(replace);
                // calculate the pointer offset in parent:
                int offset = reinterpret_cast<unsigned char*>( mref ) - reinterpret_cast<unsigned char*>(mparent->getRawPointer());
                // get the pointer to the new parent member:
                typename AssignableDataSource<T>::value_t* mref_copy = reinterpret_cast<typename AssignableDataSource<T>::value_t*>( reinterpret_cast<unsigned char*>(mparent_copy->getRawPointer()) + offset );

                replace[this] = new ArrayPartDataSource<T>(*mref_copy, mindex->copy(replace), mparent_copy, mmax);
                // returns copy
                return static_cast<ArrayPartDataSource<T>*>(replace[this]);

            }
        };

    }
}

#endif /* ORO_ARRAYPARTDATASOURCE_HPP_ */