ConsumingFanOut.h

/*
 * ConsumingFanOut.h
 *
 *  Created on: Jun 15, 2016
 *      Author: Martin Hierholzer
 */

#ifndef CHIMERATK_CONSUMING_FAN_OUT_H
#define CHIMERATK_CONSUMING_FAN_OUT_H

#include "FanOut.h"

#include <ChimeraTK/NDRegisterAccessorDecorator.h>

namespace ChimeraTK {

  /** FanOut implementation which acts as a read-only (i.e. consuming)
   * NDRegisterAccessor. The values read through this accessor will be obtained
   * from the given feeding implementation and distributed to any number of
   * slaves. */
  template<typename UserType>
  class ConsumingFanOut : public FanOut<UserType>, public ChimeraTK::NDRegisterAccessorDecorator<UserType> {
   public:
    ConsumingFanOut(boost::shared_ptr<ChimeraTK::NDRegisterAccessor<UserType>> feedingImpl,
        ConsumerImplementationPairs<UserType> const& consumerImplementationPairs)
    : FanOut<UserType>(feedingImpl), ChimeraTK::NDRegisterAccessorDecorator<UserType>(feedingImpl) {
      assert(feedingImpl->isReadable());

      _lastReceivedValue.resize(buffer_2D[0].size());

      // Add the consuming accessors
      for(auto el : consumerImplementationPairs) {
        FanOut<UserType>::addSlave(el.first, el.second);
      }
    }

    void doPostRead(TransferType type, bool updateDataBuffer) override {
      ChimeraTK::NDRegisterAccessorDecorator<UserType>::doPostRead(type, updateDataBuffer);

      if(updateDataBuffer) {
        // We have to keep a copy to write into the slaves. There might
        // be decorators arount this fanout which swap out buffer_2D, so it is
        // not available any more for a second read witout updateDataBuffer (exception case).
        _lastReceivedValue = buffer_2D[0];
      }

      // The ConsumingFanOut conceptually never has a wait_fow_new_data flags. Hence each read
      // operation returns with "new" data, even in case of an exception. So each read
      // always synchronises all slaves and pushes the content of the data buffer.
      for(auto& slave : FanOut<UserType>::slaves) { // send out copies to slaves
        // do not send copy if no data is expected (e.g. trigger)
        if(slave->getNumberOfSamples() != 0) {
          slave->accessChannel(0) = _lastReceivedValue;
        }
        slave->setDataValidity(this->dataValidity());
        slave->writeDestructively();
      }
    }

    void interrupt() override {
      // call the interrut sequences of the fan out (interrupts for fan input and all outputs), and the ndRegisterAccessor
      FanOut<UserType>::interrupt();
      if(this->_accessModeFlags.has(AccessMode::wait_for_new_data)) {
        ChimeraTK::NDRegisterAccessor<UserType>::interrupt();
      }
    }

   protected:
    using ChimeraTK::NDRegisterAccessor<UserType>::buffer_2D;
    std::vector<UserType> _lastReceivedValue;
  };

} /* namespace ChimeraTK */

#endif /* CHIMERATK_CONSUMING_FAN_OUT_H */