ArrayAccessor.h

/*
 * ArrayAccessor.h
 *
 *  Created on: Jun 07, 2016
 *      Author: Martin Hierholzer
 */

#ifndef CHIMERATK_ARRAY_ACCESSOR_H
#define CHIMERATK_ARRAY_ACCESSOR_H

#include <string>

#include <boost/smart_ptr/shared_ptr.hpp>
#include <boost/thread.hpp>

#include "Accessor.h"

/** Macros to declare an array variable/accessor more easily. The call to this macro must be placed inside the
 *  class definiton of a Module (e.g. ApplicationModule or VariableGroup).
 *
 *  UserType is the data type of the variable.
 *  name will be the C++ symbol name of the variable accessor. It will be of the type ChimeraTK::ScalarAccessor<UserType>
 *  unit is the engineering unit as a character constant.
 *  nElements is the size of the array (number of elements)
 *  mode can be either ChimeraTK::UpdateMode::push or ChimeraTK::UpdateMode::poll, deciding whether a call to read()
 *  will block until new data is available (push) or just return the latest value (poll, might not be fully realtime
 *  capable). */
#define CTK_ARRAY_INPUT(UserType, name, unit, nElements, mode, description)                                         \
    ChimeraTK::ArrayAccessor<UserType> name{this, #name, ChimeraTK::VariableDirection::consuming, unit,             \
                                            nElements, mode, description}
#define CTK_ARRAY_OUTPUT(UserType, name, unit, nElements, description)                                              \
    ChimeraTK::ArrayAccessor<UserType> name{this, #name, ChimeraTK::VariableDirection::feeding, unit,               \
                                            nElements, ChimeraTK::UpdateMode::push, description}

namespace ChimeraTK {

  /** Accessor for array variables (i.e. vectors). */
  template< typename UserType >
  class ArrayAccessor : public Accessor<UserType> {
    public:
      ArrayAccessor(Module *owner, const std::string &name, VariableDirection direction, std::string unit,
          size_t nElements, UpdateMode mode, const std::string &description)
      : Accessor<UserType>(owner, name, direction, unit, nElements, mode, description)
      {}

      void read() {
        if(Accessor<UserType>::_mode == UpdateMode::push) {
          while(impl->readNonBlocking() == false) { /// @todo TODO proper blocking implementation
            boost::this_thread::yield();
            boost::this_thread::interruption_point();
          }
        }
        else {
          /// @todo TODO empty the queue to always receive the latest value
          impl->readNonBlocking();
          boost::this_thread::interruption_point();
        }
      } // LCOV_EXCL_LINE this line somehow ends up having a negative counter in the coverage report, which leads to a failure

      void write() {
        impl->write();
        boost::this_thread::interruption_point();
      }
      
      bool readNonBlocking() {
        boost::this_thread::interruption_point();
        return impl->readNonBlocking();
      }

      /** Get or set buffer content by [] operator.
       *  @attention No bounds checking is performed, use getNumberOfElements() to obtain the number of elements in
       *  the register.
       *  Note: Using the iterators is slightly more efficient than using this operator! */
      UserType& operator[](unsigned int element) {
        return impl->accessData(0,element);
      }

      /** Return number of elements/samples in the register */
      unsigned int getNElements() {
        return impl->getNumberOfSamples();
      }

      /** Access data with std::vector-like iterators */
      typedef typename std::vector<UserType>::iterator iterator;
      typedef typename std::vector<UserType>::const_iterator const_iterator;
      typedef typename std::vector<UserType>::reverse_iterator reverse_iterator;
      typedef typename std::vector<UserType>::const_reverse_iterator const_reverse_iterator;
      iterator begin() { return impl->accessChannel(0).begin(); }
      const_iterator begin() const { return impl->accessChannel(0).cbegin(); }
      const_iterator cbegin() const { return impl->accessChannel(0).cbegin(); }
      iterator end() { return impl->accessChannel(0).end(); }
      const_iterator end() const { return impl->accessChannel(0).cend(); }
      const_iterator cend() const { return impl->accessChannel(0).cend(); }
      reverse_iterator rbegin() { return impl->accessChannel(0).rbegin(); }
      const_reverse_iterator rbegin() const { return impl->accessChannel(0).crbegin(); }
      const_reverse_iterator crbegin() const { return impl->accessChannel(0).crbegin(); }
      reverse_iterator rend() { return impl->accessChannel(0).rend(); }
      const_reverse_iterator rend() const { return impl->accessChannel(0).crend(); }
      const_reverse_iterator crend() const { return impl->accessChannel(0).crend(); }

      /* Swap content of (cooked) buffer with std::vector */
      void swap(std::vector<UserType> &x) {
        if(x.size() != impl->accessChannel(0).size()) {
          throw DeviceException("Swapping with a buffer of a different size is not allowed.",
              DeviceException::WRONG_PARAMETER);
        }
        impl->accessChannel(0).swap(x);
      }        

      /** Assignment operator */
      ArrayAccessor<UserType>& operator=(const std::vector<UserType> &rightHandSide) {
        impl->accessChannel(0) = rightHandSide;
        return *this;
      }

      bool isInitialised() const {
        return impl != nullptr;
      }

      void useProcessVariable(const boost::shared_ptr<TransferElement > &var) {
        impl = boost::dynamic_pointer_cast<NDRegisterAccessor<UserType>>(var);
        assert(impl);
        if(Accessor<UserType>::getDirection() == VariableDirection::consuming) {
          assert(impl->isReadable());
        }
        else {
          assert(impl->isWriteable());
        }
      }

    protected:

      boost::shared_ptr< NDRegisterAccessor<UserType> > impl;

  };

} /* namespace ChimeraTK */

#endif /* CHIMERATK_ARRAY_ACCESSOR_H */