IdTableImpl.H

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/*! @file
    @author Randolph Voorhies
    @copyright GNU Public License (GPL v3)
    @section License
    @verbatim
    // ////////////////////////////////////////////////////////////////////////
    //              The iLab Neuromorphic Robotics Toolkit (NRT)             //
    // Copyright 2010-2012 by the University of Southern California (USC)    //
    //                          and the iLab at USC.                         //
    //                                                                       //
    //                iLab - University of Southern California               //
    //                Hedco Neurociences Building, Room HNB-10               //
    //                    Los Angeles, Ca 90089-2520 - USA                   //
    //                                                                       //
    //      See http://ilab.usc.edu for information about this project.      //
    // ////////////////////////////////////////////////////////////////////////
    // This file is part of The iLab Neuromorphic Robotics Toolkit.          //
    //                                                                       //
    // The iLab Neuromorphic Robotics Toolkit 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 3 of the License, or (at your option) any later version.      //
    //                                                                       //
    // The iLab Neuromorphic Robotics Toolkit 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 The iLab Neuromorphic Robotics Toolkit.  If not, see       //
    // <http://www.gnu.org/licenses/>.                                       //
    // ////////////////////////////////////////////////////////////////////////
    @endverbatim */


#ifndef INCLUDE_NRT_CORE_DESIGN_DETAILS_IDTABLEIMPL_H
#define INCLUDE_NRT_CORE_DESIGN_DETAILS_IDTABLEIMPL_H

#include <nrt/Core/Typing/Exception.H>

template<class ValueType, class IdType>
class nrt::IdTable<ValueType, IdType>::IdNotFoundException : public nrt::exception::Exception
{
  public:
    IdNotFoundException(IdType const & id) throw()
    try : nrt::exception::Exception("Error IdNotFoundException, and further error while constructing the exception"),
          itsId(id)
    { whatptr = "Invalid Reverse Lookup"; } catch (...) { }

    virtual ~IdNotFoundException() throw() { }

    IdType itsId;
};

template<class ValueType, class IdType>
class nrt::IdTable<ValueType, IdType>::ValueNotFoundException : public nrt::exception::Exception
{
  public:
    ValueNotFoundException(ValueType const & value) throw()
    try : nrt::exception::Exception("Error ValueNotFoundException, and further error while constructing the exception"),
          itsValue(value)
    {  whatptr = "Invalid Forward Lookup"; } catch (...) { }

    virtual ~ValueNotFoundException() throw() { }

    ValueType itsValue;
};


// ######################################################################
template<class ValueType, class IdType> inline
nrt::IdTable<ValueType, IdType>::IdTable()
  : itsMaxId(0)
{ }

// ######################################################################
template<class ValueType, class IdType> inline
IdType nrt::IdTable<ValueType, IdType>::create(ValueType const & value)
{
  auto itr = itsValueIdMap.find(value);

  if (itr == itsValueIdMap.end()) {
    return create_internal(value);
  } else {
    // increment user count and return it:
    typename std::unordered_map<IdType, ValueData>::iterator idItr = itsIdValueMap.find(itr->second);
    ++ idItr->second.second;
    return idItr->first;
  }
}

// ######################################################################
template<class ValueType, class IdType> inline
ValueType nrt::IdTable<ValueType, IdType>::get(IdType const & id) const
{
  auto itr = itsIdValueMap.find(id);
  if (itr == itsIdValueMap.end()) throw IdNotFoundException(id);

  return itr->second.first;
}

// ######################################################################
template<class ValueType, class IdType> inline
IdType nrt::IdTable<ValueType, IdType>::get(ValueType const & value) const
{
  auto itr = itsValueIdMap.find(value);
  if (itr == itsValueIdMap.end()) throw ValueNotFoundException(value);

  return itr->second;
}

// ######################################################################
template<class ValueType, class IdType> inline
IdType nrt::IdTable<ValueType, IdType>::getcreate(ValueType const & value)
{
  auto itr = itsValueIdMap.find(value);
  if (itr == itsValueIdMap.end()) return create_internal(value);
  else return itr->second;
}

// ######################################################################
template<class ValueType, class IdType> inline
size_t nrt::IdTable<ValueType, IdType>::users(ValueType const & value) const
{
  auto itr = itsValueIdMap.find(value);
  if (itr == itsValueIdMap.end()) return 0;
  else return users(itr->second);
}

// ######################################################################
template<class ValueType, class IdType> inline
size_t nrt::IdTable<ValueType, IdType>::users(IdType const & id) const
{
  auto itr = itsIdValueMap.find(id);
  if (itr == itsIdValueMap.end()) return 0;
  else return itr->second.second;
}

// ######################################################################
template<class ValueType, class IdType>
size_t nrt::IdTable<ValueType, IdType>::remove(IdType const & id)
{
  auto idItr = itsIdValueMap.find(id);
  if (idItr == itsIdValueMap.end()) throw IdNotFoundException(id);

  // decrement user count:
  -- idItr->second.second;

  // delete the id if count down to zero:
  if (idItr->second.second == 0) {
    auto valueItr = itsValueIdMap.find(idItr->second.first);

    itsRecycleBin.push(id);

    itsIdValueMap.erase(idItr);
    itsValueIdMap.erase(valueItr);

    return 0;
  } else return idItr->second.second;
}

// ######################################################################
template<class ValueType, class IdType>
size_t nrt::IdTable<ValueType, IdType>::remove(ValueType const & value)
{
  auto valueItr = itsValueIdMap.find(value);
  if (valueItr == itsValueIdMap.end()) throw ValueNotFoundException(value);

  auto idItr = itsIdValueMap.find(valueItr->second);

  // decrement user count:
  -- idItr->second.second;

  // delete the id if count down to zero:
  if (idItr->second.second == 0) {
    itsRecycleBin.push(valueItr->second);

    itsIdValueMap.erase(idItr);
    itsValueIdMap.erase(valueItr);

    return 0;
  } else return idItr->second.second;
}

// ######################################################################
template<class ValueType, class IdType>
void nrt::IdTable<ValueType, IdType>::clear()
{
  itsIdValueMap.clear();
  itsValueIdMap.clear();
  itsRecycleBin = std::queue<IdType>();
  itsMaxId = IdType();
}

// ######################################################################
template<class ValueType, class IdType> inline
IdType nrt::IdTable<ValueType, IdType>::create_internal(ValueType const & value)
{
  // Recycle an old id, or generate a new one
  IdType id;
  if (itsRecycleBin.size()) { id = itsRecycleBin.front(); itsRecycleBin.pop(); }
  else { id = ++itsMaxId; }

  itsValueIdMap[value] = id;
  itsIdValueMap[id]    = std::pair<ValueType, size_t>(value, size_t(1));

  return id;
}

#endif // INCLUDE_NRT_CORE_DESIGN_DETAILS_IDTABLEIMPL_H