/***********************************************************************
Moses - factored phrase-based language decoder
Copyright (C) 2011- University of Edinburgh

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.

This library 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
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
***********************************************************************/

#ifndef MERT_FEATURE_DATA_ITERATOR_H_
#define MERT_FEATURE_DATA_ITERATOR_H_

/**
  * For loading from the feature data file.
**/

#include <fstream>
#include <map>
#include <stdexcept>
#include <vector>

#include <boost/iterator/iterator_facade.hpp>
#include <boost/shared_ptr.hpp>

#include "util/file_piece.hh"
#include "util/string_piece.hh"

#include "FeatureStats.h"


class FileFormatException : public util::Exception 
{
  public:
    explicit FileFormatException(const std::string& filename, const std::string& line) {
      *this << "Error in line \"" << line << "\" of " << filename;
    }
};


/** Assumes a delimiter, so only apply to tokens */
int ParseInt(const StringPiece& str );

/** Assumes a delimiter, so only apply to tokens */
float ParseFloat(const StringPiece& str); 


class FeatureDataItem 
{
  public:
    std::vector<float> dense;
    SparseVector sparse;
};

class FeatureDataIterator : 
  public boost::iterator_facade<FeatureDataIterator,
                                const std::vector<FeatureDataItem>,
                                boost::forward_traversal_tag> 
{
  public:
    FeatureDataIterator();
    explicit FeatureDataIterator(const std::string& filename);

    static FeatureDataIterator end() {
      return FeatureDataIterator();
    }


  private:
    friend class boost::iterator_core_access;

    void increment();
    bool equal(const FeatureDataIterator& rhs) const;
    const std::vector<FeatureDataItem>& dereference() const;

    void readNext();

    boost::shared_ptr<util::FilePiece> m_in;
    std::vector<FeatureDataItem> m_next;
};

#endif  // MERT_FEATURE_DATA_ITERATOR_H_