concordia-library/concordia/concordia_index.hpp

#ifndef CONCORDIA_INDEX_HDR
#define CONCORDIA_INDEX_HDR

#include <boost/shared_ptr.hpp>
#include <fstream>
#include <iostream>
#include <sstream>
#include <vector>

#include "concordia/common/config.hpp"
#include "concordia/example.hpp"
#include "concordia/hash_generator.hpp"
#include "concordia/concordia_exception.hpp"
#include "concordia/tokenized_sentence.hpp"
#include <divsufsort.h>

/*!
  Class for creating and maintaining the index. This class
  does not hold the index data structures but only operates on
  them when they are passed to ConcordiaIndex methods by
  smart pointers. This class only remembers paths to two
  files: hashed index and markers array, which are backups
  of the respective data structures on HDD.

*/

class ConcordiaIndex {
public:
    /*! Constructor.
      \param hashedIndexFilePath path to the hashed index file
      \param markersFilePath path to the markers array
      \throws ConcordiaException
    */
    explicit ConcordiaIndex(const std::string & hashedIndexFilePath,
                            const std::string & markersFilePath)
                                    throw(ConcordiaException);

    /*! Destructor.
    */
    virtual ~ConcordiaIndex();

    /*! Adds an Example to the index. Example is first hashed using
        the hash generator passed to this method. Then, hashed index
        and markers array (also passed to this method) are appended
        with the hashed example. At the same time, HDD versions of these
        two data structures are also appended with the same example.
        The method returns a tokenized version of the example.
      \param hashGenerator hash generator to be used to prepare the hash
             of the example
      \param T RAM-based hash index to be appended to
      \param markers RAM-based markers array to be appended to
      \param example example to be added to index
      \returns tokenized example
      \throws ConcordiaException
    */
    boost::shared_ptr<TokenizedSentence> addExample(
                boost::shared_ptr<HashGenerator> hashGenerator,
                boost::shared_ptr<std::vector<sauchar_t> > T,
                boost::shared_ptr<std::vector<SUFFIX_MARKER_TYPE> > markers,
                const Example & example);

    /*! Adds multiple examples to the index. Examples are first hashed using
        the hash generator passed to this method. Then, hashed index
        and markers array (also passed to this method) are appended
        with the hashed examples. At the same time, HDD versions of these
        two data structures are also appended with the same examples.
        The method returns a vector of tokenized examples.
      \param hashGenerator hash generator to be used to prepare the hash
             of the example
      \param T RAM-based hash index to be appended to
      \param markers RAM-based markers array to be appended to
      \param examples vector of examples to be added to index
      \returns vector of tokenized examples
      \throws ConcordiaException
    */
    std::vector<TokenizedSentence> addAllExamples(
                boost::shared_ptr<HashGenerator> hashGenerator,
                boost::shared_ptr<std::vector<sauchar_t> > T,
                boost::shared_ptr<std::vector<SUFFIX_MARKER_TYPE> > markers,
                const std::vector<Example> & examples);

    /*! Generates suffix array based on the passed hashed index.
      \returns the generated suffix array
      \throws ConcordiaException
    */
    boost::shared_ptr<std::vector<saidx_t> > generateSuffixArray(
                boost::shared_ptr<std::vector<sauchar_t> > T);

private:
    boost::shared_ptr<TokenizedSentence> _addSingleExample(
                std::ofstream & hashedIndexFile,
                std::ofstream & markersFile,
                boost::shared_ptr<HashGenerator> hashGenerator,
                boost::shared_ptr<std::vector<sauchar_t> > T,
                boost::shared_ptr<std::vector<SUFFIX_MARKER_TYPE> > markers,
                const Example & example);

    std::string _hashedIndexFilePath;

    std::string _markersFilePath;
};

#endif