searchengine.h

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// -*- C++ -*-
/*
  Phrasehunter - index and query text corpora
  Copyright (C) 2006  Torsten Marek (shlomme@gmx.de) &
                      Armin Schmidt (armin.sch@gmail.com)
  
  This program 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 2
  of the License, or (at your option) any later version.
  
  This program 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 this program; if not, write to the Free Software
  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
*/

#ifndef SEARCHENGINE_H
#define SEARCHENGINE_H SEARCHENGINE_H

#include <string>

#include "sqlitepp/sqlitepp.h"

#include "phexception.h"
#include "ph_types.h"
#include "support/unicodehelpers.h"

namespace PhraseHunter {

//! Class that provides functionality for querying a corpus.
class SearchEngine
{
public:
    //! Constructor. Should not be called directly. Instead, use CorpusManager::searchEngine().
    SearchEngine(SQLitePP::SqliteDB& sqlite);
    
    ~SearchEngine() {}

    //! Search for a single-word Token. For phrases, use searchPhrase().
    TokenPtr searchToken(schma::UnicodePtr stringtoken) const;
    //! Search for a Phrase.
    TokenPtr searchPhrase(schma::UnicodePtr search_string) const;

    /**
       \brief Search for all tokens that match a regular expression
       \param re The regular expression to match.
    */
    TokenVector searchRegexToken(schma::UnicodePtr re) const;
    /**
       \brief Search for all Phrase tokens, where each word matches the respective regex.
       \param re The phrasal regular expression.
    */
    TokenVector searchPhrasalRegex(schma::UnicodePtr re) const;

private:    
    template<typename _RandomAccessIt,
             typename _MinChooser,
             typename _Merger,
             typename _Validator>
    typename _RandomAccessIt::value_type combine(_RandomAccessIt begin,
                                                 _RandomAccessIt end,
                                                 _MinChooser better,
                                                 _Merger merge,
                                                 _Validator valid) const;
    
    std::string cutRegex(const std::string& re) const;
    
    SQLitePP::SqliteDB& m_db;
    const std::string SPECIAL_CHARACTERS;
};
}

#endif // SEARCHENGINE_H

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