concordia-library/concordia/index_searcher.cpp

#include "concordia/index_searcher.hpp"

#include "concordia/common/utils.hpp"
#include "concordia/tokenized_sentence.hpp"
#include <boost/filesystem.hpp>

IndexSearcher::IndexSearcher() {
    _concordiaSearcher = boost::shared_ptr<ConcordiaSearcher>(
                                   new ConcordiaSearcher());
}


IndexSearcher::~IndexSearcher() {
}

MatchedPatternFragment IndexSearcher::simpleSearch(
                  boost::shared_ptr<HashGenerator> hashGenerator,
                  boost::shared_ptr<std::vector<sauchar_t> > T,
                  boost::shared_ptr<std::vector<SUFFIX_MARKER_TYPE> > markers,
                  boost::shared_ptr<std::vector<saidx_t> > SA,
                  const std::string & pattern,
                  bool byWhitespace) throw(ConcordiaException) {
    int left;
    std::vector<INDEX_CHARACTER_TYPE> hash =
                hashGenerator->generateHash(pattern, byWhitespace).getCodes();
    saidx_t patternLength = hash.size()*sizeof(INDEX_CHARACTER_TYPE);
    sauchar_t * patternArray = Utils::indexVectorToSaucharArray(hash);

    int size = sa_search(T->data(), (saidx_t) T->size(),
                         (const sauchar_t *) patternArray, patternLength,
                         SA->data(), (saidx_t) SA->size(), &left);
    MatchedPatternFragment result(0, hash.size());
    for (int i = 0; i < size; ++i) {
        saidx_t resultPos = SA->at(left + i);
        if (resultPos % sizeof(INDEX_CHARACTER_TYPE) == 0) {
        // As we are looking for a pattern in an array of higher
        // resolution than the hashed index file, we might
        // obtain accidental results exceeding the boundaries
        // of characters in hashed index. The above check
        // removes these accidental results.
            saidx_t actualResultPos = resultPos / sizeof(INDEX_CHARACTER_TYPE);
            SUFFIX_MARKER_TYPE marker = markers->at(actualResultPos);

            SubstringOccurence occurence;
            occurence.enterDataFromMarker(marker);
            result.addOccurence(occurence);
            if (result.getOccurences().size() >= CONCORDIA_SEARCH_MAX_RESULTS) {
                break;
            }
        }
    }

    delete[] patternArray;
    return result;
}

MatchedPatternFragment IndexSearcher::lexiconSearch(
                  boost::shared_ptr<HashGenerator> hashGenerator,
                  boost::shared_ptr<std::vector<sauchar_t> > T,
                  boost::shared_ptr<std::vector<SUFFIX_MARKER_TYPE> > markers,
                  boost::shared_ptr<std::vector<saidx_t> > SA,
                  const std::string & pattern,
                  bool byWhitespace) throw(ConcordiaException) {
    int left;
    std::vector<INDEX_CHARACTER_TYPE> hash =
                hashGenerator->generateHash(pattern, byWhitespace).getCodes();

    if (hash.size() == 0) {
        // If the hash is empty, return empty result
        return MatchedPatternFragment(0, 0);
    }

    // append and prepend query with EOS (sentenceBoundaryHI) for lexicon search
    INDEX_CHARACTER_TYPE sentenceBoundaryHI = INDEX_CHARACTER_TYPE_MAX_VALUE;
    hash.insert(hash.begin(), sentenceBoundaryHI);
    hash.push_back(sentenceBoundaryHI);

    saidx_t patternLength = hash.size()*sizeof(INDEX_CHARACTER_TYPE);
    sauchar_t * patternArray = Utils::indexVectorToSaucharArray(hash);

    int size = sa_search(T->data(), (saidx_t) T->size(),
                         (const sauchar_t *) patternArray, patternLength,
                         SA->data(), (saidx_t) SA->size(), &left);

    // In this scenario the whole pattern is matched, but
    // the pattern was artificially augmented by two EOS's.
    // Therefore, the matched pattern fragment starts at 0
    // and is hash.size() - 2 long.
    MatchedPatternFragment result(0, hash.size()-2);
    for (int i = 0; i < size; ++i) {
        saidx_t resultPos = SA->at(left + i);
        if (resultPos % sizeof(INDEX_CHARACTER_TYPE) == 0) {
        // As we are looking for a pattern in an array of higher
        // resolution than the hashed index file, we might
        // obtain accidental results exceeding the boundaries
        // of characters in hashed index. The above check
        // removes these accidental results.
            saidx_t actualResultPos = resultPos / sizeof(INDEX_CHARACTER_TYPE);

            // Our search query started with an EOS and is non-empty,
            // so we should look at the marker of the next character
            SUFFIX_MARKER_TYPE marker = markers->at(actualResultPos + 1);

            SubstringOccurence occurence;
            occurence.enterDataFromMarker(marker);
            result.addOccurence(occurence);
            if (result.getOccurences().size() >= CONCORDIA_SEARCH_MAX_RESULTS) {
                break;
            }
        }
    }

    delete[] patternArray;
    return result;
}

SUFFIX_MARKER_TYPE IndexSearcher::countOccurences(
                  boost::shared_ptr<HashGenerator> hashGenerator,
                  boost::shared_ptr<std::vector<sauchar_t> > T,
                  boost::shared_ptr<std::vector<SUFFIX_MARKER_TYPE> > markers,
                  boost::shared_ptr<std::vector<saidx_t> > SA,
                  const std::string & pattern) throw(ConcordiaException) {
    int left;
    std::vector<INDEX_CHARACTER_TYPE> hash =
                            hashGenerator->generateHash(pattern).getCodes();

    // append sentence boundary marker,
    // as we are looking only for exact sentence matches
    hash.push_back(INDEX_CHARACTER_TYPE_MAX_VALUE);

    saidx_t patternLength = hash.size()*sizeof(INDEX_CHARACTER_TYPE);
    sauchar_t * patternArray = Utils::indexVectorToSaucharArray(hash);

    int size = sa_search(T->data(), (saidx_t) T->size(),
                         (const sauchar_t *) patternArray, patternLength,
                         SA->data(), (saidx_t) SA->size(), &left);

    SUFFIX_MARKER_TYPE occurencesCount = 0;
    for (int i = 0; i < size; ++i) {
        saidx_t resultPos = SA->at(left + i);
        if (resultPos % sizeof(INDEX_CHARACTER_TYPE) == 0) {
        // As we are looking for a pattern in an array of higher
        // resolution than the hashed index file, we might
        // obtain accidental results exceeding the boundaries
        // of characters in hashed index. The above check
        // removes these accidental results.
            occurencesCount++;
        }
    }

    delete[] patternArray;

    return occurencesCount;
}


std::vector<AnubisSearchResult> IndexSearcher::anubisSearch(
                  boost::shared_ptr<ConcordiaConfig> config,
                  boost::shared_ptr<HashGenerator> hashGenerator,
                  boost::shared_ptr<std::vector<sauchar_t> > T,
                  boost::shared_ptr<std::vector<SUFFIX_MARKER_TYPE> > markers,
                  boost::shared_ptr<std::vector<saidx_t> > SA,
                  const std::string & pattern) throw(ConcordiaException) {
    std::vector<INDEX_CHARACTER_TYPE> hash =
                         hashGenerator->generateHash(pattern).getCodes();
    return _concordiaSearcher->anubisSearch(config, T, markers, SA, hash);
}

boost::shared_ptr<ConcordiaSearchResult> IndexSearcher::concordiaSearch(
                  boost::shared_ptr<HashGenerator> hashGenerator,
                  boost::shared_ptr<std::vector<sauchar_t> > T,
                  boost::shared_ptr<std::vector<SUFFIX_MARKER_TYPE> > markers,
                  boost::shared_ptr<std::vector<saidx_t> > SA,
                  const std::string & pattern,
                  bool byWhitespace) throw(ConcordiaException) {
    TokenizedSentence hashedPattern =
              hashGenerator->generateHash(pattern, byWhitespace);
    boost::shared_ptr<ConcordiaSearchResult> result =
     boost::shared_ptr<ConcordiaSearchResult>(
       new ConcordiaSearchResult(hashedPattern));

    _concordiaSearcher->concordiaSearch(result, T, markers,
                                        SA, hashedPattern.getCodes());
    return result;
}